6. bermuda fts

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Government of Bermuda DCAFuel Tank System Safety

Module 6

Len Arnot-PerrettAVISA



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fuel tank system safety

Overview for managers of

airworthiness & maintenance



3

Welcome to the course

Course objectives Familiarise candidates with the elements of

Fuel Tank System Safety Issues Enable candidates to understand the historical

background and elements requiringconsideration in relation to fuel system safety

Equip candidates to understand and use thelanguage of fuel system safety issues

Allow candidates to understand and interpret

fuel system safety issues from regulatory andmanufacturer’s maintenance publications

Satisfy Parts M & 145 Amendments on fuelsystem safety

Note: this course covers level 1 requirements 3



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Fuel tank system safety – the beginning?

4



5

Fuel tank system safety – the beginning?

TWA Flight 800 crashed at 20.30 on July 17 1996

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6

Fuel tanks system safety – the end?

6



7

Fuel tank system safety – introduction for managers of


Neither the beginning nor the end!



8

The investigations surrounding the accident

led to many basic design and certificationassumptions about installed fuel tanksystem safety to be substantially revised.

What have design and certificationassumptions got to do with in-servicecontinuing airworthiness managementand maintenance of aircraft?

8

Fuel tank system safety – introduction formanagers of airworthiness &

maintenance



9

All of the continuing airworthiness processes

could be affected!

“covers all of the processes ensuring that at

any time in their operating life, all aircraftcomply with the airworthiness requirements in

force and are in a condition fit for safeoperation.”

Regulation 2042/2003 – Article 2 - Definitions

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Fuel tank system safety – introductionfor managers of airworthiness &

maintenance



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• AD

• Flight Manual• Modifications

• Repairs

• MMEL

• Life Limits

• AirworthinessLimitations

• C of A

• Records

• MaintenanceProgramme

• Maintenance

Standards

• Reliability Programme

• CertificationMaintenanceRequirements

• Weight & Balance

• Occurrence Reporting10


maintenance



11

• As you can see, these processes arethose associated with the operation,

continuing airworthiness and maintenance

of aircraft.

In the global fleet of aircraft – all of theprocesses have been affected

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maintenance



13

Or has it been safe?

13


maintenance



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14


maintenance



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15


maintenance



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A global review of in-service fuel tank

safety data demonstrated that fuel tank

safety does not meet contemporarystandards for system safety targets

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F l t k t f t



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Fuel tank system safety – introduction for managers ofairworthiness & maintenance



18


maintenance

In the period 1960 – 1996 – 17 fatality

events due to fuel tank system events!

Let us consider a sample – relevant totoday.....



19

• 8 December 1963 – Pan Am B707

• 9 May 1976 – Iranian Air Force B747

• 22 August 1985 – BA Air Tours B737

• 11 May 1990 – Philippine Air Lines B737

• 17 July 1996 – TWA 800 B747

• 3 March 2001 – Thai Airways B737• 5 September 2001 – BA B777

• 20 August 2007 – China Air B73719

Fuel tank system safety – introduction formanagers of airworthiness & maintenance



20


maintenance

Is this a Boeing problem?

Not exclusively!

Boeing had flown approximately 70% of

large commercial airplane flights in 2000

It is a matter of exposure then.



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1990 - B-737-300

Manila, Philippines

1996 - B-747, TWA

800, JFK

2001 - B-737-400

Bangkok Thailand

Almost new airplane 25 year old airplane 10 year old airplane

Air Conditioning Packsrunning during Ground

Operations


Operations


Operations

Empty CWT explosion

during pushback fromgate

Empty CWT explosion

during climb

Empty CWT explosion

minutes afterrefueling

CWT pumps operating

at time of explosion

CWT pumps operating

at time of explosion

8 fatalities 230 fatalities 1 fatality

Jet-A fuel, approx. 95

degree F ambient

temp.(35’C)

Jet-A fuel, approx.

120 degree F tank

temp.(49’C)

Jet-A1 fuel, approx.

97 degree F ambient

temp.(36’C)

NO IGNITION SOURCE

IDENTIFIED

NO IGNITION SOURCE

IDENTIFIED

NO IGNITION SOURCE

IDENTIFIED21


maintenance



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maintenance

0

1

2

3

4

5

6

7

8

9

10

1990 1995 2000 2005 2010 2015 2020

Year

C u m u l a t i v e

A c c i d e n t s

Manila

New York

Bangkok

ARAC ~10E-8

10E-9

Extremely improbable -

not anticipated to occur in the life of

the fleet

Systemic Change Needed22



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CS25.1309 AMC 1309CS25.1309 AMC 1309

Figure 1 - Relat ionship bet w een Probabi l i t y and

Sever i t y o f fa i lure Condi t ion

JAR 25

PROBABILITY

CLASSIFICATION

OF FAILURECONDITIONS

PROBABLE IMPROBABLE

EXTREMELY

IMPROBABLE

MINOR MAJOR HAZARDOUS CATASTROPHIC

100 10-3 10-5 10-7 10-9



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maintenance

Investigations revealed that the CWT were

heated to a greater extent than previouslybelieved - 140°f peak recorded on one

aircraft type

High temperature leads to high flammability

High flammability means that ignition source

energy required to initiate event is muchlower than reviousl calculated

Fuel tank system safety introduction



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Ignition

Oxygen Fuel VaporHeated tanksFlammability Reduction

“Prevent fuel system

accidents through ignition

source elimination and

flammability reduction”

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maintenance

F l t k t f t i t d ti



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Main Tanks 2-4%Tail Tanks 2-5%

Body Tanks• Pressurized <5%• Un-pressurized >20%

Heated Center Wing Tank 15-30%Un-heated Center Wing Tanks 2-6%

Fuel Tank Flammability Exposure Worldwide Fleet Average

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maintenance



2727

Fuel Tank Safety – Module 2Flammability Envelope

vs. Ignition Energy, Flash Point and O2

Level

0

10

20

30

40

50

-50 0 50 100 150 200Temperature Deg F

A l t i t u d e

1 0 0 0 ' s f t .

LFL

UFL

Heated CWTProfile

Unheated WingTank Profile

Pointer

Flammable Zone



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maintenanceReinvestigation of design certification

standards also led to need to review all

tank installations – including un-heatedtanks

• Special Federal Aviation Rulemaking –

SFAR 88 – FAA AC 25.981.1(b)

– FAA AC 25.981.2

• JAA INT/POL/25/12



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maintenance

SFAR 88

Initiated in 2001 – assessment stage

Existing fleet in Europe and North America

All basic airplane design configurations andsupplemental Designs affecting the fuel

system



F l k f



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Full reinvestigation of design – fuel tank

systems – require DAH to identify FuelTank Airworthiness Limitation Items

including

• Critical Design Configuration Control Limitations

• Airworthiness Limitation – inspections

• Airworthiness Limitation – modifications

• -

F l k f i d i



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SFAR 88 (AC 25.981.1c) & JAA TGL 47 andINT/POL/25/12

Critical Design Configuration Control Limitation(CDCCL):

A fuel system feature the design integrity of whichmust be maintained to ensure that an unsafecondition does not develop. Features in an

aircraft system or component. May exist in fuelsystem but may also be features in systems orassemblies that interact or cross-couple with

fuel systems32


maintenance

Fuel tank system safety – introduction



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SFAR 88 (AC25.981.1c) & JAA TGL 47 andINT/POL/25/12

Examples of CDCCL:-Bonding feature attaching to component and

tank

Separation of fuel gauge wiring from other high – power wiring

Fuel pump configurationWire support for high power wiring near to tank

We will later look at some characteristic CDCCLfrom TC Holders

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maintenance

Fuel tank system safety



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SFAR 88 (AC25.981.1c) & TGL 47 andINT/POL/25/12

Fuel Tank System Airworthiness Limitation

Items (ALI)Fuel System Mandatory Instructions – can

include

Design changes

Maintenance

InspectionsProcedures 34


F l k f



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SFAR 88 (AC25.981.1c) & TGL 47 andINT/POL/25/12

Fuel Tank System Airworthiness Limitation Items

(ALI)Those items necessary to ensure that

Unsafe conditions do not arise in the fuel

system throughout the service life of theairplane

ALI to be mandated by AD and included in theAirworthiness Limitations Section of ICAW

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F l t k t f t i t d ti



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For the identification and management of CDCCL

Related tasks highlighted by TCH in AMM/CMM

Airworthiness management procedures put in placeEnsure features are protected during repair/changes

Ensure maintenance organisation is aware

Implement training programmes

Remember, the feature itself may not be directly related

to the fuel system and also may be at component level e.g. fuel pump! 36


maintenance

F l k f i d i



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maintenanceIdentification and management of CDCCL – at a

component level

37




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If fuel pump configuration is to beidentified as a CDCCL, how will theoperator control the CDCCL?

Pool parts

Component suppliers

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y yfor managers of airworthiness &

maintenance




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SFAR 88 (AC25.981.1c) & JAA TGL 47 andINT/POL/25/12 – continued – 24


Fuel Pump CDCCL management:-

This will be a challenge for the operatorsEASA Part 145 Form 1, FAA 8130-3

Contracts will need to specify CDCCL

managed and complied with during MROactivity – box 13(?)

CAME procedure in place

Maintenance procedure for MRO39


maintenance



Fuel tank system safety –



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An ALI could be a modification/change:-

EASA AD 2006-0191

A330-200, A340 – 200/300 aircraft

Air Conditioning – prevention against fuel

explosion risks – installation of heatshields in belly faring

HO241

Fuel tank system safety introduction for managers ofairworthiness & maintenance

Fuel tank system safety



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Boeing Airplane MPD already published withALI/CDCCL

e.g. B767 MPD

AWL No. 28-AWL-01: Task – ALI – detailed inspection

of wire bundles over CWT – 12y/36000HAWL No. 28-AWL-02: CDCCL – External Wires over

CWT – maintain existing wire bundle routing and

clamping

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– for managers of airworthiness &



4343

for managers of airworthiness &maintenance




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Boeing Airplane MPD already published with

ALI/CDCCL

e.g. B767 MPDAWL No. 28-AWL-03: CDCCL – Lightning protection –

Engine fuel feed line - verify electrical fay surface

bond from bulkhead fitting to structure – 0.5 milliohmsor less

AWL No. 28-AWL-04: CDCCL – Lightning protection –

Hydraulic line fuel tank penetration – bond checks onheat exchanger and lines – to structure and in-lineconnectors

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Fuel tank system safety introduction for managers ofairworthiness & maintenance




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Operator required to maintain integrity ofCDCCL throughout operation and

maintenance of airplane.This could be a challenge…

• Airworthiness management processes – including modification, repair & ARC

• Maintenance procedures

• Component maintenance

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Fuel tank system safety introductionfor managers of airworthiness &

maintenance




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maintenance

FAA Aviation Rulemaking Advisory

Committee – ARAC studies heating effectson fuel Tanks 1998.

External heat sources to be avoided – forthe future!

Flammability suppression guidance

developed




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maintenance

Industry Fuel Tank System Safety

programme commenced in 1998

Sample surveys of aircraft in-service fleets




48

Industry Fuel System Safety ProgrammeSurvey was not conclusive but there were

findings

Bonding provisions missing Swarf and contamination in tanks Damaged components

Evidence of overheated pumps Wiring problems Vent systems incorrectly assembled

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maintenance




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Bonding straps in tanks

Straps missing, broken, looseStraps frayed/worn as a result of wing movement

Corroded straps and attachment points

Lightning strikes have resulted in the loss of aircraft due topoor bonding!

Poor/missing bonds are often caused by maintenanceerror! You may be only 1 fault away from an unsafecondition!

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F l t k t f t i t d ti f



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Another Survey finding that was very relevantto the future was the relatively high level ofmaintenance error induced occurrences in fueltank system installations

UK study of B747 occurrences showed 16%maintenance error correlation over a 20 yearperiod!

Another relevant finding was the comparativeseriousness of the fuel tank system relatedoccurrences

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Fuel tank system safety – introduction for



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Maintenance error? Serious occurrences?

Most regulatory systems had provisions forflying control system maintenance to reducethe likelihood of maintenance error inducedoccurrencesRequired Inspection ItemsDuplicate Inspections

Independent Inspections

Perhaps we need to build similar defences for

fuel system maintenance? 51

Fuel tank system safety introduction formanagers of airworthiness &

maintenance




52


maintenance

Another finding was that Zonal Inspection

Programmes were not proving as effectiveas they ought to be

Problems with• Mechanic licensing schemes

• Training of Inspectors at MRO

• Poor maintenance at component organisations




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Fuel tank system safety introduction for managers of

airworthiness & maintenanceMechanic licensing schemes, Training of Inspectors at

MRO

Poor maintenance at component organisations? Licensing schemes are not able to adequately address all

inspection standards and licensing schemes do not exist

at a component level e.g. Zonal Inspection standard could be • General Visual

• Surveillance

What do they mean? How are they applied?




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MSG3 Definition:

General Visual Inspection:-

A visual examination from arms length that will

detect obvious unsatisfactory conditions/ discrepancies. This type of inspection may require

removal of fillets, fairings, access panels / doors,

etc. Workstands, ladders etc. may be required togain proximity.

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maintenance




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maintenance

Mechanic licensing schemes, Training of Inspectors at MRO

Poor maintenance at component organisations?

General Visual Inspection requires the identification of obvious signs of deterioration: the Part 66/A&P examinations are not able to test the applicants

knowledge to that extent!

This determination requires visual parameters…….




56


maintenanceMechanic licensing schemes, Training of Inspectors at

MRO

Poor maintenance at component organisations?

How are the MRO’s meant to deal with this?

Part 145 requires organisation training for issue of authorisations – this would include the need to ensure that relevant inspection standards were covered at an airplane as well as a component level!

• Continuation training

• Pictures of inspection findings




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maintenance

Mechanic licensing schemes, Training of Inspectors at

MRO Poor maintenance at component organisations?

Some of the problems uncovered were probably due to poor installation standards

during modification activities!

Fuel tank system safety – introductionf f i thi &



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5959

introduction for managers ofairworthiness & maintenance

Fuel tank system safety – f f



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Fuel tank system safety – introduction for



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Wiring problems were being investigated bythe Ageing Transport Systems Rulemaking

Advisory Committee (ATSRAC) study goingon in parallel with SFAR 88

ATSRAC set up by FAA to study ageingeffects in systems – focuses on wiringsystems

Produces rule making Enhanced

Airworthiness Programme for AircraftSystems/Fuel Systems – (EAPAS)6262

managers of airworthiness &maintenance




63


2000 - ARAC 2 set up to look into

requirements for Flammability ReductionSystems – FRS – to significantly reduce the development of flammable vapours

Workable and economically viable on-board

system developed by FAA TechnicalCentre




64

1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004+

Manila New York Bangkok

NTSB

recommendations

FAA Task to Industrybased on NTSB

Recommendations

Industry Fuel

SystemsSafety

Program

SFARNPRM

SFAR 88Assessment

ARACFlammability

ReductionStudy

ARACInertingStudy

SFAR 88Implementation

NGSDevelopment

Industry and Regulatory consensus: Reducing flammabilitywould provide major benefit to enhancing fuel tank safety

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What has happened since 2004?

Things have moved slowly!

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Fuel tank system safety –introduction for managers of



66

March 2007 – EASA Agency Decisions 2007/01R,2007/02R and 2007/03R issued on Fuel systemsafety

Part 145 organisations – component and

airplane levelPart M airworthiness Management

organisations

Part 66 Licensing

NPA 2008-19 to change rules still not closed!

66





67


2007 – Flammability Reduction System

certified by FAA/EASA for Boeing products

Boeing introduce production cut-ins forcurrent models and proposals for fitmentto existing fleets




68


Why bother with FRS?

FAA estimate that in order to obtain the

order of magnitude change required toobtain the required level of safety – Ignition Source Suppression – on its own –

required to be at least 75% effective.




69


• Malaysian Register 727 tank explosion

due to wiring failure in wing – fuel pumpsupply wire.

• B777 CWT fuel leak during TO – panel left

off after maintenance

• Airbus FQIS lightning protection failures

Ignition source suppression cannot be

guaranteed to be wholly effective!




70

October 22 2007 FAA issue final rule ‘’EnhancedAirworthiness Programme for Airplane

Systems/Fuel Tank Safety (EAPAS/FTS)’’

This rulemaking was part of the ATSRACrulemaking relating to airplane wiring systemsand included fuel tank system installations

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71




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What is EAPAS and what has EAPAS got to do with Fuel Tank System Safety?

Wiring problems connected with Fuel Tank Safety were delegated to Ageing

Transport System Rulemaking Advisory Committee – ATSRAC – who developed

EAPAS.72





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July 21 2008 FAA issue final rule‘’Reduction of Fuel Tank Flammability inTransport Category Airplanes’’

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Fuel tank system safety –i t d ti f f



7474





75

What do the FAA Rules do and will theyaffect me?

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Any differences between European/USimplementation could affect

Insurance Premiums

Lease arrangements – operator/operator

Lease arrangements – operator/leasing company

Transfer/Export of Airplanes

Airbus/Boeing will be required to meet FAA productioncut-in targets – production aircraft will be standard

In addition - an operator operating an airplane inaccordance with Part 129 would obviously be affected!

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t oduct o o a age s oairworthiness & maintenance




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The FAA final rule RIN 2120-A123 simultaneouslyintroduces a number of FAA rule changes

applicable to US Design Approval Holders(DAH) and operators of US Register airplanes

Introduces Part 26 for DAH – to harmonise with

EASA(?)

Part 121 - Domestic, Flag and Supplemental Operations

Part 125 – Airplanes seating cap. 20+ pax. Or

payload>6000lbs.

Part 129 – Foreign Air Carriers and Foreign Operatorsof US Register Airplanes Engaged in Common Carriage

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A detailed knowledge of the FAA rulemaking isnot necessary for a non-US register aircraftoperator

We include a brief summary of the rule making

however since there will almost certainly be aneed to understand the basics due to thecontinuing movement of aircraft ownership

across international boundaries

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FAA Final Rule summary

Introduction of FAR 26 requirements – fuel

tanks within the fuselage contour – flam>7%, allother tanks flam>7% DAH to assess fleet average flammability exposure – to be

complete within 150 days following 19 September 2008 Fleet average flammability exposure target <7%

Flammability Reduction Means (FRM) to be identified ifexposure>7% fuselage contour tanks (AC 25.981-2)

Ignition Mitigation Means (IMM) to mitigate ignition sources intanks (AC 25.981-1)

September 20 – 2010 DAH to submit FRM ICAW including

CDCCL September 20 – 2010 DAH to submit FRM ALI 79


Fuel tank system safety – introduction for managers



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Introduction of FAR 26 requirementsALI – Airworthiness Limitation Items

CDCCL – Critical Design ConfigurationControl Limitations

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y y gof airworthiness & maintenance




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Part 121 – by September 20 2010 – new

production airplanesFRM, to be operational

Ignition Mitigation Means (IMM) to beimplemented

B747 Series Airbus A 318, A 319,

A320,A321 seriesB737 Series Airbus A 330, A 340

Series

B777 SeriesB767 Series 81





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Part 121 – Retrofit

50% of US operator’s fleet to have installations

required by Part 26 by 2014100% of US operator’s fleet to have installations

required by Part 26 by 2017

Installations to be operational

The flammability targets will effectively result in FRM

for most Airbus and Boeing types in current airlineuse 82





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Part 121 – Maintenance ProgrammesType specific ALI and CDCCL mandated by AD

Maintenance Programmes must be revised to take

into account modifications required by Part 26Compliance dates for Maintenance Programme

changes may be extended subject to use of ground

air conditioning for B737, 747, 757, 777, 767 andA300, A310, A318, A319, A320, A321, A330, A340.

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29 May 2008 EASA issue NPA No 2008-16‘’Fuel Tank Safety – incorporation of the

Critical Design Configuration ControlLimitations (CDCCL) into Acceptable Meansof Compliance for Part-M, Part-145 and Part

66’’

17 July 2008 EASA issue NPA N0 2008-19‘’Fuel tank flammability reduction’’ – this isequivalent to FAA FAR 25 and AC 25.981-1and AC 25.981-2 – this is a design and certification

code for future airplanes and is not retrospective - FAA FAR 26 is! 84

t oduct o o a age s oairworthiness & maintenance




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The EASA change to CS 25 will not result in

retrospective implementation to existing

fleets and will probably only come intoeffect for A350 and B787

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managers of airworthiness & maintenance

EASA rule making will not implement

requirement for retro-fit of flammabilityreduction systems whilst FAA rule will.




87


EASA has issued AD’s for Airbus fleet ALI

and CDCCLWill result in need for changes in

maintenance and airworthiness

management organisations – Part 145 andPart M




Changes to airworthiness management andmaintenance procedures

Task card development Maintenance Procedures including verification tasks –

tank closure

Repairs/changes Maintenance Programme development

ARC issue

MEL management Occurrence reporting standards

Training


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