The Route to Continuing
Airworthiness
Brian L Perry BSc (Eng), C.Eng, FRAeS, MIET
Vice President (Technical), International Federation of Airworthiness
Airworthiness Consultant
Processes and Programmes Leading from
Certification to Operation
1
Content
• A bit of History
• An overview of where
we are Now
• A brief look into the
Future
2
Where It All Began
3
1930’s Airliner
4
Douglas DC3 G-AMRA - Norwich UK - May 2008
Andrew McClymont
5
AIRWORTHINESS
• “Airworthiness” organisations had been set
up, before the war, both in the UK (1934)
and the USA (1938).
• Aircraft development during the war was
driven by military needs.
• By 1944 the rapid growth of Civil Aviation
led to the establishment of an International
organisation.
6
Airworthiness
• What is meant by the term
Airworthiness
My Definition:
7
Airworthiness and Continuing
Airworthiness
FITNESS TO FLY SAFELY
THROUGH OUT THE LIFE OF THE
AIRCRAFT
Dependent upon:
• Design and Manufacture
• Operations
• Maintenance and Repair
8
9
International Civil Aviation
Organisation
• Under The 1944 Chicago Convention the
various National Governments agreed to
set up an International Organisation, ICAO,
in order that:
• “----International civil aviation may be
developed in a safe and orderly manner---”
• “---and to secure the highest practicable
degree of uniformity in regulations,
standards and procedures---”
10
ICAO Annexes
• 18 Annexes including:
• Personnel Licensing and Approval of
Organisations
• Rules of the air
• Meteorological Services
• Aeronautical Charts
• Units of Measurement
• Operation of aircraft
• Aircraft registration Marks
• Airworthiness and Continuing Airworthiness
11
Annexes continued
•
•
•
•
•
•
•
•
•
•
Facilitation
Aeronautical Telecommunication
Air Traffic Services
Search and Rescue
Aircraft Accident Investigation
Aerodromes
Aeronautical Information Services
Environmental Protection
Security
Transport of Dangerous Goods by Air
12
ICAO SARPS
Standards And Recommended Practices for
the interpretation of the Annex material
13
Implementation of Annexes and
SARPS
• In practice these are implemented by
National Codes such as:
• In the Europe by JARs now EASA CS’s.
• In the USA by FAR’s.
• In most other counties by National Codes
often based upon or related to FAR’s
and/or the EASA Codes.
14
FAA---------------------------------------------EASA
FAR’s
Requirements CS’s
Acceptable Means of Compliance - AMC’s
Appendices
AC’s - Advisory Circulars
________________________________________________________
_
SAE/RTCA ------------------------------- EUROCAE
ARINC
ARINC
Detailed Specifications
and Guidance material
eg. DO 160/ED 14, DO 178/ED12 etc.
________________________________________
Prime Manufactures in-house standards which are
applicable to all sub contractors and suppliers
15
16
High Accident Rates
particularly related to
piston engine failures
17
A Major Step for Safety
Introduction of Jet Engines
• Cabin Air Conditioning and Pressurisation
• Increased cruise altitude speed and range
• Increase in engine reliability BUT in
some early jet-engined aeroplanes:
• Accidents caused by Structural Fatigue
• Results of the investigations and tests and
the resultant changes to the airworthiness
requirements were shared across the
world.
18
De Havilland Comet
19
Another Major Step
20
Concorde - Advanced Systems
•
•
•
•
•
•
•
•
High Speed and High Altitude
Limited Fly- by Wire
Extreme Temperatures on Aircraft skin
Reheat and Full Authority Electronic Engine
Controls
Full Authority, Safety Critical, Digital Air Intake
controls
Centre of Gravity Control using Aircraft Fuel
Equipment Cooling using Aircraft Fuel
Exposure to Radiation and Lightning Strikes
21
Lightning Strike
22
Current Requirements
• The Concorde and other experience led to
major changes in the requirements, in
particular for the certification of Systems
and Equipment which are applicable
throughout the in-service life of the
aeroplane
• These will be discussed in more detail
later in this presentation.
23
Airworthiness
• We shall today be concentrating upon Part
25 Requirements covering the TC (Type
Certification) of Large Aeroplanes.
• These requirements also take account of
all the ICAO annexes and their related
national standards.
• Plus Systems and Equipment fitted to
obtain a C of A (Certificate of
Airworthiness)
24
Certification Specifications for
Airworthiness of Large
Aeroplanes CS 25
• Subpart A - Applicability
• This airworthiness Code is applicable to
Turbine Powered Large Aeroplanes over
5670kg weight
• Operated under Part 121(or similar rules)
25
CS 25 Subparts
Also containing Appendices and AMC’s
•
•
•
•
•
•
•
B – Flight
C – Structure
D – Design and Construction
E – Powerplant
F – Equipment
G – Operating Limits and Information
J – Gas turbine APU Installations
26
Some Sections of CS 25 which are
particularly related to Continuing
Airworthiness
• Weight and Centre of Gravity limits.
• Guidance for in-service flight tests, where
required following maintenance actions.
• AMC 25.561 – Load conditions for seats and
other items of ‘commercial’ equipment.
• AMC 25.581-- Lightning protection and bonding
of structural elements.
• Provision of CDL (Configuration Deviation List)
information for Flight Manual.
27
Some Sections of CS 25 which are
particularly related to Continuing
Airworthiness (ctd.)
• Much of the content of Subpart D – Design and
Construction including, for example:
• AMC’s No. 1 and 2 to CS.603. Suitability of
materials including Appendix F - Fire Test
Criteria and Procedures.
• Emergency Exits arrangements and Emergency
Demonstration - Appendix J.
• Appendix H – Instructions for Continuing
Airworthiness which details, in particular, the
required content of the Maintenance Manuals.
28
•
•
•
•
Some Sections of CS 25 which are
particularly related to Continuing
Airworthiness (ctd.)
Requirement for Engine Type Certification.
Design Considerations for Minimizing
Hazards caused by Uncontained Turbine
Engine and APU Rotor Failure, AMC 20128A.
Detailed information on the contents of the
Flight Manual including CDL and MMEL,
AMC 25.1581.
Requirement for APU approval.
29
SEE ALSO
IFA WHITE PAPER
Dated April 2003
CONTINUING AIRWORTHINESS
The basic story
30
CS 25 Subpart F - Equipment
• The Concorde and other experience led to major
changes in the requirements, in particular for the
certification of Systems and Equipment which
are applicable throughout the in-service life
of the aeroplane
• For example the concept of the inverse
relationship between the probability of
occurrence of an event and the severity of its
effect.
• These and the related certification procedures
are as detailed in 25.1309 and the associated
AMC’s or AC’s.
31
32
33
FAA---------------------------------------------EASA
FAR’s
Requirements CS’s
Acceptable Means of Compliance - AMC’s
Appendices
AC’s - Advisory Circulars
________________________________________________________
_
SAE/RTCA ------------------------------- EUROCAE
ARINC
ARINC
Detailed Specifications
and Guidance material
eg. DO 160/ED 14, DO 178/ED12 etc.
________________________________________
Prime Manufactures in-house standards which are
applicable to all sub contractors and suppliers
34
Extract from CS 25.1309 (a)(1)
• Systems and equipment must be designed
and installed so that those required for
Type Certification or by operating rules, or
whose improper functioning would reduce
safety, must perform as intended under
the aeroplane operating and
environmental conditions
35
Extract from CS 1309 (a)(2)
• The aeroplanes systems and equipment
must be designed so that other equipment
and systems are not a source of danger in
themselves and do not adversely affect
the proper functioning of those covered by
CS 25,1309 (a)(1)
• SEE ALSO AMC 25.1309
36
Systems and Equipment
Certification Requirements
• While subpart F of the requirements and, in
particular, 25.1309, covers the certification of
Systems and Equipment, their specific
requirements may be detailed in other sub parts.
• For example the subparts and associated
Appendices and AMC’s, covering:
• Flight, Structures, Design and Construction,
Power Plant, Operating Limits, Auxiliary Power
Units (APU’s).
• Including any new equipment and systems
required or fitted after entry into service.
37
The Type Certification Process
• A review of this process will now be made.
• The steps shown contain information
which may need to be taken into account
when any in-service modifications, repairs
or replacements are made to the aircraft,
its systems and its equipment.
38
39
Preliminary Hazard Analysis –PHA
Failure Conditions and Criticalities
• Determines system hazards and effects –
Catastrophic, Hazardous, Major, Minor, No
Safety Effects and the associated level of
analysis required .
• Hence Safety Objectives
• Quantitative or Qualitative analysis
• Involves system designers and pilots
• Agreed between Design Organisation and
Certification Authorities
40
Software Verification and Validation
• Document used Internationally for V & V
RTCA - DO 178B (Eurocae – ED 12B)
• Amount of work depends upon Software
Levels
• Watch out for the need for ‘Partitioning’
which separates those portions which can
be modified after Type Certification and
those which cannot.
• Summarised in Accomplishment Summary
41
Software Levels
42
Equipment Approval
• All equipment fitted to the aircraft must be tested
to ensure that it meets all the relevant
environmental and safety standards, as
specified in DO 16O, or the airframe
manufacturers equivalent specification.
• Evidence must be provided to confirm this, for
example: TSO (Technical Standing Order) or
DDP (Declaration of Design and Performance.
• Information on failure modes and reliability rates
will, where relevant, be required for use in the
FMEA.
43
FMEA - Failure Modes and Effects
Analysis
• This will be required for those systems
where a quantitative analysis of the
particular event is required by the PHA.
• Normally carried out by the airframe
constructor using a computer programme.
• All sub systems and equipment failure and
reliability information used in the analyses
to be to the same standard.
44
Rig and Aircraft Tests
• These are particularly relevant in the evaluation
of complex system inter-reactions and related
system indications, warnings and procedures,
under normal, standby and emergency
conditions. For example: power supply failures
and bus-bar failures.
• Establish Flight Manual procedures.
• Involvement of the flight test crew is essential.
• In-service changes and additions must not affect
these, otherwise a formal amendment is
needed.
45
Zonal Analysis
• Initial confirmation that the design standards cover
the requisite Zonal Configurations.
• Including: fire and explosion; corrosion; segregation
and separation of power supplies and back-up
systems and associated earthing/grounding; disc
burst zones; other electrical and mechanical
segregation requirements; physical fastening and
protection of cables and equipment; safe and easy
access for required maintenance activities.
• These standards remain critical throughout the
service life of the aircraft and must not be
invalidated
46
Zonal Analysis (continued)
• Detailed inspection of the completed aircraft to
ensure that these standards are met and to
ensure that no other potential safety hazards
have been introduced during manufacture.
• This can be a difficult and potentially time
consuming task, but it is essential to ensure that
these standards are maintained throughout the
in-service life of the aeroplane.
47
System Safety Assessment - SSA
• This process confirms that:
• The assumptions of the PHA are correct, or have to be
modified, and that the derived System Safety Objectives
have been met.
• That the installation of the equipment on the aircraft
meets the design standards and no further potential
hazards have been introduced.
• Provides Flight Manual Procedures covering the relevant
system and equipment failure conditions.
• Provides MMEL (Master Minimum Equipment List)
information and any related operational or time
restraints, based upon the data used in the
assessments.
48
SSA (continued)
• Details any CMR (Certification Maintenance
Requirements) which have shown to be
essential to retaining the required levels of
reliability and availability, during the SSA and
FMEA process, and which cannot be changed
using normal in-service procedures, AMC 25-19
• Provides other information as required by the
pre-operations maintenance review panel (MSG3).
• Provides the basis for the Compliance Check
List for 25.1309.
49
In Service Experience
• The Airbus range of Fly By Wire aircraft
• (A319, A320, A330, A340) were the first
civil aircraft designed and certificated to
these standards using these or equivalent
certification processes.
• Also the FBW Boeing 777, with this aircraft
also utilising a ‘Digital Data Bus’ System.
50
Airbus A320 msn 002 F-WWDA in 1987 - One side painted in BCAL colours
Airbus original via
Andrew McClymont
51
In the Near Future
• The Boeing 787 and the Airbus A350 will
be entering service in the near future to
basically the same certification standards
but with such Special Conditions as are
required by the use of the new materials
and system design features, such as much
increased dependence upon electrical
power.
52
Boeing 787
53
Airbus A350
54
Potential Continuing Airworthiness
Issues in the use of Carbon Fibre
Materials
• Detection and repair of damage caused
mainly by collisions on the ground.
• Repair of damage to the external surfaces
metallic protection caused by lightning
strikes.
• Deterioration and corrosion due to spillage
of contaminating fluids such as fuel,
hydraulic and de-icing fluid, toilet fluids
and galley spillage.
55
ETOPS – Extended Range TwinEngine Operations
• An example of how airworthiness is achieved
and maintained for a particular type of
operation.
• Original standards did not allow commercial
operation of twin engine aircraft for more than 60
minutes, single engine flying time, away from a
‘suitable’ airport.
• Very high engine reliability gave the opportunity
to review this rule
56
ETOPS - Design and Manufacture
• Proven engine reliability and low shut-down rate
from any cause
• System augmentation:
Back–up Power supplies needed.
APU with in flight start and run capability.
Enhanced De-icing capability.
Increased cargo bay fire suppressant.
Review of other potential system effects and
procedures relevant to single engine
operation.
57
ETOPS - Operations
• Procedures and training for extended
periods of single engine operations at
lower cruise altitudes and speeds.
• Provision of additional fuel to allow an
emergency diversion at any time to an
alternate airport.
• Availability of ‘suitable’ diversion airports
and knowledge of their meteorological
conditions during the flight.
58
ETOPS - Maintenance
• Required ETOPS maintenance and
reliability programme to include:
• Maintenance of engines, systems and
equipment.
• Engine and System routine maintenance
limited to one engine or one critical system
at a given time. For example top-up of oil
or other fluids.
59
Successful ETOPS
Now extended to 180 minutes and, on certain routes, 207 minutes
Design of Aeroplane approved for ETOPS
Operator approved for ETOPS operation
Maintenance approved for ETOPS
See EASA AMC 20-6
and FAA AC 120-42A
60
61
Some Other Safety Related
Equipment and Initiatives
Examples of equipment already
mandated under ICAO and
other rules
TAWS (GPWS) Terrain Avoidance and Warning System.
TCAS (Traffic Collision and Avoidance System).
Accident Data and Cockpit Voice Recorders.
Fuel Inerting Systems.
Ageing Aircraft checks on structures and systems
Plus others.
62
Some Other Safety Related Future
Equipment and Initiatives (ctd.)
Equipment
HUMS (Health and Usage Monitoring Systems) linked with ACARS
(Aircraft Communications, Addressing and Reporting System).
Equipment providing warning of runway traffic, and potential
incursions and excursions.
Improved and extended CVR’s (Cockpit Voice Recorders) and
ADR’s (Accident Data Recorders).
ADS-B (Automatic Dependence Surveillance-Broadband).
The extended use of the failure and maintenance monitoring
systems which are an integral part of the aeroplane. “Believe
what the aeroplane is telling you”
The extension of the use of EFB’s (Electronic Flight Bags) to
include maintenance and spares information and to replace the
hard copy of the Tech. Log.
.
63
Some Other Safety Related Future
Equipment and Initiatives (ctd.)
Initiatives
Extension of non-punitive data recording to cover
incidents as well as accidents both in flight and
during maintenance.
International co-ordination of this data with detailed
analysis to ensure that ‘lessons learned’ are
understood and shared by all.
SMS (Safety Management Systems) introduced in all
the organisations involved. This provides the
opportunity to establish sound communication links
between all parts of the organisation and with
external bodies, where appropriate.
64
Longer Term Airworthiness
Driven by customer requirements, environmental pressures,
costs, including fuel and maintenance, with always the need to
maintain and improve safety standards.
• Probable changes include:
• New ATM systems, for example, NextGen in the USA and Single
Europeans Skies in Europe, plus similar systems in many parts
of the world.
• More safety critical, operational and maintenance systems.
• Many more cabin services such as entertainment systems and
internet and telephone access, which have the potential to
interfere with the airworthiness critical aircraft systems.
• All leading to increased complexity and inter-system
communication, with dependence upon ground based services
and equipment for flight critical operations.
65
Longer Term Airworthiness (ctd.)
• The outputs from CAST (Civil Aviation Safety Team) extended
to all areas of the world, such as ECAST in Europe. Many of
these Safety Enhancements relate to industry guidance
material rather than needing to change the basic airworthiness
standards
• The output from FAST (Future Aviation Safety Team) taken in
account in future design, operation and maintenance.
• Possible need to rethink, perhaps automate, the whole of the
system certification process to ensure that such complex and
inter-related systems are subjected to a thorough and
independent airworthiness review. This will affect both the
initial Type Certification and in-service modifications including
those covered by STC’s (Supplemental Type Certification)
66
Unmanned Airborne Systems?
UAS’s
• Small vehicles for limited surveillance and
maintenance roles, but penetrating controlled
airspace.
Already in operation
•
Freighter Aircraft (for long range operations?)
Probable
•
Passenger Transport Aircraft
Unlikely, but the pilot may
have more of a surveillance rather
than an operational role.
67
Major Accidents
Worldwide Commercial Jets
1998 – 1 November 2009
1.20
40
1.00
Major Accidents
30
20
0.80
19
17
13
16
13
13
17
11
19
0.60
13
0.40
10
0.20
2000
2001
2002 2003 2004 2005 2006 2007
* Reliable worldwide departure/rate data not available for Eastern-Built
Aircraft
2008 2009
68
Major Accident Rate*
Hull Losses
Western Major Accident Rate *
Back to the Future
Maintaining Continuing Airworthiness in the future will be:
COMPLEX and
CHALLENGING
.
YOU CAN BE SURE HOWEVER THAT THE FOLLOWING
AIRWORTHINESS COMMUNICATIONS CHART WILL STILL BE
APPLICABLE, PERHAPS WITH SOME ADDITIONAL TOPIC AREAS.
69
70
71
THANK YOU
72