Presentation to:
The Offshore Helicopter Safety Inquiry
SRK Coleshaw
Safety & Survival Consultant
1
Issues for Consideration
1. What personal protective equipment and clothing is necessary
for helicopter passengers and pilots; What are the standards,
and should the C-NLOPB require guidelines to ensure such
equipment is properly fitted?
2. Should the C-NLOPB more directly involve itself in studies and
research into the prevention of inversion of ditched helicopters
and enhancement of passenger’s ability to escape?
3. What are the appropriate standards of helicopter safety
training to ensure that the risk to passengers is as low as
reasonably practicable, both during training and helicopter
transport?
4. Should helicopter passengers have a level of accountability for
their own safety in helicopter transport?
2
Issue 1
Personal protective equipment needed
by helicopter passengers and pilots

Water impact:


Capsize and/or submersion:


Protection from ‘cold shock’ on sudden immersion in water
provided by the immersion suit.
Protection from drowning provided by emergency breathing
systems (EBS).
Following escape:



Buoyancy needed to support the head above water and provide
protection from breaking waves and spray.
Protection from hypothermia provided by immersion suit.
Location aided by personal locator beacons (PLBs).
3
Issue 1
Immersion suit performance

Protection from ‘cold shock’ by covering the skin surface,
preventing a rapid decrease in skin temperature.

Protection from hypothermia achieved by thermal lining
and clothing worn under the suit – insulation provided by
‘trapped air’.

Conflict caused by the fact that the trapped air also
creates buoyancy, which makes escape from the
helicopter more difficult.

Level of insulation and buoyancy are both affected by the
clothing worn under the suit, by the fit of the suit and the
size of the suit/person.

Suits are only effective when sealed – thermal stress may
be a problem during flight.
4
Issue 1
Immersion suit standards
Most Relevant Standards



CGSB (1999) Helicopter
passenger transportation suit
systems. CAN/CGSB-65.17.99.
EASA (2006) Helicopter crew
and passenger integrated
immersion suits. ETSO-2C502.
EASA (2006) Helicopter crew
and passenger immersion
suits for operations to or
from helidecks located in a
hostile sea area. ETSO-2C503.
5
Current Performance
Requirements

Levels of thermal
protection:
0.75Clo / 0.5Clo

Allowable leakage:
200g?

Min / max levels of
buoyancy:
156N min
175N / 150N max
Issue 1
Buoyancy equipment

Two options:





Buoyant suit plus integral inflatable buoyancy element
(oral inflation);
Manually inflated lifejacket.
Head needs to be supported.
Wearer must be able to (at least) turn to face-up
position and remain stable once in that position.
Spray hood necessary to protect from wave
splash.
6
Issue 1
Emergency breathing systems (EBS)
Time needed to escape > Breath-hold time


When deployed successfully, EBS provide
protection from cold shock and drowning.
EBS take time to deploy, but then extend the
available time underwater, to:





Overcome disorientation;
Release harness;
Locate and jettison exit or window;
Overcome any buoyancy problems?
Escape from helicopter.
7
Issue 1
EBS performance
To be effective, EBS must be:
 Simple in design;
 Quick to deploy;
 Easy to use in realistic conditions:





Cold water?
Whilst inverted or prone in the water?
Whilst escaping through exits/escape windows?
Compatible with other equipment;
Provide an overall safety benefit.
8
Issue 1
Technical standard for EBS
Work is ongoing to develop a full technical standard
for EBS. This will cover:







Compressed air devices, rebreathers and hybrid devices;
Work of breathing;
Minimum deployment time (one-handed?);
Performance in different body orientations;
Compatibility and snagging during helicopter escape;
Cold water performance;
Maximum additional buoyancy.
Completed standard to be submitted to EASA for
possible publication as an ETSO (late 2010?)
9
Issue 1
Personal locator beacons

Provide an aid to location in
addition to lights and
retroreflective tape.

Can be used to alert the
emergency search and
rescue services.

Are used for homing,
allowing aircraft and marine
vessels to locate those in
distress.
PLBs used in UK sector
on homing frequency
10
Issue 2
The Need for Helicopter
Flotation Systems

Helicopter ditches;

Limited range of
stability;

Upper practical limit
for preventing capsize
Sea State 5 or 6;

Significant risk of
capsize / inversion;

Breaking waves
present highest risk.
11
Issue 2
UK CAA Research - Background

Focuses on prevention of inversion of ditched helicopters
and enhancement of passengers’ ability to escape.

HARP Report (1984) - identified need to improve
crashworthiness and stability of helicopters.

RHOSS (1995) – emphasised importance of helicopter
flotation systems and the need for helicopters to stay
afloat long enough for survivors to escape. Discussed
possibility of additional flotation to cater for a crash.

EBS Workshop (2000) – recognition of mismatch between
time needed to escape from an inverted helicopter and
realistic breath-hold times in cold water.
12
Issue 2
UK CAA Research - Stability

Sea anchors:
Can help the helicopter to turn head in to the wave, but
difficult to deploy and take too much time to be effective.

‘Wet floor’ approach:
Helicopter sits lower in the water – variable results.

Float scoops:
Improved stability, mainly due to roll damping.
Increase capsize threshold by 1 sea state.
13
Issue 2
CAA Research – Prevention of inversion
(BMT Fluid Mechanics Ltd, 1997)

Model study investigating
novel flotation systems.

One set of exits above water
and air gap in cabin.

Combination of buoyant
engine cowling and long
flotation bag prevented double
rotation, and was stable in
waves.

Additional flotation, high up.
14
Issue 2
CAA Research
Human factors (RGIT Ltd, 2001)
Escape from a side-floating helicopter after rotation
of 150˚ was compared to escape from a fully
inverted helicopter.
Air gap in cabin
Escape from above-water exit
15
Issue 2
CAA Research – Human factors

Submersion time (breath-hold time):
 9.5s in side-floating cross-cabin escape;
 20s in underwater cross-cabin escape.

89% found cross-cabin underwater escape to be
‘moderately’ or ‘very’ difficult. Only 29% of subjects
rated the equivalent exercise in the side-floating escape
to be ‘moderately’ or ‘very’ difficult.

Escape from a side-floating helicopter was easier than
escape from a fully inverted helicopter, and was
preferred by 90% of subjects.
16
Issue 2
EASA Research – Type-specific design study
(Eurocopter & Aerazur, 2009)

Design objectives for an additional emergency flotation
system considered for both a light (AS355) and heavy
(EC225) helicopter.

Model of EC225 model studied in waves .

Symmetric design with buoyant cowling panel plus
flotation bags on both sides of upper cabin was most
effective with respect to stability in waves and number of
windows above water.

Better buoyancy redundancy with this design if one
standard (lower) buoyancy bag damaged.
17
Issue 2
Crashworthiness Research

Clifford (1996) – drowning is major cause of death in
helicopter water impacts, particularly with vertical
descents with limited control and fly-in accidents. Impact
injuries predominate in uncontrolled impacts and nonsurvivable accidents.

WS Atkins (2001) – recommended design modifications to
improve crashworthiness of flotation systems, including
automatic arming and deployment.

BMT (2001) – studied effects of impact and recommended
additional floats high on the cabin wall where they will be
protected from all but side impacts.
18
Issue 2
CAA Research – Emergency breathing
systems (SRK Coleshaw)

Initial study (2003):



Reviewed extent of knowledge on various EBS designs.
Satisfactory performance of EBS considered to depend
on good design, reliability of equipment, ease of use
and level of training.
Development of Technical Standard (2009-10):


Cool and cold water performance trials on three
generic designs;
Development of full technical standard, to be put out
for consultation prior to publication.
19
Issue 2
CAA/EASA Research - Overview

The side-floating scheme is considered to present the
optimum solution to the current problems with inversion.

The UK CAA have stated that they are not aware of any
insurmountable problems that would render the sidefloating scheme impractical or ineffective at least for new
build/design helicopters.

EBS provide a short–term solution for post capsize survival
pending availability of the side-floating scheme. They may
provide a degree of long-term mitigation if additional
flotation proves impractical to retrofit.

EASA proposes to establish a workshop in 2011 to review
all of the helicopter ditching and water impact
requirements, advisory material and research.
20
Issue 3
Helicopter Safety Training - Value



Evidence that survival rates are higher for those who have
received helicopter underwater escape training (HUET).
Training should provide information about what to
expect, practical training in the procedures that must be
undertaken, and allow individuals to build coping
strategies that will reduce panic in the emergency
situation.
In real emergencies a number of behaviours are seen:
 Fear/anxiety;
 Disorientation;
 Depersonalisation;

 Panic;
 Inaction / ‘freezing’.
Training should aim to reduce the likelihood of such
behaviours.
21
Issue 3
Helicopter Safety Training - Issues

Fidelity of training:

Simulator / seats / harness / exits?
Training frequency;
 Stress / anxiety caused by training.

22
Issue 3
Training Standards

Training needs to cover evacuation, underwater
escape scenarios and use of EBS where
appropriate.

Training standards are laid down by organisations
such as OPITO.

OPITO course covers dry evacuation / underwater
escape without and with EBS / escape without
and with windows / submersion and capsize.

Some differences in standards relating to the
level of realism created.
23
Issue 4
Personal Accountability for Safety

Confidence in water / swimming ability?

Clothing worn under helicopter immersion suits?

Correct sizing and fit of helicopter immersion
suits?

Attitude to training?

Personal survival strategy for helicopter
transport?

Responsibility for speaking out?
24