MINISTRY OF DEFENCE
JUL 2015
DAP 101A-1105-1A
DATED 2015-07-09
CARRIAGE OF CARGO BY HELICOPTERS
GENERAL INFORMATION
1.
DAP 101A-1105-1A, dated 2015-07-09 supersedes DAP 101A-1105-1A, dated 2014-07-30.
2.
Amendments to the DAP:
Front Cover:- Updated to new format and Issue.
DAP Issue Record: - Updated to new Issue.
Contents: - Change to footer format.
List of Associated Publications: - Change to footer format.
Introduction: - Change to footer format.
List of Chapters:- Chap 2-1-4 (unassigned) and change to footer format.
Chapter 1 - General Information:- Change to footer format.
Chapter 1-1 - HUSLE and its Management:- Change to footer format.
Chapter 2 - HUSLE and Helicopter Cargo Hook Compatibility:- Completely revised.
Chapter 2-1 - Helicopter External Hooks:- Completely revised.
Chapter 2-1-1 - TALON, SACRU:- Completely revised.
Chapter 2-1-2 - SACRU No1 Mk3:- Completely revised.
Chapter 2-1-3 - SACRU No2 Mk1:- Completely revised.
Chapter 2-1-4 - SACRU No3 Mk1:- Removed.
Chapter 2-1-5 - Chinook Cargo Hooks:- Completely revised.
Chapter 2-1-6 - Merlin Cargo Hook:- Completely revised.
Chapter 2-2 - Strops, Lifting, Single Leg, General:- Completely revised.
Chapter 2-2-1 - Strop, Lifting, Single Leg 11300 kg:- Completely revised.
Chapter 2-2-2 - Strop, Lifting, Single Leg 5000 kg:- Completely revised.
Chapter 2-2-4 - Strop, Lifting, Single Leg 16 ft and 80 ft:- Completely revised.
Chapter 2-2-5 - Strop, Lifting, Single Leg 7 ft and 30 ft:- Completely revised.
Chapter 2-3 - Supplementary Slinging Equipment:- Change to footer format.
Chapter 2-3-1 - Connectors and Shackles:- Completely revised.
3.
The DAP can be accessed via the following sites:
RAF Intranet site, Library, JADTEU Publications:
http://www.publications.raf.r.mil.uk/live/default.htm
or
Internet site, Brize Norton, Organisation, Lodger Units, JADTEU:
http://www.raf.mod.uk/rafbrizenorton/organisation/jadteu.cfm
4.
Users are to contact Hels Tech Co-ordinator at JADTEU, either by e-mail: awcjadteuhelshs8@mod.uk or Tel: 95461 6174, if experiencing difficulties accessing either site.
1
DAP 101A-1105-1A
AIR TRANSPORT OPERATIONS MANUAL
CARRIAGE OF CARGO BY HELICOPTERS
GENERAL INFORMATION
Issue No 008
JULY 2015
Sponsored for use in the
United Kingdom Ministry of Defence
and Armed Forces by ROYAL AIR FORCE – ACAS RTSA RW1
CONDITIONS OF RELEASE. This document is the property of Her Britannic
Majesty’s Government. The information in this document (excluding the
Departmental logo) may be reproduced for use by UK Government employees for
Ministry of Defence business, providing it is reproduced accurately and not used
in a misleading context. This document may be re-used under the terms of the
Open Government Licence version 2.0, http://www.nationalarchives.gov.uk/doc/
open-government-licence/version/2/, and must be acknowledged in the following
manner: ‘Air Transport Operations Manual, Carriage of Cargo by Helicopters,
Underslung Load Clearances. MOD. © Crown copyright 2015’.
© Crown Copyright 2015
Publication Authority: ACAS RTSA RW1
Prepared by JOINT AIR DELIVERY TEST AND EVALUATION UNIT
PUBLICATION AUTHORITY DETAILS. Service users should send their comments
through the channel prescribed for the purpose by the publications Sponsor.
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DAP ISSUE RECORD
Issue
Number
Initial
1
2
3
4
5
6
7
Jul 2006
Nov 2006
May 2009
Nov 2009
Feb 2011
Jun 2012
Jun 2014
Jul 2014
8
20150709
Date
Details of Change
Publication revision and update to DAP
Incorporated
Incorporated
Incorporated
Incorporated
Incorporated
Incorporated
Incorporated
Removed: Front Cover, DAP Issue Record, Contents, List of
Associated Publications, Introduction, List of Chapters, Chaps 1,
1-1, 2, 2-1, 2-1-1, 2-1-2, 2-1-3, 2-1-4, 2-1-5, 2-1-6, 2-2, 2-2-1,
2-2-2, 2-2-4, 2-2-5, 2-3 and 2-3-1.
Inserted: Front Cover, DAP Issue Record, Contents, List of
Associated Publications, Introduction, List of Chapters, Chaps 1,
1-1, 2, 2-1, 2-1-1, 2-1-2, 2-1-3, 2-1-5, 2-1-6, 2-2, 2-2-1, 2-2-2,
2-2-4, 2-2-5, 2-3 and 2-3-1.
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DAP 101A-1105-1A
CONTENTS
Preliminary material
Title Page
DAP Issue Record
Contents (this list)
List of Effective Pages
List of Associated Publications
Introduction
EXTERNAL LOAD INFORMATION
List of Chapters
External Load Information
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LIST OF ASSOCIATED PUBLICATIONS
Air Transport Operations Manuals (ATOMS)
DAP
Carriage of Cargo by Helicopters, Underslung Load Clearances
Carriage of Cargo by Helicopters, Underslung Load Clearances (AJO)
Carriage of Cargo by Helicopters, Underslung Load Summary
Information for SH Crews
Carriage of Cargo by Helicopters, Internal Load Clearances (except Chinook)
101A-1105-1B
101A-1105-1B1
101A-1105-1B2
101A-1105-1C
Helicopter Underslung Load Equipment (HUSLE)
General Orders and Special Instructions
108G-0002-2(NAR)1
Nets - General and Technical Information
Strops - General and Technical Information
Slings - General and Technical Information
Ancillary Equipment - General and Technical Information
108G-0002-1A
108G-0002-1B
108G-0002-1C
108G-0002-1D
Allied Tactical Publications
Use of Helicopters in Land Operations Doctrine
ATP-49 (latest edition)
Joint Doctrine Publication
Use of Helicopters in Land Operations (UK Supplement to ATP-49)
JDP 3-24.1
Joint Service Publication
Dangerous Goods by Air Regulations
JSP 800 Vol 4A
Military Aviation Authority (MAA)
MAA Regulatory Publications (MRP)
STANAGs
Aircraft Marshalling Signals (Army Code 71444)
Technical Criteria for the Transport of Cargo by Helicopter
Technical Criteria for External Cargo Carrying Slings, Nets and Strops/Pendants
Aerial Recovery Equipment and Techniques for Helicopters
Criteria for the Clearance of Helicopter Underslung Load Equipment (HUSLE)
and Underslung Loads (USL)
3117
3542
2286
2970
2445
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INTRODUCTION
1
In comparison with fixed wing Tactical Transport aircraft, helicopters have limited payload
and range for the carriage of cargo.
2
Helicopters are ideal, however, for those tasks that cannot be undertaken by fixed wing
aircraft due to the absence of airfields, weather limitations, difficulties of the terrain or difficulties
operating at low level in forward areas of the battlefield. In such circumstances helicopters can
transport cargo either internally, or externally suspended from the aircraft cargo hook(s) by
sling(s) or in nets.
3
Internal cargo restraint systems are designed to reduce to a minimum the time and skill
required to secure the load safely to the aircraft. Cargo carried externally can be delivered to a
point on the ground and the load disconnected by the aircraft crew whilst the helicopter remains
in the hover. Both methods provide a commander with a flexible means of transport for cargo
about the battlefield.
4
The choice of which method is to be used will depend on the type of load, the availability of
slinging equipment, the time and expertise available for the preparation of the load and the best
utilisation and safety of the aircraft. Both methods have advantages and disadvantages.
Normally a helicopter with internal cargo will be able to fly faster and further than one with an
external load, but it will have to land and spend time on the ground to load or unload cargo,
where it is more vulnerable to enemy action. On the other hand, external loads can be hooked
up and unhooked from a helicopter very quickly but the aircraft may fly slower than with the
cargo stowed internally due to the extra drag and in some cases instability of the load.
5
This publication is for the use of all Services and contains comprehensive information
concerning external loads that can be carried by helicopters. It provides a reference book for
instructors for initial training and for helicopter handlers for continuation training at Unit level.
Separate documentation is produced for the carriage of cargo internally within helicopters.
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EXTERNAL LOAD
INFOMATION
DAP 101A-1105-1A
EXTERNAL LOAD
INFORMATION
Jul 06
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LIST OF CHAPTERS
1
2
3
4
5
General information
1-1
Helicopter Underslung Load Equipment (HUSLE) and its management
Helicopter Underslung Load Equipment (HUSLE) and helicopter cargo hook
compatibility
2-1
Helicopter external cargo hooks
2-1-1 TALON, Semi-automatic cargo release unit (SACRU) 12000 lb
2-1-2 Semi-automatic cargo release unit (SACRU) No 1 Mks1, 2 & 3
2-1-3 Semi-automatic cargo release unit (SACRU) No 2 Mk1
2-1-4 Unassigned
2-1-5 Chinook HC Mk2 cargo hooks
2-1-6 Merlin Mk1, C160, cargo hook
2-2
Helicopter extension strops – general
2-2-1 Strop, lifting single leg, 11300 kg SWL
2-2-2 Strop, lifting single leg, 5000 kg SWL
2-2-3 Unassigned
2-2-4 Strop, lifting single leg (16 ft and 80 ft), 6000 lb SWL
2-2-5 Strop, lifting single leg (7 ft and 30 ft), 1500 lb SWL
2-3
Supplementary slinging equipment
2-3-1 Connectors and shackles
2-3-2 Chain assembly, extension
2-3-3 Lifting frame, BV206 Transmission Coupling
2-3-4 Weak link assembly
2-3-5 Chain clamp
2-3-6 Spreader bars
2-3-7 Adjustable spreader bars
2-4
Helicopter slings – general
2-4-1 Sling, multiple leg, heavy duty (11300 kg SWL)
2-4-2 Sling, multiple leg (redundant sling), for Chinook HC Mk2 tandem hook
operations (THO)
2-4-3 Sling, multiple leg, medium duty (4600 kg SWL)
2-4-4 Sling, multiple leg, 6000 lb SWL
2-4-5 HUSLE, Websling, lifting, SWL 10000 kg
2-5
Helicopter cargo lifting nets and allied systems – general
2-5-0 Pad, protection helicopter cargo net
2-5-1 Net, cargo lifting, helicopter (5600 kg SWL)
2-5-2 Net, cargo lifting, helicopter (5000 lb SWL)
2-6
Retainer breakaway assembly
2-7
Cargo restraint requirements for helicopter USLs
2-7-1 Restraint chains and coupling tensioners
2-7-2 Unassigned
2-7-3 Nylon cord
2-7-4 Net, cargo restraint, helicopter underslung load, 1000 kg SWL
2-8
Bag - Single Use Lift, SWL 1000 kg and strop, disposable, 2 m, SWL 2000 kg
Standard rigging practice and techniques
Preparation of loads, standard practice and techniques
Static electricity and dischargers
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DAP 101A-1105-1A
CHAPTER 1
GENERAL INFORMATION
CONTENTS
Para
1
Introduction
Clearance procedures
3
Aircraft clearance
4
Load clearance
7
Load categories
Cleared loads
8
Clearance documents
9
Clearance trials
12
Promulgation of load flying characteristics and flying limitations
13
Relating the clearance document to helicopter type
14
Load stability and attainable speed
15
Authorised loads
18
Uncleared loads
21
Preparing and rigging uncleared loads
22
Downed aircraft recovery
23
Carriage of Dangerous Goods (DG)
24
Helicopter static electricity
25
General responsibilities of units and personnel
26
Preparation and handling of loads
27
Centre of gravity and other loading considerations
28
Acceptance of a load for flight
Reporting and investigation of helicopter external load malfunctions
30
Definition of external load
31
Reporting requirement
33
Training courses and facilities for Defence Helicopter Landing Site Manager (DHLSM)
and Defence Helicopter Handling Instructor (DHHI).
INTRODUCTION
1
This chapter provides general information on the carriage of external cargo by British
Service helicopters, including the system of clearance for such cargo, generally referred to as
slung or underslung loads (USLs), and the responsibilities of both the ground user and the
helicopter operator. Subsequent chapters include a description of the different types of British
Service helicopter cargo hooks and full coverage of the practical aspects, correct usage and
standard practices for the complete range of helicopter general purpose strops, slings, cargo
lifting nets and allied equipment used in load preparation and rigging.
2
Individual load preparation, rigging and slinging instructions for specifically cleared USLs, of
all types, are contained in DAP 101A-1105-1B.
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CLEARANCE PROCEDURES
AIRCRAFT CLEARANCE
3
The Release to Service (RTS) is the release document for Service regulated flying;
underpinned by the aircraft Safety Case, the RTS defines the operating envelope, conditions
and limitations applicable to the aircraft to which it refers. With the exception of those items that
can be properly classified as freight, all equipment authorised to be carried in or fitted to the
aircraft is included in the RTS. Underslung loads are classed as freight and do not require a
separate clearance within the RTS; however, items of Helicopter Underslung Load Equipment
(HUSLE) that attach directly to the aircraft are required to be cleared within the RTS. Those
items of HUSLE that form an integral part of an USL are cleared for use in accordance with its
specific Underslung Load Clearance (USLC).
NOTE
The range of HUSLE cleared by the RTS varies by platform.
LOAD CLEARANCE
4
Loads that require regular transportation as an USL are to be formally assessed by the
Joint Air Delivery Test and Evaluation Unit (JADTEU) and an USLC produced. Requests to task
JADTEU should be submitted to the JADTEU Task Co-ordination Officer using a Task Inception
Form available on the JADTEU website. It should be noted that all tasks are to have a MOD
Sponsor.
5
The JADTEU USLC documents contain detailed instructions and advice for each specific
load. These instructions are issued after each load has undergone static rigging and lifting
trials, has subsequently been test flown in each configuration required and has been proven
acceptable for flight.
6
It is stressed that these published instructions constitute the Clearance for Flight and must
be fully adhered to. The rigging and load handling personnel must be directly supervised by a
qualified Defence Helicopter Landing Site Manager (DHLSM) or Defence Helicopter Handling
Instructor (DHHI).
LOAD CATEGORIES
7
Helicopter USLs are divided into three distinct categories, namely:
Cleared loads, Authorised loads and Uncleared loads.
CLEARED LOADS
Clearance documents
8
Cleared loads are loads for which detailed preparation, rigging and slinging instructions are
drawn up and produced in the form of USLCs. In each case clearances will have been issued
on the directions of a MOD Sponsor, and are based on the Sponsor’s acceptance of the
outcome of JADTEU trials. All but a few JADTEU clearances will be published for holding in
DAP 101A-1105-1B, which in its opening chapters contains detailed information on the content,
interpretation, general format and availability of clearance documents. The complete index of
USLCs is contained in DAP 101A-1105-1B, Chap 2-1.
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Clearance trials
9
JADTEU Helicopter and Training Sect will normally take overall responsibility for the
conduct of an USLC task. JADTEU Engineering Sect will provide any necessary specialist
knowledge and support.
10 JADTEU flight testing explores the safe speed and manoeuvre envelope in incremental
stages with a thorough and progressive check of load manoeuvre performance at each speed
increment. An extension strop with swivel hook is used to establish the flying characteristics of
the load. Strop length will normally be confined to the shortest length strop, unless the task
Sponsor, or the nature of the load or the environment, demands otherwise.
11 Trials helicopters are normally tasked by the Joint Helicopter Command (JHC). The
helicopter crew is provided by the Rotary Wing Test and Evaluation Sqn (RWTES); a RWTES
aircraft commander is the minimum requirement to conduct a flight trial. The helicopter crew
receive a full briefing before flying commences, and subsequently are accompanied by the
JADTEU Helicopter and Training Sect Trials Officer who directs the trial during all phases of
flight test. Throughout the trial the aircraft commander and the crewman maintain their normal
command function for safety and control of the helicopter.
Promulgation of load flying characteristics and flying limitations
12 Current clearances will state the maximum permitted airspeed, manoeuvre limitations and a
statement of load flying characteristics within the clearance document
Relating the clearance document to helicopter type
13 As USLCs do not specify helicopter type, operators should check firstly that the clearance
selected is suitable for the particular type of helicopter they plan to use, ie single or tandem
hook clearance, helicopter lift capabilities and aircraft/HUSLE compatibility. If the load has been
cleared to a higher speed than that permitted by the aircraft type, then a lower speed must
apply. For information on helicopter/equipment compatibility refer to the individual helicopter
RTS, the compatibility matrix in Chap 2, or the individual slinging equipment chapter. For
information on the clearance read-across capability refer to Aircrew Advisory Notes at Chap 1-2
of DAP 101A-1105-1B.
Load stability and attainable speed
14 The maximum permitted speed at which a load is flown will depend upon one or more of
the following factors:
14.1 The onset of load instability.
14.2 Load motion which causes unacceptable stress on the helicopter or interference with
control.
14.3 Aircraft flight or power limits.
14.4 The drag of the load resulting in maximum safe trail angle limits being reached.
14.5 The natural resonance of tensioned sling/strop lengths combined with aerodynamic
forces and aircraft vibration reaching unacceptable levels of sling leg flutter.
14.6 Any other limitations in the RTS for the helicopter type being used, which prevents
the carriage of the load at a higher speed.
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AUTHORISED LOADS
15 A wide variety of loads made up from commonly used stores; supplies or equipment may
be carried externally by helicopters. It is neither practicable, nor possible for JADTEU to raise
separate clearances for each load of this nature. Therefore certain loads not specifically
cleared by JADTEU, defined as ‘authorised loads’, may be carried externally without reference
to, or individual clearance from JADTEU, provided that there is compliance with the conditions
and limitations that follow.
16 Authorised loads are defined specifically as being loads carried in Service cargo lifting nets,
comprising the 5000 lb net, 5600 kg net and 7000 kg net, loaded and generally prepared in
accordance with the appropriate equipment chapters in this publication.
17 Authorised loads may not be completely stable at all speeds. However, provided that the
various authorised load equipments are used in the manner and with the type of load for which
they were designed and cleared, the onset of any instability should be gradual, and will allow
the pilot to determine a maximum speed for the prevailing conditions. Unless the pilot has
previously flown an identical load or has a means of observing load behaviour, a crewman
should be carried when authorised loads are being flown. The following important requirements
must also be fulfilled:
17.1 An extension strop with swivel hook is to be used when carrying standard ordnance
boxes to avoid wind-up and consequent damage to the slings.
17.2 A single net load may be carried without an extension strop and swivel hook,
provided that the net lifting stirrup or device is in the form of a single item for attachment
direct to the helicopter cargo hook. Two or more nets must always be carried from a
secondary hook.
17.3 An extension strop with swivel hook is to be used to give adequate clearance
between the load and the aircraft if there is any doubt in the aerodynamic stability of an
authorised load.
17.4 To employ any ‘authorised load equipment’ beyond its normal design usage or
limitations is to enter the ‘uncleared load’ sphere.
17.5 Cargo nets are not to be flown empty.
UNCLEARED LOADS
18 Loads that are neither cleared nor authorised are classified as ‘uncleared loads’ and
therefore, specialist advice from JADTEU is to be obtained regarding the rigging and possible
behaviours of such loads.
19 Operational circumstances may preclude the prior clearance of an USL by JADTEU and in
such circumstances, the Theatre Commander-in-Chief or equivalent may authorise the flight of
an uncleared load. Should this occur, advice regarding the means of rigging unusual or one-off
loads is to be obtained from JADTEU; this could involve the use of a JADTEU team to rig or
supervise the preparation of the equipment. Under no circumstances will JADTEU authorise the
carriage of an uncleared load. If it is impracticable for JADTEU to carry out the preparation, the
ground handling personnel are to contact JADTEU and obtain the best possible advice available
on rigging the load(s) in question. JADTEU will provide advice by any communicable means
available. Every effort should be made to seek an in-theatre engineering assessment of the
structural integrity of the load and the chosen lifting points as stated in DAP 101A-1105-1B,
Chap 1-2, before any attempt is made to fly it.
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20 It is essential that the commander of the helicopter carrying the load be informed that such
loads are uncleared. This serves to forewarn that the load may affect the flying characteristics
of the helicopter, as the behaviour of such loads in flight is completely unpredictable until they
have been flown.
Preparing and rigging uncleared loads
21 Other chapters in this book describe the equipment usage and standard practices to be
followed when preparing and rigging USLs. A study of these chapters and a study of USLCs for
similar loads will enable a sensible approach to be made to the problems of rigging an
uncleared load.
Downed aircraft recovery
22 Where an aircraft requiring recovery is already the subject of a JADTEU USLC, and is
substantially undamaged, it may be rigged and flown without further reference to JADTEU.
However, if damage has been incurred and/or the aircraft is not cleared, JADTEU advice is to
be sought. Such recoveries will normally be conducted by or under supervision of a JADTEU
team. Lifts will be in accordance with the provisions of STANAG 2970.
CARRIAGE OF DANGEROUS GOODS (DG)
23 The aircraft commander must be advised of any DG aspects relating to the load that he is
tasked to undersling. The most common hazards are those associated with static electricity
when carrying flammable or explosive natures, or RADHAZ where aircraft HF radio
transmissions may affect electrical explosive devices (EEDs) or fuse mechanisms of weapons
systems. For loads, which have a DG aspect, any necessary instructions or precautions will be
contained in the relevant USLC, or reference will be made to the authoritative literature. In this
respect, JADTEU is not a DG authority and any specialist DG information for inclusion in a
clearance must be provided by the task Sponsor. Where a clearance applies to dummy or inert
weapons only, operators must find out the full implications of carrying live versions prior to their
carriage. Finally, there is always the remote possibility of an irregular load release and any
likely additional hazard posed by DG aspects must be considered prior to load pick-up.
HELICOPTER STATIC ELECTRICITY
24 The static discharge at load pick-up or landing is high, especially with the Sea King, Merlin
and Chinook helicopters. This is particularly important when considering the protection of
ground handlers, and the dangers associated with inflammable materials or explosive devices.
Further information can be found in Chap 5.
GENERAL RESPONSIBILITIES OF UNITS AND PERSONNEL
25 For USL tasks it is the responsibility of the Service owning the helicopter to supply it
equipped with the helicopter cargo hooks (primary hook) and any necessary extension strop
with swivel hook (secondary hook).
Preparation and handling of loads
26 It is the user unit’s responsibility to provide slinging and load securing equipment, with the
final means of hooking up to either the primary or secondary hook. It is also the user unit’s
responsibility to provide suitably trained and qualified personnel for the purpose of load
preparation, rigging, handling and marshalling at both the pick-up and load landing points in
accordance with the published instructions. At the pick-up point, a load should be supported on
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level ground or be so disposed that its attitude in relation to the sling is the same as in flight.
This will ensure that the load will not tilt or drag at the initial stages of the lift, but will remain in
balance and so minimise the onset of oscillation in flight. When Joint Helicopter Support
Squadron (JHSS) personnel are tasked for operation they will take over all or some of the above
responsibilities and provisioning, as necessary. Precise responsibilities will normally be
included on the tasking signal. All personnel involved in the above duties should have access
to the necessary publications and guidance literature to enable them to be fully conversant with
their role.
Centre of gravity and other loading considerations
27 The requirements for correct loading and centre of gravity (cg) of a load are to be fulfilled
by strict compliance with the detailed instructions for each specified cleared or authorised load
as published in this publication and in DAP 101A-1105-1B. Failure to comply with these
instructions may result in the rejection of a load for flight or dangerous conditions developing
once the helicopter is in flight.
Acceptance of a load for flight
28 The final responsibility for the acceptance of any load for flight rests with the commander of
the helicopter concerned.
29 The weights of USLs are to be made available beforehand to the commander of the aircraft
so that flight planning can be effected. The total weight of a USL is always to be determined
accurately.
REPORTING AND INVESTIGATION OF HELICOPTER EXTERNAL LOAD MALFUNCTIONS
Definition of external load
30 The term ‘external load’ includes the cargo and all items of USL equipment used to connect
the cargo to the helicopter.
Reporting requirement
31 All malfunctions of external loads observed or suspected, in flight, are to be reported in
accordance with current regulations contained in the Military Aviation Authority (MAA)
Regulatory Publications (MRP). The report is to include any unusual behaviour exhibited by the
USL that could have instigated the malfunction. Should ground based helicopter handling
teams observe malfunctions during USL pick-up or delivery, or suspect that items of equipment
are missing, an incident report is to be raised.
32 If the malfunction is suspected to have been caused by a failure of the HUSLE or
equipment being carried, it is the responsibility of JADTEU to conduct an investigation in to the
circumstances. Should malfunctions of this nature occur JADTEU is to be informed as soon as
possible and their assistance requested.
TRAINING COURSES AND FACILITIES FOR DEFENCE HELICOPTER LANDING SITE
MANAGER (DHLSM) AND DEFENCE HELICOPTER HANDLING INSTRUCTOR (DHHI)
33 Training courses for DHLSM and DHHI are held at JADTEU. Successful completion of the
courses will enable the student to fulfil relevant responsibilities contained within Joint Doctrine
Publication 3-24.1, Use of Helicopters in Land Operations (UK Supplement to ATP 49).
34 Details of available courses can be obtained from AWC-JADTEU-Training clerk.
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DAP 101A-1105-1A
CHAPTER 1-1
HELICOPTER UNDERSLUNG LOAD EQUIPMENT (HUSLE)
AND ITS MANAGEMENT
CONTENTS
Para
1
2
3
5
6
7
8
10
11
Introduction
HUSLE definition
HUSLE classified by Safe Working Load (SWL)
HUSLE identification
Maintenance support literature
Obtaining HUSLE maintenance Air Publications (APs)
HUSLE examination
Before and after-use
Routine
HUSLE life
INTRODUCTION
1
This chapter affords an introduction to the general purpose range of HUSLE used by one or
more of the three Services. The information that follows includes guidance on equipment
management. Reference to equipments and materials, together with the stores nomenclatures
is to be found in the relevant HUSLE maintenance APs (Para 6 refers).
HUSLE DEFINITION
2
The term ‘HUSLE’ comprises nets, slings, strops and other ancillary items and refers to all
load carrying equipment mounted between the helicopters cargo hook and the USL attachment
points.
HUSLE CLASSIFIED BY SAFE WORKING LOAD (SWL)
3
Service slinging equipment is classified by its ‘SWL’, and in all cases the manufacturer’s
classification will be given in terms of SWL. The term SWL relates to the maximum static weight
of load that may be suspended from a given item. The difference between the maximum
allowable static load and the load that would be necessary to cause the item to fail (breaking
load) is the safety factor. For helicopter slinging equipment, the safety factor must allow for the
effective increase in load due to helicopter manoeuvre, and such factors as rotor downwash
impinging on the suspended load, and inadvertent snatch loading during load pick-up. The
slinging equipment must be able to sustain such treatment on a regular basis without any
degradation. To cater for this, a minimum safety factor of 4.3 to 1 is applied (ie for HUSLE with
a SWL of 5000 kg the minimum breaking load is 21500 kg).
4
Finally, for helicopter general purpose multiple leg slings, the SWL is further qualified by the
maximum allowable included angle at which the sling legs may be used.
HUSLE IDENTIFICATION
5
HUSLE is identified by its equipment nomenclature (stores description) and stores
reference numbers. The approved item name, together with the item NSN, should always be
used for equipment demands.
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MAINTENANCE SUPPORT LITERATURE
6
There is a Joint Service policy to which the three Services adopt common maintenance
procedures. HUSLE general orders and special instructions are published in AP 108G-00022(NAR)1. The maintenance procedures for given equipment items are published in the
following HUSLE APs:
AP 108G-0002-1A - Nets
AP 108G-0002-1B - Strops
AP 108G-0002-1C - Slings
AP 108G-0002-1D - Ancillary equipment
Obtaining HUSLE maintenance APs
7
Service users can access the APs using the Design Repository (DR) which hosts the Tech
Docs on Line (TDOL) viewer; alternatively requests for hardcopies can be addressed through
the MOD technical publication process.
HUSLE EXAMINATION
Before and after-use
8
Defence Helicopter Handling Instructors (DHHI), Defence Helicopter Landing Site
Managers (DHLSM), Defence Landing Point Commanders (DLPC), helicopter crewmen and
aircraft maintenance personnel can be authorised to carry out before and after-use
examinations in accordance with AP 108G-0002-2(NAR)1.
9
A before and after-use examination is to be carried out on each item of HUSLE as detailed
in the equipment’s relevant HUSLE maintenance AP.
Routine
10 The AP 108G-0002-2(NAR)1 details the joint Service maintenance policy for HUSLE.
Routine maintenance is only to be carried out by a qualified Helicopter Load Slinging Equipment
Inspector (HLSEI) who holds a valid HLSEI certificate.
HUSLE LIFE
11 The life of HUSLE components is given in the relevant HUSLE maintenance APs which
should be consulted for up to date information. The component life expiry for major HUSLE is
given below as a guide.
11.1 All metalware (including wire slings, weak link assemblies, BV206 lifting frame and
wire strops). Subject to condition, inspected for serviceability (not lifed).
11.2 Helicopter Cargo Lifting Net – 7000 kg SWL, 5600 kg SWL and 5000 lb SWL. A
finite life of 10 (ten) years with a maximum Service life of 4 (four) years.
11.3 Net Cargo Restraint, Helicopter USL 1000 kg SWL. A finite life of 10 (ten) years
with a maximum Service life of 4 (four) years.
11.4 Textile Roundsling for HD and MD Sling Assemblies and Strops. A finite life of 10
(ten) years with a maximum Service life of 4 (four) years.
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11.5 Nylon Redundant Sling (Chinook). A finite life of 10 (ten) years with a maximum
Service life of 2 (two) years.
11.6 10000 kg Websling (Belly-band). A finite life of 10 (ten) years with a maximum
Service life of 2 (two) years.
11.7 Bag-Single Use Lift, SWL 1000 kg. A finite life of 10 (ten) years with a single use
Service life. The SULB must be used within 28 days following removal from the light proof
packaging.
11.8 Strop, Disposable, 2 m, SWL 2000 kg. A finite life of 10 (ten) years with a
maximum Service life of 28 days following removal from the light proof packaging.
12 Notwithstanding the lifing periods shown above and with exception to para 11.8, all
equipment is to be inspected by suitably qualified personnel, as stated in AP 108G-00022(NAR)1 and to the requirements stated in the relevant HUSLE maintenance APs.
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DAP 101A-1105-1A
CHAPTER 2
HELICOPTER UNDERSLUNG LOAD EQUIPMENT (HUSLE)
AND HELICOPTER CARGO HOOK
COMPATIBILITY
(Completely revised)
CONTENTS
Para
1
Introduction
Matrix
Page
Slinging equipment ‘Hook-up’, ‘Inter-compatibility’ and ‘Compatibility for
Helicopter Type’ matrix           
3
INTRODUCTION
1
The subsequent chapters in this publication describe individual items of HUSLE and its
usage. To assist Service users in helicopter USL operations the compatibility matrix
consolidates the individual items to ensure correct application of HUSLE to helicopter cargo
hook type.
2
Particular items of HUSLE may not appear on the compatibility matrix as these items may
only be required for specific helicopter operations. In such cases the relevant HUSLE and
rigging/hook-up procedures will be contained on an USLC which is available from JADTEU only.
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CAUTION
UNLESS SPECIFIED IN A JADTEU CLEARANCE, ALL SLINGS MUST BE
INTERFACED TO HELICOPTER PRIMARY HOOKS BY MASTERLINK AND
SWIVEL ASSEMBLY OR EXTENSION STROP SUBJECT TO COMPATIBILITY
SEE CAUTION BELOW
1B
1B
1
1
1
STROP (7 ft or 30 ft), SWL 1500 lb (680 kg)
4
1
1
1
1
1
1
1
2 m DISPOSABLE EXTENSION STROP, SWL 2000 kg
5
SLING HD, SWL 5650 kg (2 leg)
6
1
1
2
2
1
1
1
SLING HD, SWL 8475 kg (3 leg), SWL 11300 kg (4 leg (not Griffin))
7
1
1
2
2
1
SLING MD, SWL 2300 kg (2 leg), SWL 3450 kg (3 leg), SWL 4600 kg (4 leg)
8
1
1
2
2
2
SLING REDUNDANT
9
SLING 4 LEG, SWL 6000 lb (2724 kg)
10
1
WEBSLING (Belly-band), SWL 10000 kg (22046 lb)
11
1
16 MM MASTERLINK ASSEMBLY, SWL 7000 kg (15432 lb)
12
1
SHACKLE, SWL 1500 kg, BOW
13
1
CONNECTOR SLING, 10000 lb (4536 kg)
14
B
1
B
B
1
B
F
1
1
H
1H
1
H
1
1
1
D
1D
1
1
1
1
1
1
1
C
1
1
1
1H
1
1H
1H
1
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1
1
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1
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1
2
1
1
1
1
1
1
1
1
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1
1
1
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1
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1
1
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1
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1
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1
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1
1
1
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N
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k2
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ks)
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Mk
2
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ING
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RL
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3, 4
3, 4
&5
&6
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No
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Ch
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No
2,
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k3
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3
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FW
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1
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GR
1
1
UIR
1
1
1F
SQ
1
1
1F
ZE
3
1
1H
H
GA
STROP (16 ft or 80 ft), SWL 6000 lb (2724 kg)
F
LY
N
1
LD
2
1
WI
2
1
MA
2
1
PU
2
1
AK
1
1
SE
1
1
RL
2
H
C
ME
STROP 2.5 m/5.5 m SWL, 5000 kg (11020 lb)
RL
1
ME
1
INO
1
CH
2
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DIS
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OP
,S
)
24
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1
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STROP 2.7 m/5.7 m, SWL 11300 kg (25000 lb)
CO
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CONNECTORS,
NETS AND SULB
16
SLINGS
ITE
STROPS
LIN
TO DETERMINE EQUIPMENT COMPATIBILITY, CROSS REFER LIFTING RING OF EQUIPMENT IN
SIDE COLUMN WITH HOOK OF EQUIPMENT ALONG TOP ROW OF TABLE. A FIGURE DENOTES
THE QUANTITY OF ITEMS IN SIDE COLUMN WHICH MAY BE ATTACHED TO EQUIPMENT IN TOP
ROW TOGETHER WITH ADDITIONAL EQUIPMENT SPECIFIED IN KEY IF REQUIRED
0k
VIA ITEM 20
CH
I
kg
VIA ITEM 19
(68
VIA ITEM 14, 15 OR ANY COMPATIBLE EXTENSION STROP
H
0 lb
G
EN
VIA ITEM 13
SACRUS (see WARNING)
XT
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STROPS
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110
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C
150
VIA ITEM 12
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CONNECTORS
ONLY ONE LIFTING RING/APEX DEVICE TO
BE CARRIED ON LOAD BEAMS OF BRITISH
SERVICE HELICOPTER CARGO HOOKS
SA
VIA ITEM 12 OR ITEM 15
00
A
WARNING
g(
*
NOT YET CLEARED
250
INCOMPATIBLE
ST
Fig
DAP 101A-1105-1A
ME
KEY TO SYMBOLS
SLINGING EQUIPMENT ‘HOOK-UP’,
‘INTER-COMPATIBILITY’ AND ‘COMPATIBILITY
FOR HELICOPTER TYPE’ MATRIX
1
1
MASTERLINK AND SWIVEL HOOK ASSEMBLY, 11300 kg (25000 lb)
15
NET CARGO LIFTING, SWL 7000 kg (15432 lb)
16
NET CARGO LIFTING, SWL 5600 kg (12345 lb)
17
1
NET CARGO LIFTING, SWL 5000 lb (2268 kg)
18
SHACKLE, SWL 5 TONNE, LARGE BOW
19
SHACKLE, SWL 3 TONNE, LARGE BOW
20
WEAK LINK ASSEMBLY, 6300 kg
21
SINGLE USE LIFT BAG (SULB), SWL 1000 kg
22
2
2
1
1
1
1
1
2
2
2
1
1
1
1
1
1
1
2
B
2
1
1
1
2
2
2
1
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2
2
2
2
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1
1
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1
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1
1
1B
2
1
1
2
1
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1
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1
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1
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*
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2
2
2
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DAP 101A-1105-1A
CHAPTER 2-1
HELICOPTER EXTERNAL CARGO HOOKS
(Completely revised)
CONTENTS
Para
1
2
3
4
5
6
7
11
12
13
14
15
16
18
19
21
22
Introduction
Carriage of external cargo
Carriage of load from a single cargo hook
Carriage of load by means of two cargo hooks
Nature of cargo hooks
Function as cargo release units
Modes of release
Types of cargo hook
Electro-magnetic type hooks
Chinook centre hook
Use of term ‘Primary Hook’
Maximum weight of load that can be carried on helicopter cargo hooks
Payload available
Maximum weight of external load cleared for carriage by helicopter type
Important rules of usage
Restrictions and limitations for engagement of items on cargo hook load beams
Static electricity discharge
Load hook-up/release procedures for ground handlers
Load becoming detached during or after helicopter lift off
Close monitoring of load hook-up
Fig
1
2
3
Page
Method of release if hook fails to release after load landing 
Incorrect and correct way of engaging lifting ring on load beam
Steel wire rope overriding bill of SACRU load beam  









5
6
8
INTRODUCTION
1
The aim of this chapter is to provide ground handlers with a general background to the
current range of British Service helicopter cargo hooks. The chapter also has applicability for
helicopter aircrew inasmuch as it highlights important general rules of usage. Each cargo hook
is fully identified in Chaps 2-1-1 to 2-1-6 and describes relationships of hooks to helicopter type
and points of usage for ground handlers.
CARRIAGE OF EXTERNAL CARGO
2
The normal way of carrying external cargo by helicopter is to suspend it from underneath
the helicopter by means of an external cargo hook. Depending upon the helicopter type, the
cargo hook is either suspended by cables and/or a frame from the belly of the helicopter, or is
attached to mountings on or to a connection panel within the belly of the helicopter. With the
exception of the Chinook, all British Service helicopters operating in the USL role are designed
with a single cargo hook facility.
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Carriage of load from a single cargo hook
3
The system of employing a single cargo hook for suspending a load is known as ‘single
hook suspension’, whereas the system of lifting a load from a single point on the load is known
as single point lift. Helicopters operating with a single cargo hook allow for a relatively simple
load hook-up process, but once in flight the load is free to twist and orientate into positions of
high drag, or commence spinning about its vertical axis or take on a swinging motion, the overall
effects of which generally become more pronounced with increase in helicopter speed. For this
reason single cargo hook helicopters are frequently unable to exploit their true speed capability
when carrying external loads.
Carriage of load by means of two cargo hooks
4
The Chinook helicopter is equipped with a triple cargo hook facility. One of the important
assets is the ability to suspend a load by means of two cargo hooks. This provides an
immediate benefit of reducing the loads freedom of movement and additionally it enables the
load to be hung so that it presents least drag surface to the airflow. As a result the load can be
carried at higher airspeeds than would generally be attainable by single hook suspension. The
load hook-up process will be more complex, however, and it will be necessary for ground
handlers to maintain a high degree of proficiency and act as a thoroughly co-ordinated team.
The use of the Chinook triple cargo hook system, including carriage of independent loads from
each of the hooks, is discussed more fully in Chap 2-1-5.
NATURE OF CARGO HOOKS
Function as cargo release units
5
Helicopter cargo hooks are designed to function as ‘cargo release units’, allowing for
release of an attached load by remote control, exercised by the pilot (sometimes the crewman)
from within the helicopter.
Modes of release
6
A summary of the different modes of release for current British Service helicopter cargo
hooks, together with any additional ground handler release facilities, are as follows:
6.1 Primary modes of release. All current British Service helicopter cargo hooks
incorporate an electrically initiated hook release system as the primary means of achieving
load release. Control is effected by a pilot push-button, or the like; in the Chinook the
crewman has a similar control.
6.2 Standby/emergency hook release facilities within the helicopter. All existing Service
cargo hooks incorporate a standby/emergency release system, which is mechanically
and/or electrically operated from within the helicopter.
6.3 Ground handler release facility. With the exception of the Chinook centre cargo
hook, all current cargo hooks have a mechanical/manual release facility located on the
release unit body for use, where necessary, by ground handlers.
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TYPES OF CARGO HOOK
7
The different types of cargo hooks are illustrated in Chaps 2-1-1 to 2-1-6.
Electro-magnetic type hooks
8
With the exception of the Chinook centre cargo hook, all current British Service helicopter
cargo hooks are of the ‘electro-magnetic’ type; also referred to as electro-mechanical release
units, which is an equally apt description. The hooks bear the designation ‘Semi-Automatic
Cargo Release Unit’ (SACRU); the Chinook forward and aft hooks bear the American
designation ‘cargo hooks’.
9
Although there are differences in appearance, size and design of the various electromagnetic type hooks, they all follow the same basic principle of operation. They employ a
solenoid unit, housed on the hook casing, which converts electrical force into mechanical
movement, activating the internal mechanism of the release unit so as to open an internal latch,
allowing the load carrying beam of the hook (known as the ‘load beam’) to pivot downwards and
release any attached extension strop, cargo net stirrup or any other connecting device.
10 The SACRUs, and even more so the Chinook forward and aft hooks, have a distinct hooklike appearance, with the load beam pivoted to the unit casing at one end, and tapering off to an
open ended hook bill at the other end. In each case the entrance onto and off of the load
carrying part of the load beam is protected by a spring-loaded keeper when the load beam is in
the closed position. A lifting ring can be engaged onto SACRU and Chinook type hooks with the
load beam in the closed/locked position. Also, the SACRU and Chinook forward and aft hook
load beams automatically spring load back to the closed position, following hook opening and
load release.
Chinook centre hook
11 The Chinook centre hook is unique, inasmuch as it is powered to open and back to the
closed position by a system which utilises hydraulic and/or pneumatic pressure. The activation
of the system is dependent, however, upon an electrical command. Other than this, the centre
hook is similar in appearance to the forward and aft hooks, pivoted at one end, tapering to an
open ended hook bill at the other, and protected by a spring loaded keeper when in the hook
closed position. There is no ground handler release facility, but see para 19.
USE OF TERM ‘PRIMARY HOOK’
12 The helicopter cargo hook is generally referred to as the ‘Primary hook’, which provides a
simple way of distinguishing it from the terminal hook fitting at the foot of an extension strop.
The extension strop hook is, in turn, known as the ‘Secondary hook’.
MAXIMUM WEIGHT OF LOAD THAT CAN BE CARRIED ON HELICOPTER CARGO HOOKS
13 The maximum weight of load that can be suspended from the load beam of a SACRU/
cargo hook is governed by the following:
13.1 The safe working load (SWL) of the SACRU/cargo hook (see individual hook
chapters).
13.2 The maximum allowable weight of external load cleared for carriage by a given
helicopter type, which may be less than the rated lifting capacity of the SACRU/cargo hook
with which it is fitted (see individual hook chapters).
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13.3 The SWL of the slinging equipment being used (see individual equipment chapters).
13.4 The payload available for a given sortie, and the need to keep within the cg envelope
for the helicopter.
Payload available
14 The actual payload that can be lifted (ie the payload available), for any particular sortie, is
declared by the helicopter unit to the supported unit. It will depend upon the following factors:
14.1 Required radius of action.
14.2 Number of crew.
14.3 Basic weight of the particular helicopter and role equipment installed.
14.4 Altitude at which operation is to take place, together with temperature and humidity in
which the helicopter will operate.
14.5 Full fuel plus reserves required for the sortie.
Maximum weight of external load cleared for carriage by helicopter type
15 It is emphasised that the maximum external load weight figures cleared for helicopter type,
as indicated in individual cargo hook chapters, are the absolute maximum under the most
favourable conditions. They will almost certainly be reduced in Service owing to the factors
detailed in para 14. Users should contact helicopter command formations or helicopter units for
accurate appraisals.
IMPORTANT RULES OF USAGE
Restrictions and limitations for engagement of items on cargo hook load beams
16 To ensure that the factor of safety of the load beam is not reduced and also that damage is
not caused, either to the load beam itself or to such critical items as the load beam keeper or
critical areas of the cargo hook casing, the following rules are to be strictly complied with:
16.1 All British Service helicopter cargo hooks are to be limited to the carriage of a single
lifting ring or equipment apex device attached over the load beam. Where more than one
lifting ring or apex device is to be carried, they are to be collectively engaged over an
appropriate Service extension strop secondary hook or via another acceptable form of
connector. See 2-2 series of chapters on extension strop equipments and Chap 2-3-1 on
connectors.
16.2 Under no circumstances must chain be engaged over a cargo hook load beam.
Where chain forms the apex of a lifting system it is always to be coupled via a suitable
extension strop secondary hook, or any other suitable form of connector as may be called
up in specific USLCs.
17 The suitability for engagement of an individual sling, cargo net or extension strop lifting ring
or apex device to the current range of cargo hooks is covered in individual equipment chapters.
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DAP 101A-1105-1A
Static electricity discharge
18 A helicopter in flight generates and stores a charge of static electricity. This constitutes a
hazard for ground handler/hook-up personnel, to the extent of a ground handler receiving a very
serious shock (and possibly burns) if the correct precautions are not carried out; this has
considerably added emphasis with the Chinook helicopter. For the purpose of engagement or
disengagement of an item to and from the load beam of a helicopter primary or extension strop
secondary hook, full static electricity discharge procedure must be carried out. This procedure
applies to the helicopter in the hover or on the ground with rotors running. It also applies if, for
any reason the ground handling party has to contact the load, before it has been lowered to the
ground, or after it has been lowered to the ground and prior to carrying out discharge procedure
at the helicopter primary or secondary hook. For ground handlers who are required to assist
with manoeuvring a load into position before load landing, the use of ropes (handling lines) in
contact with the ground provides an added safeguard. Full information on static electricity
discharge, ground handler static probe equipment and standard procedures to be employed
when earthing primary or secondary hooks, or suspended loads, is contained in Chap 5.
Load hook-up/release procedures for ground handlers
19 The individual procedures for load hook-up and, when necessary, release of an engaged
lifting ring by ground handlers, are covered in the individual chapters for each type of cargo
hook. As a general procedure applicable to SACRU series and Chinook type cargo hooks, the
method of removing a lifting ring from the load beam, if the hook fails to open by any release
mode, is illustrated at Fig 1.
20 For load engagement and release procedures for extension strop secondary hooks, consult
Chap 2-2.
Fig 1 Method of release if hook fails to release after load landing
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Load becoming detached during or after helicopter lift-off
21 Incidents have occurred over the years where a slung load has detached from the
helicopter, either during the lift off stage, shortly afterwards or at some later stage in flight.
Some of these incidents have been associated with suspect equipment or irregular rigging
practice, and others with some form of irregular release from the primary hook. In the latter
case, instances are generally associated with the slinging equipment lifting ring escaping from a
serviceable and closed cargo hook of the SACRU or Chinook type (ie designed with an open
ended load beam protected by a spring loaded keeper). Two particular forms of mishap, which
can occur, are as follows:
21.1 Failure to engage lifting item over the load beam during hook-up. Fig 2A illustrates
how a lifting ring can be engaged about the hook keeper instead of the load beam. Such
an occurrence could well be associated with an inexperienced or apprehensive ground
handler, who fails positively to establish that the item is correctly engaged. Conditions
could also be exacerbated when operating at night, if the helicopter is unable to maintain a
steady lateral or vertical position over the ground handler. Whatever the reason, when the
helicopter takes strain on the load, or at some stage soon after, when increasing speed or
manoeuvring over the ground, the strain and direction of pull on the lifting ring is likely to
cause the embraced keeper to open and thereby allow the ring and suspended load to drop
free. Fig 2B shows the correctly engaged position for the lifting ring, and ground handlers
should, where possible, adhere to the following procedure; upon engagement push/pull the
ring firmly to the far end of the load beam, then pull firmly downwards and into the heart of
the hook to ensure that the lifting ring is actually engaged onto the load beam. Finally,
check that the spring loaded keeper has returned to the fully closed position and is not
embraced by the lifting ring.
Fig 2 Incorrect and correct way of engaging lifting ring on load beam
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21.2 Item escaping off the load beam after correct engagement. The second situation
concerns lifting rings of apex devices, which are sufficiently spacious, in internal diameter
or length, as to be able to override the top of the load beam having been correctly engaged
in the first place. Looking at two aspects:
21.2.1 With such a lifting ring in a correct position (reverting to Fig 2B); if the
attendant sling is allowed to go slack prior to the helicopter taking strain on the load,
it is possible for the ring to be inadvertently manoeuvred over the top of the load
beam and assume the position shown in Fig 2A, thereafter detachment from the
cargo hook is likely to take place in the manner described in para 21.1. It should be
noted that the SACRU No2 Mk1, as a comparatively small cargo hook with relatively
short hook bill, is likely to be more susceptible than most of this type of occurrence.
21.2.2 The second situation concerns an item escaping by overriding the bill of the
load beam at some stage after the slinging equipment has been lifted clear of the
ground. This is considered in a narrow and broad context as follows:
21.2.2.1
Two isolated incidents have focused on the current range of
steel wire rope strops (1500 lb SWL and 6000 lb SWL equipment), when
used with the SACRU No2 Mk1. In each case the strops have a lifting eye
formed as an integral part of the leg at its top end (ie they are not articulated
at the head), and in each case they are capable of overriding the bill of the
load beam of the SACRU No2 Mk1. In one incident the strop detached
during manoeuvre with a load attached, in the other, the strop detached
during the process of load engagement to the secondary hook. In the latter
case, due to the relative rigidity of the strop head any upwards movement
transmitted along the strop leg could cause the lifting eye inadvertently to
override the load beam (Fig 3). Similarly, transit to the load with the strop
engaged to the primary hook, and the secondary hook end held at the cabin
door, could cause unusual orientation of the lifting eye, and overriding of the
load beam, which may not manifest itself until the strop has been redeployed
under its own weight. With either strop type, however, use of a suitable
connector for engagement to the SACRU No2 Mk1 averts any such risk and
this has been introduced (see relevant strop chapters).
21.2.2.2
In the wider context, there is now a relatively large mix of
slinging equipment’s and cargo hook types. There are certain other cargo
hooks/slinging equipment combinations, which introduce a similar question.
However, a problem is not yet seen to exist where equipment’s have an
articulated lifting ring or apex system and the weight of the load has been
taken under the helicopter.
Close monitoring of load hook-up
22 The crewman, when present, should ensure that the lifting ring or apex device is correctly
attached to the load beam before instructing the pilot to lift the load from the ground. The
crewman, or the pilot if no crewman is present, must watch for the affirmative signal from the
marshaller or hook-up team leader, who must in turn satisfy himself that the load is properly
suspended before giving this signal.
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Fig 3 Steel wire rope strop overriding bill of SACRU load beam
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DAP 101A-1105-1A
CHAPTER 2-1-1
TALON, SEMI-AUTOMATIC CARGO RELEASE UNIT (SACRU) 12000 lb
(Completely revised)
CONTENTS
Para
1
2
3
4
5
Introduction
Basic layout
Manual load beam release
System of release
Complete failure of the load beam to release
Hooking-up (WARNING (CAUTION))
INTRODUCTION
1
The Talon, Semi-Automatic Cargo Release Unit (SACRU) 12000 lb is an electro-magnetic
type release unit. It is fitted as a single hook installation to the Merlin Mk3 Helicopter. The
release unit has a safe working load (SWL) of 12000 lb (5443 kg). The Merlin Mk3 is limited to
a maximum of 9038 lb (4100 kg) all up weight carried from the release unit.
BASIC LAYOUT
2
The SACRU is mounted underneath the helicopter in a fore and aft manner. It is
suspended on a cross beam between two I-beams in the cargo hook bay below the cabin floor.
When the hook is not in use it is raised manually by a lanyard into the cargo hook bay and
secured in position by a retaining strap.
MANUAL LOAD BEAM RELEASE
System of release
3
There is a manual release lever on the SACRU casing which can be operated by a ground
handler. Providing that there is a minimum of 15 lb (6.8 kg) on the load beam it will open,
pivoting downwards to release the load. If there is no load on the load beam when operating
the lever, the ground handler will have to apply a force of 15 lb (6.8 kg) to open the load beam.
The load beam, being spring loaded, will close and lock automatically after release.
Complete failure of the load beam to release
4
Following load landing, with the helicopter in the hover, should the load beam fail to release
then the ground handling party may achieve load disengagement by depressing the spring
loaded keeper and sliding the engaged lifting ring/device off the load beam. See the
‘CAUTION’ after para 5 concerning static electricity discharge probe procedures..
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HOOKING UP
5
Carry out the following procedures:
WARNING
ONLY ONE LIFTING RING/APEX DEVICE IS TO BE CARRIED ON THE LOAD BEAM
OF THIS SACRU.
5.1
Ensure that the white datum lines on the release lever assembly are in alignment.
5.2 Only one lifting ring or lifting device may be suspended from the SACRU load beam.
Engage the device over the bill of the load beam and push it fully past the keeper, onto the
load carrying part of the beam. Ensure that the keeper has returned to the fully closed
position.
CAUTION
See Chap 5 concerning static electricity discharge and employment of a static
electricity discharge probe for the hooking-up process, or any other allied ground
handler functions described in foregoing paragraphs.
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DAP 101A-1105-1A
CHAPTER 2-1-2
SEMI-AUTOMATIC CARGO RELEASE UNIT (SACRU) No 1 MK3
(Completely revised)
CONTENTS
Para
1
3
Introduction (WARNING)
Basic layout
Manual load beam release
System of release
Complete failure of the load beam to release
Hooking-up (WARNING (CAUTION))
4
5
6
INTRODUCTION
WARNING
WHEN OPERATING WITH THE SACRU NO1 MK3, HOOK-UP PERSONNEL AND
CREWMAN SHOULD PAY PARTICULAR ATTENTION TO MASTERLINK/ STIRRUP
ATTACHMENT TO THE LOAD BEAM AS AN INCREASED RISK OF ROLL-OUT
EXISTS.
1
The semi-automatic cargo release unit (SACRU) No 1 Mk3 is an electro-magnetic type
release unit. The SACRU No 1 Mk3 is fitted with a modified (increased aperture) load beam
and keeper to accord with the requirements of STANAG 3542.
2
The SACRU is fitted as a single hook installation to Merlin, Sea King and Puma helicopters.
The release unit has a Safe Working Load (SWL) of 2724 kg (6000 lb), which is within the
cleared limits for Sea King helicopters. However, the all up weight of load carried from the
release unit for the Puma is limited to a maximum of 2250 kg (4960 lb); the Merlin Mk 2 and 3A
are limited to a maximum of 2272 kg (5000 lb).
NOTE
The Merlin Mk2 and 3A also operate with the Chinook C-160 hook connected to the hook
carriage of an H-frame assembly, when in full VERTREP role, chap 2-1-6 refers. This
configuration allows for external load uplift of 3650 kg (8046 lb) weight of load maximum.
BASIC LAYOUT
3
The SACRU is mounted underneath the helicopter in a fore and aft manner. It is
suspended from the fuselage by means of four wire rope legs in the case of the Merlin Mk2 and
3A and Sea King helicopters. In the case of the Puma helicopter it is suspended from a pole
(known as the ‘load pole’), which is attached to the main gearbox casing (in the cabin roof) and
passes down to the floor hatch. A shorter arm engages the SACRU to the bottom of the load
pole by means of a universal link.
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MANUAL LOAD BEAM RELEASE
System of release
4
There is a manual release lever on the side of the SACRU casing which can be operated
by the ground handler. The manual release lever direction of movement is indicated by the
word OPEN and an arrow. Providing that there is a minimum load of 8lb on the load beam it will
open, pivoting downwards to release the load. If there is no load on the load beam, the ground
handler will have to apply a force of 8 lb to open the load beam against its spring.
Complete failure of the load beam to release
5
Following load landing, with the helicopter in the hover, should the load beam fail to release
then the ground handling party may achieve load disengagement by depressing the spring
loaded keeper and sliding the engaged lifting ring/device off the load beam. See the
‘CAUTION’ after para 6.
HOOKING UP
6
Carry out the following procedures:
WARNING
ONLY ONE LIFTING RING/APEX DEVICE IS TO BE CARRIED ON THE LOAD BEAM
OF THIS SACRU.
6.1 Ensure that the groove in the end of the manual release lever shaft and the RED
engraved datum line on the release lever assembly cover are in alignment.
6.2 Only one lifting ring or lifting device may be suspended from the SACRU load beam.
Engage the device over the bill of the load beam and push it fully past the keeper, onto the
load carrying part of the beam. Ensure that the keeper has returned to the fully closed
position.
CAUTION
See Chap 5 concerning static electricity discharge and employment of a static
electricity discharge probe for the hooking-up process, or any other allied ground
handler functions described in foregoing paragraphs.
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CHAPTER 2-1-3
SEMI-AUTOMATIC CARGO RELEASE UNIT (SACRU) No 2 MK1
(Completely revised)
CONTENTS
Para
1
2
3
4
5
Introduction (WARNING)
Basic layout
Manual load beam release
System of release
Complete failure of the load beam to release
Hooking-up (WARNING (CAUTION))
INTRODUCTION
WARNING
WHEN OPERATING WITH THE SACRU NO2 MK1, HOOK-UP PERSONNEL AND
CREWMAN SHOULD PAY PARTICULAR ATTENTION TO MASTERLINK/ STIRRUP
ATTACHMENT TO THE LOAD BEAM AS AN INCREASED RISK OF ROLL-OUT
EXISTS.
1
The semi-automatic cargo release unit (SACRU) No 2 Mk1 is an electro-magnetic type
release unit. The SACRU is fitted as a single hook installation to Wildcat, Lynx and Gazelle
helicopters. The release unit has a Safe Working Load (SWL) of 1360 kg (3000 lb). Lynx is
cleared to lift to this capacity, however the maximum permitted external weight of load for
Wildcat is 1000 kg (2200 lb) and 600 kg (1323 lb) for Gazelle.
BASIC LAYOUT
2
The SACRU is mounted underneath the Wildcat and Lynx helicopter in a fore and aft
manner. Its fittings allow the release unit to swing fore and aft or from side to side. The release
unit is mounted in an athwartships manner underneath Gazelle. It has similar freedom of
movement about its fittings.
MANUAL LOAD BEAM RELEASE
System of release
3
There is a manual release knob on top of the SACRU casing which can be operated by a
ground handler. Providing that there is a minimum load of 10 lb (3.5 kg) on the load beam it will
open, pivoting downwards to release the load. If there is no load on the load beam, when
operating the manual release plunger, the ground handler will have to apply a force of 10 lb to
open the load beam against its spring.
Complete failure of the load beam to release
4
Following load landing, with the helicopter in the hover, should the load beam fail to release
then the ground handling party may achieve load disengagement by depressing the spring
loaded keeper and sliding the engaged lifting ring/device off the load beam. See the
‘CAUTION’ after para 5 concerning static electricity discharge probe procedures.
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HOOKING-UP
5
Carry out the following procedures:
WARNING
ONLY ONE LIFTING RING/APEX DEVICE IS TO BE CARRIED ON THE LOAD BEAM
OF THIS SACRU.
5.1 Before engaging the load onto the load beam, check that the flag in the release unit
indicator window shows WHITE.
5.2 Only one lifting ring or lifting device may be suspended from the SACRU load beam.
Engage the device over the bill of the load beam and push it fully past the keeper, onto the
load carrying part of the beam. Ensure that the keeper has returned to the fully closed
position.
CAUTION
See Chap 5 concerning static electricity discharge and employment of a static
electricity discharge probe for the hooking-up process, or any other allied handler
function described in foregoing paragraphs.
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CHAPTER 2-1-5
CHINOOK CARGO HOOKS
(Completely revised)
CONTENTS
Para
1
2
3
4
5
6
7
8
9
10
11
Triple cargo hook facility
Modes of employment
Centre hook
System of release
Safe Working Load (SWL)
Forward and aft hooks
System of release
Safe Working Load (SWL)
Joint centre hook and fore and aft hook operation
Inter-hook release
Complete failure of the load beam to release
Hooking-up - Centre or fore and aft hooks (CAUTION)
Fig
1
Page
Modes of hook employment …
…
…
…
…
…
…
…
…
…
…
2
TRIPLE CARGO HOOK FACILITY
1
The Chinook has a triple cargo hook facility, allowing for the fitment of three releasable
hooks spaced in tandem along the bottom centre-line of the fuselage (Fig 1). The hooks are
referred individually as the ‘CENTRE HOOK’ and the ‘FORWARD and AFT HOOKS’. The
centre hook is of a different design to the forward and aft hooks. The forward and aft hooks are
identical to each other.
Modes of employment
2
The Chinook triple cargo hook system allows for four modes of employment, as follows:
2.1 Single hook operations (SHOs). This is where only one hook out of the three (the
centre hook) is used for carrying the load, and can be likened to operations with single
cargo hook helicopters (see Fig 1a).
2.2 Multiple hook operations (MHOs). This is where two or all three hooks are used
simultaneously, each carrying an independent load (see Fig 1b).
2.3 Tandem hook operations ‘redundant rigging’ (THORR). This is where a single load is
suspended by means of the forward and aft hooks, with redundant rigging to the centre
hook (see Fig 1c).
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Fig 1 Modes of hook employment
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NOTE
Redundant rigging calls for the use of an additional and special sling, designed solely
for the purpose. In normal circumstances the legs of the redundant sling will remain
slack/unused throughout the entire flight. However, the sling affords a safeguard
against the possibility of an irregular release of either the forward or the aft hook or a
failure of the primary sling legs at one end of the load. In such a situation, the
redundant sling (suspended from the centre hook) will arrest the load drop at the
relevant end, absorb the attendant shock loading in the process, and thereafter
enable retrieval of the load. Without a redundant slinging system, an irregular hook
release or sling leg failure, as described, could lead to severe structural damage of
the airframe, due to shock loading. This would be accompanied by the risk of the
load swinging in an arc, about the remaining cargo hook attachment point, leading to
a possible fuselage or rotor strike before the crew could effect load jettison.
2.4 Tandem hook operations ‘long stropping’ (THOLS). This is where a single load is
suspended employing slings, strops and weak link assemblies by means of the fore and aft
hooks. The weak link enables the use of long stropping without the need for redundant
rigging (see Fig 1d).
NOTE
The weak link assembly, with a specified breaking load, is fitted directly to the fore
and aft hooks of the aircraft. In the event of a failure of the fore and aft hook/rigging,
the remaining weak link will shear, protecting the aircraft structure from excessive
forces.
CENTRE HOOK
3
The centre hook is attached to a removable beam mounted in the centre floor hatch of the
helicopter. The hook is free to move from side to side at its attachment point to the beam. The
beam is free to swing forwards and aft.
System of release
4
There is no externally mounted hook opening facility for ground handlers (note para 11).
Safe Working Load (SWL)
5
The maximum all up weight (AUW) that may be carried on the centre hook is 11300 kg
(25000 lb), which is also the maximum AUW of external loads cleared for carriage under the
Chinook helicopter.
FORWARD AND AFT HOOKS
6
The forward and aft hooks are of the electro-magnetic type release unit, similar to the
SACRU range of hooks. The hooks are fitted in watertight compartments in the under fuselage.
The fittings allow the hooks to swing fore and aft or from side to side. The hooks are identical to
each other.
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System of release
7
There is a manual release knob on the cargo hook casing which can be operated by a
ground handler. The knob has an arrow engraved on its face indicating the direction of
operation (anti-clockwise). Providing that there is a minimum load of 9 kg (20 lb) on the load
beam it will open, pivoting downwards to release the load. If there is no load on the load beam,
when operating the manual release knob, the ground handler will have to apply a force of 9 kg
(20 lb) to open the load beam against its return spring.
Safe Working Load (SWL)
8
The maximum AUW of load that may be carried per hook is currently 5000 kg (11023 lb),
providing that the aircraft remains within cg limits. This refers to separate loads carried on each
hook. For tandem hook operations (ie combined use of both hooks to lift a single load), the
maximum mass that may be carried is 10500 kg (23148 lb). The longitudinal cg of the load
must not result in a hook load distribution in excess of 40-60% (fwd-aft), 60-40% (fwd-aft).
JOINT CENTRE HOOK AND FORE AND AFT HOOK OPERATION
Inter-hook release
9
The three hooks can be released individually or simultaneously by electrical command
(normal mode). Electrical emergency release mode operates all three hooks simultaneously.
COMPLETE FAILURE OF THE LOAD BEAM TO RELEASE
10 Following load landing, with the helicopter in the hover, should the beam fail to release then
the ground handler party may achieve load disengagement by depressing the spring loaded
keeper and sliding the engaged lifting ring/device off the load beam. See the ‘CAUTION’
concerning static electricity discharge probe procedure.
HOOKING-UP – CENTRE OR FORE AND AFT HOOKS
11 Carry out the following procedures:
WARNING
ONLY ONE LIFTING RING/APEX DEVICE IS TO BE CARRIED ON THE LOAD BEAM
OF THESE HOOKS.
11.1 With the forward and aft hook, check through the inspection window that the ‘hook
locked’ indication is in accordance with the adjacent decal. Check the release knob
RED/BLACK datum marks are in line. If the indicator shows the hook as being unlocked,
manually open and close the hook. If the indicator still shows the hook as being unlocked
then the hook is unserviceable.
11.2 In the case of all hooks, only one lifting ring or lifting device may be suspended from
the hook load beam. Engage the device over the bill of the load beam and push it fully past
the keeper, onto the load carrying part of the beam. Ensure that the keeper has returned to
the fully closed position.
CAUTION
See Chap 5 concerning static electricity discharge and employment of a static
electricity discharge probe for the hooking-up process, or any other allied
handler function described in foregoing paragraphs.
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CHAPTER 2-1-6
MERLIN MK2 AND MK3A, C160, CARGO HOOK
(Completely revised)
CONTENTS
Para
1
2
3
4
5
Introduction
Basic layout
Manual load beam release
System of release
Complete failure of the load beam to release
Hooking-up (WARNING (CAUTION))
INTRODUCTION
1
The C160, cargo hook is an electro-magnetic type release unit. It is fitted as a single hook
installation to the Merlin Mk2 and Mk3A helicopter, when in full VERTREP role, and is limited to
a maximum of 8046 lb (3650 kg) all up weight carried from the release unit.
SYSTEM OF OPERATION
Basic layout
2
The cargo hook is mounted underneath the helicopter in a fore and aft manner and used in
conjunction with an ‘H’ frame. The frame is attached to strong-points on the lower fuselage with
the cargo hook suspended from the centre of the frame.
MANUAL LOAD BEAM RELEASE
System of release
3
There is a manual release knob on the cargo hook casing which can be operated by a
ground handler. The knob has an arrow engraved on its face indicating the direction of
operation (anti-clockwise). Providing that there is a minimum load of 9 kg (20 lb) on the load
beam it will open, pivoting downwards to release the load. If there is no load on the load beam,
when operating the manual release knob, the ground handler will have to apply a force of 9 kg
(20 lb) to open the load beam against its return spring.
Complete failure of the load beam to release
4
Following load landing, with the helicopter in the hover, should the load beam fail to release
by any of the release modes, then the ground handling party may achieve load disengagement
by depressing the spring loaded keeper and sliding the engaged lifting ring/device off the load
beam. See the ‘CAUTION’ after para 5 concerning static electricity discharge probe
procedures.
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HOOKING UP
5
Carry out the following procedures:
WARNING
ONLY ONE LIFTING RING/APEX DEVICE IS TO BE CARRIED ON THE LOAD BEAM
OF THESE HOOKS.
5.1 Check through the inspection window that the ‘hook locked’ indication is in
accordance with the adjacent decal. Check the release knob RED/BLACK datum marks
are in line. If the indicator shows the hook as being unlocked, manually open and close the
hook. If the indicator still shows the hook as being unlocked then the hook is unserviceable.
5.2 Only one lifting ring or lifting device may be suspended from the hook load beam.
Engage the device over the bill of the load beam and push it fully past the keeper, onto the
load carrying part of the beam. Ensure that the keeper has returned to the fully closed
position.
CAUTION
See Chap 5 concerning static electricity discharge and employment of a static
electricity discharge probe for the hooking-up process, or any other allied
handler function described in foregoing paragraphs.
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CHAPTER 2-2
STROPS, LIFTING, SINGLE LEG - GENERAL
(Completely revised)
CONTENTS
Para
1
2
3
4
5
6
7
9
10
14
16
17
21
22
Introduction
Nature of the equipment
Purpose of equipment
Additional facility of the polyester strop
Further application of extension strops
Materials used for strop legs
Steel Wire Rope (SWR)
Textiles
General principles of strop usage
Underslung load clearances (USLCs)
Hooking-up (WARNING)
Strop release
Non-strop release operations (WARNING)
Coupling of strops in series
Factors affecting use of longer length strops
Further application of strop coupling
Fig
1
2
Page
British Service helicopter extension strops
   
11300 kg strop assemblies, branching two strops from one 






3
8
INTRODUCTION
1
Helicopter extension strops are aircraft role equipment items and the purpose of this
chapter is to cover the general aspects relating to the make up and use of British Service
helicopter extension strops.
NATURE OF THE EQUIPMENT
2
The current range of extension strops are shown in Fig 1. Each equipment is classified by
its Safe Working Load (SWL). Equipments vary in length, with the legs being constructed from
textile or steel wire rope (SWR). The top of the leg is either formed with a lifting loop or eye, or
is fitted with a shackle or similar device for engagement onto the helicopter cargo hook or
another strop hook. The bottom of the leg is fitted with a hook, known as the ‘secondary’ hook
for reception of sling lifting ring, net stirrup or a similar device. The employment of a swivelling
secondary hook is MANDATORY.
PURPOSE OF EQUIPMENT
3
Extension strops are normally associated in their use with loads suspended from a single
helicopter cargo hook. In this context, British Service helicopter extension strops have a
threefold function as described below:
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Increased vertical clearance
3.1 An extension strop enables a load to be underslung at an extended distance from the
helicopter, serving the following purpose:
3.1.1 Avoidance of load strike on helicopter. It provides a safe suspension distance
for loads which, because of their size or flying characteristics, pose the risk of striking
the helicopter in flight.
3.1.2 Avoidance of surface obstacles. It affords a means of attaching or landing a
load when the helicopter is unable to descend because of surface obstacles such as
trees, buildings or ships rigging.
3.1.3 Reduction of rotor downwash effect. It allows the helicopter to hover high
enough for rotor downwash to be minimised, thus avoiding dust or snow disturbance,
and damage to surrounding structures or loose items. It also reduces the possibility of
objects or debris being drawn up into the helicopter rotors or engine intakes.
3.1.4 Making hook-up of awkward shaped loads safer. It makes the process of load
hook-up safer and simpler for the helicopter crew and for ground handlers operating
with awkward shaped loads; avoiding the risk of helicopter wheel or skid strikes and,
for the helicopter crew, removing the need for precise positioning over the load until
the moment of the load uplift.
3.1.5 Making hook-up under a particular helicopter type safer/simpler. It makes for
safer and simpler load hook-up, when there is little room to spare for ground handlers
between the cargo hook and surrounding wheels/skids or other items attached to the
underside of the helicopter fuselage.
3.1.6 Avoidance of load collisions in Chinook multiple cargo hook operations. It
enables load suspension distances to be staggered in Chinook operations involving
carriage of separate loads on two or all three of its cargo hooks, thus avoiding the risk
of load collisions in flight.
Connector/coupling facility
3.2 The extension strop ‘secondary’ hook provides a means of connection for strops,
slings or cargo lifting nets. The secondary hook also affords the means of coupling
equipment lifting rings or apex devices in multiples. This is an important facility and is allied
to current UK safety practice whereby only one lifting ring or apex device may be carried
from the load beam of existing type British Service helicopter cargo hooks.
NOTE
In certain instances, specified ‘connector devices’ can be used as an alternative means
of connecting or coupling equipment to a helicopter cargo hook (see Chap 2-3-1).
Swivel facility
3.3 Certain loads have a tendency to rotate in flight, either intermittently or in the form of a
sustained spin. Without a swivel device in the suspension system this would lead to a
winding up of sling legs or strop, causing damage to these items and torsional strain on the
helicopter cargo hook and/or its point of attachment to the helicopter. The end result could
be loss of a load. The extension strop allows for the introduction of such a device.
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Fig 1 British Service helicopter extension strops
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Additional facility of the polyester strop
4
In certain situations it is advantageous for the swivel/connector/coupler facility, provided by
the extension strop secondary hook, to be used without the increased load suspension distance
afforded by the strop leg. The 11300 kg strop equipment caters for this, in its design which
allows for easy removal of the polyester leg element and connection of the strop lifting ring
(masterlink) direct to the swivel hook.
Further application of extension strops
5
Means of improving or averting unfavourable load handling characteristics for a given
helicopter. QinetiQ, ATEC, Boscombe Down clearance for a given helicopter type may make
the use of an extension strop mandatory, outside of such requirements as simpler/safer hook-up
facility for ground handlers (para 3.1.5) or specified needs for a strop when called for in
JADTEU USLCs. The mandatory requirement may be a general one, for carriage of any USL,
because the use of a suitable strop can significantly enhance load handling characteristics of it
under that helicopter type. The requirement may, however, be specific to carriage of one type
of sling, for example, where the strop may overcome a problem of vertical bouncing of the load
resulting from helicopter vibrational characteristics and the stretch characteristics of the
particular sling. Such mandatory requirements for use of a strop will be laid down in the RTS
document for the helicopter type (see Chap 1).
MATERIALS USED FOR STROP LEGS
Steel wire rope (SWR)
6
Longer length strops have traditionally been constructed from SWR. This is because the
stretch in SWR is negligible when operating within its load range, thus posing no rebound
hazard should the load detach from the strop secondary hook in flight. However, SWR is
comparatively heavy, and not as pliant or easy to handle as textile equipment. Whilst the
current range of SWR strops are of manageable weight and rope diameter, greater weight/
payload performance is achieved in the heavier duty range of equipment’s by the use of textile
materials.
Textiles
7
Polyester. The heavy duty polyester strop equipment is not limited in the length of
assembly which may be used. This is because the stretch characteristics of polyester are
negligible compared with nylon under similar load conditions. Like nylon, polyester is a
lightweight material, supple and easy to handle. However, unlike nylon, polyester is much less
prone to deterioration as the result of regular exposure to sunlight (actinic degradation).
8
Textile life. Polyester and nylon strop legs are ‘lifed’ items, Chap 1-1, para 11 or AP 108G0002-1B, HUSLE Strops refers.
GENERAL PRINCIPLES OF STROP USAGE
Underslung load clearances (USLCs)
9
All USLCs published by JADTEU state clearly when an extension strop is required,
amplified by a statement of flying characteristics for the loads concerned and specifying the
strop equipment to be used. Clearances calling up 11300 kg strop equipment will also indicate
whether a strop lifting ring (masterlink) may alternatively be connected to the swivel hook
assembly without inclusion of the polyester roundsling leg. Further amplification on USLCs and
use of strops is contained in DAP 101A-1105-1B (Chap 1-2, para 9, Aircrew Advisory Notes).
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Hooking up
10 Static electricity discharge. If the extension strop is to be engaged to the cargo hook with
the helicopter in the hover, or with the helicopter on the ground with rotors running, first carry
out the static discharge procedure as described in Chap 5. Engagement of items to the strop
secondary hook will normally be carried out with the strop deployed from the helicopter in the
hover, and with the same static discharge procedure being carried out.
11 Engagement of strop to helicopter cargo hook. Consult Chap 2-1 for the process of
engaging the strop lifting eye, ring or strop connector where applicable, onto the SACRU and
Chinook series of cargo hooks. Consult individual strop chapters for detailed points concerning
each strop equipment.
12 Engagement of items onto strop secondary hook. The current range of extension strop
secondary hooks are broadly similar in appearance and all equipped with the same form of
spring loaded keeper. Having carried out static discharge procedures as required, it is normally
necessary to grasp the secondary hook with one hand whilst pushing the sling lifting ring, net
stirrup, or the like, past the spring loaded keeper fully onto the beam of the hook. Confirm that
the spring loaded keeper has returned to its fully closed position and give a tug on the
connected item to ensure correct and positive engagement. Repeat this process for any further
items to be engaged onto the secondary hook.
NOTE
The number of equipment lifting rings or apex devices that can be accommodated by a
given type of secondary hook will depend upon the size and nature of the apex device.
Whilst these factors will automatically be catered for in USLCs, the standard
accommodation limits for different types of strop hook are set down in the individual strop
equipment chapters, for general information and to cater for ‘Authorised loads’.
13 Chinook multiple hook operations. The following points should be noted concerning
Chinook multiple hook operations (see also Chap 2-1-5):
WARNING
HOOKING-UP MULTIPLE LOADS CAN BE HAZARDOUS TO GROUND PERSONNEL,
PARTICULARLY IN POOR WEATHER. CLEAR COMMUNICATION IN THE FORM OF
UNAMBIGUOUS SIGNALS BETWEEN MARSHALLERS, HOOK-UP TEAM AND THE
HELICOPTER CREW IS ESSENTIAL.
13.1 When carrying a separate load on each of the three hooks, the preferred
configuration is with the front load attached to a masterlink with swivel hook (11300 kg
strop items), the centre load on a medium length 11300 kg strop and the rear load on a
longer length 11300 kg strop. This combination may, however, be varied to suit operational
circumstances.
13.2 There is no hooking-up sequence. However, it is usually easier to attach the load
with the shortest suspension length first. Horizontal load separation can be improved by
attaching the densest load to the forward hook and the bulkiest load to the aft hook.
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Strop release
14 Following load landing the helicopter crew will endeavour to release the strop to one side of
the load, to avoid risk of damage. During this process, ground handler personnel must keep
well clear of the release area and the attendant danger of being struck by the heavy and
potentially lethal metal elements of a strop assembly. See Chap 2-1 for the methods of
manually releasing the strop from the various types of helicopter cargo hook, should this be
required of the ground handlers.
15 Following strop release, the helicopter will normally land nearby to retrieve the strop.
Where this is not possible, it is the responsibility of the ground unit to return the strop to the
helicopter unit without delay.
Non-strop release operations
16 For certain operations the helicopter crew may require disengagement of the load,
following load landing, without releasing the strop from the helicopter cargo hook. A common
practice is to use a strop recovery line, which enables the crewman to haul the free end of the
strop up to the helicopter cabin, following disengagement of the load at the secondary hook.
The following points concerning non-strop release operation are to be noted:
16.1 Disengagement of equipment from secondary hook. Although the load has been
landed, the static discharge procedure is to be carried out in full before disengagement of
the load from the strop secondary hook. Disengagement involves depressing the spring
loaded keeper, whilst removing the item(s) from the hook. Throughout the process ground
handlers must remain alert to the danger of inadvertent release from the helicopter cargo
hook end, with the consequent falling of the strop assembly possibly fitted with heavy metal
lifting ring.
16.2
Established procedures.
WARNING
TO AVOID CONFUSION AND POSSIBLE HAZARD TO GROUND HANDLER
PERSONNEL IT IS IMPORTANT THAT THEY ARE FULLY BRIEFED ON THE
HELICOPTER OPERATOR’S INTENT, INCLUDING THE VISUAL SIGNALS THAT
ARE TO BE USED FOR UNDERLUNG LOAD OPERATIONS INVOLVING NONSTROP RELEASE.
Strop recovery line
17 In order to recover a strop following completion of an external load lift without requiring the
helicopter to land, or to facilitate swift transit speeds when conducting frequent short range load
lifts, a recovery line may be fitted so that the strop may be drawn up into the helicopter when not
in use.
18 Information on the construction of the recovery line should be detailed in instructions
pertinent to the aircraft type. The recovery line should have the following characteristics:
18.1 Be fitted to the strop so as not to interfere with the use of the primary or secondary
hooks.
18.2
Be slightly longer than the strop; dependant on strop length.
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18.3
Use of cord or rope that is easy to handle; this may include knots to assist grip.
18.4 Incorporate a weak link to allow detachment from the aircraft if the load is jettisoned
from the primary hook.
19 A recovery line may be used to help stabilise a flailing strop.
Coupling of strops in series
20 Complete strop assemblies from the same family (eg 16 ft and/or 80 ft SWR strops (SWL
6000 lb)) may be coupled to each other in series to make a longer assembly, providing the
requirements of para 21.1 to 21.3 below are adhered to. For further details consult individual
strop chapters. In an extreme operational need, strops of mixed SWL and/or material (ie SWR
and textile assemblies) may be coupled in series if compatible for connection to each other, as
indicated in individual strop chapters. In all cases the following rules are to be applied:
20.1
All secondary hooks in the coupled assembly are to be of the swivelling type.
20.2 The overall SWL of the assembly is to be determined by the strop(s) with the lowest
SWL classification.
20.3 The total weight of equipment and terminal load suspended from any one secondary
hook in series is not to exceed the SWL of that particular hook and parent strop leg. Thus
in calculating the weight of load suspended from any one secondary hook, account must be
taken of the weight of all strops suspended below it.
NOTE
The 11300 kg and 5000 kg strop equipment’s also allows for connection in series of 2 m
and/or 5 m roundsling elements, with a single lifting ring (masterlink) at the top of the
assembly and a single swivel hook at the bottom. In these circumstances the SWL
remains 11300 kg or 5000 kg, respectively, for any length of assembly within the
operating capability of the helicopter type cleared to operate with this strop equipment.
Factors affecting use of longer length strops
21 Ground units should note that any of the following factors may limit the extent to which
longer length extension strops can be employed, either by a given helicopter type or in general
terms:
21.1
Individual helicopter performance limits at the high hover.
21.2
Maximum allowable load suspension distance imposed for a given helicopter type.
21.3 Operating conditions affording poor visibility, lack of visual clues or difficulty for the
helicopter crew in accurate perception of distance to the ground.
Further application of strop coupling
22 By coupling a pair of 11300 kg or 5000 kg extension strops to the secondary hook of an
equivalent rated single extension strop, it is possible, for example, to carry a cluster of netted
loads which would otherwise need lifting chains because there would be too many for direct
suspension from or accommodation onto a single strop secondary hook; consult appropriate
USLCs. Fig 2 illustrates the system; a maximum of two masterlink lifting rings may be
accommodated on the strop swivel hook.
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Fig 2 11300 kg strop assemblies, branching two strops from one
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CHAPTER 2-2-1
STROP, LIFTING, SINGLE LEG (11300 kg SWL)
(Completely revised)
CONTENTS
Para
1
3
4
5
6
7
8
9
10
13
Introduction
Equipment description
Standard assembly
Use of masterlink lifting ring and swivel hook assembly connected direct
Safe Working Load (SWL)
Life expiry of roundsling leg element
Technical support literature
Strop usage
Suitability for engagement to current range of helicopter cargo hooks
Coupling of 11300 kg strops
Secondary hook engagement and accommodation limits
Fig
1
2
3
4
5
6
7
Page
Assembled strop             
Masterlink and swivel            
Typical arrangement showing method of connecting roundslings to produce
an extended strop             
11300 kg strops, coupling complete assemblies together in series
 
Accommodation limits for the heavy duty strop secondary hook –
engaging SML 6000 lb SWL
         
Accommodation limits for the heavy duty strop secondary hook –
engaging nets 5000 lb SWL or 5600 kg SWL       
Accommodation limits for the heavy duty strop secondary hook –
engaging SML 4600 kg SWL or SML 11300 kg SWL
    
2
2
4
5
6
7
8
INTRODUCTION
1
The 11300 kg extension strop, otherwise known as the ‘Heavy Duty Strop’, is designed for
easy dismantling/assembly by component parts. The equipment length assembled is either
2.7 m or 5.7 m. Full NSN details and nomenclature for the equipment’s are contained in AP
108G-0002-1B, HUSLE Strops.
2
The strop lifting ring and swivel hook, otherwise known as the ‘Masterlink and Swivel’, may
be connected one to the other direct if the added length of the roundsling leg element is not
required. Full NSN details for the equipment and nomenclature are contained in AP 108G0002-1D, HUSLE Ancillary Equipment.
EQUIPMENT DESCRIPTION
Standard assembly
3
The assembled strop incorporates a 2 m or 5 m length roundsling leg (Fig 1). A strop lifting
ring (masterlink) is connected to one end of the strop and a swivel assembly with hoist hook
(secondary hook) is connected to the other end. The strop is fitted with two identification labels,
one external and one internal for fallback reference. Each label contains the NSN, the SWL
classification, the life expiry date of the roundsling leg and the assembly serial number.
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Fig 1 Assembled strop
Use of masterlink lifting ring and swivel hook assembly connected direct
4
The masterlink lifting ring may be connected directly to the swivel hook assembly using a
locking set. The ability to employ the equipment thus, without the inclusion of a roundsling leg,
is of benefit when a swivel capability only is required. This is particularly useful for Chinook
multiple hook operations (Chap 2-1-5 and Chap 2-2).
Fig 2 Masterlink and swivel
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SAFE WORKING LOAD (SWL)
5
The SWL of the complete strop assembly, with masterlink lifting ring, single or
interconnected roundsling legs and terminating swivel hook assembly is 11300 kg (25000 lb).
The SWL remains the same for the masterlink and swivel hook assembly connected one to the
other direct (para 4).
LIFE EXPIRY OF ROUNDSLING LEG ELEMENT
6
The roundsling leg element of the strop is a ‘Lifed’ item, policy for which is laid down in the
technical support literature for the equipment (para 7 and Chap 1-1). The life expiry date is to
be marked legibly and indelibly, with black permanent marker pen, on the strop identification
label(s).
TECHNICAL SUPPORT LITERATURE
7
Full technical supporting literature for the assembled 2.7 m or 5.7 m is published in
AP108G-0002-1B, HUSLE, Strops; full technical supporting literature for the masterlink and
swivel hook is published in AP108G-0002-1D, HUSLE Ancillary Equipment. Chap 1-1 gives
general advice on obtaining HUSLE maintenance APs.
STROP USAGE
8
Consult Chap 2-2 for the general principles applying to strop usage, hook-up, load release
etc.
Suitability for engagement to current range of helicopter cargo hooks
9
A range of helicopter cargo hooks are described in Chaps 2-1-1 to 2-1-6. The masterlink
lifting ring of the 11300 kg strop is suitable for direct engagement onto the Chinook centre,
forward and aft hooks. For applications with other helicopter types consult Chap 2,
Compatibility matrix.
Coupling of 11300 kg strops
10 Longer length assemblies may be made up by joining 2 m and/or 5 m length roundslings
end to end, using two roundsling couplings and a locking set at each interconnect point (Fig 3).
The assembly metalware is connected to the top and bottom of the overall roundsling assembly.
Refer to AP 108G-0002-1B, HUSLE Strops, for roundsling couplings and locking sets NSN and
nomenclature details.
11 An alternative way of achieving longer strop lengths is by coupling strop assemblies
together in series, two, three or more in number, within the load suspension/performance limit
for helicopter type. The coupling process simply involves engaging the masterlink lifting ring of
one strop onto the swivel hook of the next strop (one lifting ring per secondary hook) until all
strops have been linked. Individual strop assemblies may include 2 m and/or 5 m length
roundsling legs, and the masterlink, swivel hook assembly may also be included in the coupled
series. In each case check that the hook keeper returns to the fully closed position after
engagement of the lifting ring (Fig 4)
12 Any number of 5000 kg, 16 ft, 80 ft, 7 ft or 30 ft strops may be included in a linked series of
11300 kg strops. In this respect, the masterlink lifting ring is suitable for engaging the swivel
common to the 5000 kg, 16 ft and 80 ft strop but is too large to engage the smaller swivel hook
of the 7 ft and 30 ft strops.
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Fig 3 Typical arrangement showing method of connecting roundslings
to produce an extended strop
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Fig 4 11300 kg strops, coupling complete assemblies together in series
Secondary hook engagement and accommodation limits
13 Figs 5, 6 and 7 provide information on the suitability of the different types of sling and net
for engagement to the secondary hook of the 11300 kg strop. Guidance is also given on the
maximum number of equipment’s/apex devices that may be carried on the secondary hook,
unless otherwise specified in individual USLCs.
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SML 6000 lb SWL
Suitable for direct engagement to the heavy duty strop secondary hook.
Maximum of two slings for accommodation on this hook, unless specified
otherwise in individual USLCs.
(In all cases, the maximum AUW of equipment and load suspended from this secondary hook is
not to exceed 11300 kg (25000 lb) or such lower figures as may be set for the helicopter cargo
hook/helicopter type).
Fig 5 Accommodation limits for the heavy duty strop secondary hook engaging SML 6000 lb SWL
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Nets - 5000 lb SWL or 5600 kg SWL
Suitable for direct engagement to the heavy duty strop
secondary hook. As an ‘Authorised’ load, a maximum
of two net stirrups can be accommodated on this hook,
unless specified otherwise in individual USLCs.
(In all cases, the maximum AUW of equipment and load suspended from this secondary hook is
not to exceed 11300 kg (25000 lb) or such lower figures as may be set for the helicopter cargo
hook/helicopter type).
Fig 6 Accommodation limits for the heavy duty strop secondary hookengaging nets 5000 lb SWL or 5600 kg SWL
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SML 4600 kg SWL
SML 11300 kg SWL
Suitable for direct engagement to the heavy duty strop secondary hook.
A maximum of two SML 4600 kg or two SML 11300 kg masterlink lifting
rings are suitable for accommodation on this hook.
(In all cases, the maximum AUW of equipment and load suspended from this secondary hook is
not to exceed 11300 kg (25000 lb) or such lower figures as may be set for the helicopter cargo
hook/helicopter type).
Fig 7 Accommodation limits for 11300 kg SWL heavy duty strop secondary hookengaging SML 4600 kg SWL or SML 11300 kg SWL
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DAP 101A-1105-1A
CHAPTER 2-2-2
STROP, LIFTING, SINGLE LEG (5000 kg SWL)
(Completely revised)
CONTENTS
Para
1
2
3
4
5
6
7
8
11
Introduction
Equipment description
Standard assembly
Safe working load (SWL)
Life expiry of roundsling leg element
Technical support literature
Strop usage
Suitability for engagement to current range of helicopter cargo hooks
Coupling of 5000 kg strops
Secondary hook engagement and accommodation limits
Fig
1
2
3
4
5
6
Page
Assembled strop             
Typical arrangement showing method of connecting roundslings to produce
an extended strop             
5000 kg strops, coupling complete assemblies together in series   
Accommodation limits for the medium duty strop secondary hook engaging SML 6000 lb SWL
         
Accommodation limits for the medium duty strop secondary hook engaging nets 5000 lb SWL or 5600 kg SWL       
Accommodation limits for the medium duty strop secondary hook engaging SML 4600 kg SWL or 11300 kg SWL
     
2
3
4
5
6
7
INTRODUCTION
1
The 5000 kg extension strop, otherwise known as the ‘Medium Duty Strop’, is designed for
easy dismantling/assembly by component parts. The assembled equipment length is either
2.5 m or 5.5 m. Full NSN details and nomenclature for the equipment’s are contained in AP
108G-0002-1B, HUSLE Strops.
EQUIPMENT DESCRIPTION
Standard assembly
2
The assembled strop incorporates a 2 m or 5 m length roundsling leg (Fig 1). A strop lifting
ring (masterlink) is connected to one end of the strop and a swivel assembly with hoist hook
(secondary hook) is connected to the other end. The strop is fitted with two identification labels,
one external and one internal for fallback reference. Each label contains the NSN, the SWL
classification, the life expiry date of the roundsling leg and the assembly serial number.
SAFE WORKING LOAD
3
The SWL of the complete strop assembly, with masterlink lifting ring, single or
interconnected roundsling legs and terminating swivel hook assembly is 5000 kg (11020 lb).
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Fig 1 Assembled strop
LIFE EXPIRY OF ROUNDSLING LEG ELEMENT
4
The roundsling leg element of the strop is a ‘Lifed item’, the policy for which is laid down in
the technical support literature for the equipment (para 5 and Chap 1-1). The life expiry date is
to be marked legibly and indelibly, with black permanent marker pen, on the strop identification
label(s).
TECHNICAL SUPPORT LITERATURE
5 Full technical supporting literature for this equipment is published in AP 108G-0002-1B,
HUSLE Strops. Chap 1-1 gives general advice on obtaining HUSLE maintenance APs.
STROP USAGE
6
Consult chap 2-2 for the general principles applying to strop usage, hook up, load release
etc.
Suitability for engagement to current range of helicopter cargo hooks
7
A range of helicopter cargo hooks are described in chaps 2-1-1 to 2-1-6l. The masterlink
lifting ring of the 5000 kg strop is suitable for direct engagement onto all of the current range of
helicopter cargo hooks with the exception of the SACRU No 2 MK1. For helicopters fitted with
SACRU No 2 MK1 consult Chap 2, Compatibility matrix.
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DAP 101A-1105-1A
Coupling of 5000 kg strops
8 Longer length assemblies may be made up by joining 2 m and/or 5 m length roundslings
end to end, using two roundsling couplings and a locking set at each interconnect point (Fig 2).
The assembly metalware is connected to the top and bottom of the overall roundsling assembly.
Refer to AP 108G-0002-1B, HUSLE Strops for roundsling couplings and locking sets.
Fig 2 Typical arrangement showing method of connecting roundslings
to produce an extended strop
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DAP 101A-1105-1A
9
An alternative way of achieving longer strop lengths is by coupling strop assemblies
together in series, two, three or more in number, within the load suspension/performance limit
for the helicopter type. The coupling process simply involves engaging the masterlink lifting ring
of one strop onto the swivel hook of the next strop (one lifting ring per secondary hook), until all
strops have been linked. Individual strop assemblies may include 2 m and/or 5m length
roundsling legs in the coupled series. In each case check that the hook keeper returns to the
fully closed position after the engagement of the lifting ring (Fig 3).
Fig 3 5000 kg strops, coupling complete assemblies together in series
10 Any number of 11300 kg, 16 ft, 80 ft, 7 ft or 30 ft strops may be included in a linked series
of 5000 kg strops. In this respect, the masterlink lifting ring is suitable for engaging the swivel
hook common to the 11300 kg, 16 ft, 80 ft, 7 ft and 30 ft strops. In all cases, the maximum
AUW of the equipment and the load suspended from this secondary hook is not to exceed 5000
kg (11020 lb), or such lower figure as may be set for the helicopter cargo hook, linked strop or
helicopter type.
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Secondary hook engagement and accommodation limits
11 Figs 4, 5 and 6 provide information on the suitability of the different types of sling and net
for engagement to the secondary hook of the 5000 kg strop. Guidance is also given on the
maximum number of equipment’s/apex devices that may be carried on the secondary hook,
unless otherwise specified in individual USLCs.
SML 6000 lb SWL
Suitable for direct engagement to the medium duty strop secondary hook.
Maximum of two slings for accommodation on this hook, unless specified
otherwise in individual USLCs.
(In all cases, the maximum AUW of equipment and load suspended from this secondary hook is
not to exceed 5000 kg (11020 lb) or such lower figures as may be set for the helicopter cargo
hook/helicopter type).
Fig 4 Accommodation limits for the medium duty strop secondary hook engaging SML 6000 lb SWL
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Nets - 5000 lb SWL or 5600 kg SWL
Suitable for direct engagement to the medium duty strop
secondary hook. As an ‘Authorised’ load, a maximum
of two net stirrups can be accommodated on this hook,
unless specified otherwise in individual USLCs.
(In all cases, the maximum AUW of equipment and load suspended from this secondary hook is
not to exceed 5000 kg (11020 lb) or such lower figures as may be set for the helicopter cargo
hook/helicopter type).
Fig 5 Accommodation limits for the medium duty strop secondary hook engaging nets cargo 5000 lb SWL or 5600 kg SWL
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SML 4600 kg SWL
Suitable for direct engagement to the
medium duty strop secondary hook. A
maximum of two SML 4600 kg sling
masterlink lifting rings are suitable for
accommodation on this hook.
SML 11300 kg SWL
Suitable for direct engagement to the
medium duty strop secondary hook. A
maximum of one SML 11300 kg sling
masterlink lifting ring is suitable for
accommodation on this hook.
(In all cases, the maximum AUW of equipment and load suspended from the secondary hook is
not to exceed 5000 kg (11020 lb) or such lower figures as may be set for the helicopter cargo
hook/helicopter type).
Fig 6 Accommodation limits for medium duty strop secondary hook engaging SML 4600 kg SWL or SML 11300 kg SWL
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DAP 101A-1105-1A
CHAPTER 2-2-4
STROP, LIFTING, SINGLE LEG (16 FT AND 80 FT (6000 LB SWL))
(Completely revised)
CONTENTS
Para
1
2
3
4
5
6
7
8
12
15
Introduction
Equipment description
Standard assembly
Vinyl sleeve
Metal tally
Safe Working Load (SWL)
Technical support literature
Strop usage
Suitability for engagement to current range of helicopter cargo hooks (WARNING)
Coupling of 16 ft/80 ft strops
Secondary hook engagement and accommodation limits
Fig
1
2
3
4
5
6
Page
16 ft/80 ft strops (6000 lb SWL)        
Using a ‘connector sling’ to connect lifting loop of 16 ft/80 ft strop to
SACRU No 2 Mk1 and a 5 tonne SWL, bow shackle to connect lifting
loop 16 ft/80 ft strop to SACRU No 1 Mk3      
16 ft/80 ft strops coupling in series       
Accommodation limits for the 16 ft/80 ft strop secondary hook engaging SML 6000 lb SWL
       
Accommodation limits for the 16 ft/80 ft strop secondary hook engaging nets 5000 lb SWL or 5600 kg SWL     
Accommodation limits for the 16 ft/80 ft strop secondary hook engaging SML 4600 kg SWL or SML 11300 kg SWL
  


2




4
5


6


7


8
INTRODUCTION
1
The 16 ft and 80 ft Steel Wire Rope (SWR) extension strops are mainly associated with RN
and RAF helicopter units. There is no restriction on their use with any British Service
helicopters, within the normal ambit of operating provisions for helicopter type, and subject to
suitability for engagement, direct or by connector/coupling means, to the particular type of
helicopter cargo hook. Full NSN details for the equipment are contained in AP 108G-0002-1B,
HUSLE Strops.
EQUIPMENT DESCRIPTION
Standard assembly
2
The 16 ft and 80 ft strops are identical in construction, differing only in length and/or weight.
They derive their common usage titles from the respective length of wire rope leg (measured
datum points as shown in Fig 1). In each case the leg consists of a single length of SWR, each
end formed into a loop (Fig 1). The upper loop which is oval in shape forms the ‘lifting loop’ for
engagement onto a helicopter cargo hook, and is formed around a steel thimble. A smaller loop
is formed at the bottom of the leg, to enclose a ‘deadeye’ to which is attached a secondary hook
with spring loaded keeper (Fig 1).
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Fig 1 16 ft/80 ft strops (6000 lb SWL)
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Vinyl sleeve
3
A vinyl sleeve is fitted the length of the strop leg for protective purposes and to make the
strop easier to handle. Damage to the sleeve does not render the strop unusable, and the strop
may continue to be used with the sleeve removed completely providing that the strop is
serviceable in all other respects. A split sleeve may be taped, a badly torn sleeve should be
trimmed back or removed completely.
Metal tally
4
A metal tally is attached to the strop leg, identifying the equipment and containing details of
the NSN, equipment SWL, equipment serial number and date of ‘proof test’. If this tally is lost,
the equipment is to be withdrawn from use immediately and back-loaded for technical inspection
and further ‘proof test’.
SAFE WORKING LOAD
5
The SWL for the complete strop assembly, with secondary hook, is 6000 lb (2724 kg).
TECHNICAL SUPPORT LITERATURE
6
Full technical supporting literature for this equipment is published in AP 108G-0002-1B,
HUSLE Strops. Chap 1-1 gives general advice on obtaining HUSLE maintenance APs.
STROP USAGE
7
Consult Chap 2-2 for the general principles applying to strop usage, hook-up, load release
etc.
Suitability for engagement to current range of helicopter cargo hooks
8
The lifting loop of these strops is suitable for direct engagement onto the Talon (1200 lb)
cargo hook, listed in Chap 2, compatibility matrix. The lifting loop is not large enough however,
to fit the Chinook cargo hooks. If these strops have to be employed with Chinook, a 16 mm
‘closed and open masterlink assembly’ would serve as a suitable connector for engagement to a
Chinook hook. The strop lifting loop would be engaged onto the bottom of the ‘open’ masterlink.
When employed with Merlin Mk2/3A cargo hook, in full VERTREP role, a shackle, 5 tonne SWL,
large bow is to be used as means of connecting the strop lifting loop to the SACRU load beam.
See Chap 2-3-1 for further details of use of 16 mm masterlink assembly and shackles as
connectors.
9
Use with SACRU No 1 Mk3, SACRU No 2 Mk1 and Breeze Eastern. The lifting loop of
these strops will comfortably engage the load beams of SACRU’s, currently fitted to Merlin
Mk2/3A, Sea King, Puma, Wildcat, Lynx, Gazelle and Griffin helicopters. However, subsequent
upwards movement or unusual orientation of the strop leg could cause the lifting loop to jam
tight onto the widest section of the load beam or ride over the relatively short hook bill of these
SACRU’s and thereafter pull free from the keeper and detach from the SACRU. Such an
occurrence would normally be associated with events prior to engaging a load to the strop
secondary hook or before the weight of the load is taken by the extension strop following load
engagement. Two likely ways in which this could happen are as follows:
9.1 Operations where the strop is pre-engaged to the helicopter cargo hook, with the
secondary hook end of the strop held at the cabin door whilst in transit to or from a load,
could lead to flexing of the strop leg and movement of the lifting loop in a way to override
the bill of the SACRU, or moving to the rear of the load beam of the SACRU jamming tight.
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9.2 In other circumstances, where the load is being engaged to the secondary hook of
the deployed strop, and vertical flexing of the strop leg occurs, due perhaps to inadvertent
loss of height by the helicopter or due to movement with a seaborne load, the same issues
of the strop lifting loop overriding the bill of the SACRU or moving to the rear of the load
beam of the SACRU jamming tight could result.
10 In order to avoid any such risk it is MANDATORY to use one or the other of the following
connection devices as the means of coupling the strop lifting loop to the SACRU load beam
(see Fig 2):
10.1 Connector, sling (SWL 10000 lb) for attachment to the SACRU No 2 Mk1 (Fig 2)
WARNING
WHEN OPERATING WITH THE SACRU NO 1 MK3, HOOK-UP PERSONNEL AND
CREWMAN SHOULD PAY PARTICULAR ATTENTION TO SHACKLE ATTACHMENT
TO THE LOAD BEAM AS AN INCREASED RISK OF ROLL-OUT EXISTS, CHAP 2-1-2
REFERS.
10.2 A Shackle, 5tonne SWL, Large Bow for attachment to the SACRU No 1 Mk3.
10.3 A shackle, 3 tonne SWL, large bow for attachment to the Breeze Eastern.
Fig 2 Using a ‘connector sling’ to connect lifting loop of 16 ft/80 ft strop
to SACRU No 2 Mk1 and a 5 tonne SWL, bow shackle to connect
lifting loop of 16 ft/80 ft strop to SACRU No 1 Mk3
11 The sling connector and bow shackle are described in Chap 2-3-1.
Coupling of 16 ft/80 ft strops
12 The 16 ft and 80 ft extension strops may be linked together in series to make a longer
assembly. This may be conducted on the basis of ‘like with like’ or alternatively by a mix of 16 ft
and 80 ft strops, two, three or more in number, within the load suspension/performance limit for
helicopter types. The coupling process simply involves engaging the lifting loop of one strop
onto the swivel hook of the next strop (one lifting loop per secondary hook), until all strops have
been linked. In each case, check that the hook keeper returns to the fully closed position after
engagement of the lifting loop (Fig 3).
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Fig 3 16 ft/80 ft strop coupling in series
13 The lifting loop of these strops may be connected, in the manner described in para 12, to
the swivel hook of the 11300 kg strop, the 5000 kg strop and the 7 ft/30 ft SWR strops, for which
there is no limitation on numbers in making up an extended length assembly. The lifting loop is
not however, suitable for engagement to the swivel hook of the 11300 kg or 5000 kg strops,
although coupling via a 16 mm ‘open and closed masterlink assembly, would be possible.
14 For detailed rules which apply to strop coupling, mixing of strop types and assessment of
SWL, consult Chap 2-2, paras 20 and 21.
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DAP 101A-1105-1A
Secondary hook engagement and accommodation limits
15 Figs 4, 5 and 6 provide information on the suitability of different types of sling and net for
engagement to the secondary hook of the 16 ft and 80 ft strops. Guidance is also given on the
maximum number of equipments/apex devices that may be carried on the secondary hook,
unless otherwise specified in individual USLCs.
SLING MULTIPLE LEG
(6000 lb SWL)
Suitable for direct engagement to the 16 ft/80ft strop secondary hook.
Maximum of two slings for accommodation on this hook, unless
specified otherwise in individual USLCs.
(In all cases, the maximum AUW of equipment and load suspended from this secondary hook is
not to exceed 6000 lb (2724 kg) or such lower figures as may be set for the helicopter cargo
hook/helicopter type).
Fig 4 Accommodation limits for the 16 ft/80 ft strop secondary hook engaging SML 6000 lb SWL
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Net - 5000 lb SWL
Net - 5600 kg SWL
Suitable for direct engagement to the 16 ft/
80 ft strop secondary hook. As an
‘Authorised’ load, a maximum of two
stirrups can be accommodated on this
hook, unless specified otherwise in
individual USLCs.
Suitable for direct engagement to the 16 ft/
80 ft strop secondary hook. Normally only
one of these nets would be carried from
these strops, unless specified otherwise in
individual USLCs. However, two of these
net stirrups will comfortably engage the
swivel hook,
(In all cases, the maximum AUW of equipment and load suspended from this secondary hook is
not to exceed 6000 lb (2724 kg) or such lower figures as may be set for the helicopter cargo
hook/helicopter type).
Fig 5 Accommodation limits for the 16 ft/80 ft strop secondary hook engaging nets 5000 lb SWL or 5600 kg SWL
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DAP 101A-1105-1A
SML 4600 kg SWL
SML 11300 kg SWL
Suitable for direct engagement to the 16 ft/
80 ft strop secondary hook. A maximum of
two 4600 kg sling masterlink lifting rings
can be accommodated on this hook.
Suitable for direct engagement to the 16 ft/
80 ft strop secondary hook. A maximum of
one 11300 kg sling masterlink lifting rings
can be accommodated on this hook.
(In all cases, the maximum AUW of equipment and load suspended from this secondary hook is
not to exceed 6000 lb (2724 kg) or such lower figures as may be set for the helicopter cargo
hook/helicopter type).
Fig 6 Accommodation limits for the 16 ft/80 ft strop secondary hook engaging SML 4600 kg SWL or SML 11300 kg SWL
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DAP 101A-1105-1A
CHAPTER 2-2-5
STROP, LIFTING, SINGLE LEG (7 FT AND 30 FT (1500 LB SWL))
(Completely revised)
CONTENTS
Para
1
2
3
4
5
6
7
8
13
16
Introduction
Equipment description
Standard assembly
Vinyl sleeve
Metal tally
Safe Working Load (SWL)
Technical support literature
Strop usage
Suitability for engagement to current range of helicopter cargo hooks
Coupling of 7 ft/30 ft strops
Secondary hook engagement and accommodation limits
Fig
1
2
3
4
5
6
Page
7 ft/30 ft strops (1500 lb SWL)        
Using a ‘connector sling’ to connect lifting loop of 7 ft/30 ft strop to
SACRU No 2 Mk1           
7 ft/30 ft strops coupling in series
      
Accommodation limits for the 7 ft/30 ft strop secondary hook engaging SML 4600 kg SWL or SML 6000 lb SWL    
Accommodation limits for the 7 ft/30 ft strop secondary hook engaging nets 5000 lb SWL or 5600 kg SWL     
Accommodation limits for the 7 ft/30 ft strop secondary hook engaging SML 11300 kg SWL        

2



4
5


6

7

8
INTRODUCTION
1
The 7 ft and 30 ft Steel Wire Rope (SWR) extension strops are available to the 3 Services;
the 30 ft strop, in particular, is used both by RN and RAF helicopter units. There is no restriction
on their use with any of the current British Service helicopter types, within the normal ambit of
operating provisions for helicopter type, and subject to suitability for engagement, direct or by
connector/coupling means, to the particular type of helicopter cargo hook. Full NSN details for
the equipment are contained in AP 108G-0002-1B, HUSLE Strops.
EQUIPMENT DESCRIPTION
Standard assembly
2
The 7 ft and 30 ft strops are identical in construction, differing only in length and/or weight.
They derive their common usage titles from the respective length of wire rope leg (measured
datum points as shown in Fig 1). In each case the leg consists of a single length of SWR, each
end formed into a loop (Fig 1). The upper loop, which is approximately egg shaped, forms the
‘lifting loop’ for engagement onto a helicopter cargo hook and is formed around a steel thimble.
A smaller loop is formed at the bottom of the leg, to enclose a ‘deadeye’ to which is attached a
1500 lb SWL secondary hook with spring loaded keeper (Fig 1).
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Fig 1 7 ft/30 ft strops (1500 lb SWL)
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Vinyl sleeve
3
A vinyl sleeve is fitted the length of the strop leg for protective purposes and to make the
strop easier to handle. Damage to the sleeve does not render the strop unuseable, and the
strop may continue to be used with the sleeve removed completely providing that the strop is
serviceable in all other respects. A split sleeve may be taped, a badly torn sleeve should be
trimmed back or removed completely.
Metal tally
4
A metal tally is attached to the strop leg, identifying the equipment and containing details of
the NSN, equipment SWL, equipment serial number and date of ‘proof test’. If this tally is lost,
the equipment is to be withdrawn from use immediately and back-loaded for technical inspection
and further ‘proof test’.
SAFE WORKING LOAD
5
The SWL for the complete strop assembly, including secondary hook, is 1500 lb (680 kg).
TECHNICAL SUPPORT LITERATURE
6
Full technical supporting literature for this equipment is published in AP 108G-0002-1B,
HUSLE Strops. Chap 1-1 gives general advice on obtaining HUSLE maintenance APs.
STROP USAGE
7
Consult Chap 2-2 for the general principles applying to strop usage, hook-up, load release
etc.
Suitability for engagement to current range of helicopter cargo hooks
8
The lifting loop of these strops is suitable for direct engagement onto the SACRU No 1 Mk3
and Breeze Eastern cargo hooks, listed in Chap 2, compatibility matrix.
9
Use with SACRU No 2 Mk1. The lifting loop of these strops will comfortably engage the
load beam of the SACRU, currently fitted to Wildcat, Lynx and Gazelle helicopters. However,
subsequent upwards movement or unusual orientation of the strop leg could cause the lifting
loop to ride over the relatively short hook bill of this SACRU. Such an occurrence would
normally be associated with events prior to engaging a load to the strop secondary hook, or
before the weight of the load is taken by the extension strop following load engagement. Two
likely ways in which this could happen are as follows:
9.1 Operations where the strop is pre-engaged to the helicopter cargo hook, with the
secondary hook end of the strop held at the cabin door whilst in transit to or from a load,
could lead to flexing of the strop leg and movement of the lifting loop in a way to override
the bill of the SACRU.
9.2 In other circumstances, where the load is being engaged to the secondary hook of the
deployed strop, and vertical flexing of the strop leg occurs, due perhaps to inadvertent loss
of height by the helicopter or due to movement with a seaborne load, the same situation of
the strop lifting loop overriding the bill of the SACRU could result.
10 In order to avoid any such risk it is MANDATORY to use a Connector, sling (SWL 10000 lb)
as the means of coupling the strop lifting loop to the SACRU load beam (see Fig 2). The sling
connector is described in Chap 2-3-1.
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Fig 2 Using a ‘connector sling’ to connect lifting
loop of 7 ft/30 ft strop to SACRU No 2 Mk1
11 Use with Chinook cargo hooks. The lifting loop of the 7 ft and 30 ft strop is not large
enough however, to engage the Chinook cargo hooks. If these strops have to be employed with
Chinook, a 16 mm ‘closed and open masterlink assembly’ would serve as a suitable connector
for engagement to a Chinook hook. The strop lifting loop would be engaged onto the bottom of
the ‘open’ masterlink. When employed with Merlin Mk2/3A cargo hook, in full VERTREP role, a
shackle, 5 tonne SWL, large bow is to be used as means of connecting the strop lifting loopto
the SACRU lifting beam. See Chap 2-3-1 for further details of use of 16 mm masterlink
assembly and shackles as connectors.
12 Use with Talon cargo hook. The lifting loop of these strops is not wide enough to sit
comfortably on the Talon cargo hook, fitted to the Merlin Mk3, due to two bevelled edges on the
load beam. Therefore, to minimise damage which may occur to the lifting loop, a shackle, SWL
1500 kg, bow is suitable to use as a means of coupling the strop lifting loop to the load beam.
Coupling of 7 ft/ 30 ft strops
13 The 7 ft and 30 ft extension strops may be linked together in series to make a longer
assembly. This may be conducted on the basis of ‘like with like’ or alternatively by a mix of 7 ft
and 30 ft strops, two, three or more in number, within the load suspension/performance limit for
helicopter types. The coupling process simply involves engaging the lifting loop of one strop
onto the swivel hook of the next strop (one lifting loop per secondary hook), until all strops have
been linked. In each case, check that the hook keeper returns to the fully closed position after
engagement of the lifting loop (Fig 3).
14 The lifting loop of these strops may be connected, in the manner described in para 13, to
the larger swivel hook of the 16 ft and 80 ft SWR strops. The lifting loop is not, however,
suitable for engagement to the swivel hook of the 11300 kg strop or 5000 kg strop, although
coupling via a 16 mm ‘open and closed masterlink assembly’, would be possible.
15 For detailed rules which apply to strop coupling, mixing of strop types and assessment of
SWL, consult Chap 2-2, paras 20 and 21.
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Fig 3 7 ft/30 ft strops coupling in series
Secondary hook engagement and accommodation limits
16 Figs 4, 5 and 6 provide information on the suitability of different types of sling and net for
engagement to the secondary hook of the 7 ft and 30 ft strops. Guidance is also given on the
maximum number of equipment’s/apex devices that may be carried on the secondary hook,
unless otherwise specified in individual USLCs.
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DAP 101A-1105-1A
SML 4600 kg SWL
Suitable for direct engagement to
7 ft/30 ft strop secondary hook.
Maximum of one sling for
accommodation on this hook.
SML 6000 lb SWL
Suitable for direct engagement to
7 ft/30 ft strop secondary hook.
Maximum of one sling for
accommodation on this hook.
(In all cases, the maximum AUW of equipment and load suspended from this secondary hook is
not to exceed 1500 lb (680 kg) or such lower figures as may be set for the helicopter cargo
hook/ helicopter type).
Fig 4 Accommodation limits for 7 ft/30 ft strop secondary hook engaging SML 4600 kg SWL or SML 6000 lb SWL
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Net - 5000 lb SWL
Net - 5600 kg SWL
Suitable for direct engagement to 7 ft/30 ft
strop secondary hook. As an ‘Authorised’
load, only one net stirrup can be
accommodated on this hook.
Suitable for direct engagement to 7 ft/30 ft
strop secondary hook. Only one net stirrup
to be suspended from this hook, in unlikely
event of this net being employed with these
strops.
(In all cases, the maximum AUW of equipment and load suspended from this secondary hook is
not to exceed 1500 lb (680 kg) or such lower figures as may be set for the helicopter cargo
hook/ helicopter type).
Fig 5 Accommodation limits for 7 ft/30 ft strop secondary hook engaging nets 5000 lb SWL or 5600 kg SWL
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DAP 101A-1105-1A
SML 11300 kg SWL
‘Masterlink lifting ring too large to engage 7 ft/30 ft strop secondary hook. Requires a
1500 kg SWL, bow shackle, or 16 mm masterlink assembly, to serve as connector. One
sling to be carried only, in unlikely event of operations with this strop.
(In all cases, the maximum AUW of equipment and load suspended from this secondary hook is
not to exceed 1500 lb (680 kg) or such lower figures as may be set for the helicopter cargo hook
/helicopter type).
Fig 6 Accommodation limits for 7 ft/80 ft strop secondary hook engaging SML 11300 kg SWL
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CHAPTER 2-3
SUPPLEMENTARY SLINGING EQUIPMENT
INTRODUCTION
1
To achieve the suspension of a load under a helicopter, it is often necessary to call upon
supplementary items of slinging equipment, ie items in addition to the basic sling, cargo lifting
net or extension strop equipment to be employed. These items generally serve the following
purposes:
1.1 They provide the basic means or, in some cases, more secure retention of primary
equipment at equipment attachment/engagement points, starting at the load itself and
terminating at the helicopter cargo hook. Thus shackles are often specified to provide a
means of connecting the sling legs to load lifting points. Shackles or special connector
devices may also be necessary for connection of slinging equipment to the helicopter
cargo hook, and on occasion to extension strop secondary hooks.
1.2 In the case of extension chains, they provide the means of extending, when
necessary, the leg length of general purpose wire rope or textile and chain leg slings.
They also serve as ‘risers’/connectors from cargo net lifting stirrups to extension strop
secondary hooks, used specifically if cargo nets are being carried in large clusters. It
should be noted that chains are never to be engaged directly onto the load beam of a
helicopter cargo hook (Chap 2-1 refers).
1.3
Occasionally a special role item may be introduced.
RULE OF USE AS ITEMS OF SLINGING EQUIPMENT
2
Most items of supplementary slinging equipment are designed for use as items of load
lifting equipment and are classified by their Safe Working Load (SWL). Where equipment
bears a manufacturer’s classification based on the items ultimate strength (ie the load or force
under which the item can be expected to fail (breaking load)) then the Service(s) will specify the
SWL for the item, when used as helicopter slinging equipment. This is discussed more fully in
Chap 1-1.
COVERAGE IN THIS PUBLICATION
3
Chaps 2-3-1 and 2-3-2 describe supplementary slinging items which are commonly called
into use for helicopter slinging operations and which are not necessarily restricted to use with
one specific item of primary slinging equipment. Items such as chain extension legs which are
provisioned for use with specific equipment (eg extension legs for the heavy duty and medium
duty slings) are described under the particular chapter for that equipment. Occasionally USLCs
will call up supplementary items of lifting equipment which are not covered by this publication,
in which case all necessary information on the use of the item will be contained in the particular
USLC.
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DAP 101A-1105-1A
CHAPTER 2-3-1
CONNECTORS AND SHACKLES
(Completely revised)
CONTENTS
Para
1
2
3
4
5
8
9
10
11
12
Connector, sling
Introduction
Equipment Description
Safe Working Load (SWL)
Maintenance support literature
‘Connector, sling’ usage
Shackles (Warning)
Application of Safe Working Load (SWL)
Maintenance support literature
Use of 16 mm masterlink assembly as fallback connector
Safe Working Load (SWL)
Fig
1
2
3
4
Page
Connector, sling            
Sling connector engaging lifting loop of 1500 lb SWL and 6000 lb SWL
extension strop to SACRU No 2 Mk1        
Shackle, two basic shapes          
‘Open and closed masterlink assembly’       

2



3
4
5
CONNECTOR, SLING
Introduction
1
Commonly known as the ‘sling connector’, this item provides a secure means of connection
to the SACRU No 2 Mk1 cargo hook, fitted to the Lynx, Wildcat and Gazelle helicopters, for a
1500 lb SWL or 6000 lb SWL extension strop. Full NSN details for the equipment are contained
in AP 108G-0002-1D, HUSLE Ancillary Equipment.
Equipment description
2
The sling connector (Fig 1) consists of two parallel plates connected at the flat edged end
by a welded pin. At the other end a detachable link pin, with spacer fitted, is locked in position
by a sliding plate and locking plunger.
Safe Working Load (SWL)
3
The SWL of the sling connector is 10000 lb (4536 kg), but is to conform to any lower figure
as dictated by the equipment with which it is being employed which includes the helicopter
cargo hook.
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DAP 101A-1105-1A
FIXED PIN MUST BE
AT TOP ON BEAM
FLATS AT TOP END
OF SIDE PLATES
LOCK PLATE
LINK PIN
DEPRESS LOCKING
PLUNGER AND SLIDE
LOCK PLATE UPWARD
TO REMOVE LINK PIN
SPACER
LOCKING PLUNGER
SPACER
Fig 1 Connector, sling
Maintenance support literature
4
Full maintenance support literature for this equipment is published in AP 108G-0002-1D,
HUSLE Ancillary Equipment. Chap 1-1 gives general advice on obtaining HUSLE maintenance
APs.
‘Connector, sling’ usage
5
The sling connector is too small to engage the Chinook cargo hooks, and is not suitable or
intended for engagement to any existing extension strop secondary hooks.
6
To connect a strop to the sling connector, and subsequently the connector to load beams of
specified helicopter hook, proceed as follows (see Fig 1).
6.1 Depress the locking plunger and slide the lock plate over the plunger so that the link
pin is free. Remove the link pin and collect the spacer.
6.2 Insert the eye of the strop between the side plates so that the link pin and its spacer
can be inserted through the eye to close the open end of the connector.
6.3 Insert the link pin with its spacer and slide the lock plate down to engage in the
groove in the end of the link pin. Ensure that the locking plunger is engaged in the hole
formed in the lock plate.
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6.4 On hook up, place the sling connector over the beam, as shown in Fig 2, so that its
integral fixed pin rests on the beam and the strop hangs from the link pin. When engaging
onto a SACRU type load beam, ensure that the spring loaded keeper returns to the fully
closed position having completed engagement.
Fig 2 Sling connector engaging lifting loop of 1500 lb SWL and 6000 lb SWL
extension strop to SACRU No 2 Mk1
Use with strops, lifting, single leg 1500 lb SWL and 6000 lb SWL
7
The sling connector provides a secure means of engagement for 1500 lb SWL and 6000 lb
SWL extension strops, when they are being used with the SACRU No 2 Mk1 primary hook,
fitted to Lynx, Wildcat and Gazelle helicopters. Use of the connector overcomes the risk of the
strop lifting loop inadvertently overriding the bill of the relatively short nosed load beam on this
SACRU. The lifting loop of the strop is engaged onto the sling connector as explained by the
procedures set out in paras 6.1 to 6.4, which should be followed fully. For a more detailed
background consult the individual strop chapters.
SHACKLES
WARNING
SHACKLE PINS ARE TO BE TIGHTENED BY HAND SUFFICIENTLY TO PREVENT THE
PIN FROM BECOMING LOOSE DURING USE.
8
Shackles are the most commonly called up items of supplementary slinging equipment.
Each shackle bears a unique serial number, on both body and pin, in permanent (stamped)
characters. The body additionally carries the NSN, SWL and the legend ‘HUSLE USE ONLY’.
There are two shapes of shackle commonly manufactured as shown in Fig 3.
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DAP 101A-1105-1A
‘D’ SHACKLE
BOW SHACKLE
Fig 3 Shackle, two basic shapes
Application of Safe Working Load (SWL)
Use of shackles as connectors to helicopter cargo hooks and extension strop secondary hooks
9
Shackles are used in various instances as a suitable interface for connecting specified
equipments to helicopter cargo hooks or extension strop secondary hooks where the
equipments, for one reason or another, are not suitable for direct engagement. The SWL of a
shackle is to conform to any lower figure, as dictated by the equipment with which it is being
employed, which includes the helicopter cargo hook or extension strop secondary hook.
Maintenance support literature
10 Full maintenance support literature for this equipment is published in AP 108G-0002-1D,
HUSLE Ancillary Equipment. Chap 1-1 gives general advice on obtaining HUSLE maintenance
APs.
USE OF 16 MM MASTERLINK ASSEMBLY AS FALLBACK CONNECTOR
11 The 16 mm ‘open and closed masterlink assembly’ (Fig 5) is provisioned as part of the
4600 kg sling (Chap 2-4-3) and 5000 kg strop (Chap 2-2-2). However, it is compatible for
engagement to the secondary hooks of all current British Service helicopter extension strops.
Safe Working Load (SWL)
12 Used as a connector, the SWL of the 16 mm masterlink assembly is 7000 kg (15432 lb).
However, it is to conform to any lower figure as dictated by the equipment with which it is being
employed, which includes the helicopter cargo hook or extension strop secondary hook.
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CLOSED
LOCKING SET
OPEN MASTERLINK
Fig 5 ‘Open and closed masterlink assembly’
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DAP 101A-1105-1A
CHAPTER 2-3-2
CHAIN ASSEMBLY, EXTENSION
(Completely revised)
CONTENTS
Para
1
3
4
5
9
10
11
12
13
14
15
17
Introduction
Equipment description
Standard assembly
Use of shortening clutches
Maintenance support literature
Extension chain usage
Criteria when used with sling equipment
Safe Working Load (SWL)
Passage of chain through or about an object
Used with Sling Multiple Leg (SML) 11300 kg and its variants
Used with Sling Multiple Leg (SML) 4600 kg and its variants
Used with Sling Multiple Leg (SML) 6000 lb
Maximum allowable included angle of chain loop at closure of chain loop/chain
assemblies
An independent chain loop
Taping clutches and loose chain
Fig
1
2
3A
3B
4
5
6
7
8
9
10
Page
Extension chain assembly          
Chain locking lever
          
Engaging clutch to form a chain loop - correct method    
Engaging clutch to form a chain loop - incorrect method    
Correct and incorrect method of clutch engagement when connecting one
chain to another of the same type and classification
   
Example taken from USLC 5324         
Chains used with 11300 kg sling         
Chains used with 4600 kg sling         
Chains used with 6000 lb sling         
Maximum included angle of chain loop at closure of chain loop/chain
assemblies             
Extension chain used as independent chain loop     



2
3
4
5





6
8
9
10
10


11
12
INTRODUCTION
1
Extension chain assemblies (Heavy Duty (HD) and Medium Duty (MD)) are primarily
supporting items of helicopter equipment used for extending sling leg lengths, of the various
helicopter slings, within the load path. Alternatively the MD chains may be used as restraint
equipment; refer to Chap 2-7-1 for USL restraint. Full NSN details and nomenclature for the
equipment’s are contained in AP 108G-0002-1D, HUSLE Ancillary Equipment.
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DAP 101A-1105-1A
EQUIPMENT DESCRIPTION
Standard assembly
2
The extension chain assembly consists of a welded link chain fitted with a shortening clutch
at one or both ends. The chain link size is identical to that used on the fixed chain legs of the
MD, HD and 6000 lb slings. The MD extension chains, available in 2 m and 4.5 m lengths, are
fitted with a 7 mm clutch(es) and may be used to extend the sling legs of the MD sling, its
variants and the 6000 lb sling. The HD extension chain, available in a 2 m length, is fitted with a
10 mm clutch(es) and used to extend the sling legs of the HD sling, its variants and the
redundant sling.
WARNING
WHEN USED AS HELICOPTER SLINGING
EQUIPMENT, EXTENSION CHAINS MUST
ALWAYS BE USED IN ACCORDANCE WITH
ITS STATED SWL. WHEN USED AS
RESTRAINT EQUIPMENTAND USING THE
10000 LB QUICK RELEASE COUPLING (QRC),
THE CHAINS ARE TO BE RATED AT 10000 LB
MINIMUM ULTIMATE STRENGTH
CHAIN CLUTCH
Fig 1 Extension Chain Assembly
Use of shortening clutches
3
The shortening clutch provides the means of engaging the chain back on itself to form a
closed loop around a lifting point, or for engaging onto another chain of the same type and
classification, for the purpose of extending sling leg lengths or for belly-banding. The clutch
incorporates a chain locking lever (Fig 2). Should a locking lever become unserviceable the
chain is to be declared unfit for use until the locking lever or entire clutch is replaced by a
qualified HLSEI. Correct and incorrect ways of engaging the clutch are shown in Figs 3A/B
and 4.
MAINTENANCE SUPPORT LITERATURE
4
Full maintenance support literature for this equipment is published in AP 100G-0002-1D,
HUSLE Ancillary Equipment. Chap 1-1 gives general advice on obtaining HUSLE maintenance
APs.
Chap 2-3-2
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DAP 101A-1105-1A
LINK A
CHAIN POCKET OF
CLUTCH CLAW,
HOUSES ENGAGED
LINK
LINK B
CAM ON CHAIN
LOCKING LEVER
ABUTS AGAINST
LINK A AND PREVENTS
THE CLUTCH FOM
DISENGAGING FROM
ENGAGED LINK B
CHAIN LOCKING LEVER,
PIVOT PIN AND TORSION
SPRING. LOCKING LEVER
SHOWN SPRING LOADED
TO CLOSED POSITION
CHAIN LOCKING LEVER,
(THUMBED OPEN AGAINST
SPRING) FOR CLUTCH
ENGAGEMENT OR
DISENGAGEMENT
Fig 2 Chain locking lever
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DAP 101A-1105-1A
CAUTION
Having engaged the clutch always pull the
chain taut to ensure that the clutch has been
engaged in the correct manner as shown and
not in the incorrect manner as shown in Fig 3B.
Finally check visually or by feel that the chain
locking lever is fully closed in the clutch
DIRECTION OF PULL
NOTE
When forming a chain loop, the Underslung
Load Clearance (USLC) will either call for a
loop of so many links (eg a 25 link loop,
meaning that the clutch is to be engaged on
th
the 25 link as counted from the fixed end
of the clutch) or alternatively that the clutch
is to be engaged on a specified link as
counted from the textile sling leg
attachment point (eg engage the clutch
on the 10th link from the sling leg
attachment point)
PRE-SELECTED CHAIN
LINK ENGAGED IN THE
CHAIN POCKET OF THE
CLUTCH CLAW
CLUTCH BODY ADOPTS
THE NATURAL LINE OF
THE CHAIN LOOP
LENGTH OF CHAIN
EMERGING ON EITHER
SIDE OF CLUTCH
CLAW TAKES UP A
SYMMETRICAL LINE WITH
THE ENGAGED LINK
BELLY OF CLUTCH
FACES TO THE INSIDE
OF THE CHAIN LOOP
120º MAX
MAXIMUM ALLOWABLE
INCLUDING ANGLE OF
CHAIN LOOP, WITH
CHAIN IN TENSION, IS
120 DEGREES
Fig 3A Engaging clutch to form a chain loop - correct method
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DAP 101A-1105-1A
WARNING
HAVING ENGAGED THE CLUTCH ALWAYS
PULL THE CHAIN TAUT TO ENSURE THAT
THE CLUTCH HAS NOT BEEN ENGAGED IN
THE INCORRECT MANNER AS SHOWN.
LIFTING IN THIS CONFIGURATION CAN
CAUSE PREMATURE FAILURE OF THE
CLUTCH
BELLY OF CLUTCH
FACING TO THE
OUTSIDE OF THE
CHAIN LOOP
DIRECTION OF PULL
CHAIN ‘DOG-LEGGED’
THROUGH CLAW OF
CLUTCH
FORCE APPLIED
THROUGH ENGAGED
LINK IS TRYING TO
PRISE OPEN THE
CLUTCH CLAW
Fig 3B Engaging clutch to form a chain loop - incorrect method
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DAP 101A-1105-1A
NOTE
Individual USLCs will outline in detail the form that the specific chain to chain connection
is to take. The requirement to connect chains together is generally confined to those
USLCs which call for the use of extension chain assemblies. Occasionally a USLC may
call for one chain leg of a sling to be directly connected to a partner chain leg of the sling,
for the purposes of forming a continuous loop under the load, ie the bellyband technique
or similar. When forming chain loops, count each link from the datum point given when
engaging the chain clutch onto the pre-selected chain link of the chain that is to be
engaged
CORRECT
PARENT CHAIN
ENGAGED CLUTCH
ENGAGED CHAIN
THE PULL ON THE ENGAGED CHAIN IS TAKEN
THROUGH THE NOSE OF THE ENGAGED
CLUTCH AND TAKES A SYMMETRICAL LINE
WITH THE BODY OF THE CLUTCH
CAUTION
PARENT CHAIN
Having engaged the clutch always pull the
chain taut to ensure the clutch has been
engaged in the correct manner
NON-ENGAGED
CLUTCH
INCORRECT (DOG-LEGGED)
IN THIS CASE THE PULL ON THE ENGAGED
CHAIN IS IN EFFECT TAKEN FROM THE MOUTH
SECTION OF THE CLUTCH CLAW, TRYING TO
PULL THE CLAWS OFF
ENGAGED CLUTCH
WARNING
SEE ALSO THE EXAMPLE WITH THE
CHAIN LOOP (FIG 3B), THE DOG LEG
EFFECT IS ALSO PRESENT. LIFTING IN
THIS CONFIGURATION CAN CAUSE
PREMATURE FAILURE OF THE CLUTCH
Fig 4 Correct and incorrect method of clutch engagement when connecting one chain to
another of the same type and classification
Chap 2-3-2
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DAP 101A-1105-1A
EXTENSION CHAIN USAGE
5
Primarily the extension chains are used to extend the sling leg length. However, specific
USLCs may require the chains to be used as lifting loops, typically as riser/connectors for
engaging cargo lifting net stirrups to an extension strop secondary hook, for a large number of
net cluster loads, using one looped chain per net.
6
Extension chains feature in many USLCs. Where the use of a particular length of chain is
stipulated but not available, MD chain only, it may be substituted using the other chain length ie
2 m/4.5 m (MD). When a substitute is being used the distance between the sling leg attachment
point and the clutch of the extension chain, which is attached to the lift point, must not be
altered. The difference in weight must be taken into account when calculating the AUW.
7
To carry out a substitution the number of links per extension chain length is as follows:
2 m (MD)
4.5 m (MD)
=
=
94 links
210 links
8
To substitute the front 2 m chains (Fig 5) of USLC 5324, with 4.5 m chains, proceed as
follows:
8.1
Calculate the in use length of chain ie 94 links (total linkage of 2 m chain) minus 4
links (unused chain from free end) = 90 links (in use chain from clutch end)
8.2
Using the substitute 4.5 m extension chain form 40 link loops around the front lifting
bracket. Attach the sling leg clutch to the 90th link from the extension chain clutch end.
8.3 Tape up all excess chain.
CRITERIA WHEN USED WITH SLING EQUIPMENT
Safe Working Load (SWL)
9
When used as sling chain(s):
9.1
Independent of sling.
2 m/4.5 m (MD)
2 m (HD)
SWL 1500 kg
SWL 3117.5 kg
) Acting along the line of the chain,
) at a factor of safety of 4.3 to 1
9.2
As extension legs for specified slings. SWL is in accordance with the single leg
rating for the particular sling, operating up to the maximum leg angle from vertical as
specified for the sling.
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DAP 101A-1105-1A
ENGAGE SLING LEG CLUTCHES ON
th
TO 90 LINK FROM EXTENSION
CHAINS CLUTCH END
FRONT EXTENSION CHAINS
40 LINK LOOPS AROUND
LIFTING BRACKETS
Fig 5 Example taken from USLC 5324
Passage of chain through or about an object
10 In all cases the following criteria applies when looping the extension chains through lifting
points or around the load. The chain is not to be looped around:
10.1
2 m/4.5 m (MD) extension chain:
10.1.1
Circular sections of less than 13 mm (½ in.) diameter.
10.1.2 Angular or flat sections with square or rounded edges whose thickness of
section is less than 13 mm (½ in.).
10.2
2 m (HD) extension chain:
10.2.1
Circular sections of less than 25 mm (1 in.) diameter.
10.2.2 Angular or flat sections with square or rounded edges whose thickness of
section is less than 25 mm (1 in.).
Chap 2-3-2
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DAP 101A-1105-1A
Used with Sling Multiple Leg (SML) 11300 kg and its variants
11 When used with the SML 11300 kg SWL and its variants, the SWL of the 2 m (HD)
extension chain is to conform with the single leg rating for the sling ie 2825 kg applying to all
angles from the vertical up to a maximum leg angle of 25° from the vertical and 2387 kg
applying to all angles from the vertical up to a maximum leg angle of 40° from the vertical
(Fig 6). Chap 2-4-1, para 10.3 also refers.
Used with Sling Multiple Leg 4600 kg and its variants
12 When used with the SML 4600 kg SWL and its variants, the SWL of the 2 m/4.5 m (MD)
extension chain is to conform with the single leg rating for the sling ie 1150 kg applying to all
angles from the vertical up to a maximum leg angle of 40° (Fig 7). Chap 2-4-3, para 9.3 also
refers.
Used with Sling Multiple Leg 6000 lb
13 When used with the SML 6000 lb SWL, the SWL of the 2 m/4.5 m (MD) extension chain is
to conform with the single leg rating for the sling ie 1500 lb applying to all angles from the
vertical up to a maximum leg angle of 50° (Fig 8). Chap 2-4-4, para 7.3 also refers.
Fig 6 Chains used with 11300 kg sling
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DAP 101A-1105-1A
Fig 7 Chains used with 4600 kg sling
Fig 8 Chains used with 6000 lb sling
Chap 2-3-2
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DAP 101A-1105-1A
Maximum allowable included angle of chain loop at closure of chain loop/chain
assemblies
14 When a loop is formed at the terminal end of a single or interconnected series of extension
chains, the maximum allowable included angle of the chain loop at the point of connection of the
chain clutch is 120° (Fig 9).
Fig 9 Maximum included angle of chain loop at closure of chain loop/chain assemblies
An independent chain loop
15 When the chain is engaged back onto itself to form an independent loop ie engaged at the
bottom of the loop to an equipment lifting ring, and at the top of the loop engaged over an
extension strop secondary hook, the SWL of the independent loop is theoretically doubled ie
2 m (HD) extension chain SWL = 6235 kg and 2 m/4.5 m (MD) extension chain SWL = 3000 kg.
16 In practice, however, allowance has to be made for additional stress on the links at the top
and bottom ends of the chain loop, and the SWL for the chain loop is reduced to 70% of the
theoretical, ie 2 m (HD) extension chain SWL = 4364.5 kg and 2 m/4.5 m (MD) extension chain
SWL = 2100 kg (see Fig 10).
Taping clutches and loose chain
17 The claws of an engaged clutch does not require taping, however to prevent inadvertent
snagging on the load or with other parts of slinging equipment, non-engaged claws are to be
taped, facing out, to indicate they are not in use. Similarly, all loose chain is to be taped to
prevent snagging or possible flailing in flight. For further instructions and illustrations refer to
Chap 3.
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DAP 101A-1105-1A
STROP SECONDARY HOOK
CHAIN ASSEMBLY SINGLE LEG SWL
OF INDEPENDENT CHAIN LOOP =
MD (1500 KG X 2) REDUCED TO 70% = 2100 KG
HD (3117.5 KG X 2) REDUCED TO 70% = 4364.5 KG
Fig 10 Extension chain used as independent chain loop
Chap 2-3-2
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DAP 101A-1105-1A
CHAPTER 2-3-3
LIFTING FRAME, BV206 TRANSMISSION COUPLING
(Completely revised)
CONTENTS
Para
1
2
3
4
5
6
7
Introduction
Equipment description
Frame identification labels
Frame classification (WARNING)
Life expiry of equipment
Maintenance support literature
Equipment usage (WARNING)
Fig
1
2
Page
BV206 transmission coupling lifting frame   
Positioned BV206 transmission coupling lifting frame










2
4
INTRODUCTION
1
The BV206 transmission lifting frame is a special item designed to be used, with the Sling
Multiple Leg (SML) 11300 kg SWL, for the carriage of one Hägglund BV206 articulated utility
vehicle. Full NSN details and nomenclature for the equipment are contained in AP 108G-00021D, HUSLE Ancillary Equipment.
EQUIPMENT DESCRIPTION
2
The lifting frame (Fig 1) consists of twin channel-section transverse link assemblies
connected between two lifting yokes. The upper link is cushioned on its lower surface by nitrile
rubber sheeting. The lower link is inverted, closed to a box section by a steel web welded
between the flanges, and padded on its upper surface by a block of plywood shaped to fit the
transmission coupling torsion member. Each lifting yoke is formed by two side plates joined at
the top by a special shoulder bolt. The inner pair of sling legs are connected to these bolts
between the two vehicle units, providing central support while the outer sling legs connect to the
fore/aft ends of the combination using multiple extension chains. The lifting frame is finished in
yellow paint indicating that it must be removed prior to operating the vehicle.
Frame identification labels
3
The lifting frame has a manufacturer’s plate screwed to the reverse flange of the top link.
The plate shows the equipment Part No, Issue, Description, Serial No, SWL and Proof Load.
FRAME CLASSIFICATION
WARNING
THE EQUIPMENT IS NOT TO BE USED FOR ANY PURPOSE OTHER THAN THAT
SPECIFIED IN THIS CHAPTER.
4
The lifting frame has a fixed geometrical configuration, and a definitive load rating of SWL
4000 kg (8818 lb) at the specified loading point.
Jul 2014 (Iss 7)
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Chap 2-3-3
Page 1
DAP 101A-1105-1A
Fig 1 BV206 transmission coupling lifting frame
Chap 2-3-3
Page 2
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Jul 2014 (Iss 7)
DAP 101A-1105-1A
LIFE EXPIRY OF EQUIPMENT
5
The lifting frame is not a ‘lifed’ item. The various items of padding are to be maintained in a
good condition. The manufacturer’s plate and all painted markings are to remain legible at all
times.
MAINTENANCE SUPPORT LITERATURE
6
Full maintenance support literature for this equipment is published in AP 108G-0002-1D,
HUSLE Ancillary Equipment . Chap 1-1 gives general advice on obtaining HUSLE maintenance
APs.
EQUIPMENT USAGE
WARNING
WHEN REMOVING/REFITTING THE LINK SECURING PINS FOR INSTALLATION OF
THE
FRAME,
OR
WHEN
REPLACING
DEFECTIVE
PINS
DURING
MAINTENANCE/REPAIR, THE UPPER PIN MUST NOT BE SUBSTITUTED FOR THE
LOWER PIN, NOR MUST UNDERSIZE/ UNDERSTRENGTH REPLACEMENTS BE
FITTED IN EITHER LINK.
7
The lifting frame is of fixed geometry. It is fitted by lowering the frame onto the
transmission coupling with the bottom link removed. The link is refitted and the centre extension
chains/clutches of the sling assembly are fed through the frame legs and around the lifting pins
(Fig 2).
Jul 2014 (Iss 7)
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Chap 2-3-3
Page 3
DAP 101A-1105-1A
Fig 2 Positioned BV206 transmission coupling lifting frame
Chap 2-3-3
Page 4
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Jul 2014 (Iss 7)
DAP 101A-1105-1A
CHAPTER 2-3-4
WEAK LINK ASSEMBLY (6300 kg SWL)
(Completely revised)
CONTENTS
Para
1
2
4
5
6
7
8
Introduction
Equipment Description
Assembly identification
Safe Working Load (SWL)
Life expiry of assembly
Maintenance support literature
Assembly usage
Fig
1
Page
Weak link assembly

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2
INTRODUCTION
1
The 6300 kg weak link assembly was designed for Tandem Hook Operations Long
Stropping (THOLS) with the Chinook helicopter, without the need for redundant rigging (Chap
2-1-5 refers). Full NSN details and nomenclature for the equipment are contained in AP 108G0002-1D, HUSLE Ancillary Equipment.
EQUIPMENT DESCRIPTION
2
The weak link assembly (Fig 1) has a specified breaking load and is attached to the fore
and aft cargo hooks of the helicopters. In the event of a failure in the fore or aft cargo
hooks/slinging equipment, the weak link in the remaining assembly will shear, protecting the
aircraft structure from the excessive forces generated by the suspended load.
3
The assembly consists of two weak link bodies, secured together by a shear pin and collar.
Attached to the outer end of one weak link body is a hoist hook and attached to the outer end of
the other weak link body is a closed masterlink.
Assembly identification
4
The weak link bodies are painted a distinctive red colour for identification.
Safe Working Load (SWL)
5
The SWL for the weak link assembly is 6300 kg, based on 60% of the 10500 kg tandem
hook maximum payload (Chap 2-1-5, Para 17).
LIFE EXPIRY OF ASSEMBLY
6
The weak link assembly has an indefinite life with the exception of the shear pin, the policy
for which is laid down in the maintenance support literature for the equipment (see para 7).
Jul 2014 (Iss 7)
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Chap 2-3-4
Page 1
DAP 101A-1105-1A
WEAK LINK BODY
COLLAR
SHEAR PIN
WEAK LINK BODY
Fig 1 Weak link assembly
Chap 2-3-4
Page 2
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DAP 101A-1105-1A
MAINTENANCE SUPPORT LITERATURE
7
Full maintenance support literature is published in AP 108G-0002-1D, HUSLE Ancillary
Equipment. Chap 1-1 gives general advice on obtaining HUSLE maintenance APs.
ASSEMBLY USAGE
8
The assembly usage is only for THOLS. In addition to the weak link assembly, the range of
equipment that may be used for load suspension is as follows:
Masterlink and swivel hook assembly, 11300 kg SWL
2.7 m or 5.7 m, H/D strop, 11300 kg SWL
5 m, soft eye strop, 5000 kg SWL
SML, 5650 kg SWL
Soft eye SML, 5438 kg SWL (RIB bow and stern)
2 m, H/D extension chain
9
In the event of a SML, 5650 kg SWL being unavailable, a SML, 11300 kg SWL or SML,
8475 kg may be used in lieu ensuring the rules for securing not in use legs are adhered to
(Chap 3 refers).
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Page 3
DAP 101A-1105-1A
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Chap 2-3-4
Page 4
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Jul 2014 (Iss 7)
DAP 101A-1105-1A
CHAPTER 2-3-5
CHAIN CLAMP
(Completely revised)
CONTENTS
Para
1
Introduction
Equipment description
2
Standard assembly
4
Clamp classification (WARNING)
5
Life expiry of equipment
6
Maintenance support literature
7
Equipment usage
Fig
1
2
Page
Chain clamp   
Positioned chain clamp
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2
3
INTRODUCTION
1
The chain clamp is a special item primarily designed to be used, with Slings Multiple Leg
(SML) 4600 kg and 6000 lb, for the carriage of the 105 mm light gun. However, the clamp may
also be used for similar applications providing the limitations in para 4 are not exceeded. Full
NSN details and nomenclature for the equipment are contained in AP 108G-0002-1D, HUSLE
Ancillary Equipment.
EQUIPMENT DESCRIPTION
Standard Assembly
2
The chain clamp (Fig 1) consists of two identical steel links joined head-to-tail. At one end,
a clevis pin acts as the pivot by which the clamp hinges open. At the other end, the
corresponding position is occupied by a quick-release pin of the drop-nose type. A sheathed
steel wire lanyard attaches the quick-release pin to one of the links. When closed, the clamp
forms an elongated ring with a 9 mm central slot, which locks together two runs of chain by
trapping adjacent in-line links. The clamp is used to retain the chain in a close loop around
each wheel hub, to prevent disengagement when slack. The chain clamp will function only with
chain of 7.1 mm wire diameter, as used on SML 4600 kg and 6000 lb, and their respective
extension chains. The chain clamp is finished in yellow paint indicating that it must be removed
prior to disengaging the lifting equipment.
Clamp identification
3
The clamp carries the same markings on both links. On each upper face is marked the part
number, serial number and NSN of the complete assembly. Each lengthwise outer edge is
marked HUSLE USE ONLY. The equipment SWL is not marked as the capacity of the clamp,
when used in accordance with para 4, exceeds that of one SML 4600 kg or 6000 lb sling leg.
Jul 2014 (Iss 7)
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Chap 2-3-5
Page 1
DAP 101A-1105-1A
Fig 1 Chain clamp
CLAMP CLASSIFICATION
WARNING
THE EQUIPMENT IS NOT TO BE USED FOR ANY PURPOSE OTHER THAN THAT
SPECIFIED IN THIS CHAPTER.
4
The chain clamp is designed to be used with 7.1 mm chain, rated at 1500 kg SWL for the
SML 4600 kg and 1059 kg SWL for the SML 6000 lb. The following limitations apply:
Included angle of chain above clamp
Included angle of chain below clamp
0 (chain parallel)
90 max
LIFE EXPIRY OF EQUIPMENT
5
The chain clamp is not a ‘Lifed’ item. All parts are to be maintained in a good condition,
and all markings are to remain legible at all times.
MAINTENANCE SUPPORT LITERATURE
6
Full maintenance support literature for this equipment is published in AP 108G-0002-1D,
HUSLE Ancillary Equipment. Chap 1-1 gives general advice on obtaining HUSLE maintenance
APs.
Chap 2-3-5
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Jul 2014 (Iss 7 )
DAP 101A-1105-1A
EQUIPMENT USAGE
7
The chain clamp is fitted after the chain loop has been formed around the wheel hub. The
loop must be free of twists and snags, and held firmly in position to ensure that it will contain the
correct number of links (as defined in the relevant USLC published in DAP 101A-1105-1B) when
the clamp is in position. One link of the open clamp is then passed behind the two runs of chain,
which must be necked together and held in alignment as the clamp is closed around the
appropriate pair of chain links. The quick-release pin is then re-fitted to lock the clamp (Fig 2).
8
The clamp is removed by reversing the fitting procedures in para 7.
Fig 2 Positioned chain clamp
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Page 3
DAP 101A-1105-1A
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Chap 2-3-5
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DAP 101A-1105-1A
CHAPTER 2-3-6
SPREADER BARS
(Completely revised)
CONTENTS
Para
1
2
3
5
7
8
10
11
12
Introduction
Equipment description
Standard assembly
End fitting
Strut tubes
Spreader bar identification
Spreader bar classification (WARNING)
Life expiry of equipment
Maintenance support literature
Equipment usage
Fig
1
2
3
Page
Spreader bar      
Sling leg chain engaged into end-fitting
Chain angle limits     

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2
2
4
INTRODUCTION
1
There are two categories of spreader bars that are available, Medium Duty (MD) or Heavy
Duty (HD). The purpose of the spreader bars is to hold apart sling leg or extension chains that
would otherwise foul or damage part of an Underslung Load (USL). Full NSN details and
nomenclature for the equipment are contained in AP 108G-0002-1D, HUSLE Ancillary
Equipment.
EQUIPMENT DESCRIPTION
Standard assembly
2
The spreader bar (Fig 1) consists of a strut tube and two identical end-fittings. The MD and
HD spreader bars are identical in their method of construction, the only difference being the
physical size of the components and the range of available lengths.
End fitting
3
The end-fitting plugs into the end of the strut tube with a close, but free, fit such that
compression is transmitted uniformly around the abutment flange. Alignment of each end-fitting,
and retention to the strut tube, is provided by a single capscrew. When positioned, the screw is
recessed into a hole in the tube wall, such that its head acts as a locating spigot. A small
clearance around the screw head ensures that it takes no load in normal operation.
4
The sling leg or extension chains are located in specially-shaped pockets in the end-fittings
and retained by quick-release pins (Fig 2). The pins are of the drop-nose type and are attached
to the end-fitting by a steel wire lanyard. The chain is positioned such that the link to be
captured lies flat against the loadbearing face of the end-fitting, between the lugs. The pin
cannot be passed through the lugs of the end-fitting unless the chain is fully and correctly
seated. Clearance channels are provided for the adjacent chain links; each channel allows for
the maximum permitted chain angle, so that the assembled spreader bar can be used either
way up.
Jul 2014 (Iss 7)
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Page 1
DAP 101A-1105-1A
Fig 1 Spreader bar
Fig 2 Sling leg chain engaged into end-fitting
Chap 2-3-6
Page 2
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DAP 101A-1105-1A
Strut tubes
5
The MD and HD spreader bars use 3 in. and 4 in. OD tubing respectively. Strut tube length
varies in 50 mm increments to give the following range of spreader bar effective lengths:
5.1
MD spreader bar -
5.2
HD spreader bar
1.00 m - 2.90 m
- 1.20 m - 3.40 m
6
Each complete assembly can be identified by its own NSN. The required assembly size
and NSN for given loads can be found on the relevant USLCs published in DAP 101A-1105-1B.
Spreader bar identification
7
The complete spreader assemblies are painted NATO green. Each assembly carries an
identification (ID) plate at one end of the tube. The ID plate carries the manufacturer’s code,
contract number, part number, serial number, the NSN of the assembly and the legend HUSLE
USE ONLY. The equipment SWL is not stated as the capacity of the spreader bar, when used
in accordance with paras 9 and 12, exceeds that of one pair of sling legs of the relevant type.
SPREADER BAR CLASSIFICATION
WARNING
THE EQUIPMENT IS NOT TO BE USED FOR ANY PURPOSE OTHER THAN THAT
SPECIFIED IN THIS CHAPTER.
8
The spreader bars have been designed to be used with the following Slings Multiple Leg
(SML):
9
8.1
MD spreader bar - used with SML 4600 kg, 3450 kg, 2300 kg and 6000 lb
8.2
HD spreader bar - used with SML 11300 kg, 8475 kg, 5650 kg and redundant
The following limitations apply (Fig 3):
9.1
Angle of chain above spreader bar (MD with SML 4600 kg, 3450 kg and 2300 kg)
(MD with SML 6000 lb)
(HD with SML 11300 kg, 8475 kg, 5650 kg and
redundant)
9.2
Angle of chain below spreader bar
-
40 in from vertical
(80 apex)
50 in from vertical
(100 apex)
-
25 in from vertical
(50 apex)
-
10 in from vertical
LIFE EXPIRY OF EQUIPMENT
10 The spreader bar is not a ‘Lifed’ item. All parts are to be maintained in a good condition,
and all markings are to remain legible at all times.
Jul 2014 (Iss 7)
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Chap 2-3-6
Page 3
DAP 101A-1105-1A
MAINTENANCE SUPPORT LITERATURE
11 Full maintenance support literature for this equipment is published in AP 108G-0002-1D,
HUSLE Ancillary Equipment. Chap 1-1 gives general advice on obtaining HUSLE maintenance
APs.
80º/100º MAX (MD)
50º MAX (HD)
40º/50º MAX (MD)
25º MAX (HD)
10º MAX
Fig 3 Chain angle limits
Chap 2-3-6
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DAP 101A-1105-1A
EQUIPMENT USAGE
12 With the quick-release pins removed, the spreader bar is fitted between the appropriate
chain links of the two adjacent legs (as defined in the relevant USLC published in DAP 101A1105-1B), ensuring that there are no twists. The pins are then re-fitted to lock the bar in
position.
13 The spreader bar is removed by reversing the fitting procedures in para 12.
14 Apart from detail contained in USLCs, a generalisation for the usage of both MD and HD
spreader bars in differing modes of operation is as follows:
14.1 SHO. MD and HD spreader bars may be used with the SMLs described in para 8
and subject to the chain angle limitations described in para 9. The spreader bars may be
attached either laterally or longitudinally between chain legs.
14.2 THOLS. HD spreader bars are only to be used with SMLs described in para 8.2
(less redundant) and subject to the chain angle limitations described in para 9. The
spreader bars are to be attached laterally only.
14.3 THORR. HD spreader bars are only to be used with SML 5650 kg and redundant
described in para 8.2 and subject to the chain angle limitations described in para 9.
Spreader bars used with the primary and redundant slings are to be positioned as close to
the load as possible whilst still complying with the chain angle limitations. Also, due care is
to be taken when selecting the position of the spreader bar(s) to prevent interference with
the top of the load during normal flight and a primary sling failure. The spreader bars are to
be attached laterally only.
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Page 5
DAP 101A-1105-1A
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Chap 2-3-6
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DAP 101A-1105-1A
CHAPTER 2-3-7
ADJUSTABLE SPREADER BARS
(Completely revised)
CONTENTS
Para
1
2
10
12
13
14
Introduction
Equipment description
Standard assembly
Spreader bar classification (WARNING)
Life expiry of equipment
Maintenance support literature
Equipment usage
Fig
1
2
3
Page
Adjustable spreader bars   
Sling leg chain engaged into end-fitting
Chain angle limits     
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2
3
5
INTRODUCTION
1
There are two types of adjustable spreader bars, used by JADTEU for the development of
USLCs, that are items of Helicopter Underslung Load Equipment (HUSLE). The purpose of the
spreader bars is to hold apart sling leg or extension chains that would otherwise foul or damage
part of an Underslung Load (USL). Full NSN details and nomenclature for the equipment are
contained in AP 108G-0002-1D, HUSLE Ancillary Equipment.
EQUIPMENT DESCRIPTION
Standard assembly
2
The spreader bar (Fig 1) consists of an aluminium outer tube and two aluminium inner
tubes which are a sliding fit into the outer tube. Steel end-fittings are fitted to the outer end of
each inner tube. The Medium Duty (MD) and Heavy Duty (HD) adjustable spreader bars are
identical in their method of construction, the only differences being the physical size of
components.
End fitting
3
The end-fitting plugs into the outer end of the spreader bar inner tube with a close, but free,
fit such that compression is transmitted uniformly around the abutment flange. Alignment of
each end-fitting and retention to the strut tube, is provided by eight ¼ in. UNF pan head bolts
and washers.
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Page 1
DAP 101A-1105-1A
HD SPREADER BAR SHOWN
END FITTING OF MD
SPREADER BAR
END FITTING OF HD
SPREADER BAR
Fig 1 Adjustable spreader bars
Chap 2-3-7
Page 2
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DAP 101A-1105-1A
4
The sling leg or extension chains are located in specially shaped pockets in the end-fittings
and retained by quick release pins (Fig 2). The pins are of the drop-nose type and are attached
to the end-fitting by a steel wire lanyard. The chain is positioned such that the link to be
captured lies flat against the load bearing face of the end-fitting, between the lugs. The pin
cannot be passed through the lugs of the end-fitting unless the chain is fully and correctly
seated. Clearance channels are provided for the adjacent chain links; each channel allows for
the maximum permitted chain angle, so that the assembled spreader bar can be used either
way up.
Fig 2 Sling leg chain engaged into end-fitting
Strut tubes
5
The outer tube has two holes through each end, which allow four quick release pins (dropnose pins for MD, pip pins for HD spreader bars) to be fitted. The quick release pins are
secured by cable assemblies, which are secured to the outer tube.
6
The spreader bars offer the following effective lengths:
6.1
MD spreader bar - 1.70 m - 2.80 m
6.2
HD spreader bar - 1.93 m - 3.30 m
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Page 3
DAP 101A-1105-1A
7
Each inner tube is through drilled at 110 mm (MD) and 95 mm (HD) intervals to allow the
quick release pins to lock the complete assembly at the length required. The MD inner tube has
7 bushes, equal in length to the diameter of the tube, inserted into the drilled holes and secured
with Loctite. These serve to prevent the drop-nose pins opening inside the tube.
8
The outer tube has a protective foam cover over its whole length with cut-outs around the
four pin holes and the identification (ID) label. The protective cover is secured by a number of
plastic ties.
Spreader bar identification
9
The complete spreader assemblies are painted NATO green. Each assembly carries an ID
label attached to one end of the outer tube. The ID label carries the manufacturer’s code,
reference numbers, the NSN of the assembly and the legend HUSLE USE ONLY. The
equipment SWL is not stated as the capacity of the spreader bar, when used in accordance with
paras 10 and 14, exceeds that of one pair of sling legs of the relevant type.
SPREADER BAR CLASSIFICATION
WARNING
THE EQUIPMENT IS NOT TO BE USED FOR ANY OTHER PURPOSE THAN THAT
SPECIFIED IN THIS CHAPTER.
10 The spreader bars are designed to be used with the following Slings Multiple Leg (SML):
10.1
MD spreader bar - used with SML 4600 kg, 3450 kg, 2300 kg and 6000 lb
10.2
HD spreader bar - used with SML 11300 kg, 8475 kg, 5650 kg and redundant
11 The following limitations apply (Fig 2):
11.1
Angle of chain above spreader bar (MD with SML 4600 kg, 3450 kg and 2300 kg)
(MD with SML 6000 lb)
(HD with SML 11300 kg, 8475 kg, 5650 kg and
redundant)
11.2
Angle of chain below spreader bar
-
40 in from vertical
(80 apex)
50 in from vertical
(100 apex)
-
25 in from vertical
(50 apex)
-
10 in from vertical
LIFE EXPIRY OF EQUIPMENT
12 The adjustable spreader bar is not a ‘Lifed’ item. All parts are to be maintained in a good
condition, and all markings are to remain legible at all times.
Chap 2-3-7
Page 4
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Jul 2014 (Iss 7)
DAP 101A-1105-1A
MAINTENANCE SUPPORT LITERATURE
13 Full maintenance support literature for this equipment is published in AP 108G-0002-1D,
HUSLE Ancillary Equipment. Chap 1-1 gives general advice on obtaining HUSLE maintenance
APs.
80º/100º MAX (MD)
50º MAX (HD)
40º/50º MAX (MD)
25º MAX (HD)
10º MAX
Fig 3 Chain angle limits
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Chap 2-3-7
Page 5
DAP 101A-1105-1A
EQUIPMENT USAGE
14 With the chain locking quick release pins removed, the pre-adjusted spreader bar is fitted
between the appropriate chain links of two adjacent sling legs (as defined in the relevant USLC
published in DAP 101A-1105-1B), ensuring that there are no twists. The pins are then re-fitted
to lock the bar in position.
15 The spreader bar is removed by reversing the fitting procedures in para 14.
16 Apart from detail contained in USLCs, a generalisation for the usage of both MD and HD
spreader bars in differing modes of operation is as follows:
16.1 SHO. MD and HD spreader bars may be used with the SMLs described in para 10
and subject to the chain angle limitations described in para 11. The spreader bars may be
attached either laterally or longitudinally between chain legs.
16.2 THOLS. HD spreader bars are only to be used with SMLs described in para 10.2
(less redundant) and subject to the chain angle limitations described in para 11. The
spreader bars are to be attached laterally only.
16.3 THORR. HD spreader bars are only to be used with SML 5650 kg and redundant
described in para 10.2 and subject to the chain angle limitations described in para 11.
Spreader bars used with the primary and redundant slings are to be positioned as close to
the load as possible whilst still complying with the chain angle limitations. Also, due care is
to be taken when selecting the position of the spreader bars to prevent interference with the
top of the load during normal flight and a primary sling failure. The spreader bars are to be
attached laterally only.
Chap 2-3-7
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Jul 2014 (Iss 7)
DAP 101A-1105-1A
CHAPTER 2-4
HELICOPTER SLINGS - GENERAL
(Completely revised)
CONTENTS
Para
1
5
6
7
8
9
10
11
12
Introduction
Sling classification
Safe Working Load (SWL)
Maximum included angle
Maximum working angle for individual sling legs
Loading in sling legs
General rigging procedures
Maintenance support literature
Load hook-up/release and static electricity discharge procedures
Fig
1
2
Page
A theoretical 1000 lb SWL sling, max included angle 90
Loads in sling legs working at varying angles   
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2
3
INTRODUCTION
1
This series of chapters deals with helicopter slings, of which there are three general
purpose slings and one special to Chinook redundant sling for Tandem Hook Operations (THO).
2
Of the general purpose slings:
2.1 The oldest is steel wire rope (SWR) equipment; namely, the SML 6000 lb four legged.
The remaining two equipments, the Sling Multiple Leg (SML) Heavy Duty (HD) and SML
Medium Duty (MD) are available as four, three or two legged variants, and are equipped
with polyester roundsling upper legs.
2.2 All terminate with chain leg assemblies. The chain legs of the SML 6000 lb terminate
with either chain shortening clutches or hooks. By engagement back onto its parent leg,
the chain clutch/hook allows for a lifting loop to be formed about a load lifting point, by
engaging the clutch/hook further up or down the leg, the leg length may be varied to suit
the geometry of the lift. The chain clutch/hook also allows for engagement onto an adjacent
chain leg or to a 2 m/4.5 m MD extension chain assembly.
2.3 The chain leg assemblies of the SML, HD and SML, MD terminate in chain shortening
clutches. Extension chain assemblies are also provisioned, special to each sling, and are
generally used with a shortening clutch fitted to one end. The shortening clutch, unlike the
hook, is equipped with a spring loaded locking lever for retaining it in position when
engaged back onto its parent chain leg or onto another chain.
3
The Chinook special purpose redundant sling has four nylon legs and employs the same
apex and terminal chain leg assembly as the SML, HD (see Chap 2-1-5 for concept of THOs).
4
Full NSN details and nomenclature for the equipment are contained in AP 108G-0002-1C,
HUSLE Slings.
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DAP 101A-1105-1A
SLING CLASSIFICATION
5
With the exception of the redundant sling, which must only be used for its primary function,
all Service helicopter slings are classified by SWL. In the case of the three general purpose
slings, they are further classified by the maximum included angle at which the sling legs may
operate. The following points should be noted with regard to the system of sling classification:
Safe Working Load (SWL)
6
The SWL classification relates to all legs of the sling being in use and, unless clearly
specified otherwise, each leg taking an equal share of the load. It is therefore necessary to
divide the specified SWL by the total number of legs on the sling to ascertain the SWL for each
leg. Thus, assuming a four-legged sling is classified with a SWL of 1000 lb, the SWL for each
leg will be 250 lb. When only some of the legs on a sling are used to achieve a load lift, then
the SWL of the sling is reduced to the combined SWL of the legs in use; thus, in the example
given, if only three legs of the sling legs are being used to lift the load then the SWL of the sling
is reduced to 3 x 250 lb which equals 750 lb.
Maximum included angle
7
Each of the three general purpose slings is further classified by ‘maximum included angle’.
Taken at the apex of the sling, it is the maximum allowable angle measured between
diametrically opposed sling legs, with each leg taking an equal share of the load (up to the SWL
limit for the legs). Thus the sling may be used to lift a load not in excess of its SWL
classification (and number of legs in use), with the legs working at any angle from vertical up to
the specified maximum included leg angle for the sling. This is illustrated in Fig 1, using the
example of a 1000 lb SWL four-legged sling (quoted in para 6) which is classified with a
maximum included angle of 90.
Fig 1 A theoretical 1000 lb SWL sling, max included angle 90
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DAP 101A-1105-1A
Maximum working angle for individual sling legs
8
It will also be seen, from Fig 1, that the maximum included angle when halved gives the
maximum allowable working angle for any one sling leg, ie the angle as measured between the
line of the sling leg and the true vertical running down from the apex of the sling through the
loads centre of gravity (cg). In practice, this angle, together with the SWL limit for an individual
leg are the important factors to relate to, and they are immediately derived from the sling
classification. The reason for their importance is simply because in many cases the cg of the
load is not evenly distanced from available load lifting points. Therefore sling legs are working
at different angles, and bearing differing shares of the load in relationship to each other. Also,
with a four-legged sling for example, where only three of the legs are being used to lift a load,
there are no diametrically opposed legs and it is necessary to relate to the maximum allowable
working angle for an individual leg.
LOADING IN SLING LEGS
9
In most cases the legs of a sling are working at an angle; the general principle applying to
use of helicopter slings being that loads should be suspended from points as far from and above
the cg position of the load as possible, this makes for better all-round stability of the load, for
initial lifting, subsequent carriage and subsequent load landing. Against this background, it is
important to bear in mind that, for a given weight of load being suspended, the tension or
loading along the line of the sling legs will be greater when the legs are working at an angle to
the vertical - the greater the leg angle the greater the tension or loading in the legs (see Fig 2).
It also follows that, whatever the leg angle, the tension or loading in the sling legs will increase if
the weight of the suspended load is increased. These various factors are automatically catered
for in USLCs, providing that the instructions in the clearance are followed in every respect - this
includes taking note of the maximum AUW of load stipulated for a given rigging scheme.
Fig 2 Loads in sling legs working at varying angles
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DAP 101A-1105-1A
GENERAL RIGGING PROCEDURES
10 USLCs are specific rigging schemes for specified USLs. There are certain standard rules
and practices, however, which apply to the use of slings and allied equipment, and these are
fully covered in Chap 3. Any points of usage particular to a given sling will be highlighted in the
individual equipment chapter for that sling.
MAINTENANCE SUPPORT LITERATURE
11 Full maintenance support literature for each sling is published in AP 108G-0002-1C,
HUSLE Slings. Chap 1-1 gives general advice on obtaining HUSLE maintenance Aps.
LOAD HOOK-UP/RELEASE AND STATIC ELECTRICITY DISCHARGE PROCEDURES
12 General procedures for load hook-up and release are contained in the chapters covering
helicopter hooks (Chaps 2-1 to 2-1-6) and helicopter extension strops (Chaps 2-2 to 2-2-5). Any
points, which are specified to a given sling, are highlighted in the appropriate sling equipment
chapter. Users should also consult Chap 5 for full information on static electricity discharge,
ground handler static probe equipment and standard procedures to be employed when earthing
helicopter primary or secondary hooks, or suspended loads.
Chap 2-4
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DAP 101A-1105-1A
CHAPTER 2-4-1
SLING, MULTIPLE LEG, HEAVY DUTY (11300 KG SWL)
CONTENTS
Para
1
2
7
8
10
11
12
13
14
15
16
17
18
Introduction
Equipment Description
Standard assembly
Accessories
Supplementary equipment
Sling classification
Life expiry of roundsling legs
Technical support literature
Sling usage
Use of shortening clutches
Limits for passage of chain
Preparation of slings and general rigging techniques
Suitability for engagement to helicopter cargo hooks
Suitability for engagement to helicopter extension strop secondary hooks
Static electricity discharge procedure
Fig
1
2
Page
Sling, Multiple Leg, Heavy Duty together with chain extensions legs ¼ ¼
Two-part sling classification
¼ ¼ ¼ ¼ ¼ ¼ ¼ ¼ ¼ ¼
2
5
INTRODUCTION
1 The Heavy Duty (HD) sling was introduced for the Chinook helicopter and is designed for
easy dismantling/assembly by component parts. The sling is configured more commonly with
four legs; three leg and two leg variants may also be used when called for on certain Underslung
Load Clearances (USLCs). The equipment has the NATO stores description of ‘Sling, Multiple
Leg, Heavy Duty’. Full NSN details for the equipment are contained in Army Equipment
Support Publication (AESP) 1670-H-100.
EQUIPMENT DESCRIPTION
Standard assembly
2 The sling legs, each consist of an upper textile element and a lower/terminal chain leg
element. At their apex, the textile legs are attached to a masterlink assembly (Fig 1).
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Textile legs
3 The inner part of each textile leg consists of a polyester fibre roundsling in a continuous
textile sleeve, which is then further sleeved in textile so that the roundsling forms a single leg
culminating in a loop at each end. All sleeving to this stage is known as the inner sleeving. Each
end loop is then fitted with a protective leather anti-chafe sleeve. Replacement roundslings are
issued thus assembled. When issued intact with a complete sling assembly, each roundsling leg
is further protected by an outer protective textile sleeve (which for replacement purposes is
demanded under its own NSN). The outer sleeve is retained in position, at each end, by PVC
adhesive tape wrapping, so as to leave the extremities of the anti-chafe sleeve and roundsling
loop ends exposed.
Apex assembly
4 The upper end loops of the roundsling legs are engaged to an ‘open masterlink’, which in
turn is connected to a ‘closed masterlink’ to form the lifting ring assembly. These are steel
items.
Fig 1 Sling, Multiple Leg, Heavy Duty together with chain extension legs
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Fixed chain legs
5 Attached to the lower end loop of each roundsling, by means of a roundsling shackle and
half link shackle, is a 2 m length of 10.3 mm diameter chain. Attached to the bottom end of each
chain leg is a shortening clutch, stores description ‘Clutch, Chain Shortening (10 mm)’. The
clutch in its simplest use provides the means of coupling the chain back onto itself to form a
closed loop about a lifting point; the leg length may be varied depending on the position along
the chain that the clutch is engaged. The clutch may also be used as the means of engaging and
thereby coupling to another 10.3 mm diameter chain. The clutch incorporates a chain locking
lever. The locking lever prevents the clutch from inadvertent detachment from an engaged
position, when the chain is slack, eg prior to load hook-up and the helicopter taking tension on
the load. Chap 2-4 details workings of the chain locking lever and basic principles of clutch
usage.
Sling identification labels
6 Each leg has two identification labels; one over the exterior of the outer protective sleeving,
the other attached directly to the roundsling inside the outer protective sleeve. The inner label
provides fallback reference in case the outer label becomes illegible or lost. Each label contains
the NSN of the equipment, the equipment SWL classification and the life expiry date of the
textile leg.
Accessories
Retainer breakaway
7 In brief, the item is of textile construction and consists of a single leg, which is attached
along the polyester section of one of the sling legs, and which has a number of velcro cross
straps. The velcro straps allow for the sling legs to be retained together, either for storage or to
prevent sling leg snagging during initial load lift. In the latter case, as tension is taken on the
load the cross straps will pull open allowing the sling legs to deploy naturally. The retainer
breakaway is fully described in Chap 2-6.
Supplementary equipment
Chain extension legs
8 For certain loads it will be necessary to have the facility for lengthening the sling legs.
Extension chain assemblies, 2 m or 4.5 m with terminal chain clutches, are used for this purpose.
These chains serve the same function as a sling chain leg, allowing for the chain clutches to be
engaged back onto its parent chain, to form a lifting loop about a load lifting point, or to be
engaged onto a further extension chain. Leg length can be varied, by engaging the clutch higher
up or lower down the sling leg or extension chain leg, with the final aim of achieving equilibrium
of the load. The chains are fully described in Chap 2-3-2 and full NSN details for the equipment
are contained in AESP 1670-H-100.
Masterlink/hook assembly
9 For certain loads it will be necessary to have the facility to employ the use of a
masterlink/hook assembly, more commonly known as a’Speedhook’. The assembly is attached
to the sling via the sling chain or an extension chain. The assembly consists of an ‘open
masterlink’ and ’13 mm hook’ secured together using a locking set. These are demanded as
individual items. Full NSN details for the equipment are contained in AESP 1670-H-100.
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SLING CLASSIFICATION
10 The sling is NATO codified as ‘Sling, Multiple Leg, Heavy Duty’. The sling has a two part
classification to cater for the use of the sling at included angles in excess of 50°, up to a
maximum included angle of 80°, but at a reduced working load rating. The sling classification is
therefore summarised as follows (see also general notes in Chap 2-4):
SML, HD (four legs), -
SWL 11300 kg up to 50° maximum included angle
SWL 9500 kg up to 80° maximum included angle
SML, HD (three legs), -
SWL 8475 kg up to 50° maximum included angle
SWL 7165 kg up to 80° maximum included angle
SML, HD (two legs), -
SWL 5650 kg up to 50° maximum included angle
SWL 4775 kg up to 80° maximum included angle
SWL
10.1 The SWL rating relates to all legs of the particular sling being used, and all legs
taking an equal share of the load. Thus, taking the 11300 kg rating, the SWL for any one
sling leg is 2825 kg, taking the 9500 kg rating, the SWL for any one sling leg is 2387 kg. It
follows that if less than four legs of the sling are being employed to lift a load, then the sling
SWL is reduced accordingly.
Maximum included angle
10.2 With both parts of the sling classification the sling SWL rating is related to a
maximum included angle. Taken at the apex of the sling, it is the maximum allowable angle
measured between diametrically opposed sling legs, with each leg taking an equal share of
the load up to the SWL limit for the 50° or 80° angle rating. From Fig 2 it is seen that the
maximum included angle when halved gives the maximum allowable working angle for any
one sling leg, ie the angle as measured between the line of the sling leg and the true vertical
running down from the apex of the sling through the load cg.
Chain extension legs
10.3 The chain extension legs conform to the sling leg rating for the sling, ie 2825 kg SWL
per chain leg, operating up to a maximum leg angle of 25° from vertical; and 2387 kg SWL
per chain leg, operating up to a maximum angle of 40° from vertical.
2 x SML 5650 kg used as a SML 11300 kg
10.4 Although uncommon, 2 x SMLs 5650 kg may be used to form a four-legged sling
configuration with an 11300 kg classification for a single point lift. However, it is to be
noted that this configuration is only to be connected to a helicopter extension strop
secondary hook.
Chap 2-4-1
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DAP 101A-1105-1A
Fig 2 Two - part sling classification
LIFE EXPIRY OF ROUNDSLING LEGS
11 The roundsling elements of the sling legs (excluding the outer protection sleeves) are
‘Lifed’ items, the policy for which is laid down in the technical support literature for the sling
(para 12). Equipment holders are to ensure that the life expiry date for each roundsling is
marked legibly and indelibly (by black permanent marker pen) on the individual leg
identification labels.
TECHNICAL SUPPORT LITERATURE
12 Full technical supporting literature for this equipment, including before and after use
examination, general care, unit repairs and fitment instructions for component parts technical
inspection procedures and any Service modification action or other changes, is published in
AESP 1670-H-100. Chap 1-1 gives general advice on obtaining AESPs.
SLING USAGE
Use of shortening clutches
13 Information on the use of chain shortening clutches, as fitted to the HD sling (incl variants)
and associated chain extension legs, is contained in Chap 2-3-2.
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DAP 101A-1105-1A
Limits for passage of chain
14 The following limits for passage of chain through lifting points, or around the load, apply to
the fixed chain legs and chain extension legs of the HD sling. The chain is not to be looped
around:
14.1 Circular sections of less than 25 mm (1 in.) diameter.
14.2 Angular or flat sections with square or rounded edges whose thickness of section is
less than 25 mm (1 in.).
Preparation of slings and general rigging techniques
15 Consult Chap 3 for standard rigging practice and techniques.
Suitability for engagement to helicopter cargo hooks
16 The masterlink lifting ring of the HD sling is suitable for direct engagement onto all cargo
hooks of the Chinook helicopter. Consult the Chap 2-1 series for full details of Chinook cargo
hooks and allied hook-up and load release procedures.
NOTE
The compatibility chart, Chap 1-1, Pg 5/6, states the ‘Non Standard Usage’ of sling direct to
cargo hook. It is now common practice to use an extension strop, with swivel hook, as an
interface between cargo hook and USL, unless otherwise specified in an USLC.
Suitability for engagement to helicopter extension strop secondary hooks
17 The masterlink lifting ring of this sling is suitable for direct engagement onto the secondary
hooks of all British Service helicopter extension strops when used with Chinook, with the
exception of the 7 ft or 30 ft SWR strops, SWL 1500 lb. In the event that the sling ever had to be
carried from a 7 ft or 30 ft 1500 lb SWL strop, then a shackle, 1500 lb SWL, or alternatively a
16 mm ‘open and closed masterlink assembly’ would provide a suitable means of connecting the
masterlink lifting ring of the sling to the 1500 lb SWL secondary hook. This is illustrated in
Chap 2-2-5.
Static electricity discharge procedure
18 Consult Chap 5 for full details of helicopter static electricity discharge procedures and
associated items of ground handler equipment.
Chap 2-4-1
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CHAPTER 2-4-2
SLING MULTIPLE LEG (‘REDUNDANT SLING’)
FOR CHINOOK HC MK2 TANDEM HOOK OPERATIONS (THO)
CONTENTS
Para
1
2
9
10
11
12
13
15
16
17
Introduction
Equipment description
Standard assembly
Sling classification
Life expiry of textile sling legs
Technical support literature
Sling usage
Use of shortening clutches
Limits for passage of chain
Suitability for engagement to helicopter cargo hooks
Suitability for engagement to helicopter extension strop secondary hooks
Static electricity discharge procedure
Fig
1
Page
SML (Redundant) ¼ ¼ ¼ ¼ ¼ ¼ ¼ ¼ ¼ ¼ ¼ ¼ ¼
3
INTRODUCTION
1 The SML (Redundant) is a special multiple-leg slingset for the Chinook helicopter. Known
as the ‘Chinook Redundant Sling’, it is an emergency equipment only, ensuring retention of the
load if an irregular release of a cargo hook occurs during Chinook HC MK2 THOs. The
equipment has the NATO stores description of ‘Sling, Multiple Leg (SML), Redundant’. Full
NSN details for the equipment are contained Army Equipment Support Publication (AESP)
1670-H-100.
EQUIPMENT DESCRIPTION
Standard assembly
2 The sling (Fig 1) has four legs, each consisting of an upper textile element and a lower chain
leg element. At their apex, the textile legs are attached to a masterlink assembly.
Textile leg
3 The inner part of each textile leg consists of flat nylon webbing, made from a single length
formed into three concentric loops, stitched through at the overlap. The resulting single loop is
held together as a compact bundle by tape wrapped around at regular intervals, to form a nominal
length of 5.2 m. This construction is known as the ‘Strap’. A label is taped to one end of the strap
and is the ‘internal label’. For replacement purposes, straps are demanded under a separate NSN.
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DAP 101A-1105-1A
4 The strap is fitted with a protective sleeve of tubular polyester webbing, secured at each end
by tape. The sleeve is red in colour and carries prominent black identification markings. As a
non-loadbearing element, the protective sleeve is considerably longer than the strap, to allow for
stretch in the latter when under load. This construction is known as the ‘Strap Assembly’, and
carries a second identical label (the ‘external’ label) taped to the same end as the internal label.
For replacement purposes, protective sleeves are demanded under a separate NSN.
5 Two strap assemblies are joined by binding their upper end loops together with tape,
forming a ‘Double Strap Assembly’. One redundant sling contains two such assemblies.
Apex assembly
6 The upper end loops of the two double strap assemblies are engaged to an ‘open masterlink’,
which in turn is connected to a ‘closed masterlink’ to form the lifting ring assembly. These are
steel items.
Fixed chain legs
7 Attached to the lower end loop of each textile leg, by means of a roundsling shackle and half
link shackle, is a 2 m length of 10.3 mm diameter chain. Attached to the bottom end of each
chain leg is a shortening clutch, stores description ‘Clutch, Chain Shortening (10mm)’. The
clutch in its simplest use provides the means of coupling the chain back onto itself to form a
closed loop about a lifting point; the leg length may be varied depending upon the position along
the chain at which the clutch is engaged. The clutch incorporates a chain locking lever. The
locking lever prevents inadvertent detachment of the clutch from an engaged position, when the
chain is slack, eg prior to the load hook-up and the helicopter taking tension on the load. Chap
2-4 details the workings of chain locking levers and basic principles of clutch usage.
Sling identification labels
8 Each sling leg carries two identification labels; one fitted over the outer protective sleeving,
the other attached directly to the strap within. The inner label provides fallback reference in case
the outer label becomes illegible or lost. Each label contains the NSN of the equipment and the
life expiry date of the textile leg. An additional ID label, stamped with the assembly part
number, is strapped to the masterlink.
SLING CLASSIFICATION
9 The sling is NATO codified as ‘Sling, Multiple Leg (SML), Redundant’. It is an item of
emergency equipment, and is not classified for use as a conventional sling.
LIFE EXPIRY OF TEXTILE SLING LEGS
10 The inner textile elements of the sling legs (excluding the outer protection sleeves) are
‘Lifed’ items, the policy for which is laid down in the technical support literature for the sling
(para 11). Equipment holders are to ensure that the life expiry date for each strap is marked
legibly and indelibly, by black permanent ink, on the associated ID labels (inner and outer).
Chap 2-4-2
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DAP 101A-1105-1A
CLOSED MASTERLINK
(LIFTING RING)
IDENTIFICATION LABEL
LOCKING SET
PVC TAPE
OPEN MASTERLINK
STRAP
OUTER PROTECTIVE SLEEVE
IDENTIFICATION
LABELS (EACH LEG,
INNER AND OUTER)
DOUBLE STRAP ASSEMBLY
(2 PER SLING)
ROUNDSLING
SHACKLE
LOCKING SET
HALF LINK SHACKLE
CHAIN
SHORTENING
CLUTCH
Fig 1 SML (Redundant)
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DAP 101A-1105-1A
TECHNICAL SUPPORT LITERATURE
11 Full technical supporting literature for this equipment, including before and after use
examination, general care, unit repairs and fitment instructions for component parts, technical
inspection procedures and any Service modification action or other changes, is published in
AESP 1670-H-100. Chap1-1 gives general advice on obtaining AESPs.
SLING USAGE
Use of shortening clutches
12 Information on the use of chain shortening clutches, as fitted to the Redundant sling, is
described in Chap 2-3-2, para 3.
Limits for passage of chain
13 The following limits for passage of chain through lifting points, or around the load, apply to
the chain legs of the redundant sling. The chain is not to be looped around:
13.1
Circular sections of less than 25 mm (1 in.) diameter.
13.2 Angular or flat sections with square or rounded edges whose thickness of section is
less than 25 mm (1 in.).
14 The chain legs of the redundant sling must not connect to any part of the main lifting sling,
ie the redundant sling must be connected directly to the load.
Suitability for engagement to helicopter cargo hooks
15 The masterlink lifting ring of the redundant sling is intended for direct engagement onto the
centre cargo hook of the Chinook HC MK2 helicopter. Consult the Chap 2 series for full details
of Chinook cargo hooks and allied hook-up and load release procedures.
Suitability for engagement to helicopter extension strop secondary hooks
16 The redundant sling is not to be attached to an extension strop, or to any lifting point other
than as described in para 15.
Static electricity discharge procedure
17 Consult Chap 5 for full details of helicopter static electricity discharge procedures and
associated items of ground handler equipment.
Chap 2-4-2
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CHAPTER 2-4-3
SLING, MULTIPLE LEG, MEDIUM DUTY (4600 KG SWL)
CONTENTS
Para
1
2
7
8
9
10
11
12
13
14
15
16
17
18
Introduction
Equipment Description
Standard assembly
Accessories
Supplementary equipment
Sling classification
Life expiry of roundsling legs
Technical support literature
Sling usage
Use of shortening clutches
Limits for passage of chain
Preparation of slings and general rigging techniques
Suitability for engagement to helicopter cargo hooks
Suitability for engagement to helicopter extension strop secondary hooks
Additional use of 16 mm ‘open and closed masterlink’ hardware
Static electricity discharge procedure
Fig
1
2
Page
Sling, Multiple Leg, Medium Duty together with chain extension legs ¼ ¼
Two-part sling classification
¼ ¼ ¼ ¼ ¼ ¼ ¼ ¼ ¼ ¼
2
5
INTRODUCTION
1 The Medium Duty (MD) sling was introduced for the Chinook helicopter and is a scaled down version of the Heavy Duty (HD) sling. It is designed for easy dismantling/assembly by
component parts. The sling is configured more commonly with four legs; three leg and two leg
variants may also be used when called for on certain Underslung Load Clearances (USLCs). The
equipment has the NATO stores description of ‘Sling, Multiple Leg, Heavy Duty’. Full NSN
details for the equipment are contained in Army Equipment Support Publication (AESP) 1670H-100.
EQUIPMENT DESCRIPTION
Standard assembly
2 The sling legs, each consist of an upper textile element and a lower/terminal chain leg
element. At their apex, the textile legs are attached to a masterlink assembly (Fig 1).
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Textile legs
3 The inner part of each textile leg consists of a polyester fibre roundsling in a continuous
textile sleeve, which is then further sleeved in textile so that the roundsling forms a single leg
culminating in a loop at each end. All sleeving to this stage is known as the inner sleeving. Each
end loop is then fitted with a protective leather anti-chafe sleeve. Replacement roundslings are
issued thus assembled. When issued intact with a complete sling assembly, each roundsling leg
is further protected by an outer protective textile sleeve (which for replacement purposes is
demanded under its own NSN). The outer sleeve is retained in position, at each end, by PVC
adhesive tape wrapping, so as to leave the extremities of the anti-chafe sleeve and roundsling
loop ends exposed.
Apex assembly
4 The upper end loops of the roundsling legs are engaged to an ‘open masterlink’, which in
turn is connected to a ‘closed masterlink’ to form the lifting ring assembly. These are steel
items.
Fig 1 Sling, Multiple Leg, Medium Duty together with chain extension legs
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DAP 101A-1105-1A
Fixed chain legs
5 Attached to the lower end loop of each roundsling, by means of a roundsling shackle and
half link shackle, is a 2 m length of 7.1 mm diameter chain (which incorporates a ‘joiner link’ for
connection to the half link shackle). Attached to the bottom end of each chain leg is a shortening
clutch, stores description ‘Clutch, Chain Shortening (7 mm)’. The clutch in its simplest use
provides the means of coupling the chain back onto itself to form a closed loop about a lifting
point; the leg length may be varied depending on the position along the chain that the clutch is
engaged. The clutch may also be used as the means of engaging and thereby coupling to another
7.1 mm diameter chain. The clutch incorporates a chain locking lever. The locking lever
prevents the clutch from inadvertent detachment from an engaged position, when the chain is
slack, eg prior to load hook-up and the helicopter taking tension on the load. Chap 2-4 details
workings of the chain locking lever and basic principles of clutch usage.
Sling identification labels
6 Each leg has two identification labels; one over the exterior of the outer protective sleeving,
the other attached directly to the roundsling inside the outer protective sleeve. The inner label
provides fallback reference in case the outer label becomes illegible or lost. Each label contains
the NSN of the equipment, the equipment SWL classification and the life expiry date of the
textile leg.
Accessories
Retainer breakaway
7 In brief, the item is of textile construction and consists of a single leg, which is attached
along the polyester section of one of the sling legs, and which has a number of velcro cross
straps. The velcro straps allow for the sling legs to be retained together, either for storage or to
prevent sling leg snagging during initial load lift. In the latter case, as the tension is taken on the
load the cross straps will pull open allowing the sling legs to deploy naturally. The retainer
breakaway is fully described in Chap 2-6.
Supplementary equipment
Chain extension legs
8 For certain loads it will be necessary to have the facility for lengthening the sling legs.
Extension chain assemblies, 2 m or 4.5 m with terminal chain clutches, are used for this purpose.
These chains serve the same function as a chain leg, allowing for the chain clutches to be
engaged back onto its parent chain, to form a lifting loop about a load lifting point, or to be
engaged onto a further extension chain. Leg length can be varied, by engaging the clutch higher
up or lower down the sling leg or extension chain leg, with the final aim of achieving equilibrium
of the load. The chains are fully described in Chap 2-3-2 and full NSN details for the equipment
are contained in AESP 1670-H-100.
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SLING CLASSIFICATION
9 The sling is NATO codified as ‘Sling, Multiple Leg, Medium Duty’. The sling has a single
classification to cater for the use of the sling at a maximum included angle of 80°. The sling
classification is therefore summarised as follows (see also general notes in Chap 2-4):
SML, MD (four legs), SWL 4600 kg up to 80° maximum included angle
SML, MD (three legs), SWL 3450 kg up to 80° maximum included angle
SML, MD (two legs), SWL 2300 kg up to 80° maximum included angle
SWL
9.1 The SWL rating relates to all legs of the particular sling being used, and each leg
taking an equal share of the load. Thus the SWL for any one sling leg is 1150 kg. It follows
that if less than four legs are being employed to lift a load, then the sling SWL is reduced
accordingly
Maximum included angle
9.2 The sling SWL classification is also related to a maximum included angle of 80°.
Taken at the apex of the sling, it is the maximum allowable angle measured between
diametrically opposed sling legs, with each leg taking an equal share of the load up to the
SWL limit for the legs. From Fig 2 it is seen that the maximum included angle when halved
gives the maximum allowable working angle for any one sling leg, ie the angle as measured
between the line of the sling leg and the true vertical running down from the apex of the
sling through the load cg.
Chain extension legs
9.3 The chain extension legs conform to the sling leg rating for the sling, ie 1150 kg SWL
per chain leg, operating up to a maximum angle of 40° from vertical.
2 x SML 2300 kg used as a SML 4600 kg
9.4 Although uncommon, 2 x SMLs 2300 kg may be used to form a four-legged sling
configuration with a 4600 kg classification for a single point lift. However, it is to be noted
that this configuration is only to be connected to a helicopter extension strop secondary
hook.
LIFE EXPIRY OF ROUNDSLING LEGS
10 The roundsling elements of the sling legs (excluding the outer protection sleeves) are
‘Lifed’ items, the policy for which is laid down in the technical support literature for the sling
(para 11). Equipment holders are to ensure that the life expiry date for each roundsling is
marked legibly and indelibly (by black permanent marker pen) on the individual leg
identification labels.
Chap 2-4-3
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TECHNICAL SUPPORT LITERATURE
11 Full technical supporting literature for this equipment, including before and after use
examination, general care, unit repairs and fitment instructions for component parts technical
inspection procedures and any Service modification action or other changes, is published in
AESP 1670-H-100. Chap 1-1 gives general advice on obtaining AESPs.
Fig 2 Two-part sling classification
SLING USAGE
Use of shortening clutches
12 Information on the use of chain shortening clutches, as fitted to the MD sling (incl variants)
and associated chain extension legs, is described in Chap 2-3-2, para 3.
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Limits for passage of chain
13 The following limits for passage of chain through lifting points, or around the load, apply to
the fixed chain legs and chain extension legs of the MD sling. The chain is not to be looped
around:
13.1 Circular sections of less than 13 mm (½ in.) diameter.
13.2 Angular or flat sections with square or rounded edges whose thickness of section is
less than 13 mm (½ in.).
Preparation of slings and general rigging techniques
14 Consult Chap 3 for standard rigging practice and techniques.
Suitability for engagement to helicopter cargo hooks
15 The masterlink lifting ring of the MD sling is suitable for direct engagement onto all cargo
hooks of the Chinook helicopter. Consult the Chap 2-1 series for full details of Chinook cargo
hooks and allied hook-up and load release procedures.
NOTE
The compatibility chart, Chap 1-1, Pg 5/6, states the ‘Non Standard Usage’ of sling direct to
cargo hook. It is now common practice to use an extension strop, with swivel hook, as an
interface between cargo hook and USL, unless otherwise specified in an USLC.
Suitability for engagement to helicopter extension strop secondary hooks
16 The masterlink lifting ring of this sling is suitable for direct engagement onto the secondary
hooks of all British Service helicopter extension strops when used with Chinook. Consult the
Chap 2-2 series for full details of the current range of British Service helicopter extension strop
equipments, and allied hook-up and load release procedures.
Additional use of 16 mm ‘open and closed masterlink’ hardware
17 The 16 mm ‘open and closed’ masterlink assembly, forming the apex of the MD sling, can
also be used as a fallback connector for older range equipments that are not compatible for
engagement onto Chinook cargo hooks or the 11300 kg strop. The use of the apex hardware in
this manner is discussed in Chap 2-3-1.
Static electricity discharge procedure
18 Consult Chap 5 for full details of helicopter static electricity discharge procedures and
associated items of ground handler equipment.
Chap 2-4-3
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CHAPTER 2-4-4
SLING, MULTIPLE LEG, 6000 lb SWL
CONTENTS
Para
1
2
5
6
7
8
9
10
11
12
14
15
Introduction
Equipment description
Standard assembly
Supplementary equipment
Accessories
Sling classification
Technical support literature
Sling usage
Use of shortening clutches
Limits for passage of chain
Preparation of slings and general rigging techniques
Suitability for engagement to helicopter cargo hooks
Suitability for engagement to helicopter extension strop secondary hooks
Static electricity discharge procedures
Fig
1
2
3
4
Page
SML 6000 lb SWL with clutches attached … … … … … … … …
SML 6000 lb SWL with hooks attached … … … … … … … …
Sling classification
… … … … … … … … … … … …
Maximum included angle of chain loop at terminus of leg when using 6000 lb
sling with hooks or clutches attached … … … … … … … … …
3
4
5
6
INTRODUCTION
1 The SML 6000 lb is a general purpose helicopter sling, traditionally used by the Royal
Navy/Royal Marines. Originally introduced for RM vehicle uplift, the sling later became known
as the RN/RM sling. The sling has the NATO stores description of ‘Sling, Multiple Leg’. Full
NSN details for the equipment are contained in Army Equipment Support Publication (AESP)
1670-H-100.
EQUIPMENT DESCRIPTION
Standard assembly
2 The sling consists of four steel wire rope (SWR) and chain legs, which are attached to an
► oval shaped steel connecting ring at the apex (Figs 1 and 2). The upper portion of each leg
◄
comprises a 6 ft (1.83 m) length of SWR, the upper end of which is formed into a loop encircling
the lifting ring. The loop is formed about a thimble, with the free end of the wire rope secured
back (swaged) to the parent leg by means of a ‘Talurit’ ferrule. The lower end of each leg
terminates in a swaged loop, with the free end of wire rope similarly secured back to the parent
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leg by means of a ‘Talurit’ ferrule. Each lower loop houses a ‘deadeye’. The wire rope legs are
protected over their length, between ferrules, by a translucent vinyl sleeve.
3 The lower part of each sling leg consists of a standard 10000 lb chain, reduced to a length of
5 ft 6 in. (1.68 m) and terminating in a chain clutch or hook. Each chain leg is secured to the
foot of its wire rope leg by means of ‘link plates’, bolted at one end of the terminal ‘deadeye’ of
the wire rope leg and at the other end to the top link of the chain.
Metal tally/identification plate
4 A brass plate (tally) is attached to one of the sling legs, and contains the sling description,
NSN, SWL, manufacturer and date of ‘proof test’. If the tally is lost, the equipment is to be
withdrawn from use immediately.
Supplementary equipment
Chain extension legs
5 For certain loads it will be necessary to have the facility for lengthening the sling legs.
Extension chain assemblies, 2 m or 4.5 m with terminal chain clutches, are used for this purpose.
These chains serve the same function as a chain leg, allowing for the chain clutches to be
engaged back onto its parent chain, to form a lifting loop about a load lifting point, or to be
engaged onto a further extension chain. Leg length can be varied, by engaging the clutch higher
up or lower down the sling leg or extension chain leg, with the final aim of achieving equilibrium
of the load. The chains are fully described in Chap 2-3-2 and full NSN details for the equipment
are contained in AESP 1670-H-100.
Accessories
Retainer breakaway
6 In brief, the item is of textile construction and consists of a single leg, which is attached to
the upper/non-chain element of a sling leg, and which has a number of velcro cross straps. The
velcro straps allow for the sling legs to be held together, either for storage or to prevent sling leg
snagging during initial load lift. In the latter case, as tension is taken on the load the cross straps
will open allowing for the sling legs to deploy naturally. The retainer breakaway may be adapted
for use with the SML 6000 lb and the item is fully described in Chap 2-6 (which includes an
example of its installation on this sling). The item is readily replaceable and full NSN details for
the equipment are contained in AESP 1670-H-100.
SLING CLASSIFICATION
7 The sling is classified as ‘Sling, Multiple Leg, 6000 lb SWL (2724 kg) up to 100° maximum
included angle’. The classification is considered as follows (see also general notes in Chap 2-4):
SWL
7.1 The SWL classification of 6000 lb relates to all four legs of the sling, and to each leg
taking an equal share of the load. Thus the SWL for each leg is 1500 lb. It follows that if
only three of the four legs are being employed to lift a load the sling SWL is reduced to
4500 lb; if only two of the legs are being employed to lift a load the sling SWL is reduced to
3000 lb.
Chap 2-4-4
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Fig 1 SML 6000 lb SWL with clutches attached
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DAP 101A-1105-1A
Fig 2 SML 6000 lb SWL with hooks attached
Chap 2-4-4
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Maximum included angle
7.2 The sling SWL classification is also related to a maximum included angle of 100°.
Taken at the apex of the sling, it is the maximum allowable angle measured between
diametrically opposed sling legs, with each leg taking an equal share of the load up to the
SWL limit for the legs. From Fig 3 it will be seen that the maximum included angle when
halved gives the maximum allowable working angle for any one sling leg, ie the angle as
measured between the line of the sling leg and the true vertical running down from the apex
of the sling through the load cg.
2 m and 4.5 m MD extension chains
7.3 When used as extension chain legs for this sling, 2 m and 4.5 m MD extension chains
(Chap 2-3-2) conform to the single leg rating for the sling; ie 1500 lb SWL per chain leg,
operating up to a maximum leg angle of 50° from vertical.
TECHNICAL SUPPORT LITERATURE
8 Full technical supporting literature for this equipment, including before and after use
examination, general care, unit repairs and fitment instructions for component parts, technical
inspection procedures and any Service modification action or other changes, is published in
AESP 1670-H-100. Chap 1-1 gives general advice on obtaining AESPs.
Fig 3 Sling classification
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DAP 101A-1105-1A
SLING USAGE
Use of shortening clutches
9 Information on the use of chain shortening clutches, as fitted to the 6000 lb sling and
associated chain extension legs, is described in Chap 2-3-2.
NOTE
For a 6000 lb sling leg terminating with a chain hook or shortening clutch the maximum
allowable included angle at closure of chain loop is 90° and 120° respectively (Fig 4).
10 The following limits for passage of chain through lifting points, or around the load, apply to
the fixed chain legs of the 6000 lb sling. The chain is not to be looped around:
10.1 Circular sections of less than 11 mm diameter.
10.2 Angular or flat sections with square or rounded edges whose thickness of section is
less than 11 mm.
Fig 4 Maximum included angle of chain loop at terminus of leg
when using 6000 lb sling with hooks or clutches attached
Preparation of slings and general rigging techniques
11 Consult Chap 3 for standard rigging practice and techniques.
Chap 2-4-4
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Suitability for engagement to helicopter cargo hooks
12 The lifting ring of this sling is suitable for direct engagement onto any of the SACRU series
of cargo hooks currently fitted to British Service helicopters. The lifting ring is also suitable for
direct engagement onto the forward and aft hooks of the Chinook helicopter, but not onto the
centre hook of that helicopter. In the latter case, the lifting ring is suitable, however, for
engagement onto the secondary hook of the Chinook 11300 kg extension strop; alternatively it
could be engaged to the Chinook centre hook by means of a 16 mm ‘open and closed’ masterlink
assembly (see Chap 2-3-1).
NOTE
►
The compatibility matrix, Chap 2, states the ‘Non Standard Usage’ of sling direct to cargo
hook. It is now common practice to use an extension strop, with swivel hook, as an
interface between cargo hook and USL, unless otherwise specified in an USLC.
◄
13 Consult the Chap 2-1 series for full details of current British Service helicopter cargo hooks,
and allied hook-up and load release procedures.
Suitability for engagement to helicopter extension strop secondary hooks
14 The lifting ring of this sling is suitable for direct engagement onto the secondary hooks of
all current British Service helicopter extension strops. Consult the Chap 2-2 series for full details
of the current range of British Service helicopter extension strop equipments, and allied hook-up
and load release procedures.
Static electricity discharge procedures
15 Consult Chap 5 for full details of helicopter static electricity discharge procedures and
associated items of ground handler equipment.
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Nov 06 (Issue 1)
DAP 101A-1105-1A
CHAPTER 2-4-5
HUSLE, WEBSLING, LIFTING, SWL 10000 KG
CONTENTS
Para
1
2
3
4
5
6
Introduction
Equipment description
Websling identification
Life expiry of equipment
Technical support literature
Equipment usage
Fig
1
Page
10000 kg Websling
¼ ¼ ¼ ¼ ¼ ¼ ¼ ¼ ¼ ¼ ¼ ¼
2
INTRODUCTION
1 The 10000 kg Websling (more commonly known as a Belly-band) has been designed and
introduced into Service to provide an alternative and versatile method of lifting unusual and
fragile loads that have no suitable lifting points. The equipment has the NATO stores description
of ‘HUSLE, Websling, Lifting, SWL 10000 kg’. Full NSN details for the equipment are
contained in Army Equipment Support Publication (AESP) 1670-H-100.
EQUIPMENT DESCRIPTION
2 The Websling (Fig 1) is 14 m long and manufactured from 2 ply 100% polyester webbing.
Stitched loops at each end provide a means of attachment to appropriate in-service HUSLE.
Protective sleeves, manufactured from 100% polyester, are used to prevent damage to the
Websling when lifting loads with sharp or abrasive edges. The SWL of the equipment is 10000
kg (22046 lb).
Websling identification
3 The Websling has two sewn on labels: one with the manufacturers name and SWL; the other
with equipment description, NSN, drawing number, serial number, date of manufacture, life
expiry and the legend ‘FOR JATEU USE ONLY’. The serial number and legend ‘FOR JATEU
USE ONLY’ are also stencilled on the Websling.
LIFE EXPIRY OF 10000 KG WEBSLING
4 The Websling is a ‘Lifed’ item the policy for which is laid down in the technical support
literature for the sling (para 5). Equipment holders are to ensure that the life expiry date is
entered onto the equipment log card. The protective sleeves are not ‘Lifed’ but are replaced on
condition.
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DAP 101A-1105-1A
Fig 1 10000 kg Websling
Chap 2-4-5
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TECHNICAL SUPPORT LITERATURE
5 Full technical supporting literature for this equipment including before and after use
examination and general care is published in AESP 1670-H-100. Chap 1-1 gives general advice
on obtaining AESPs.
EQUIPMENT USAGE
6 The Websling provides an alternative method to low speed crane lifts of unusual loads
which can be used with various helicopter types, subject to limitations in their respective Release
to Service. The Websling can be used in the following configurations:
6.1 Tandem hook operations with redundant sling. Although the use of a redundant sling
with Webslings is cleared for use, this method is not deemed to be normal practice.
However, it may be used when operationally essential.
6.2 Tandem hook operations ‘long stropping’. The preferred method of use, extension
strops and weak links are to be used to prevent damage occurring to the aircraft or
Webslings. The hook of a Heavy Duty (HD) extension strop will accommodate two
Websling lifting loops, however, it is recommended that a 16 mm ‘open and closed master
link assembly’ (Chap 2-3-1) is used as a connector for ease of attachment and disengagement.
6.3 Single hook operations. A HD extension strop is to be used for single hook
operations. The use of a 16 mm ‘open and closed master link assembly’ (Chap 2-3-1) is
recommended as a connector between the Websling and extension strop secondary hook.
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DAP 101A-1105-1A
CHAPTER 2-5
HELICOPTER CARGO LIFTING NETS AND ALLIED SYSTEMS - GENERAL
CONTENTS
Para
1
2
3
4
Introduction
Netted loads
Authorised loads
Two net cluster load
INTRODUCTION
► 1 This series of chapters deals with helicopter cargo lifting nets and allied systems. There are
currently three cargo lifting net equipments, 5000 lb, 5600 kg and 7000 kg. Purpose made net
protection pads are also described at Chap 2-5-0.
◄
NETTED LOADS
2 Loads carried in cargo lifting nets are commonly known as ‘netted loads’, and this method
of carrying external cargo has certain advantages which are as follows:
2.1 Most loads are fairly simple to prepare.
►
2.2 A wide variety of loads can be carried including mixed load items that can be lifted as
a single unit. The 5600 kg and 7000 kg nets also have the capability of carrying certain
types of vehicles, where slinging by other means may prove difficult in terms of finding
suitable lifting points.
◄
2.3 Both high and low density loads can generally be lifted without affecting the flying
characteristics of the helicopter.
Authorised Loads
► 3 On the basis of para 2.3 above, it is normally unnecessary for netted loads to be specially
cleared or test flown at JADTEU. As a result, cargo lifting nets are normally categorised as
‘Authorised Load’ equipments. The rules for ‘Authorised Loads’, together with the
identification of loads/load carrying equipments which come into the category, are set out in
Chap 1. In respect of cargo nets, it is worth reiterating the following:
◄
3.1 Loads carried in specified cargo net equipments are treated as authorised loads
providing that they conform with the type of load for which the equipment was designed.
On this basis, flying characteristics can be reasonably guaranteed based on original trials.
Typical loads and loading schemes, or loading parameters, are given in individual net
chapters.
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3.2 With such loads, although it cannot be guaranteed that they will remain stable at all
speeds, providing that the helicopter crew exhibits the normal caution that they would show
for any new load, then they are unlikely to be confronted with the type of load which with
little or no warning enters a severely unstable condition of flight.
3.3 Cargo nets must not be flown empty. The minimum acceptable loads are discussed in
each chapter referring to the particular equipment.
TWO NET CLUSTER LOAD
4 Two net cluster loads are not to be attached to a helicopter cargo hook. These loads are only
to be lifted on the secondary swivel hook of an extension strop or masterlink assembly.
5 The stirrups of the two nets are not to be secured or tied together in any way as spinning of a
two net cluster load leads to net separation which can cause the two stirrups to open like butterfly
wings pivoting at the stirrup to stirrup tie. This action can force one stirrup past the hook keeper
and off the hook.
6 Stirrups should be held together by hand, or attached to the secondary hook one stirrup at a
time. Alternatively, a single turn of 2 in. adhesive tape may be used to secure together the lifting
strops of both nets just below the two stirrups.
Chap 2-5
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DAP 101A-1105-1A
CHAPTER 2-5-0
PAD, PROTECTION, HELICOPTER CARGO NET
(Completely revised)
CONTENTS
Para
1
2
3
4
Introduction
Equipment description
Maintenance support literature
General usage
Fig
1
Page
Net Protection Pad… … … … … … … … … … … … …
1
INTRODUCTION
1 The ‘pad, protection, helicopter cargo net’ (Fig 1) is a custom made item, introduced for use
with the 5600 kg cargo lifting net and also suitable for the smaller 5000 lb cargo lifting net. Also
available is a larger net protection pad specifically introduced into service for use with the 7000
kg net. The purpose of the pads is to prevent damage to helicopter cargo nets caused by sharp
edges or protrusions on loads, and also to reduce damage to the load caused by net snagging.
Full NSN details for the equipment are contained in AP 108G-0002-1D, HUSLE Ancillary
Equipment.
EQUIPMENT DESCRIPTION
2 The pads, are manufactured from PVC covered polyester fabric sheet (‘Transilon’).
Eyeletted holes are spaced at intervals near the edges, allowing for the pad to be tied in position
on the load (not to the net) and also for pads to be tied together. Pads are not issued with nets so
should be demanded as separate items.
MAINTENANCE SUPPORT LITERATURE
3 Maintenance support literature for this equipment is published in AP 108G-0002-1D,
HUSLE Ancillary Equipment. Chap 1-1 gives general advice on obtaining HUSLE maintenance
APs.
GENERAL USAGE
4
Use of the pads is basically self-explanatory but the following points should be noted:
4.1 Pads should normally be used under the load as well as around the load. The method
of use is detailed in Chap 2-5-1 for the 5600 kg net.
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4.2 Inadequately secured pads are likely to be disrupted once the helicopter positions for
load pick-up, and as a result could fail to provide the protection intended. They could also
become detached and end up in the helicopter rotors. It is therefore vitally important to
ensure that the pads are well secured, held down firmly by the load and, where possible, tied
securely to or about the load (never the net).
4.3 Finally, loose pads must never be left lying about in the vicinity of a helicopter pickup/landing point as they could end up in a helicopters rotors.
Net protection pad, for use with 5600 kg net and 5000 lb net, shown
Fig 1 Net protection pad
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DAP 101A-1105-1A
CHAPTER 2-5-1
NET, CARGO LIFTING, HELICOPTER (5600 KG SWL)
CONTENTS
Para
1
2
4
5
6
7
8
9
10
11
12
15
16
17
18
19
20
21
22
23
24
25
26
27
28
Introduction
Equipment description
Net lifting strop assemblies
Net stirrup (WARNING)
Associated equipment
Retainer breakaway
Pad, protection, helicopter cargo net
Life expiry of net
Net storage (WARNING)
Technical support literature
Flying limitations
Lifting design and general safe practices relating to 5600 kg net
Preparation of net for carriage of NATO pallets
Net handlers
Laying out the net
Loading of NATO pallets and net securing
Loading schemes
Net protection pads
Like loads
Net loading process - single net uplifts (CAUTION)
Fork lift operation
Securing net pads around load
Closing and securing the net and net strop assemblies
Two-netted loads in cluster, preparing the second net
Helicopter hook-up (WARNINGS/CAUTIONS)
Hooking-up single net loads
Hooking-up a two-net cluster load
Precautions during initial lift and net release following load landing (WARNING)
Net dragging during load pick-up and landing
Fig
1
2
3
4
5
6
Page
5600 kg net basic layout
¼ ¼ ¼ ¼ ¼ ¼
Net lifting strop assemblies (Pre Mod and Post Mod)
Stirrup with net strop assembly lifting hooks engaged
Net suspended
¼ ¼ ¼ ¼ ¼ ¼ ¼ ¼
Net end wall formation with full and short loads
¼
NATO pallet loading schemes ¼ ¼ ¼ ¼ ¼
¼
¼
¼
¼
¼
¼
¼
¼
¼
¼
¼
¼
¼
¼
¼
¼
¼
¼
¼
¼
¼
¼
¼
¼
¼
¼
¼
¼
¼
¼
2
4
6
8
9
12
Continued
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CONTENTS (continued)
7
8
9
Cross-sectional view of load showing net side wall ‘holding tie’ ¼ ¼ ¼
Loading second net of two-net cluster¼ ¼ ¼ ¼ ¼ ¼ ¼ ¼ ¼
Stirrup engagement
¼ ¼ ¼ ¼ ¼ ¼ ¼ ¼ ¼ ¼ ¼ ¼
14
15
17
Annex
A
B
Additional types of load
Rolled 5600 kg net used as a belly-band
INTRODUCTION
1 The 5600 kg helicopter cargo net has been specifically designed for USL carriage of NATO
pallets and for container type loads. The net can also be used for the carriage of other specified
loads and certain types of vehicles. The net is cleared for carriage under all current Service
helicopters, less Gazelle (all Mks), Squirrel HT Mk2 and subject to the limitations laid down in
para 11.
Fig 1 5600 kg net basic layout
Chap 2-5-1
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EQUIPMENT DESCRIPTION
2 The 5600 kg helicopter cargo net, square in shape, measuring 6.25 m x 6.25 m (20.5 ft x
20.5 ft) is constructed from 3569 kg (break strength) black nylon braid formed into a 200 mm
(8 in.) knotless mesh. The periphery of the net is fitted with a border cord, forming an integral
part of the net and constructed from twin nylon braid. As an aid to correct alignment when
loading the net, the net centre lines (running between opposite net edges) are identified by red
nylon cord following the ‘zig-zag’ lines of the mesh. A fabric net identification label, showing
the SWL and NSN, is located on the net border cord. A small metal plate, giving the life expiry
date of the textile elements of the net, is attached to the mesh section.
3 The net is suspended from two of its four sides, ie folding about one centre axis, known as
the loading axis. Four composite lifting strop assemblies (each culminating at its upper end in a
metal lifting hook) are attached to the net border cord, two assemblies each on the two net sides
in question. The four lifting hooks of the combined net strop assemblies attach to a stirrup. The
stirrup forms the connection between the net assembly and the load beam of the helicopter cargo
hook or the secondary hook of a helicopter extension strop. It is attached to the apex of one of
the net lifting strop assemblies by a nylon retaining cord as shown in Fig 1.
Net lifting strop assemblies
4
Each of the four composite net lifting strop assemblies is made up as follows:
4.1 An inner and outer lifting member (both constructed from 45 mm width nylon
webbing, folded and stitched for greater aerodynamic stability) are reeved through the eye
of a parent lifting hook, to form four legs (Figs 2A and 2B).
Pre Mod
4.2 At their lower end (Fig 2C) the four legs are spaced out and formed into loops, each
leg loop encircling the net border cord and held closed by a metal connector link (detachable
for the purpose of replacing a worn or damaged lifting member). The legs measure
approximately 4 m from the border cord to the lifting hook. An anti-chafe sleeve is fitted
over the looped section of each leg, at the border cord attachment point.
4.3 At the apex of each strop assembly (Fig 2A) a length of nylon strap is stitched to the
inside face of the inner lifting member (serving as an anti-chafe pad where the inner
member bears against the lower rim of the lifting hook eye). One end of this anti-chafe
strap is folded over and stitched. The other end (on the opposite side of the lifting hook eye)
is reeved through a detachable metal buckle (the restrictor buckle) which is in turn taped to
the parent section of the lifting member. The folded end and buckle end of the anti-chafe
strap serve as ‘stops’, preventing undue travel of the lifting hook away from the apex of the
lifting members. To enable the lifting member to be pulled clear of the lifting hook eye, for
purposes of replacement etc, the restrictor buckle is simply untaped and removed from the
anti-chafe strap.
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Fig 2 Net lifting strop assemblies (Pre Mod and Post Mod)
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Post Mod
4.4 At their lower end (Fig 2D) the four legs are spaced out and formed into loops, each
leg loop encircling the net border cord and stitched back onto itself.
4.5 At the apex of each strop assembly (Fig 2B) a length of nylon strap is stitched to the
inside face of the inner lifting member (serving as an anti-chafe pad where the inner
member bears against the lower rim of the lifting hook eye). A small piece of webbing is
stitched across the apex of the loop to position the hook centrally on the lifting members.
Net stirrup
5 For helicopter single point suspension operations, all four net strop assembly lifting hooks
are attached to one stirrup only. Stirrup assembly description and system for engagement/
disengagement of associated assembly lifting hooks is as follows (Fig 3):
5.1 The 5600 kg net stirrup is oval in outline and is manufactured from a one piece steel
forging, which incorporates a crossbar dividing the stirrup into two approximately equal
parts, referred to as the upper part and lower part. The frame and crossbar of the stirrup are
predominately of the same circular cross section and thickness.
5.2 The upper part of the stirrup accommodates the load beam of the helicopter cargo
hook or the hook of a helicopter extension strop.
5.3 The lower part of the stirrup accommodates all four assembly lifting hooks. It is
necessary for the hooks to be detached from the stirrup to allow the net to be laid flat with
all four lifting strop assemblies lying clear of the mesh for the purpose of loading and
unloading and to enable a thorough pre-flight and after use inspection of hook engagement/
disengagement.
5.3.1 The mouth of a serviceable net strop hook will not pass over any part of a
serviceable stirrup structure other than at one intentionally ‘waisted’ section located on
the lower part of the stirrup on one side frame, immediately below the stirrup crossbar.
5.3.2 A robust spring loaded metal safety latch, hinged to the crossbar, provides a
close contact guard on the inside face of the ‘waisted’ section of the stirrup frame.
5.3.3 The safety latch is formed with a trigger shaped lever, which when depressed
opens the latch against its spring. This enables the mouth of a net strop lifting hook to
pass over the ‘waisted’ section, allowing the (larger) hook eye to pass onto the stirrup
frame and to slide down captive to the base of the stirrup. Upon release, the spring
loaded safety latch returns to its safe position at the ‘waisted’ section of the stirrup
frame.
NOTE
Fig 3 shows the ‘bills’ of the assembly lifting hooks all facing uniformly in one
direction in their engaged position on the stirrup. This not essential. The main
criterion is that the lifting legs of the individual assemblies, are not twisted 360°, at
the moment of engaging the hooks onto the stirrup.
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5.3.4 For disengagement, the lifting hooks are slid up the frame to the ‘waisted’
section and with the safety latch depressed to the open position, are removed from the
stirrup.
Fig 3 Stirrup with net strop assembly lifting hooks engaged
WARNING
IT IS DANGEROUS FOR THE LOWER PART OF THE STIRRUP TO BE USED AS
THE MEANS OF ENGAGING A HELICOPTER CARGO HOOK OR THE
SECONDARY HOOK OF A HELICOPTER EXTENSION STROP.
ASSOCIATED EQUIPMENT
Retainer breakaway
6 The retainer breakaway assembly, an issue item, is fully described in Chap 2-6 and Army
Equipment Support Publication (AESP) 1670-H-100, and must be fitted by a qualified HLSEI.
In brief, the 5600 kg net lifting members are retained together in a compact and manageable
form, prior to hook-up to the helicopter. Full NSN details for the equipment are contained in
AESP 1670-H-100.
Pad, protection, helicopter cargo net
7 Helicopter net protection pad equipment is an issue item for the 5600 kg net and is fully
described in Chap 2-5-0 and AESP 1670-H-100. In brief, the pads protect the net from damage
which may be caused by sharp edges and protrusions on the load and also provides a measure of
protection for the load, or its fitting. Full NSN details for the equipment are contained in AESP
1670-H-100.
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LIFE EXPIRY OF NET
8 The 5600 kg net is fitted with a metal label which is woven into the net mesh. The label
records the net life expiry date. All nets are to be taken out of Service when reaching their life
expiry date and action taken in accordance with the procedures laid down in AESPs.
NET STORAGE
9
Storage instructions for the 5600 kg net are contained in AESP 1670-H-100.
WARNING
THE NET MAY BE SUBJECT TO SNATCH LOADING OR DRAGGING ALONG
THE SURFACE DURING LOAD LIFTING OR LOAD LANDING OPERATIONS.
DELAYING THE REPAIR OR REPLACEMENT OF FAULTY EQUIPMENT
COULD RESULT IN SERIOUS INJURY TO PERSONNEL OR SERIOUS
DAMAGE TO EQUIPMENT.
TECHNICAL SUPPORT LITERATURE
10 Full technical supporting literature for this equipment, including before and after use
examination, general care, unit repairs and fitment instructions for component parts, technical
inspection procedures and any Service modification action or other changes, is published in
AESP 1670-H-100. Chap 1-1 gives general advice on obtaining AESPs.
FLYING LIMITATIONS
11 The 5600 kg net is not to be underslung unladen. The empty net deploys rapidly towards
the horizontal at a speed as low as 30 kts, with the subsequent danger that it may be drawn up
into the helicopter rotors.
11.1 The weight of cargo should not be less than 450 kg (1000 lb) in total, and this in turn
should be related to the drag profile presented by a normally stacked single NATO pallet
load. For loads of the same weight, but with a larger surface area, the stability
characteristics may prove less predictable than the standard NATO pallet load. Certain low
drag, high density loads, with a total cargo weight lower than 450 kg, may prove acceptable.
Ultimately, the safe carriage of any ultra-low density/ultra-lightweight load will depend on
the speed at which maximum allowable trail angles are attained and the speed at which any
deterioration in load handling characteristics takes place.
11.2 With two nets in cluster loads, net separation can occur at the higher speed range and
the speed at which the load is carried, must be limited by the onset of this phenomenon.
LIFTING DESIGN AND GENERAL SAFE PRACTICES RELATING TO 5600 KG NET
12 The 5600 kg net was designed specifically for carriage of NATO pallet loads in multiples
and for box shape container loads.
12.1 The net is suspended from two of its four sides, folding about one centre-line known
as the loading axis (Fig 4).
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Fig 4 Net suspended
12.2 Loads should be evenly distributed about and along the line of the loading axis, with
the longest sides or (for cylindrical items) rolling axes running parallel to the loading axis
(unless specific load clearance shows otherwise).
12.3 Heaviest items should be as close to the net centre as possible.
12.4 The net, when lifted, must provide end restraint for the assembled load, in the form of
a mesh wall. For normal length loads, the net only provides a limited depth of end walling
which is entirely satisfactory for pallet or container loads in a single layer, where the load is
secured at its base, within the end net walling. In the case of free layered or free stacked
loads, where they rise clear of the end walling, net side wall pressure may provide a useful
‘binding’ effect on the load (Fig 5A). With certain types of load, suitable load lashing
schemes for end restraint, are required.
12.5 With shorter length loads, end sections of the net will form into large vertical folds
(Fig 5 B).
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Fig 5 Net end wall formation with full and short loads
13 The long standing safe practices covered under load preparation for the 5000 lb octagonal
cargo lifting net (Chap 2-5-2) have a similar application for the 5600 kg net. In particular:
Even loading
13.1 The safety of the net depends upon the load weight being reasonably distributed in
terms of mesh loading across the net. Uneven loading could, if significantly
disproportionate be dangerous at higher laden weights, particularly if the net is lifting the
load at snagging points where mesh severance or failure could easily occur, with a risk of
the failure spreading.
Sharp edged loads
13.2 Carriage of such loads without suitable net protection can result in severe damage to
the net, particularly at potential load snagging points. The resulting damage could lead to an
in-flight hazard. See Chap 2-5-0 concerning net protection pads.
Low density items
13.3 Unless adequately secured there is always the danger that airflow may propel low
density load items out of the net (this has a particular bearing in relation to the end restraint
factor for the 5600 kg net). Under certain conditions such unsecured items could hazard the
aircraft.
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Securing cord ties
14 Unless a specific load clearance states otherwise, or a specific practice is highlighted in this
chapter, do not use the net mesh or net border as anchoring points for ‘securing-cord ties’. They
may interfere with the natural position that the net mesh or net border cord should adopt as it
comes into tension about the load. Although the ‘securing-cord tie’ may snap (no longer serving
the purpose for which it was intended) the net braid may also sustain damage, including heat
searing, as a result.
PREPARATION OF NET FOR CARRIAGE OF NATO PALLETS
Net handlers
15 The 5600 kg net is large, heavy and difficult to manage without an adequate net handler
team. Experience has shown that a team of six men is the ideal, allowing for hooking-up to the
helicopter and for subsequent load lifting.
Laying out the net
16 To lay out the net:
16.1 When operating in a Chinook uplift area do not lay out nets and net protection pads
until the loads are assembled. Empty nets and protection pads could be blown away, with
the added danger that loose protection pads could be drawn up into a helicopter’s rotors.
16.2 When ready, stretch the net out flat on the ground, with all four strop assemblies
pulled out into an untangled form, uncrossed and clear of the net. Do not leave the net strop
assembly lifting hooks engaged on the net stirrup. To reduce wear and tear, a reasonably
firm and flat grass surface is preferable to hardstanding.
16.3 Before laying out the net protection pads (procedures covered under ‘Pallet Loading
Scheme’ section) pull the net into a square, with the net mesh taking up square and not
elongated diamond form.
Setting up a two-net cluster load
16.4 When preparing a two-net cluster load, complete the laying out, loading and securing
process on the first net before laying out and loading the second net. In this way the second
net can be prepared in close formation to the first, with the result that both nets present a
compact load for lifting. This allows an easier hook-up operation and prevents unnecessary
damage to the nets and loads, caused by the nets dragging in towards each other as the
helicopter lifts them clear of the ground. The process of laying out the second net is
explained under the ‘Pallet Loading’ section.
LOADING OF NATO PALLET LOADS AND NET SECURING
Loading schemes
17 The correct layout of laden NATO pallets in the 5600 kg net, ranging from carriage of 1, 2,
3, 4 and the maximum number, six NATO pallet loads is shown in Fig 6. All loads on pallets
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must be securely restrained to the parent pallets by ‘banding’ or restraint lashings. The total
assembled weight of the load for carriage in the net is not to be less than 450 kg (1000 lb) para
11.1 also refers. The total assembled weight of the load for carriage in the net is not to exceed
5600 kg (12345 lb). Ideally pallet loads should be of uniform weight for any one net load. If
there is no alternative, then the maximum difference in weight not exceeding 450 kg (1000 lb)
may be accepted between the heaviest and lightest laden pallet in the loads. When dealing with
loads of three pallets length, place the heaviest pallet in the centre. The loading schemes do not
allow stacking of pallets in two layers, nor for the carriage of five laden pallets in a net. Five
pallets do not allow a balance load, resulting in pallet crushing and a misshapen net when the
load is suspended. NATO pallets are to be loaded in the net with their longer sides running
parallel to the loading axis.
Net protection pads
18 There is to be one protection pad per pallet. As with the pallets, the net pads are to be laid
out with their longer sides running parallel to the net loading axis. When working in multiples,
the net pads are to be set, end to end, or side to side in the case of two pallet rows. The centre
axis of the total net pad assembly should surmount the centre axis of the net. The loaded pallets
are to be placed squarely on top of the assembled net pads (Fig 6). Net pads are to be secured to
the load and not to the net.
Like loads
19 (Refer to para 11.1). The clearance for NATO pallet loads extends to the carriage of box
shape container loads with minimum base dimensions approximately equal to NATO pallets.
The same loading principles are to be adhered to. In particular the container(s) must be loaded as
a single layer load. When assembled in the net the load must not exceed the maximum length
and breadth dimensions of an assembled load of six NATO pallets with a maximum height from
floor of net of 70 in.
NOTE
Certain types of box container may not be suitable for movement by fork lift, and another
form of ground handling aid will be necessary. The requirement to avoid damaging the net
in any way during load emplacement or removal remains of paramount importance.
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Fig 6 NATO pallet loading schemes
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Net loading process - single net uplifts
20 Fork lift the pallets onto their allocated positions on the net. Fork lift vehicles and load
handlers will tend to ‘ruck’ the net. Keep the net pulled out evenly as loading progresses.
Net centre line marker
20.1 Net centre line markers play an important part and are to be kept in good order and
replaced as necessary.
CAUTION
Erratic handling of the fork lift can result in serious damage to the net border cord
or mesh. Avoid wheel spin or unnecessary turning on the net and ensure the forks
are raised when departing the net.
Fork lift operation
21 It is recommended that a fork lift approaches from the net lifting strop sides with pallets
forked broadside-on. This allows greater accuracy of the load emplacement. When approaching
from this direction, the net lifting strop assemblies are, as far as possible, opened out. When
passing over any section of strop leg, fork lift drivers are to avoid the apex of strop assemblies,
(where strop lifting hooks and restrictor buckles are located) and the loop ends of the strop legs
at the border cord attachment points (where the loop connector links are located). This also
applies when reversing off the net.
Securing net pads around load
22 Secure the outlying stretches of net pad up and around the walls of the loads. Join the edges
of the pad together using cord ties. Secure the padding firmly in position against the side and
end walls of the load, using cord ties directly to the load or over-the-load to the opposite net pad.
Upon completion, the bottom outer corners of the assembled load should be firmly contained
within the net protection padding.
Closing and securing the net and net strop assemblies
23 To close and secure the net and net strop assemblies:
Side wall netting
23.1 When loading and protection pad securing is complete, the lifting sides of the net are
to be pulled up against the side walls of the load, ensuring they are firm and even along their
length. Hold the net side walls in position against the load using up and over-the-load
‘holding-ties’, to secure opposite sides of the net around the load side walls (Fig 7). This
will reduce the work load on the net handling team during the initial stage of the helicopter
lifting process and as an aspect of load preparation should help reveal snagging points and
the need for extra protective padding (which will have to be secured to the load). When
lifted, the netted load is under tension and the net side wall ‘holding ties’ will automatically
slacken off until the load is returned to the ground and tension removed.
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Connecting-up to net stirrup
23.2 Locate the net lifting strop assembly, to which the net stirrup is secured. Engage the
assembly lifting hook onto the stirrup lower part by depressing the stirrup safety latch lever
and engaging the hook at the ‘waisted’ section of the stirrup side frame. Check that the legs
of the connected assembly are not twisted through 360° or more. Taking a clockwise or
anti-clockwise order of precedence (related to strop assembly mounting points around the
net border cord) engage the remaining strop assembly lifting hooks onto the lower part of
the stirrup. Check that the individual assemblies are not twisted through 360° or more
before engaging their hooks. It is not mandatory for the mouths of the lifting hooks to point
uniformly when engaged on the stirrup. When all hooks have been engaged ensure the
safety latch has returned to the fully closed position.
Securing net strop assembly legs
23.3 To make net lifting strop assemblies more manageable for helicopter hook-up and
during initial stage of lift, secure the legs together using the retainer breakaway assembly,
starting at the stirrup. If the retainer breakaway assembly is not fitted, secure by taping the
legs together, at intervals along their length, starting from the top.
Fig 7 Cross-sectional view of load showing net side wall ‘holding tie’
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TWO-NETTED LOADS IN CLUSTER, PREPARING THE SECOND NET
Pallet numbers in each load
24 Trials have shown that, with a maximum load variation of six laden pallets in one net and a
single laden pallet in the other, flying characteristics remain unaffected.
24.1 (Refer to para 16.4). With the first net loaded and secured ready for lifting, the
second net of a two-net cluster load is built immediately alongside the first with the loading
axis/lifting sides of both nets aligned as shown (Fig 8).
24.2 With the second net of the cluster laid out, carry out the remaining net preparation,
loading, net pad and net side wall securing procedures.
24.3 Secure the assembled net lifting strop assemblies on the second net, using the net
retainer breakaway. The lifting strop assemblies of both nets should be held together, to the
side of the combined load, in readiness for hooking-up.
Fig 8 Loading second net of two-net cluster
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HELICOPTER HOOK-UP
WARNINGS
(1) A HAZARD EXISTS FROM STATIC ELECTRICITY. BEFORE THE
HOOKING-UP PROCESS OF AN EXTERNAL LOAD AND OTHER ALLIED
FUNCTIONS IS COMMENCED, STATIC ELECTRICITY MUST BE
DISCHARGED BY THE USE OF A STATIC ELECTRICITY DISCHARGE PROBE.
(2) IT IS DANGEROUS FOR THE LOWER PART OF A STIRRUP TO BE USED
AS THE MEANS OF ENGAGING A HELICOPTER CARGO HOOK OR THE
SECONDARY HOOK OF A HELICOPTER EXTENSION STROP.
(3) THERE IS A DANGER TO PERSONNEL OF SLIPPING, OR GETTING
ENMESHED IN A BILLOWING NET, IF HELICOPTER HOOK-UP IS
CONDUCTED FROM THE TOP OF A NETTED LOAD. WHENEVER POSSIBLE
HOOK-UP IS TO BE CARRIED OUT TO ONE SIDE OF THE NETTED LOAD.
CAUTIONS
(1) When employing the 5600 kg net for helicopter single point suspension
operations, all four net lifting strop assembly hooks must be connected to one net
lifting stirrup.
(2) For single net uplifts, the net stirrup may be attached either, directly to the
helicopter cargo hook or to the secondary hook of a helicopter extension strop. A
cluster of two 5600 kg net loads must always be suspended from the secondary hook of
a helicopter extension strop or by such other means as a specific JATEU clearance
may allow (Chap 2-5, paras 5 to 7 also refers).
Hooking-up single net loads
25 The 5600 kg stirrup is a heavy item and, whilst it may be attached to the helicopter cargo
hook or extension strop hook using one hand, most people will probably find it easier to use two
hands.
25.1 Ensure that the combined assembly of net lifting legs is not twisted along its run by
360° or more. Grasp the lower half of the stirrup side frame, so that the fingers are above
the engaged net strop hooks and below the stirrup crossbar (Fig 9). Visually check that the
stirrup safety latch is fully closed at the ‘waisted’ section of the side frame.
25.2 To hook up, place the upper half of the stirrup firmly over the helicopter cargo hook
or, if being used, the secondary hook of the helicopter extension strop. With the stirrup
fully engaged on the helicopter cargo hook or the extension strop hook, check that the hook
keeper has returned to the fully closed position.
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Fig 9 Stirrup engagement
Hooking-up a two-net cluster load (see also Chap 2-5, paras 5 to 7)
26 With a two-net cluster load full of pallets, it is still possible to conduct the helicopter hookup operation from the side of the combined load.
26.1 Avoid hooking-up with substantial twists in the assembled legs of each net. The
twists may not be removed by the loads freedom to rotate beneath the helicopter on the
extension strop swivel hook.
26.2 When engaging the stirrup of each net, some personnel may be able to hold both
stirrups together and engage them onto the helicopter extension strop hook in one operation.
Other personnel will find it easier to engage one stirrup at a time. Engage the stirrups onto
the extension strop swivel hook in the order that the nets lie with reference to the
helicopter’s likely departure path. Of greater importance, as a means of avoiding wear on
the net lifting strop assemblies, ensure the lifting legs on the individual nets are not badly
twisted.
26.3 The checks and correct manner of engagement for each stirrup, on the helicopter
extension strop hook are stated in para 25.
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Precautions during initial lift and net release following load landing
27 There must always be sufficient ground handlers to manage any loose netting and to prevent
snagging during the initial stage of load pick-up. The 5600 kg net is a large net to handle and in
addition to the need for good load preparation techniques a team of four men is fully employed
during the initial stage of lift with a large load. The success, or otherwise, of loading and net
protection measures will not become evident until helicopter uplift. At any stage, where poor
loading or bad net snagging becomes evident, the load must be returned to the ground and
released if necessary, to enable re-preparation.
WARNING
TO AVOID THE DANGER OF BEING STRUCK BY THE POTENTIALLY
LETHAL METAL ELEMENT OF A STIRRUP OR EXTENSION STROP
ASSEMBLY, GROUND PERSONNEL ARE TO KEEP CLEAR OF THE LOAD
RELEASE AREA DURING NET RELEASE.
27.1 Following net landing the helicopter crewman will attempt to release the net stirrup
and helicopter extension strop, if employed, clear of the load to avoid possible damage to
the load.
27.2 If the net stirrup is to be manually disengaged from an extension strop, whilst the
strop remains attached to the helicopter, it is important that reference is made to Chap 2-2.
Net dragging during load pick-up and landing
28 The helicopter crew, and ground marshallers (and load preparation team dealing with the
cluster loads), should ensure that the netted load(s) are not dragged along the ground during liftoff or landing. Wear or serious damage can result, particularly with heavy loads, and it is
important if dragging has occurred, that the net(s) receive a thorough and early after-flight
inspection.
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CHAPTER 2-5-1 ANNEX A
ADDITIONAL TYPES OF LOAD
CONTENTS
Para
1
2
3
4
5
General
Specified ‘Authorised Loads’
APFCs
Class 30 and 60 trackway (WARNINGS)
Vehicles/Trailers
Metal tracked or studded/wheel chained vehicles and use of dunnage
Fig
1
2
3
4
5
6A
6B
6C
Page
Positioning of Airportable Fuel Containers (APFCs)
¼ ¼
Airportable Fuel Containers (APFCs) suspended in 5600 kg net
Single roll of Class 30 trackway ¼ ¼ ¼ ¼ ¼ ¼ ¼
Two rolls of Class 60 trackway ¼ ¼ ¼ ¼ ¼ ¼ ¼
Land Rover (LR) in 5600 kg net ¼ ¼ ¼ ¼ ¼ ¼ ¼
Dunnage with boards laid edge to edge (abutting) ¼ ¼ ¼
Dunnage with boards laid overlapping
¼ ¼ ¼ ¼ ¼
Lead-in dunnage laid in foreground ¼ ¼ ¼ ¼ ¼ ¼
¼
¼
¼
¼
¼
¼
¼
¼
¼
¼
¼
¼
¼
¼
¼
¼
¼
¼
¼
¼
¼
¼
¼
¼
2
3
4
4
5
7/8
7/8
7/8
GENERAL
1 Although the 5600 kg net has been specifically designed for the carriage of NATO pallets,
JATEU trials have confirmed that the net is suitable for the carriage of certain other specified
equipments and vehicles, examples of which are given in this Annex and Annex B. It should be
noted, however, that it is always better to use the primary recommended slinging scheme, if one
is published in AP 101A-1105-1B, when time permits and if the appropriate slinging equipment
is available. While carrying items in a net may well be a short term expedient when time is at a
premium there is always the attendant risk, particularly in the case of vehicles, that damage to the
load and/or the net may result.
SPECIFIED ‘AUTHORISED LOADS’
APFCs
2 A maximum of two full APFCs can be carried in the 5600 kg net, giving a maximum lift of
four containers carried in a two-net cluster.
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Load preparation
2.1 Carry out the standard serviceability checks on the APFCs. Ensure that the fuel filler
valve protection cap is fitted and that the air pressure valve is tight. The air pressure in a
full APFC should not exceed 5lb/in2. Position the two APFCs end to end in the centre of the
net, along the net loading axis (Fig 1) ensuring that adequate suitable padding is placed
between them. If only one APFC is being carried it is unnecessary to pad the ends of the
container as the net is not drawn up around the end plates.
Rigging
2.2 Pull the net around the APFCs ensuring that the mesh does not snag on any part of the
load. Retain the net side-walls in position against the load using up and over ties (see Fig 7
of Chap 2-5-1) of 150 lb NBC. Attach the net lifting strop hooks to the lower part of the
stirrup, checking for twists in the strops. Ensure that the stirrup safety latch is fully closed.
Fig 1 Positioning of Airportable Fuel Containers (APFCs)
2.3 A second load, with two APFCs, can be prepared in the same manner but ensure that it
is built up immediately alongside and parallel with the first to minimise dragging the nets on
the ground during pick-up.
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Fig 2 Airportable Fuel Containers (APFCs) suspended in 5600 kg net
Class 30 and 60 trackway
3 Rolls of Class 30 and 60 trackway can be carried either singly (Fig 3) or in pairs (Fig 4) as a
single or two-net clustered load. One spooled 45.7 m roll of Class 30 trackway weighs 3300 kg
and one spooled 15.2 m roll of Class 60 weighs 2400 kg (clean weights).
Load preparation
3.1 There is no special load preparation required prior to placing the trackway in the net.
Rigging
3.2 Place or roll the trackway in the net so that it is positioned centrally and parallel to the
loading axis. Ensure that ample padding is placed around the ends of the load to protect the
net mesh and retain the net side-walls in position against the load with 150 lb NBC up and
over ties (see Fig 7 of Chap 2-5-1). Attach the net lifting strop hooks to the lower part of
the stirrup, checking for twists in the strops. Finally, ensure that the stirrup safety latch is
fully closed.
Second load
3.3 A second load can be prepared in the same manner to form a two-net cluster if
required (aircraft payload permitting) but ensure that it is built up immediately alongside the
first to minimise dragging the nets on the ground during pick-up.
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Fig 3 Single roll of Class 30 trackway
Fig 4 Two rolls of Class 60 trackway
Vehicles/Trailers
4 Trials have been conducted at JATEU with the ½ ton, ¾ ton and 1 tonne LRs (hard and soft
top variants) underslung in the 5600 kg net. Experience has shown that, while this method of
underslinging vehicles or trailers in the field may offer a more convenient tactical alternative to
the primary method of using slings (assuming they are available), it is very likely that minor
damage to both the vehicle and net will be sustained. The decision as to whether this damage is
acceptable or not, rests with the local ground unit commander whose vehicles are being moved.
Load preparation
4.1 The normal vehicle preparation actions (excluding securing the doors together and
securing the spare wheel with additional nylon cord) should be taken as per the appropriate
clearances. Particular attention should be paid to removing or folding in all items such as
radio antennae and wing mirrors, which could snag on the net mesh during load pick-up. If
vehicle canvas covers are left on they must be serviceable and fully secured. Laden vehicle/
trailer contents must be secured to prevent possible loss during flight. It should also be
remembered that, in many cases, laden vehicle/trailer weights will be more difficult to
determine.
Rigging
4.2 Having laid out the net on flat ground drive the vehicle/trailer carefully onto the centre
of the net along the loading axis. It is important that the load is placed accurately in the
centre of the net so that the vehicle/trailer does not tip sideways on lifting. Secure ample
padding around sharp edges of bumpers, wheel hubs, towbars etc. Draw the net up around
the load, ensuring that the mesh does not snag on any part, and secure the net walls in
position against the load by using 150 lb nylon cord up and over ties (see Fig 7 of
Chap 2-5-1). Attach the net lifting strop hooks to the lower part of the stirrup checking for
twists in the strops. Ensure that the stirrup safety latch is fully closed. Where possible
employ a retainer breakaway assembly to gather the net strops and lay the net stirrup to one
side of the load ready for hook up.
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WARNINGS
(1) A HAZARD EXISTS FROM STATIC ELECTRICITY. BEFORE HOOKINGUP AN EXTERNAL LOAD AND OTHER ALLIED FUNCTIONS IS COMMENCED,
STATIC ELECTRICITY MUST BE DISCHARGED BY THE USE OF A STATIC
ELECTRICITY DISCHARGE PROBE.
(2) IT IS DANGEROUS FOR THE LOWER PART OF A STIRRUP TO BE USED
AS THE MEANS OF ENGAGING A HELICOPTER CARGO HOOK OR THE
SECONDARY HOOK OF A HELICOPTER EXTENSION STROP.
(3) THERE IS A DANGER TO PERSONNEL OF SLIPPING OR GETTING
ENMESHED IN A BILLOWING NET IF HELICOPTER HOOK-UP IS
CONDUCTED FROM THE TOP OF A NETTED LOAD. WHENEVER POSSIBLE
HOOK-UP IS TO BE CARRIED OUT TO ONE SIDE OF THE NETTED LOAD.
Initial lift
4.3 During the lifting process ground personnel should continually monitor the net to
ensure that no snagging has occurred and that the vehicle hangs square in the net (Fig 5). If
it leans excessively one way or the other damage to the vehicle canopy struts could occur
and therefore the load should be set down and re-rigged.
Fig 5 Land Rover (LR) in 5600 kg net
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Flying limitations
4.4 No limiting speeds can be predicted for netted vehicle/trailer loads but gradual
incremental speed changes should be made with careful continuous monitoring of canvas
covers, windscreens, vehicle contents etc for any signs of deterioration or coming loose.
Metal tracked or studded/wheel chained vehicles and use of dunnage
5 Operationally it may prove necessary to uplift metal tracked or studded/wheel chained
vehicles in the 5600 kg net. Without appropriate protection the net would almost certainly
sustain critical damage during vehicle loading, and thereafter. Net protection pads, on their own,
would be an inadequate safeguard and the use of ‘dunnage’ would be necessary.
Selection of dunnage
5.1 Suitable sheets of durable wood, eg plywood, should be selected, of ½ in. minimum
thickness and measuring up to the length and width of the vehicle. A single sheet is not
necessary and overlapping of several sheets where the material cannot be cut to size, is
acceptable. The area of dunnage should not, however, exceed the vehicle track length/
wheelbase. Dunnage trackways will also be required to allow the vehicle to be driven onto
the net.
Preparation and loading
5.2 Proceed as follows:
5.2.1 Fully stretch out the net in accordance with practice.
5.2.2
Position net pads.
5.2.3 Place the primary dunnage on the pads spanning the vehicle carrying location
in the net (Figs 6A or 6B).
5.2.4 Lay down lead-in dunnage (Fig 6C). Carefully drive the vehicle onto its
central location in the net, travelling across the lead-in dunnage. When the vehicle is
satisfactorily located on the primary dunnage, remove lead-in dunnage and associated
net pads around net border.
5.2.5 Fold primary net padding about ends of vehicle track sections or wheels.
Secure padding, and then continue with net securing and preparation for uplift in
accordance with procedures in this chapter.
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Fig 6C Lead-in dunnage laid in foreground
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CHAPTER 2-5-2
NET, CARGO LIFTING, HELICOPTER (5000 LB SWL)
CONTENTS
Para
1
2
3
5
7
14
15
16
17
18
19
20
21
22
25
27
30
31
32
33
34
37
40
41
42
43
45
46
47
48
49
50
53
56
57
60
62
64
66
Jul 06
Introduction
Equipment description
General
Netting
Lifting strops
Stirrup and hooks
Associated equipment
Retainer breakaway
Pad, protection, helicopter cargo net
Net life expiry
Technical support literature
Preparation of netted loads
Use of net pads
Laying out the net
Even loading
Uneven loading
Low density items
Fragile stores
Sharp or rough edged loads
Flat sheets of metal
Securing cord ties
Batteries and battery electrolyte
Baseboards
Closing and securing the net and net strop assemblies
Ground or deck transportation
Flat bed vehicles
Fork lift trucks
Nets with baseboards
Nets without baseboards
Hooking-up, flying and release
Checks before hook-up
Hooking-up (WARNING)
Single-netted load
Two-net cluster load
Precautions during initial lift
Flying limitations
Precautions during release (WARNING)
Typical netted loads
Composite ration packs
Jerricans
45 Gallon drums
Carriage of single NATO pallet loads
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CONTENTS (continued)
Table
1
2
Page
Jerricans typical weight (each) ¼ ¼ ¼ ¼ ¼ ¼ ¼ ¼ ¼ ¼
All-up weight of filled 45 gallon drums ¼ ¼ ¼ ¼ ¼ ¼ ¼ ¼
Fig
1
2
3
4
5
6
7
8
9
17
18
Page
5000 lb cargo lifting net
¼ ¼ ¼ ¼ ¼ ¼ ¼
Stirrup with all four hooks engaged ¼ ¼ ¼ ¼ ¼
Typical netted load
¼ ¼ ¼ ¼ ¼ ¼ ¼ ¼
Recommended design of baseboard ¼ ¼ ¼ ¼ ¼
Cross sectional view showing net side wall ‘holding tie’ ¼
Hooking-up single netted load ¼ ¼ ¼ ¼ ¼ ¼
Arrangement of composite ration pack load ¼ ¼ ¼
Arrangement of maximum 89 jerrican load
¼ ¼ ¼
Arrangement of seven x 45 gallon drums ¼ ¼ ¼ ¼
¼
¼
¼
¼
¼
¼
¼
¼
¼
¼
¼
¼
¼
¼
¼
¼
¼
¼
¼
¼
¼
¼
¼
¼
¼
¼
¼
¼
¼
¼
¼
¼
¼
¼
¼
¼
3
4
7
10
10
13
15
16
18
Annex
A
Rolled 5000 lb net used as a belly-band
INTRODUCTION
1 The 5000 lb cargo lifting net is designed to contain and lift external cargo loads, up to a
maximum weight of 5000 lb, suspended from the load beam of a helicopter cargo hook or
extension strop secondary hook. It can be used on all current British helicopters and is in use
with the three Services.
EQUIPMENT DESCRIPTION
General
2 The complete net assembly (Fig 1) consists of an octagonal-shaped net made from Nylon
Braided Cord (NBC) to which are attached four, four-legged nylon webbing lifting strops each
with a steel hook attached. The eye of one of these strops is permanently connected by a nylon
cord grommet to a steel stirrup (or loading ring) to which the four hooks can be attached for net
closure and lifting. The dry weight of the net is 45 lb.
Netting
3 The NBC is coreless, with a minimum breaking strain of 3500 lb, and is interlaced to form a
net mesh of approximately 6 in. The periphery of the net is fitted with a border cord
(corresponding to the headrope of a conventional net) which forms an integral part of the net.
The cord is braided nylon, coreless and with a minimum breaking strain of 7000 lb. Owing to
the construction of the net and to changes in dimensions that may occur in use it is impossible to
give the exact dimensions but, when laid out flat, there will be a distance of between 14 ft 9 in.
and 15 ft 5 in. between the opposing flats of its octagonal perimeter.
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4 During manufacture, the nylon cord is given an anti-abrasive treatment. The treatment can
cause some stiffness of the cord but this effect diminishes through use and does not affect the
strength or handling qualities of the net to any material extent.
Fig 1 5000 lb cargo lifting net
Lifting strops
5 Each of the four strops is formed from two lengths of nylon webbing both passed through
the eye in its hook. A small piece of webbing is stitched across the apex of the loop to position
the hook centrally on the lifting members.
6 The four ends of each lifting member are attached to the border cord by folding back and
stitching so that the four hooks can suspend the net from 16 points around the perimeter.
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Stirrup and hooks
7 The stirrup (Fig 2) forms the connection between the net and the load beam of the helicopter
cargo hook or extension strop secondary hook. It is constructed from a one piece steel forging,
which incorporates a cross bar dividing the stirrup into two approximately equal parts (the upper
part and the lower part). The frame and the crossbar are of a circular cross section. The stirrup
upper part engages the load beam of a cargo hook or extension strop secondary hook. The lower
part accommodates the four hooks.
Fig 2 Stirrup with all four hooks engaged
8 The stirrup is fitted with a robust loaded metal safety latch, hinged to the crossbar. A
‘waisted’ area is positioned on the stirrup side frame immediately adjacent to the safety latch.
The safety latch is formed with a trigger shaped lever, which when depressed opens the latch and
enables engagement or disengagement of the strop hooks. When released the latch closes under
spring pressure.
9 Each of the four hooks (Fig 2) is made from flat steel plate. The hooks can be readily
detached from or attached to the stirrup when required. The removal of the hooks from the
stirrup allows the net to be laid out flat for loading purposes with all four strops clear of the net.
All hooks must be attached to the stirrup before the net is lifted.
10 The lower portion of the stirrup is of sufficient size to allow it to be held by hand with the
fingers clear of the hooks and below the crossbar so that hook-up can be effected without
trapping or pinching the fingers (see Fig 6). It is normally easier to use two hands to engage the
stirrup.
11 The stirrup will engage on to the cargo hooks of the Chinook helicopter.
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12 The mouth of a serviceable/non-defective net hook will not pass over any part of its
associated stirrup structure (assuming that item to be serviceable) other than by means of the
‘waisted’ section.
13 Diagrams in the chapter show engaged stirrup hooks to be facing uniformly in one direction
on the stirrup lower part. This is not essential, and the most important consideration is that the
net lifting strop legs are not twisted in a complete 360° turn about themselves at the time the
hook is engaged to the stirrup.
ASSOCIATED EQUIPMENT
Retainer breakaway
14 The retainer breakaway assembly, an issue item, is fully described in Chap 2-6 and Army
Equipment Support Publication (AESP) 1670-H-100, and must be fitted by a qualified HLSEI.
In brief, the 5000 lb net lifting strops are retained together in a compact and manageable form,
prior to hook-up to the helicopter. Full NSN details for the equipment are contained in AESP
1670-H-100.
Pad, protection, helicopter cargo net
15 Helicopter net protection pad equipment is an issue item and is fully described in Chap
2-5-0 and AESP 1670-H-100. In brief, the pads protect the net from damage which may be
caused by sharp edges and protrusions on the load and also provides a measure of protection for
the load, or its fitting. Full NSN details for the equipment are contained in AESP 1670-H-100.
NET LIFE EXPIRY
16 The 5000 lb net is fitted with a metal label which is woven into the net mesh. The label
records the net life expiry date. All nets are to be taken out of Service when reaching their life
expiry date and action taken in accordance with the procedures laid down in AESPs.
TECHNICAL SUPPORT LITERATURE
17 Full technical supporting literature for this equipment, including before and after use
examination, general care, unit repairs and fitment instructions for component parts, technical
inspection procedures and any Service modification action or other changes, is published in
AESP 1670-H-100. Chap 1-1 gives general advice on obtaining AESPs.
PREPARATION OF NETTED LOADS
18 Although one of the advantages of the net is that loads are easily and relatively quickly
prepared, this does not mean that the load items can simply be piled into the net. Both for
reasons of safety and to obtain maximum life from the net, some basic principles must be
followed when preparing the netted loads. These principles, together with notes on general load
items, use of baseboards and the transportation of a loaded net on the ground, are covered in
paras 19 to 45. Some typical netted loads, with instructions on loading, are shown at the end of
the chapter.
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Use of net pads
19 Whenever possible net pads (see para 30 and Chap 2-5-0) should be used. The practical use
of these items is shown in Chap 2-5-1 (5600 kg net), also in USLC document serial 3052
(carriage of NATO pallet loads in the 5000 lb net, using Chinook heavy duty strop and other
equipments).
Laying out the net
20 Three hooks should be detached from the stirrup and the net stretched out flat on the ground
with all four lifting strops clear of the net. The net must be kept stretched during loading; with
multi-item loads, it should be pulled taut at intervals as loading progresses. When loading is
complete, the net when lifted by its lifting strops must encompass the outer corners of the load
items such that no part of the load contacts the strops.
NOTE
Users will have to use their best judgement as to how to assemble a pair of net loads for
uplift (para 47.7 refers). See paras 40 and 45 (ground or deck transportation); also
Chap 2-5-1 provides some worthwhile considerations when making up two nets alongside
each other for direct uplift as a pair by the helicopter.
Even loading
21 Load items should be evenly stacked around the centre of the net, if possible, in a near
circular pattern to accord with the octagonal shape of the net. If items of varying height are to be
carried, the higher items should be in the centre of the net load.
Uneven loading
22 Uneven loading, meaning that when lifted some portions of the net will be taking more
weight than others, will result in some lifting strops and some portions of the net taking unequal
shares of the load. This is particularly dangerous when at, or near, the maximum load of 5000 lb.
If possible, place heavier items near the centre of the net and avoid placing heavy items
immediately adjacent to light items.
23 The safety of the net depends upon the weight being evenly distributed over the net as a
whole. If this rule is disregarded, a failure at one point may be quickly followed by a progressive
failure of the whole net.
24 Uneven loading may not be obvious until the helicopter starts to lift when it becomes
immediately apparent by the over-tautness of some cords with comparative slackness in others.
Pulling the net tightly away from the load during the initial lift will help reduce the bad effects
but the only certain cure is to rearrange the load.
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Low density items
25 When a net is correctly loaded with a large number of small items it adopts a deep inverted
saucer-like shape in flight (Fig 3). Provided that the individual load items are tightly packed
against each other and that the outer edges of the net enclose the outer packages, there is little
danger of spillage. In fact, the outer edges of the net (being pulled inwards) help to hold the
whole load together as a solid mass.
Fig 3 Typical netted load
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26 With low density items such as empty jerricans, empty drums or similar items of
comparatively large size and little weight, there is a real danger that the airflow will force them
out of the open top of the net. It is essential, therefore, that such loads be lashed together (but
not tied to the net), or for their numbers to be so reduced so that the top of the net effectively
encloses them. Alternatively they can be wrapped in net pads (paras 15 and 19) or in a tarpaulin
or in hessian, securely parcelled and tied, and thus carried in the net.
Fragile stores
27 Fragile stores can easily be crushed by the net and so damaged.
28 In this sense, ‘fragile’ or ‘flimsy’ applies to such items as fresh rations, thin-walled plastic
fuel or water containers, or equipment that has delicate protrusions such as radio aerials etc.
29 Apart from packaging such items in separate protective containers, crushing can be
prevented by placing them on a locally manufactured circular baseboard or pallet and tying them
to the base. A suitable baseboard is described in para 34.
Sharp or rough edged loads
30 Sharp or rough edges of load items will cut the nylon cord/mesh of the net. Ammunition
boxes are common offenders in this respect. All sharp edges of items must be encompassed
within net pads (paras 15 and 19) or be padded with felt, sandbags, or other suitable material to
avoid damage to the net when the load is lifted or thereafter during transit under the helicopter.
Padding can be kept in place by the use of masking tape; issued net pads are manufactured with
eyeletted holes around the edges, allowing for the pad to be tied in position on the load (not to
the net) and also for pads to be tied together.
Flat sheets of metal
31 Flat thin sheets of metal such as corrugated iron sheets and similar material are not to be
loaded into nets unless:
31.1 The sheets are tightly lashed or banded to form one dense load.
31.2 All sharp edges, particularly the corners, are padded.
31.3 The total weight of the load exceeds 500 lb.
Securing cord ties
32 Unless a specific load clearance states otherwise, or other than for a specific practice
highlighted in this chapter, do not use the mesh or net border cord as anchoring points for
‘securing cord ties’. The problem with such ‘ties’ is that they may interfere with the natural
position that the net mesh or net border cord should adopt as it comes into tension about the load.
Although the ‘securing cord tie’ may simply snap (no longer serving the purpose for which it
was possibly intended) the net braid may also sustain damage including heat searing as a result.
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Batteries and battery electrolyte
33 Most acids will rapidly rot the net and must not be allowed to come into contact with it. The
net material is particularly susceptible to sulphuric acid and net failures are known to have
occurred due to contamination by this acid, probably arising from contact with battery
electrolyte. Wet batteries (acid or alkali) and containers of battery electrolyte must be prepared
for lift in accordance with current instructions for air transportation of Dangerous Cargo.
Baseboards
34 A circular wooden baseboard that can be placed inside the net is shown in Fig 4, which
provides sufficient information for its local manufacture. This baseboard can advantageously be
used for:
34.1 Crushable loads.
34.2 Delicate loads.
34.3 Awkward or difficult-to-load loads such as engines, flexible fuel tanks, batteries,
radios, etc.
35 Using a baseboard imposes a weight penalty that must be taken into account. Fig 4 gives
the maximum permissible outside diameter compatible with normal load containment and
smaller (and lighter) baseboards can be constructed when required. Other wood can be used, but
to gain strength equivalent to that of plywood will usually impose a greater weight penalty. The
essentials are:
35.1 Sufficient strength to carry the load when supported by its edges alone.
35.2 Sufficient holes to allow adequate lashing down of load items.
35.3 If fork lifting is envisaged, the height of the cross-members must be sufficient to
allow the forks of the fork lift truck to pass under the board and clear of the net. The height
of the cross-member shown in Fig 4 is the absolute minimum for this purpose.
36 It is essential that the net is well stretched under the baseboard before starting to build the
load up on the baseboard.
Closing and securing the net and net strop assemblies
Side wall netting
37 When loading and protection pad securing is complete, the lifting sides of the net are to be
pulled up against the side walls of the load ensuring it is firm and even along its length. Hold the
net side walls in position against the load by using up and over-the-load ‘holding ties’ to secure
opposite sides of the net about the load side walls (see Fig 5). This will reduce the work load on
the net handling team during the initial stage of the helicopter lifting process and as an aspect of
load preparation should help reveal possible snagging points and the need for extra protective
padding (which will have to be secured to the load). When lifted, the netted load is under tension
and the net side wall ‘holding ties’ will automatically slacken off until the load is returned to the
ground and helicopter lifting tension removed.
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Fig 5 Cross sectional view showing net side wall ‘holding tie’
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Connecting-up to net stirrup
38 Locate the net lifting strop to which the net stirrup is secured. Engage the lifting hook onto
the stirrup lower part by depressing the stirrup safety lever and engaging the hook at the
‘waisted’ section of the stirrup side frame. Check that the lifting members of the connected
lifting hook are not twisted through 360° or more. Taking a clockwise or counter clockwise
order of precedence (related to lifting strop mounting points around the net border cord) engage
the remaining lifting hooks onto the lower part of the stirrup. Check that the individual lifting
members are not twisted through 360° or more, before engaging their hooks. It is not mandatory
for the mouths of the lifting hooks to point uniformly when engaged on the stirrup. When all
hooks have been engaged ensure the stirrup safety latch has returned to the fully closed position.
Securing net lifting strops
39 To make net lifting strops more manageable for helicopter hook-up and during the initial
stage of lift, secure their legs together in combined form using the retainer breakaway starting at
the stirrup end. If a retainer breakaway is not fitted, secure by taping the legs together, at
intervals along their length, starting from the top.
GROUND OR DECK TRANSPORTATION
40 Loaded nets are very awkward to move on the ground or on a deck. Ideally the net should
be loaded at the pick-up point and the load broken down at the dropping point, but this is not
always either practicable or desirable. If a loaded net has to be moved one of the following
methods can be used:
Flat bed vehicles
41 For loading, the net can be laid out on the flat bed of a truck or trailer, the load completed
and the vehicle and the loaded net moved to the pick-up point, the net being picked up by the
helicopter from the vehicle. For unloading, the helicopter lowers the net on to the vehicle and
the vehicle is then moved to the unloading point.
Fork lift trucks
42 For movement of a loaded net by fork lift truck, a baseboard (inside or outside the net) or a
suitable pallet, is essential.
Nets with baseboards
43 If the load is to be mounted on a baseboard (para 34) for flight, the load should be prepared
in the usual manner with the net well stretched out on the ground, the baseboard placed on the
net and the load built up and secured, where necessary to the baseboard. The net is then to be
well stretched around the complete load and the net strops taped to keep the net taut. The
complete assembly can then be picked up by the forks of a fork lift truck inserted through the net
immediately below the board and over the bottom part of the net, care being taken to avoid the
forks damaging the net.
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44 For unloading, if the load has been secured to the board, it is usually more convenient to
unhook the net and throw the sides clear of the load and then pick up the baseboard and its load
leaving the net at the dropping point.
Nets without baseboards
45 Alternatively, the net may be placed centrally over a baseboard or a pallet before being
loaded and the baseboard, with the loaded net on top, then picked up and moved to the pick-up
point. After pick-up the baseboard must be returned to the distribution point.
HOOKING-UP, FLYING AND RELEASE
46 The following paragraphs 47 to 59 deal with those precautions to be observed before and
during hook-up, flying and release. Detailed information on the preparation of loads is given in
paragraphs 18 to 45 and 60 to 66.
Checks before hook-up
47 Immediately before hook-up, the following items must be checked. They are given here as
an aide-memoire and the paragraph reference that follows most items indicates where more
detailed information will be found in this chapter.
47.1 The net is serviceable (para 17).
47.2 The All Up Weight (AUW) is known. This is the total weight of all items plus the
weight of the net.
47.3 No exposed sharp edges can damage the net (para 30).
47.4 Any items of comparatively large volume and light weight, ie low density items such
as empty jerricans or empty drums, are positively secured in the net (paras 25 and 26).
47.5 Net lifting strops are taped together, or held by a retainer breakaway, so that they
cannot catch on any projecting portions of the load during the initial stages of lift.
47.6 The net is as evenly loaded as possible (para 21).
47.7 It is permissible to lift clusters of two or more nets at once. Each net is to weigh
approximately the same, and the load in each net is to be of approximately the same bulk, ie
the loads should be of approximately equal density and weight. Refer to USLC 3052 for
details. However, in order to accommodate safely the net stirrups of a two or more net
cluster the use of an extension strop with swivel hook is MANDATORY.
Hooking-up
48 A hazard exists from static electricity therefore:
WARNING
ALWAYS USE A STATIC PROBE PRIOR TO HOOK-UP OR BEFORE
HANDLING A SUSPENDED LOAD.
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Single netted load
49 Hold the stirrup so that the fingers are above the hooks and below the crossbar, slide the
upper part of the stirrup over the extended forward portion of the load beam of the cargo hook.
Slide it aft past the spring-loaded hook keeper latch. To confirm that the stirrup is engaged
correctly pull back the stirrup and ensure it does not disengage (Fig 6).
NOTE
The load beam is never to be engaged in the lower portion of the stirrup.
Fig 6 Hooking-up single netted load
Two-net cluster load (see also Chap 2-5, paras 5 to 7)
50 Avoid hooking-up with substantial twists in the lifting strops of each net. The twists may
not be entirely removed as the result of the loads freedom to rotate beneath the helicopter on the
extension strop swivel hook.
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51 When engaging the stirrup of each net, some personnel may be able to hold both stirrups
together, and engage them onto the helicopter extension strop hook in one operation. Other
personnel will find it easier to engage one stirrup at a time. Engage the stirrups on to the
extension strop swivel hook, in the order that the nets lie with reference to the helicopters likely
departure path. Of greater importance, a means of avoiding wear on the net lifting member is to
ensure the lifting strops on the individual nets are not badly twisted.
52 The checks and correct manner of engagement for each stirrup on the helicopter extension
strop hook are as stated in para 47.
Precautions during initial lift
53 Care must be taken that the lifting strops of the net do not catch or snag on any projection of
the load. Taping the lifting strops will assist in keeping them clear but it may be necessary for
personnel to assist by holding the lifting strops and the upper portion of the net tight and clear of
the load as the helicopter takes the weight.
54 With some loads it is difficult to prevent individual parts of the net from being overloaded
but every effort must be made to prevent this. Ideally each cord length should be of equal
tension, but this is impossible to achieve exactly in practice. If one or two cords in any one area
of the net are taut while adjacent cords are comparatively slack, the net must be adjusted to
equalise the tension as far as possible.
55 Marshallers, crewman and pilots must ensure that the helicopter cargo hook is central over
the loaded net before the helicopter starts to lift. If it is not, the load will be dragged along the
ground with consequent wear and even breakage of the net where it rubs on the ground.
Flying limitations
56 The 5000 lb net is not to be underslung unladen. The empty net deploys rapidly towards the
horizontal at a speed as low as 30 kts, with the subsequent danger that it may be drawn up into
the helicopter rotors.
56.1 The weight of cargo should not be less than 227 kg (500 lb) in total, and this in turn
should be related to the drag profile presented by a normally stacked single NATO pallet
load. For loads of the same weight but with a larger surface area, the stability characteristics
may prove less predictable than the standard NATO pallet load. Certain low drag, high
density loads, with a total cargo weight lower than 227 kg, may prove acceptable.
Ultimately, the safe carriage of any ultra-low density/ultra-lightweight load will depend on
the speed at which maximum allowable trail angles are attained and the speed at which any
deterioration in load handling characteristics takes place.
56.2 With two nets in cluster loads, net separation can occur at the higher speed range and
the speed at which the load is carried, must be limited by the onset of this phenomenon.
Precautions during release
57 Marshallers, crewman and pilots must ensure that the helicopter is stationary in relation to
the ground before release and that the net is lowered gently to the ground, otherwise, the net will
drag and wear will be caused. If the load is dropped the net may be cut by edges or corners of
the load items.
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WARNING
TO AVOID THE DANGER OF BEING STRUCK BY THE POTENTIALLY
LETHAL METAL ELEMENT OF A STIRRUP OR EXTENSION STROP
ASSEMBLY, GROUND PERSONNEL ARE TO KEEP CLEAR OF THE LOAD
RELEASE AREA DURING NET RELEASE.
58 Following net landing, the helicopter crewman will attempt to release the net stirrup, and
helicopter extension strop if used, clear of the load to avoid possible damage to the load.
59 If the stirrup is to be manually disengaged from an extension strop, whilst the strop remains
attached to the helicopter, it is important that the static electricity discharge procedure be carried
out.
TYPICAL NETTED LOADS
Composite ration packs
60 Eighty-five 10 man composite ration packs can be carried, arranged in a single layer as
shown in Fig 7. The packs are stacked on their ends so that their 16 in. lengths are vertical. The
weights of composite packs vary so it is essential that the AUW is checked before lifting.
Fig 7 Arrangement of composite ration pack load
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61 The net must be kept reasonably tight during the stacking of the packs so that the loaded net,
when lifted by its lifting strops, completely covers the outer corners of the packs.
Jerricans
62 Eighty-nine filled jerricans of fuel or water, can be carried in a net (Fig 8). The outer
jerricans must be positioned with their filler caps inward so that the lifting strops or the cords of
the net do not catch on the projections of the filler caps and their locking devices as the net is
lifted.
Fig 8 Arrangement of maximum 89 jerrican load
63 It is essential that when the net is lifted by its lifting strops, the net completely covers the
outer corners of the assembled load. Empty jerricans carried in this manner must be lashed
together, but not to the net (paras 26 and 32 refer). This may be done by passing rope or 1200 lb
NBC through the handles until the jerricans are all laced together, either as a single entity or in
clutches of 15 to 20 cans. When passing cord through cans on the periphery of the load, some
slack in the cord should be allowed to cater for these outer cans rising when the side walling of
the net is brought into tension about the load (see Fig 3). Alternatively, empty cans may be
parcelled and tied in net pads, tarpaulin or the like, to form an enveloped load within the net. If
such securing measures cannot be taken, then the carriage of empty jerricans within the net must
be limited to the number which allow for the net side walling effectively to close over the load
with a smaller base area taken up by the load. A certain amount of double stacking of jerricans
may prove possible whilst still remaining well enclosed by the net walls.
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TABLE 1 JERRICANS TYPICAL WEIGHT (EACH)
Metal type
Plastic type
Empty
4.5 lb (2 kg)
Filled with 4.5 to 5
galls Water
55 lb (25 kg)
Empty
10 lb (4.5 kg)
Filled with 4.5 galls:
Civgas
Diesel
Kero
46 lb (21 kg)
50 lb (22.7 kg)
55 lb (25 kg)
45 gallon drum
64 Seven filled 45 gallon drums can be carried in a net. The weight of one to seven drums with
their more common contents are given in Table 2. To prepare a load of seven drums:
64.1 Lay out the net with the lifting strops clear of the net. Lay net pads (para 15 and 19)
if available.
64.2 Join together two sets of two web lashings. Lay parallel to each other about 3 ft apart
across the net so that they are equally disposed about the centre of the net.
64.3 Position four drums, on their sides, over the web lashings so that the sides of the
drums are at right angles to the lashings and the whole assembly forms a rectangle centred
in the net (see Fig 9).
64.4 Check all the drums against outward movement, with chocks, and position the
remaining drums so that they lie naturally in the ‘valleys’ formed by the lower drums.
64.5 Tighten each web lashing with a ratchet tensioner and then remove the chocks.
64.6 If using net pads, draw them up and secure in position about the outer edges of the
drums using cord. In the absence of net pads, use felt, sacking, sandbags or the like to pad
the outer edges of the drums where the net will be pulled tight over the edges; secure the
padding in place with masking tape.
64.7 Finally, pull the net tightly up and around the load, so that when lifted the net will
completely encompass the drums. Secure the net in the ‘ready for lift’ position by means of
up and over ‘holding ties’ (para 37 refers).
65 Empty drums can also be carried in this manner but in this instance the web lashings must
be tied to the net so that there is no danger of the drums being blown out of the net (para 26
refers).
Carriage of single NATO pallet loads
66 See AP 101A-1105-1B, USLC 3052 for carriage of single NATO pallet loads in 5000 lb
nets; either as a single net load, or in cluster, using Chinook heavy duty extension strop and
assorted net suspension methods.
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TABLE 2 ALL UP WEIGHT OF FILLED 45 GALLON DRUMS
AUW (lb) including drums
Contents
One Two Three Four Five Six Seven
Drum drums drums drums drums drums drums
Water at 10.0 lb/gallon
503
1006
1509
2012
2515
3017
3520
AVTUR at 8.0 lb/gallon
413
826
1239
1652
2065
2477
2890
AVTAG at 7.7 lb/gallon
399
798
1197
1596
1995
2393
2792
AVGAS at 7.2 lb/gallon
377
754
1131
1508
1885
2261
2638
Lubricating oil at 9.1 lb/gallon (average)
463
926
1389
1852
2315
2777
3240
Fig 9 Arrangement of seven x 45 gallon drums
Chap 2-5-2
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CHAPTER 2-6
RETAINER BREAKAWAY ASSEMBLY
CONTENTS
Para
1
3
5
Introduction
Equipment description
Technical support literature
Fig
Page
1
2
3
4
General details of retainer breakaway assembly¼
Retainer fitted to helicopter cargo nets
¼ ¼
Retainer fitted to textile slings ¼ ¼ ¼ ¼
Retainer fitted to SML 6000 lb ¼ ¼ ¼ ¼
¼
¼
¼
¼
¼
¼
¼
¼
¼
¼
¼
¼
¼
¼
¼
¼
¼
¼
¼
¼
¼
¼
¼
¼
3
4
5
6
INTRODUCTION
1 For helicopter USLs employing slings or cargo nets with multiple lifting legs it is necessary,
as the final part of the rigging process, to secure together the sling set or net lifting members.
This is to reduce the chance of their snagging on the load during the hook-up process, or as the
helicopter takes strain on the load, prior to lifting it to the hover. The traditional way of doing
this was to tape the sling or lifting members together, at intervals, with wraps of adhesive tape.
2 The retainer breakaway assembly has been designed as a re-usable and more reliable
method of temporarily securing sling or net legs together, until hook-up has been effected and
the load brought to tension under the helicopter; the retainer may also be used for sling stowage.
EQUIPMENT DESCRIPTION
3 The retainer breakaway is manufactured from nylon webbing and consists of a longitudinal
strap to which (in the case of the master assembly) nine cross straps are sewn. Velcro straps are
attached to each leg of the cross straps, providing the means of closure about the assembled legs
of a sling or lifting members of a cargo net.
4 The full/master length retainer is employed on the 5600 kg helicopter cargo net and the
11300 kg sling. The retainer may be cut to shorter lengths, to allow for its wider employment
with other specified sling or net equipments (Figs 1 to 4). For instructions and individual fitment
procedures for specified sling and cargo net equipments, consult Army Equipment Support
Publication (AESP) 1670-H-100.
4.1 The retainer breakaway assembly is attached to a specified leg of the given sling or
cargo net equipment.
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4.2 A loop is provided at the lower end of the longitudinal strap, which is secured with a
double loop nylon cord tie to a specified point at the lower end of the parent sling or net leg.
A further loop is provided at the approximate mid-point of the retainer longitudinal strap
(mid-point related to full/master length assembly) so that the strap can be cut into two ‘Type
A’ lengths (Fig 1).
NOTE
Reinforcing patches are attached to the longitudinal strap adjacent to all cutting
positions.
4.3 The retainer longitudinal strap is secured along the remainder of the parent sling or net
lifting member by encircling wraps of adhesive tape, placed at both sides of each cross strap
(tape wraps three full turns).
4.4 In the case of the full/master length retainer, an additional nylon cord tie is likely to be
introduced at the top end of the longitudinal strap, when the assembly is employed with the
5600 kg helicopter cargo net.
TECHNICAL SUPPORT LITERATURE
5 Full technical supporting literature for this equipment, including before and after use
examination, general care, unit repairs and fitment instructions, technical inspection procedures
and any Service modification action or other changes, is published in AESP 1670-H-100.
Chap 1-1 gives general advice on obtaining AESPs.
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RETAINER BREAKAWAY CONFIGURATIONS
TYPE A - SML 6000 lb SWL
NET CARGO LIFTING 5000 lb SWL
TYPE B - SML 4600 kg SWL
TYPE C - NO CURRENT APPLICATION
TYPE D - SML 11300 kg SWL
NET CARGO LIFTING 5600 kg SWL
Fig 1 General details of retainer breakaway assembly
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Fig 2 Retainer fitted to helicopter cargo nets
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Fig 3 Retainer fitted to textile slings
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Fig 4 Retainer fitted to SML 6000 lb
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CHAPTER 2-7
CARGO RESTRAINT REQUIREMENTS FOR HELICOPTER UNDERSLUNG LOADS
(Completely revised)
CONTENTS
Para
1
2
3
5
6
7
8
9
10
12
13
14
15
16
Introduction
The basis of restraint
Restraint for helicopter underslung loads (USLs)
Directional restraint
Location of loose items/freight
Range of restraint equipment and securing materials
Load categories
Load categories and restraint equipment rating
Aerodynamic load
Non-aerodynamic load
Restraint equipment rating
Determination of restraint
Determine restraint required
Estimate the number of lashings required
Optimum restraint
Fig
1
2
3
4
5
6
Page
Palletised load… … … … … … … … … … … … … …
Combined use of load structure and lashings to provide restraint/securement
against movement of loose items
… … … … … … … … …
Aerodynamic load on a vehicle flatbed or pallet
… … … … … …
Aerodynamic load in trailer … … … … … … … … … … …
Non-aerodynamic load … … … … … … … … … … … …
Partially exposed non-aerodynamic load … … … … … … … …
2
3
4
4
5
5
INTRODUCTION
1
Underslung load restraint equipment is used to secure those parts of a load which might
otherwise be free to shift their position, or detach from the load, at any stage from helicopter
load hook-up, to load landing of the load at its destination. During this process, the load must
be capable of remaining intact when subjected to rotor downwash, airflow effect and any load
oscillations induced during flight. Movement of part of the load could cause imbalance and
undue strain being placed on part of the slinging system. It would cause damage to or
severance of parts of the slinging equipment, and could result in the load entering an unstable
condition, which might culminate in the crew having to jettison the load. Items detaching from
the load pose a threat to the safety of the helicopter, as well as to persons or property on the
ground.
THE BASIS OF RESTRAINT
2
To restrain any load it is necessary to identify the direction and magnitude of forces that are
likely to be applied to the load. The restraint equipment must be used inside the margin of its
ultimate strength/breaking point to cater for the normal forces, which are likely to affect the load.
Identification of normal and likely extreme forces is relatively straightforward for the purpose of
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aircraft internal load restraint, and the criteria are laid down for restraint to be applied in each
primary plane, ie forwards, aft, sideways and vertically up and down. The criteria allow for a
margin of safety between normal operating conditions and the restraint equipment reaching its
breaking point.
RESTRAINT FOR HELICOPTER UNDERSLUNG LOADS (USLs)
3
To identify the magnitude and direction of forces, which are likely to affect the security of
individual parts of an USL, is extremely difficult. This is particularly so with loads suspended
from a single cargo hook, where the load may display random tendencies to turn, or spin and
even enter violent forms of oscillation.
4
To allow for the various forces that will affect different types of USLs, the rating of restraint
equipment used will vary according to the category of the load being restrained. Paras 8 to 16
deal with the different load categories and the rating of restraint equipment.
NOTE
It is important to remember that the overall rating of a restraint system is no higher than that
of its weakest link.
Directional restraint
5
Loose items or freight, making up or forming part of an USL, require to be secured against
movement of individual items (best illustrated by banding of palletised loads, Fig 1). Where
container, vehicle or trailer walls, flooring or similar, provide adequate restraint in given
directions, lashing requirements are reduced to securing against movement in those directions
not covered by immediately surrounding structure (Fig 2). Where the structure is all enclosing,
as in a trailer, it is sufficient to restrain the items by means of the trailer canopy and a load
restraint net.
RESTRAINT STRAPS
Fig 1 Palletised load
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RESTRAINT STRAPS
Fig 2 Combined use of load structure and lashings to provide restraint/securement against
movement of loose items
Location of loose items/freight
6
In deciding upon the disposition of loose freight or other items, there must be suitable
means or facilities for securing them in location. It is vitally important that loose items and
associated lashing equipment do not come into contact with deployed sling legs or associated
items of slinging equipment. Positioning of loose items/freight must avoid upsetting the balance
of the load with the result that any one sling leg may become overloaded. Where these
requirements cannot be met, Underslung Load Clearances (USLCc) will only cover carriage of
vehicles in the unladen state.
RANGE OF RESTRAINT EQUIPMENT AND SECURING MATERIALS
7
The current range of tie-down chains, tensioner equipment and cargo restraint nets
provisioned for the USL restraint role is covered in Chaps 2-7-1 and 2-7-4. Chap 2-7-3
discusses the use of nylon cord which, together with adhesive tape, serve as additional securing
materials commonly called up in USLCs.
LOAD CATEGORIES
Load categories and restraint equipment rating
8
To determine the restraint equipment rating, the load weight and category must first be
established. Loads, regardless of their shape, can be categorised as aerodynamic or nonaerodynamic. The difference between these two categories is explained in paras 9 and 10.
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Aerodynamic load
9
An aerodynamic load is a load which is exposed on its sides to the airflow, eg a load on a
flatbed vehicle or pallet (Fig 3) or a load which does not completely fill and protrudes above the
sides of the cargo compartment of a vehicle/trailer or container (Fig 4).
LOAD SIDES EXPOSED
TO THE AIRFLOW
VEHICLE FLATBED
OR PALLET
DIRECTION
OF AIRFLOW
Fig 3 Aerodynamic load on a vehicle flatbed or pallet
HEAVY LOADS MUST BE
PLACED CENTRALLY WITHIN
THE CARGO COMPARTMENT
LOAD PROTRUDING ABOVE
AND NOT SUPPORTED BY
THE TRAILER SIDES
DIRECTION
OF AIRFLOW
Fig 4 Aerodynamic load in trailer
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Non-aerodynamic load
10 A non-aerodynamic load is a load which may be either:
10.1
Not exposed on any of its sides to the airflow (Fig 5).
LOADS MAY COMPLETELY OR PARTIALLY FILL
THE CARGO COMPARTMENT. HEAVY LOADS
MUST BE PLACED CENTRALLY
LOAD SIDES PROTECTED
FROM THE AIRFLOW
HIGH SIDED
VEHICLE, TRAILER
OR CONTAINER
THE LOAD
MUST NOT
PROTUDE
ABOVE
THE SIDES
DIRECTION
OF AIRFLOW
Fig 5 Non-aerodynamic load
10.2 Partially exposed to the airflow on one or more sides, ie the load height does not
exceed 25% of the sideboard height of the vehicle, trailer or container etc (Fig 6).
10.3 Fully exposed to the airflow on one side only, eg a load in a vehicle without a
tailboard which may also be partially exposed on its other sides as per para 10.2.
LOAD PROTRUDING
ABOVE THE SIDEBOARD
EXPOSED TO THE
AIRFLOW
MAX HEIGHT THAT THE LOAD MAY
PROTRUDE ABOVE THE VEHICLE/
TRAILER/CONTAINER SIDEBOARD
IS 25% OF THE MEASURED
SIDEBOARD HEIGHT (x)
THE LOAD MUST FILL
THE CARGO
COMPARTMENT AND
BE FULLY SUPPORTED
BY THE VEHICLE
TRAILER OR CONTAINER
SIDEBOARDS
SIDEBOARD
HEIGHT = (X)
DIRECTION
OF AIRFLOW
Fig 6 Partially exposed non-aerodynamic load
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11 If a load as described in paras 10.2 and 10.3 exceeds the limits stated, it is to be classified
as aerodynamic.
Restraint equipment rating
12 The forces acting on these two types of load are different, therefore the amount of restraint
required will also differ. The simple rule of thumb to be applied is to use the Ultimate Tensile
Strength (UTS) of the total restraint system for non-aerodynamic loads and to use ⅔ of the UTS
for aerodynamic loads, eg a non-aerodynamic load of 1000 lb (453.6 kg) would require a
minimum restraint of 1000 lb (453.6 kg) and an aerodynamic load of 1000 lb (453.6 kg) would
require a minimum of 1500 lb (680 kg). For individual UTS ratings, refer to Chap 2-7-1 to 2-7-4
for HUSLE and to the respective vehicle or equipment handbook for vehicle or equipment tiedown rings.
DETERMINATION OF RESTRAINT
13 The following instructions should be used to ensure that items of load are adequately
restrained.
Determine restraint requirement
14 The restraint required in each direction is to be determined by multiplying the all up weight
(AUW) of the load by the directional restraint factor (1G in all directions), the restraint required
for example for a load weighing 1000 lb is:
Forward
Aft
Vertical
Side
-
1000 times
1000 times
1000 times
1000 times
1
1
1
1
=
=
=
=
1000 lb
1000 lb
1000 lb
1000 lb
Estimate the number of lashings required
15 The approximate number of lashings required to adequately restrain a load, can be
estimated by applying the following rule of thumb:
15.1 For forward and aft restraint. Multiply the AUW of the load by the G factor and
divide by the rated strength of the lashing, eg:
For an aerodynamic load of 4000 lb using 5000 lb web lashing with a ⅔ UTS rating
of 3333 lb you would calculate as follows:
Load WT 4000 lb x 1G
Lashing rating 3333 lb
=
1.2
=
2 lashings forward
Load WT 4000 lb x 1G
Lashing rating 3333 lb
=
1.2
=
2 lashings aft
15.2 If all lashings are attached to the load at angles of between 30 and 45 (both to the
cargo compartment floor and the centre line) adequate vertical and lateral restraint will be
achieved.
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Optimum restraint
16 To achieve optimum load restraint the following basic principles should be applied
whenever possible:
16.1 All lashings should be used in pairs and be arranged to provide restraint in three
directions (see Fig 4).
16.2 All lashings (used in any particular direction) should be of equal length and strength
and be attached to the load at equal angles.
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CHAPTER 2-7-1
RESTRAINT CHAINS AND COUPLING TENSIONERS
(Completely revised)
CONTENTS
Para
1
3
4
5
6
7
2 m or 4.5 m, M/D extension chains used as restraint chains
Limits for passage of chain around tie-down rings or part of the load
Quick release coupling (QRC), 10000 lb
Classification of equipment and rating
Taping practice
Maintenance support literature
Fig
1
2
3
4
5
Page
Quick release coupling (QRC), 10000 lb        
2 m or 4.5 m, M/D extension chain assembly and QRC with chain engaged in
chain anchor housing            
QRC, jaws in ‘open’ position
         
QRC, jaws in ‘closed’ position          
2 m or 4.5 m, M/D extension chain and QRC, examples of ‘claws to tie-down
point/claws to chain loop’ engagement
       
2
3
4
4
5
2 M OR 4.5 M, M/D EXTENSION CHAINS USED AS RESTRAINT CHAINS
1
2m or 4.5 m, M/D extension chain assemblies are also to be used as items of restraint
equipment. Their basic description, together with the correct method of engaging the chain
shortening clutch, is given in Chap 2-3-2.
2
When called up as items of USL restraint equipment, the chains are used with the 10000 lb
QRC. Chain and QRC equipment is particularly useful for providing anti-jack knife restraint with
vehicle and trailer type combination loads when carried externally by helicopter, and instructions
relating to the particular methods used for specific vehicle/trailer type combinations are
contained in the relevant USLCs.
Limits for passage of chains around tie-down rings or parts of the load
3
For use as items of restraint equipment the following limits apply for passage of 2 m or
4.5 m, M/D extension chains around tie-down rings or parts of the load. The chain is not to be
looped around:
3.1
Circular sections of less than 13 mm (½ in.).
3.2
Angular or flat sections with square or rounded edges whose thickness of section is
less than 13 mm (½ in.).
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QUICK RELEASE COUPLING (QRC), 10000 LB
4
A QRC, 10000 lb is a device that allows for connected chains to be hand tensioned,
thereby removing any final element of slack in the length of the chain which would otherwise be
difficult to eliminate. A description and its method of operation is given:
4.1
The QRC consists of a central turnbuckle barrel with a quick release claw fitting at
one end and chain anchor housing at the other (Fig 1).
4.2
The turnbuckle barrel can be rotated by an external tensioning ring to extend or
retract the overall length of the coupling, thus slackening or tightening an attached length of
chain.
4.3
The chain anchor housing is slotted to accommodate a 2 m or 4.5 m M/D chain
which is retained by a locking ring. This ring is also slotted to permit entry of the chain
which is locked by a half turn of the locking ring (Figs 1 and 2).
4.4
The quick release claws are opened and closed by a quarter turn of a knurled claw
operating ring (Figs 1, 3 and 4). The tensioners have a red dot engraved on the turnbuckle
cover and on the claw operating ring. It is essential that the two red dots be aligned before
the claws can be considered as being positively locked (Fig 4).
4.5
In use, the QRC claws lock the coupling to a tie down/load securing ring or to a
extension chain loop (Fig 5). The maximum tension applied via the QRC must not exceed
that which can be applied by hand, ie tools are never to be used as an aid to tensioning.
TURNBUCKLE BARREL
CLAWS
TURNBUCKLE COVER
TENSIONING RING
Fig 1 Quick release coupling (QRC), 10000 lb
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FREE END OF CHAIN
CLUTCH ASSEMBLY
Fig 2 2 m or 4.5 m, M/D extension chain assembly and QRC
with chain engaged in chain anchor housing
CLASSIFICATION OF EQUIPMENT AND RATING
5
The extension chain assemblies and QRC are classified by ‘ultimate strength’ (breaking
load). In this case the extension chains have a far greater breaking load than the QRC which
ultimately becomes the weak link and would be expected to fail before the extension chains.
Therefore, in the case of the QRC, under a force or load in excess of 10000 lb, taken along the
line of the chain/tensioner, the QRC can be expected to fail. The rating of the QRC is
dependent on the category of load being restrained (Chap 2-7 refers) and are as follows:
5.1 For non-aerodynamic loads the rating is 10000 lb (4536 kg).
5.2 For aerodynamic loads the rating is 6666 lb (3023 kg).
TAPING PRACTICE
6
See Chap 3 for examples of taping practice.
TECHNICAL SUPPORT LITERATURE
7
Full maintenance support literature for this equipment is published in AP 108G-0002-1D,
HUSLE Ancillary Equipment. Chap 1-1 gives general advice on obtaining HUSLE maintenance
APs.
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CLAW OPERATING RING
Fig 3 QRC, jaws in ‘open’ position
RED DOTS IN ALIGNMENT
Fig 4 QRC, jaws in ‘closed’ position
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DAP 101A-1105-1A
QRC CLAWS TO ATTACHMENT
POINT ENGAGEMENT
QRC TO CHAIN LOOP,
TWO CHAIN CIRCUIT
QRC TO CHAIN LOOP,
TWO CHAINS INDEPENDENT
FREE END
OF CHAIN
FREE END
OF CHAIN
FREE END
OF CHAIN
QRC TO CHAIN LOOP,
SINGLE CHAIN CIRCUIT
FREE END
OF CHAIN
Fig 5 2 m or 4.5 m, M/D extension chain and QRC, examples of
‘claws to tie-down point/claws to chain loop’ engagement
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DAP 101A-1105-1A
CHAPTER 2-7-3
NYLON CORD
CONTENTS
Para
1
2
3
4
5
6
7
8
Introduction
General features
Knots
Ties
Types of securing tie
Practical strength of ties
Strength criteria
Practical applications
Fig
1
2
3
Page
Tying various useful knots … … … … … … … … … … …
Various useful ties
… … … … … … … … … … … …
Tying a bowline, round turn and two half hitches … … … … … …
5
6
7/8
INTRODUCTION
1 Nylon cord is used extensively in USL preparation and is suitable for restraining or securing
lightweight items, where chains or web lashings and their associated tensioners cannot be used.
This chapter highlights some general and important points concerning the practical use of nylon
cord.
GENERAL FEATURES
2 In general cords, that are commonly called up in USLCs, have a high strength/weight ratio
with a high degree of strength before breakage. Being pliable, nylon cord is relatively tolerant of
passage around acute corners providing there are no sharp or jagged edges. Nylon cord is
normally classified by minimum breaking strength (min BS), which equates to breaking load, but
this figure does not include the degrading effect of knotting.
KNOTS
3 The effect which makes a knot hold securely is friction; the more tension on the cord the
more tightly the knot should bind together. Nevertheless, with smoothly finished material such
as nylon braided cord (NBC), it is sound practice to apply ‘stop’ knots (thumb knots) having
completed the main knot. Stop knots prevent the cord ends from slipping back through the main
knot and will also help to prevent fraying of the cord ends. A more permanent means of
preventing fraying is to fuze the end filaments of the cord by directing a soft flame for a few
seconds across the end of the cord. This practice is normally called upon for the purposes of
USLs and may be debarred by the nature of the load, eg flammable materials. Figs 1 and 3
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DAP 101A-1105-1A
illustrate various types of knot which have a useful application for securing items, or parts of the
load, in preparation for helicopter underslinging.
TIES
4 The purpose of a securing tie is that it will hold one item to another in a sufficiently and
robust manner to ensure that the items remain secured together for the duration intended. For a
helicopter USL this includes all phases of the operation, from ground transit to the helicopter
hook-up point to eventual landing of the load at its destination.
TYPES OF SECURING TIES
5 The following information details various types of securing ties which feature regularly in
USLCs:
Single tie
5.1 A single tie connects two items, with a single thickness of cord (Fig 2).
Double tie
5.2 A double tie connects two items, with two thicknesses of cord (Fig 2).
Single loop tie
5.3 A single loop tie connects or secures two or more items together with two thicknesses
of cord (Fig 2).
Double loop tie
5.4 A double loop tie connects or secures two or more items together with four thicknesses
of cord (Fig 2).
5.4.1 Double running loop tie. A double loop tie connects or secures two or more
items together with four thicknesses of cord. A single part of cord is passed twice
around the items and the two single cord ends tied together with a reef knot and two
stop knots (Fig 2).
Parcel tie
5.5 A parcel tie is made with a bowline knot, a round turn and two half hitches (see Fig 2).
This tie is useful when two or more items are to be secured tightly together, and is made in
the fashion of the first tie around a postal parcel. The bowline knot is used to form a loop or
eye in one end of the cord and the cord is passed around the items to be tied, with the end
passing through the bowline loop. The end is then tightened and pinched with the fingers in
a bight at the bowline loop to maintain the tension of the tie, while securing with the round
turn and two half hitches. The main benefits with this tie are that a mechanical advantage of
two is offered (neglecting friction) when the end is being hauled through the loop, and the
tension obtained can be maintained whilst making fast the tie.
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DAP 101A-1105-1A
Vantage strop
5.6 This tie is very useful where two items need to be drawn powerfully towards each
other and secured (see Fig 2). The tie can be made to perform the function of a tie-down or
lashing. Viewing the strop as depicted (Fig 2) it offers a mechanical advantage of two if the
upper end moves, and three if the lower end moves (neglecting friction). If the main
consideration is for the maximum pulling force, the tie should be made so that the pull
exerted by the operator (indicated by the black arrow, Fig 2) is away from the moving end
of the system. Where the maximum of force is not the main consideration, the tie may be
made in a way the operator finds convenient.
PRACTICAL STRENGTH OF TIES
6
In practice, the efficiency and strength of a tie is affected by the following:
The ability of cord to stretch under load
6.1 It has to be accepted that under sufficient load, nylon cord will stretch and allow a
certain amount of movement of the item restrained. Providing the stretch is not too great,
and limited movement of the item is not critical, this should not prove a problem with most
USLs.
Reduction of strength resulting from knots
6.2 The reduction of strength of cord by the inclusion of knots affects ties of all types. As
a general rule, the use of knots effectively reduces the breaking strength of a cord to half of
the rated figure. Although knots reduce the strength of the cord, it is seldom that the knot
itself breaks under load; failure usually occurs at or near the point where the standing part of
the cord enters the knot.
Sharp edges or corners
6.3 Sharp edges or corners cut into the cord when a load is imposed; they should be
avoided, or alternatively padded to protect the cord.
STRENGTH CRITERIA
7 The strength criterion to be applied when using nylon cord (or similar materials) for
securing items on USLs and, where cord ties are being made in the absence of specific
instructions for USLCs, the following rules are to apply:
7.1 To provide a safe working tolerance for unforeseen load forces, including allowance
for knots and for the possibility of the cord operating at acute angles and round acute bends,
the practical strength of the cord is to be reckoned as being one third of its rated breaking
strength, eg 1200 lb NBC is to have the capability of restraining a load or force not in excess
of 400 lb.
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7.2 As a general rule the ‘working’ strength of the cord may be multiplied by the number
of parts of the cord passing between the items tied, eg a 1200 lb nylon cord ‘double tie’
(Fig 2), having two parts of the cord passing between the items, may be considered to have a
working strength of 400 lb x 2 = 800 lb.
Use of alternatives to 1200 lb NBC (when not available)
7.3 The use of alternative lower strength NBC to 1200 lb NBC is permitted provided
multiple ties are used to give an equivalent or greater strength than 1200 lb
NOTE
If continuous running ties are used to replace single ties the NBC is degraded and an
additional ⅓ more turns must be made to compensate, eg to replace a single 1200 lb
NBC tie with a running tie of 150 lb NBC:
►
1200
150 x 2
►
◄
= 4
4 + (4 x ⅓) = 5.333
◄
6 complete turns are required.
PRACTICAL APPLICATIONS
8
For practical applications see Chap 4.
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Fig 1 Tying various useful knots
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DAP 101A-1105-1A
Fig 2 Various useful ties
Chap 2-7-3
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DAP 101A-1105-1A
Fig 3 Tying a bowline, round turn and two half hitches
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DAP 101A-1105-1A
CHAPTER 2-7-4
NET CARGO, THROW-OVER RESTRAINT FOR HUSLE SWL 1000 KG
(Completely revised)
CONTENTS
Para
1
2
3
4
5
6
7
8
9
12
14
16
19
Introduction
Equipment description
Hooks
Net identification labels
Associated equipment
Pad, protection, helicopter cargo net
Net life expiry policy
Net storage
Maintenance support literature
Instructions for use
General
Preparation to vehicles/trailers
Attachment to vehicles
Attachment to trailers
Net tensioning
Fig
1
Page
Net cargo, throw-over restraint for HUSLE SWL 1000 kg




2
INTRODUCTION
1
The net cargo, throw-over restraint has been designed to restrain loads up to 1000 kg of
loose cargo loaded in a vehicle or trailer when carried as a helicopter underslung load. Full
NSN details and nomenclature for the equipment are contained in AP 108G-0002-1A, HUSLE
Nets.
EQUIPMENT DESCRIPTION
2
The net cargo, throw-over restraint (Fig 1), measuring 3.25 m x 2.44 m, is constructed in
knotless intersections to a one piece rectangular shape, with diamond meshes. A continuous
peripheral border cord forms an integral part of the net assembly. A ‘marker row’ (red) is
attached to the mesh row adjacent to the border cord on one narrow side; the marker row
therefore identifies one narrow side of the net. Lashing lines used for final net tensioning are
attached to the net, four meshes in from each corner. The dry weight of the net is 10 kg.
Hooks
3
Twenty-two hooks are permanently attached around the net periphery. These are used to
attach the net to a vehicle or trailer. A further 14 hooks are permanently attached to the net
mesh and are equally spaced 3.5 or 4 meshes inboard from the net periphery. These hooks are
used for initial tensioning of the net.
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NET
BODY
BORDER
CORD
HOOK
LASHING
LINE
MARKER
ROW
IDENT LABEL
Fig 1 Net cargo, thrower-over restraint for HUSLE SWL 1000 kg
Net identification label
4
The net has an identification label located near the centre of the net and provides details as
shown in Fig 1. The rear of the ident label is used to record the net life expiry date.
ASSOCIATED EQUIPMENT
Pad, protection, helicopter cargo net
5
Net protection pads are described fully in Chap 2-5-0. The pads protect the net from
damage which may be caused by sharp edges and protrusions in the load and also provides a
measure of protection for the load or its fittings. Full NSN details and nomenclature for this
equipment are contained in AP 108G-0002-1D, HUSLE Ancillary Equipment.
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DAP 101A-1105-1A
NET LIFE EXPIRY POLICY
6
The net is a ‘Lifed item’, the policy for which is laid down in the maintenance support
literature for the equipment (para 8). Users are to ensure that the life expiry date is recorded on
the rear of the ident label with either a permanent black/blue marker pen or a metal etching tool.
NET STORAGE
7
Storage instructions for the net cargo, throw-over restraint SWL 1000 kg are contained in
AP 108G-0002-1A, HUSLE Nets.
MAINTENANCE SUPPORT LITERATURE
8
Full maintenance support literature for this equipment is published in AP 108G-0002-1A,
HUSLE Nets. Chap 1-1 gives general advice on obtaining HUSLE maintenance APs.
INSTRUCTIONS FOR USE
General
9
All items with sharp edges within the load must be padded to prevent damage to the net.
10 The load should be covered with a canvas to restrain small items. Chaps 2-7 and 4
describe fully the restraint of equipment within a vehicle or trailer.
11 Before attaching, lay out the net on a dry flat surface, free off any hooks that may have
tangled in the meshes and untangle the lashing lines.
Preparation to vehicles/trailers
12 Prior to loading, if the load is small and not expected to project beyond the rear of the
vehicle or above the sides, action must be taken to provide the means of securing the net. This
can be achieved by tying double lengths of braided nylon cord laterally and longitudinally to the
vehicle or trailer internal restraint brackets. Tie the cord with stop knots.
13 Action before loading is not required if the load is in excess of that described in para 12, in
which case the net will be secured by using the external canopy lugs.
Attachment to vehicles
14 Drape the net over the load, ensuring that the red marker row is at the front or rear of the
vehicle and that there is an equal amount of netting hanging down each side of the load.
14.1 Small load. Pass the hooks located on the border cord around the length of the
braided nylon cord and then engage them back on to the net mesh.
14.2 Large load. Engage the net border cord on the external canopy securing lugs on
each side of the vehicle and engage the hooks located on the border cord back on to the
net mesh.
15 Tension the net by using the hooks located in the net mesh and also the lashing lines (see
paras 19-21).
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Attachment to trailers
16 Drape the net over the load, ensuring that the red marker row is at the front or rear of the
trailer and that there is an equal amount of netting hanging down each side of the load.
17 Engage the net border cord on the cover securing lugs on each side of the trailer and
engage the hooks located on the border cord back on to the net mesh.
18 Tension the net by using the hooks located in the net mesh and also the lashing lines (see
paras 19-21).
Net tensioning
19 The method of tensioning the net is common in all tensioning procedures given in this
chapter for vehicles or trailers. The net is tensioned on completion of attachment by using the
hooks and lashing lines located in the mesh, ideally with equal tension over the whole of the net
surface.
20 Initial tensioning is achieved by pulling on each hook in turn towards the net centre, taking
up some slack in the net and attaching the hooks to convenient mesh legs. Repeat the process
until the net is equally tensioned over the net surface.
21 Final tensioning is achieved by reeving each lashing line in turn in and out of the net
meshes, pulling tight and tying off with double stop knots.
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DAP 101A-1105-1A
CHAPTER 2-8
BAG - SINGLE USE LIFT, SWL 1000 KG
AND
STROP, DISPOSABLE, 2 M, SWL 2000 KG
(Completely revised)
CONTENTS
Para
1
2
3
4
5
6
10
11
12
13
14
15
18
Bag – Single Use Lift
Introduction
Equipment description
Single use lift bag identification
Life expiry of Single Use Lift Bag
Technical support literature
Equipment usage (WARNING)
Strop, Disposable, 2 m
Introduction
Equipment description
Disposable Strop identification label
Life expiry of the Disposable Strop
Technical support literature
Equipment usage (CAUTION)
Suitability for engagement to current range of helicopter cargo hooks
Fig
1
2
3
Page
Single Use Lift Bag, showing user advice and identification details
… …
Strop, Disposable, 2 m … … … … … … … … … … … …
Disposable Strop connecting 2 SULBs to helicopter cargo hook … … …
3
4
6
BAG – SINGLE USE LIFT
Introduction
1 The Single Use Lift Bag (SULB) has been introduced into Service as a disposable item of
HUSLE to enable small items of stores and equipment to be carried by helicopter. The
equipment has the NATO stores description of ‘Bag - Single Use Lift, SWL 1000 kg, HUSLE’.
Full NSN details for the equipment are contained in Army Equipment Support Publication
(AESP) 1670-H-100.
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EQUIPMENT DESCRIPTION
2 The SULB (Fig 1) is manufactured from polypropylene and available in 4 colours, Sand,
Olive Drab, Snow and Red. Four lifting loops are fitted to the bag, one to each corner. The two
adjacent loops are connected via Stevedore harnesses to provide a single point lift. The top of
the bag is secured by means of a draw-corded skirt. The SULB SWL is as follows:
Maximum
Minimum
SWL 1000 kg
SWL 250 kg
Single use lift bag identification
3 The bags are stencilled with various identification details as shown in Fig 1. Additionally,
when removed from its protective packaging, users are to record the date on the bag.
LIFE EXPIRY OF SINGLE USE LIFT BAG
4 The SULB is a ‘Lifed’ item the policy for which is laid down in the technical support
literature, para 5 and also described in Chap 1-1. On removal from its protective packaging,
equipment holders are to ensure that the removal date is marked legibly and indelibly with black
permanent marker pen on the front of the SULB (Fig 1).
TECHNICAL SUPPORT LITERATURE
5 There is no technical supporting literature for the SULB apart from operating information
and NSN details which are published in AESP 1670-H-100. Chap 1-1 gives general advice on
obtaining AESPs.
EQUIPMENT USAGE
WARNING
THE SULB IS FOR ONE SORTIE PER BAG ONLY.
6 The SULB allows for miscellaneous items of equipment and general cargo to be carried as
authorised loads within the given SWL. Items with sharp edges/corners are to be prepared
accordingly to minimise the risk of splitting/tearing the SULB. A skirt, sewn around the top
edges of the bag with a draw-cord incorporated (Fig 1), enables items to be contained securely
within the bag.
7 If there is a requirement to carry equipment with a Dangerous Air Cargo (DAC) aspect, it is
to be prepared in accordance with current instructions for air transportation of DAC. The bag is
resistant to most solvents, oils and greases, however it may be vulnerable to corrosive substances
such as battery acid that may cause structural failure of the bag.
8 The SULB has a tendency to twist in flight and therefore is not to be attached direct to the
aircraft cargo hook but to either an extension strop with swivel hook assembly or to a 2 m
Disposable Strop. As the characteristics of a failed single SULB are unacceptable, it is not to be
flown individually but as a pair.
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9 A maximum of 2 SULBs can be attached direct to an extension strop secondary hook or 2 m
Disposable Strop, with a minimum of 250 kg SWL in each SULB. Multiple SULBs may be
carried with the appropriate multi-legged sling. The SULB is to be prepared, rigged and flown
in accordance with DAP 101A-1105-1B, USLC 3030.
Fig 1 Single Use Lift Bag, showing user advice and identification details
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DAP 101A-1105-1A
STROP, DISPOSABLE, 2 M
Introduction
10 The Disposable strop (Fig 2) has been introduced into Service as an alternative method of
lifting 2 SULBs from a helicopter cargo hook. The equipment has the NATO description of
‘Strop, Disposable, 2 m, SWL 2000 kg’. Full NSN details for the equipment are contained in
Army Equipment Support Publication (AESP) 1670-H-100.
Fig 2 Strop, Disposable, 2 m
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DAP 101A-1105-1A
EQUIPMENT DESCRIPTION
11 The Disposable Strop is constructed from braid into an endless 4 m loop, with a protection
sleeve to interface with the Stevedore harnesses of the SULB. Soft eyes are formed at each end
of the strop as a method of attachment to a helicopter cargo hook. The strop can only be used in
a ‘parallel basket hitch’ configuration giving an effective working length of 2 m. The SWL of
the Disposable Strop is 2000 kg.
Strop identification label
12 The Disposable Strop has an identification label attached over one leg and is taped in
position. The label details are shown in Fig 2.
LIFE EXPIRY OF THE DISPOSABLE STROP
13 The Disposable Strop is a ‘Lifed’ item the policy for which is laid down in the technical
support literature, para 14 and also described in Chap 1-1. On removal from its protective
packaging, equipment holders are to ensure that the removal date is marked legibly and indelibly
with black permanent marker pen on the strop identification label.
TECHNICAL SUPPORT LITERATURE
14 Full technical supporting literature for this equipment including before and after use
examination and general care is published in AESP 1670-H-100. Chap 1-1 gives general advice
on obtaining AESPs.
EQUIPMENT USAGE
15 The Disposable Strop allows for 2 SULBs to be attached to a helicopter hook and delivered
to a Drop-Off-Point without the need for a ground handling team. The Disposable strop may be
used several times, within its 28 day service life, subject to its serviceability.
CAUTION
The design of the Disposable Strop includes a protective sleeve onto which the SULB
Stevedore harnesses are to be placed. Should the Stevedore harnesses make direct
contact with the unprotected braid of the Disposable Strop, significant chafing may
result in failure of the Disposable Strop.
16 One soft eye end of the Disposable Strop is looped through both Stevedore harnesses on
each SULB to create a ‘parallel basket hitch’ configuration (Fig 3). The Stevedore harnesses are
to be centralised on the Disposable Strop and placed over the protective sleeve; a failure of the
strop may occur should the Stevedore harnesses be positioned directly around the unprotected
braid. The Disposable Strop is to be taped just above the ends of the protective sleeve and at the
soft eye ends to reduce incorrect attachment of the Disposable Strop to a helicopter cargo hook.
17 Chap 2-1, para 16 describes that only one lifting ring/apex device is to be carried on the load
beams of British Service helicopter cargo hooks, however as the Disposable Strop can only be
used in the ‘parallel basket hitch’ configuration, 2 soft eye ends need to be attached to the
helicopter cargo hook. When connecting the Disposable Strop to the helicopter cargo hook,
ground personnel are to ensure that both soft eye ends of the strop are attached correctly to the
cargo hook load beam.
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DAP 101A-1105-1A
Suitability for engagement to current range of helicopter cargo hooks
18 The current range of applicable helicopter cargo hooks are described in Chaps 2-1-1 to
2-1-6.
19 Consult Chap 2, compatibility matrix and DAP 101A-1105-1B, USLC 3030 for application
of the Disposable Strop to helicopter cargo hook.
Fig 3 Disposable Strop connecting to 2 SULBs to helicopter cargo hook
Chap 2-8
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DAP 101A-1105-1A
CHAPTER 3
STANDARD RIGGING PRACTICE AND TECHNIQUES
CONTENTS
Para
1
2
3
4
5
7
8
Introduction
Basic rules for slings and cargo lifting nets
Use of NBC
Use of tape (WARNING)
Systems for chain leg measurement in USLCs
Chain loops
Chain to chain
Forming chain lifting loops around vehicle spring hanger brackets
Fig
1
2
3
4
5
6
7
8
Page
Securing loose chain and not in use sling legs ¼ ¼ ¼ ¼ ¼ ¼ ¼
Taping loose chain and chain hooks ¼ ¼ ¼ ¼ ¼ ¼ ¼ ¼ ¼
Use of extension chain leg supporting ties ¼ ¼ ¼ ¼ ¼ ¼ ¼ ¼
Retainer breakaway assembly, or tape, securing lifting strops/sling legs after
rigging ¼ ¼ ¼ ¼ ¼ ¼ ¼ ¼ ¼ ¼ ¼ ¼ ¼ ¼ ¼
Correct use of a sling leg support tie ¼ ¼ ¼ ¼ ¼ ¼ ¼ ¼ ¼
Incorrect use of a sling leg support tie
¼ ¼ ¼ ¼ ¼ ¼ ¼ ¼
Method of connecting chains
¼ ¼ ¼ ¼ ¼ ¼ ¼ ¼ ¼ ¼
Chain loops around vehicle spring hanger brackets ¼ ¼ ¼ ¼ ¼ ¼
4
5
6
7
8
8
9
10
INTRODUCTION
1 Preceding chapters have described individual items of slinging equipment in detail, and
rigging instructions in USLCs will give precise instructions for employment of items of
equipment when they are called into use for a specific load. Older generation clearances, in
particular, assume a thorough knowledge of standard practice on the part of personnel using the
rigging scheme. Such clearances will generally afford a basic outline diagram in support of
rigging instructions. Current clearances aim to provide maximum guidance by use of pictorial
presentation. Whatever the age or format of the clearance, it remains implicit that personnel
using an USLC have been trained, are in current practice with the slinging equipment called up,
or are directly supervised by authorised personnel. The purpose of this chapter is to ensure that
all personnel understand what constitutes standard rigging practice, together with applicable
techniques.
BASIC RULES FOR SLINGS AND CARGO LIFTING NETS
2 The following basic rules apply to slings and, where applicable, cargo lifting nets:
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2.1 Sling legs are to be arranged about the load in a symmetrical manner; eg with a four
legged sling, the two outer legs are led to one end of the load and the two inner legs led to the
other.
2.2 It is very important to ensure that sling legs are not crossed at the stage of attaching
them to the load. The same principle applies to the lifting strops on nets at the stage of
engaging lifting hooks to the net stirrups. It is also important to ensure that individual net
lifting members are not twisted along their own length.
2.3 When the sling legs are in full lifting attitude, with the load suspended, the steel wire
rope and textile element of the sling legs are to be clear of the load.
2.4 With four legged slings, if less than four legs are being used to lift the load, the legs not
in use must be securely taped to the legs in use (Fig 1). This is to prevent snagging of the
unused legs during initial load lift and any possibility of flailing in flight.
2.5 Loose chain must be taped back securely onto the standing part of the chain, or secured
in such other manner as may be called for in individual USLCs (Fig 2). The mouths of all
chain hooks are to be taped after their engagement onto a chain, to prevent inadvertent
detachment prior to load lift or at any time when the chain is slack. Similarly, to prevent
snagging, shortening clutch claws must be taped (Fig 2). Chain shortening clutches are fitted
with chain locking levers and do not require taping in their ‘chain engaged’ position
(Chap 2-4-1).
2.6 There is a correct and incorrect method of engaging chain hooks and chain shortening
clutches. The included angle of chain loops are limited and dependent upon the type of
chain, minimum diameters or thickness of section around which the chain may pass, are also
limited. Refer to the appropriate equipment chapter.
2.7 After the sling has been attached to the load, the final stage of rigging involves steering
the sling legs (or net lifting strops) clear of potential snagging points on the load and securing
them in this position using NBC, the retainer breakaway or turns of adhesive tape. NBC is
used to support the sling legs to prevent them dropping down below the load attachment
points and becoming trapped or twisted on lift or to prevent them from snagging on load
protrusions (Fig 3). The retainer breakaway or adhesive tape is used to secure the sling
legs/net lifting strops together at intervals just above the load (Fig 4). When the sling
legs/net lifting strops come under tension the Velcro fasteners or turns of tape will break and
the legs take up their natural line of lift. At this stage the NBC support ties will become
loose or break. The retainer breakaway (Chap 2-6) is used with all available slings, the
5000 lb and 5600 kg nets.
Use of NBC
3 When applying NBC leg support ties, unless otherwise specified on the USLC, a single tie of
150 lb NBC is to be used. The incorrect use of support ties could lead to serious problems. Fig
5 shows the correct use with the tie fully supporting the sling leg. Fig 6 shows the incorrect use,
the tie being tied off to the sling leg above the attachment point on the load. If tied incorrectly
the sling leg will slacken off before the load is lifted allowing the attachment loop to drop down
below the spring hanger bracket, where it could become trapped or twisted and shorten the length
of the sling leg. The shortened leg would then take a greater proportion of the load weight which
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could overload the leg causing a breakaway or alter the load attitude, both of which could
seriously effect its flying characteristics. The incorrect strength of NBC used as supporting ties
could also cause the same problems.
Use of tape
4 When securing hook mouths, loose chain or shortening clutches to a standing chain, there
must be a minimum of three full turns of tape around the item being secured (2 in. tape is
normally used). This rule also applies when securing not in use sling legs to those in use. For
the final securing of an assembled sling or net prior to load lift, one and a half turns of 2 in. tape
must be used.
WARNING
DO NOT EXCEED TAPING PRACTICE ON PARTS OF SLINGING EQUIPMENT
WHICH EXTENDS BEYOND THE PRACTICE STATED HERE, IN PRECEDING
EQUIPMENT CHAPTERS OR IN INDIVIDUAL USLCs. IF THERE IS CONCERN
IN ANY AREA THEN THIS SHOULD BE EXPRESSED DIRECTLY TO JATEU.
SYSTEMS FOR CHAIN LEG MEASUREMENT IN USLCs
Chain loops
5 Chain loops are normally related to the number of links forming the loop, as counted from
the fixed end of the chain hook or shortening clutch. In a 24 link loop, link No 1 is the link
which is attached to the tail of the chain hook or clutch (whether or not this link is a special
joiner or out-sized link). Counting along the links from that start point, the chain hook or clutch
is engaged onto the 24th link (Fig 7).
6 For larger chain loops, the chain hook or clutch engagement point may be related to the far
end of the chain, ie the point where the chain is fixed to the end of the wire rope or textile
element of the sling. To engage the chain hook or clutch onto the 8th link from the sling leg
fixture point, link No 1 is the link attached to the fixture at the end of the wire rope or textile leg
element (whether or not this link is a special joiner or out-sized link). Counting along from link
No 1, the chain hook or clutch would be engaged onto the 8th link from the start point (Fig 7).
Chain to chain
7 For engagement of a chain clutch, of one chain onto another like chain, eg chain extension
leg, the link for engagement will normally be identified as a numbered link, counting from a
specified end of the chain, for engagement (Fig 7).
FORMING CHAIN LIFTING LOOPS AROUND VEHICLE SPRING HANGER BRACKETS
8 The typical method for forming a chain lifting loop, about the spring hanger brackets on a
vehicle, is shown in Fig 8.
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Fig 1 Securing loose chain and not in use sling legs
NOTES
(1) Unless a specific USLC calls for loose chain to be taped, or otherwise secured to the
load itself, the standard practice is for loose chain, assembled into folds, to be taped to its
parent chain as illustrated.
(2) The length of chain folds will be dictated by the routing and available length of the
‘working’ section of the parent chain; four thicknesses of chain is the normal manageable
number of folds.
(3) Do not pull the loose chain tightly back on the engaged chain hook or clutch, allow
slack in the ‘U’ turn.
(4) The claw of a non-engaged clutch is taped, facing out, to indicate it is not in use.
(5) The claw of an engaged clutch does not require taping, though if non-engaged it must be
taped.
(6) An engaged chain hook must be taped and the mouth of a non-engaged chain hook must
also be taped.
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Fig 2 Taping loose chain and chain hooks
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Fig 3 Use of extension chain leg supporting ties
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Fig 4 Retainer breakaway assembly, or tape, securing lifting strops/sling legs after rigging
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Fig 5 Correct use of a sling leg support tie
Fig 6 Incorrect use of a sling leg support tie
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Fig 7 Methods of connecting chains
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Fig 8 Chain loops around vehicle spring hanger brackets
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CHAPTER 4
PREPARATION OF LOADS, STANDARD PRACTICES AND TECHNIQUES
CONTENTS
Para
1
2
3
4
5
6
Introduction
General handling of restraint or securing equipment
Taping practice
Use of nylon braided cord
Vehicles and trailers
Securing typical trailer load
Fig
1
2
3
4
5
6
7
8
9
Page
Typical methods of interconnecting and taping web lashings and ratchet
assemblies ¼ ¼ ¼ ¼ ¼ ¼ ¼ ¼ ¼ ¼ ¼ ¼ ¼
Typical anti-jack-knife chain configuration
¼ ¼ ¼ ¼ ¼ ¼
Securing seats, ignition key, fire extinguisher and vehicle tool kit ¼ ¼
Securing soft top vehicle canopy using net cargo restraint
¼ ¼ ¼
Securing bonnet catches
¼ ¼ ¼ ¼ ¼ ¼ ¼ ¼ ¼ ¼
Securing doors of soft/hard top land rovers
¼ ¼ ¼ ¼ ¼ ¼
Securing canopy and equipment into vehicles ¼ ¼ ¼ ¼ ¼ ¼
Trailer restraint using net cargo restraint ¼ ¼ ¼ ¼ ¼ ¼ ¼
Routing of web lashings ratchet assemblies
¼ ¼ ¼ ¼ ¼ ¼
¼
¼
¼
¼
¼
¼
¼
¼
¼
2
3
4
5
5
6
7
7
8
INTRODUCTION
1 Many of the practices and techniques for the preparation of a load follow a common pattern,
particularly in the case of vehicle loads. The aim of this chapter is to provide illustrations of
those practices or techniques for securing items on loads which have a wide application. In this
chapter the emphasis is upon general features of Land Rover vehicle and trailer preparation.
GENERAL HANDLING OF RESTRAINT OR SECURING EQUIPMENT
2 The 2-7 series of chapters cover current items of restraint equipment and materials
provisioned for the USL role, and also lay down the rules of usage.
TAPING PRACTICE
3 In general the taping practices which apply to the use of chains, in the slinging role (Chap 3)
should be followed for the purpose of load restraint. Loose chain should be secured and the
mouths of chain hooks should be taped. Similarly, loose strap with web lashings should be
neatly secured together with tape. The aim is to avoid the risk of snagging, particularly with
sling legs or the like, and any chance of flailing or subsequent catching on items of slinging
equipment during flight. Chap 3, Fig 2 gives examples of taping loose chain; Fig 1 of this
chapter gives examples of connecting and taping ratchet assemblies and web lashings.
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Fig 1 Typical methods of interconnecting and taping
web lashings and ratchet assemblies
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USE OF NYLON BRAIDED CORD
4 Nylon braided cord is probably the most used material for general/lightweight securing
purposes, and the securing ties illustrated in Chap 2-7-3 (Figs 1 to 3) provide a useful basis for
tackling various types of securing required with helicopter USLs.
VEHICLES AND TRAILERS
5 Figs 2 to 9 cover general points of preparation for vehicles and trailers.
Fig 2 Typical anti-jack-knife chain configuration
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Fig 3 Securing seats, ignition key, fire extinguisher and vehicle tool kit
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Fig 4 Securing soft top vehicle canopy using net cargo restraint
Fig 5 Securing bonnet catches
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Fig 6 Securing doors of soft/hard top Land Rovers
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Fig 7 Securing canopy and equipment into vehicles
SECURING TYPICAL TRAILER LOAD
6 There are two methods of restraining loads within a trailer:
Using trailer canvas and net cargo restraint, helicopter USL
6.1 The new and more common method is the use of the trailer canvas cover and net cargo
restraint, helicopter USL (Fig 8). Loose stores or equipment in the trailer must be fully
secured against movement, utilising the lashing rings, and securing with vehicle ratchet
assembly and web lashings (see para 6.2) prior to fitment of canvas and net. Stores or
equipment, which totally fill the trailer compartment and abuts the trailer sides, may be
restrained by the canvas and net only (Chap 2-7, para 5 refers).
Fig 8 Trailer restraint using net cargo restraint
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Using trailer canvas and duck-board
6.2 The stores or equipment in the trailer must be fully secured against movement, utilising
the trailer lashing rings (Fig 9). The rings are used in conjunction with web lashings and
ratchet assemblies. The sequence of operations is as follows:
6.2.1 Remove the canvas and duck-board.
6.2.2 Attach a web lashing or ratchet assembly to the side lashing rings, as required.
6.2.3 Pack the stores or equipment in the trailer, ensuring that the load does not project
beyond the top edge. Place the cam net (if carried) and canvas cover evenly over the
load tucking it inside the trailer. Position the duck-board on top of the canvas cover.
6.2.4 Ensure the web lashings are routed under the outer edges of the duck-board.
Attach web lashings to the ratchet assemblies.
6.2.5 Tighten web lashings with the ratchet assemblies. Lock ratchet assemblies and
tape loose ends of web lashings.
Fig 9 Routing of web lashings and ratchet assemblies
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CHAPTER 5
STATIC ELECTRICITY AND DISCHARGERS
(Completely revised)
CONTENTS
Para
1
2
4
5
7
9
12
14
15
17
Introduction
Equipment description
Life expiry policy
Maintenance support literature
The dissipation of static electricity
Method of use
Ammunition, explosives and missiles
Flammable liquids
Static electricity in dry and cold conditions
Operations during thundery conditions
Fig
1
2
3
Page
Mk1 Static discharge probe 
Mk2 Static discharge probe 
RN earthing pole   






























2
3
4
INTRODUCTION
1
The electrostatic discharge pole, commonly known as a ‘static probe’, is a manufactured
item that provides a means of dissipating static electricity from a hovering helicopter safely. Full
NSN details and nomenclature for the equipment are contained in AP 108G-0002-1D, HUSLE
Ancillary Equipment.
EQUIPMENT DESCRIPTION
2
Two static probes (Mk1 and Mk2) are available and similarly assembled with several
components (Fig 1 and Fig 2). One end of a length of wire rope, double insulated on the Mk2
probe, is passed through the end link of a length of chain, looped back and secured using a wire
grip. An interface is used to connect the other end of the wire rope with the hook. The handle is
secured around the interface and encloses the end of the hook and wire rope. The handle is
insulated and designed with a wasted area, marked ‘Grip Here’ on the Mk2 probe, for the user
to hold.
3
The Mk1 and Mk2 static probes are not authorised for use in the maritime environment. An
RN vertrep earthing pole (Fig 3) is to be used and is available from Naval stores.
LIFE EXPIRY POLICY
4 The static probe is not subject to an in-service or finite life and is to be rejected only on
condition.
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WIRE LOOP
WIRE GRIP
Fig 1 Mk1 Static discharge probe
MAINTENANCE SUPPORT LITERATURE
5
Full maintenance support literature for this equipment is published in AP 108G-0002-1D,
HUSLE Ancillary Equipment. Chap 1-1 gives general advice on obtaining HUSLE maintenance
APs.
6
The RN vertrep earthing pole is to be serviced to current RN regulations.
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WIRE LOOP
WIRE GRIP
Fig 2 Mk2 Static discharge probe
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9 FT PVC COVERED
BRASS CHAIN
6 FT 10 in.
RUBBER CUFF
EARTHING WEIGHT
Fig 3 RN earthing pole
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THE DISSIPATION OF STATIC ELECTRICITY
7
The structure of a helicopter can become charged with static electricity during flight and this
charge can be a hazard when hooking-up external loads. In most instances, if a member of a
hooking-up team were to grasp a primary/secondary hook before applying a probe/pole hook, it
is unlikely that a fatal electric shock would result.
8
The helicopter load handling team is responsible for the discharge of static electricity from
an aircraft. Instructions on helicopter load handling procedures will include the methods of
dissipation to be used by load handling teams.
METHOD OF USE
NOTE
Static electricity is discharged at the point where the wire grip and wire loop touch the
ground. The chain acts as a weight only and will not discharge static electricity.
9
Ensuring that the wire grip and wire rope is properly earthed, hold the probe/pole by the
insulated handle. When the helicopter is correctly positioned in the hover at the loading point,
the probe/pole hook, is to be placed firmly over the load beam of either the primary or
secondary hook.
10 Hook-up the load to the primary or secondary hook and then remove the probe/pole hook
(in that order).
NOTE
A lapse of two or three seconds, without the earthing device being in contact with the
aircraft and the ground, is long enough for an appreciable further charge to be induced in
the aircraft.
11 It is not necessary to follow the earthing drill when releasing external loads except when
the load is dangerous goods (para 12). Any induced charge in the helicopter and its load will be
dissipated through the load as soon as the load touches the ground; this may be a hazard to
dangerous goods. Obviously, the load should not be touched by hand until it is grounded.
AMMUNITION, EXPLOSIVES AND MISSILES
12 Irrespective of weather conditions or the type of helicopter concerned, it must always be
assumed that a discharge arc will occur when an external load is earthed by contact with the
ground. The possibility exists and is of particular concern with external loads of ammunition or
live missiles (especially those electrically detonated) or highly volatile flammable liquids such as
fuels or liquid oxygen.
13 The following information concerns the carriage of ammunition, explosives and missiles as
USLs.
13.1 Items not containing Electro Explosive Devices (EEDs) are safe to carry as USLs,
providing they are packed in their authorised outer container.
13.2 Ammunition or explosives etc, containing EEDs packed as follows, are safe USLs:
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13.2.1 Packed in authorised metal outer containers with any type of authorised
inner container.
13.2.2 Packed in authorised non-metal containers with authorised metal inner
containers.
13.3 Items covered by paras 13.1 and 13.2 can be carried safely in cargo nets. During
delivery, it is safe to earth the helicopter through the load if this is necessary.
13.4 The hazard to personnel during pick-up or delivery of the load is minimal for items
covered by paras 13.1, 13.2 and 13.3 above providing:
13.4.1 During pick-up, the normal earthing procedures in force are carried out
using either a probe/pole hook, before HUSLE is engaged on to primary or
secondary hooks.
13.4.2 During delivery, neither the helicopter nor the load is touched by personnel
before it is earthed, either through the load touching the ground, or via the probe/
pole hook.
13.5 Unpacked ammunition or explosives etc, containing EEDs are not safe, because
discharge may occur through the open, unprotected casing of the store.
13.6 Packed ammunition or explosives etc, other than those described in para 13.2, are
not safe, irrespective of the method of carriage.
FLAMMABLE LIQUIDS
14 Flammable liquids, carried in cargo nets, are to be earthed through a suitable chain
attached to the metal fuel container and suspended at least 9 ft below the load. The main
hazard with flammable liquids is ignition of the vapour. This is minimised by the chain
maintaining a safe distance between the load and any possible spark, providing there is no
leakage from the containers.
STATIC ELECTRICITY IN DRY AND COLD CONDITIONS
15 The build-up of static electricity is very rapid in dry and cold conditions. It is not unusual for
personnel to receive a noticeable shock when they touch a well-earthed object. Static electricity
dischargers are essential when external load operations are in progress.
16 Before operating in dry and cold conditions, all personnel must be aware:
16.1 There is increased build-up of static electricity in dry and cold conditions.
16.2 Static electricity dischargers must be used for all external load operations.
OPERATIONS DURING THUNDERY CONDITIONS
17 Vertical replenishment operations during thundery conditions should be avoided when
operationally possible. Not only do such conditions increase the electrostatic hazards by reason
of the high ambient charged atmosphere, in addition, the configuration of a hovering helicopter
with external load, is susceptible to lightning strike.
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CARRIAGE OF
CARGO AND
EQUIPMENT
BY
HELICOPTERS
CARRIAGE OF
CARGO AND
EQUIPMENT
BY
HELICOPTERS
CARRIAGE OF
CARGO AND
EQUIPMENT
BY
HELICOPTERS
CARRIAGE OF
CARGO AND
EQUIPMENT
BY
HELICOPTERS
GENERAL
INFORMATION
GENERAL
INFORMATION
GENERAL
INFORMATION
GENERAL
INFORMATION
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