awakenings fall 2001

8/14/2019 Awakenings Fall 2001

1/20

Fall 2001

A A W W A A K K EENN II NN GG SS

TSB WIRE RECOMMENDATIONS

TRUTH & RECONCILIATION

SAFETY DATA FOR ALL FACT OR FICTION?

INTOLERABLE DAMAGE

LIMITING FACTORS FOR GLASSCOCKPIT IMPLEMENTATION

The Magazine of the International AviationSafety Association

http://www.iasa.com.au http://www.iasa-intl.com/
http://www.iasa.com.au/http://www.iasa-intl.com/http://www.iasa-intl.com/http://www.iasa.com.au/


2/20

Awakenings ~ The Magazine of the International Aviation Safety AssociationFall 2001 Edition Page 2

2001 IASA (International Aviation Safety Association)

TSB Wiring Recommendations . the inadequacy of aircraft wire certification testing

The Futility of Collation in the absence ofCoordinationWe look at the realities of data sharing among different agencies assigned to tackle theproblem of aging aircraft.

Australian Senate Inquiry considers health

implications of exposure to smoke & Fumes ..Do you know what organophosphates are? You should you may breathe them when youfly. AOPIS.org look at the phenomenon of airborne contaminants.

Prevention or Cure? ....The GAO recently asked the FAA to re-evaluate how their resources were allocated intackling the problem of aircraft wiring. Is this part of a larger problem?

Intolerable Damage..Martin Aubury discusses damage tolerance and the need for timely inspections.

Limiting Glass Cockpit Implementation ..How power system return currents can have the final say.

Feature Story Truth and Reconciliation

Fall 2001

AwakeningsThe Magazine of the International Aviation Safety AssociationContents

3

5

7

8

9

11

13


3/20



August 28, 2001 : ``A specific spark,whatever the location, should not bringdown an airplane with 229 people onboard,'' Daniel Verreault, the board'sdirector of air investigations, told anews conference releasing the report.``There should be defenses in place to

prevent this, and that is an objective

that we have and that is the way thatwe believe we can contribute toadvancing aviation safety.'' Of the 2million pieces of aircraft recovered fromthe Atlantic seabed in their efforts todetermine the cause of the crash,

Stringent flammability regulations areapplied to materials in the passengercompartments of aircraft, but Gerdensaid there are fewer restrictions onmaterials used in inaccessible areas ofplanes. The board is particularlyconcerned about the qualificationtesting of aviation wiring that examines

only individual wires, not live wirebundles, and inexplicably does not lookat how wires carrying an electricalcurrent can ignite a fire. Some types ofaromatic polyimide wiring (such asKapton) are known to arc-track. Arc

Transportation Safety Board of Canada

Wire RecommendationsBy ohn Sampson IASA Australia

some 65,000 piecesshowed evidence of firedamage, the TSB said. VicGerden, the safety board

official in charge of theSwissair investigation, saidthe probe was looking at allpossible safety issues. ``Ifthere were no combustiblematerials in an airplanethere could not be asustained fire. If we canbreak the links then we

tracking is a processwhereby the wiring'sinsulation itself becomesa current-carrying

conductive carbon char.Once a wiring bundle arc-tracks, heat of the orderof thousands of degreesCelsius can quicklyincendiarise anythingadjacent to it - and fatallycripple vital aircraftsystems.

could stop the next accident,'' he said.

``We are looking at all the links, theignition sources, the combustiblematerials, the oxygen contributors andother safety deficiencies that we find enroute that are links in the chain to otheraccidents that might occur. It is time toraise the bar on the type of materialthat is put in airplanes," said Gerden.

TSB investigators speculate that ashort-circuit or arcing wire aboardFlight 111 may have ignited a fire fedby flammable thermal/acoustic blankethidden from sight above the cockpitceiling's lining. Frighteningly, one of thelife-support systems intended to helpthe pilots get the plane down to a safelanding may have contributed to the

Vic Gerden


4/20



fire. The MD-11's emergency oxygensupply, intended to feed 100%oxygen to the cockpit crew's masksduring a fire, may have instead fedthe fire like a blowtorch. Investigators

found the stainless-steel oxygen lineshad aluminium fittings, which couldleak during a fire and feed enoughoxygen to turn a small blaze into aninferno.

ConclusionThe TSB is concerned that thereremain safety deficiencies in thematerial flammability standards, andthat these pose an unacceptable riskto the flying public.

First, in a series of aviation safetyrecommendations issued inDecember 2000 and entitled In-Fligh Firefighting, the Board stated thatmaterial flammability standards foraeronautical products are an integralcomponent of any in-flight firefighting

"system". The Board is concernedthat the flammability standards forcertain materials used in thepressurized portion of aircraft areinadequate.

Second, despite many ongoinginitiatives to mitigate electrical wirediscrepancies, the Board believesthat the certification test criteria foraircraft wires do not adequately

address the potential for wire failuresto ignite or propagate fires .

Third, indications that the failure ofcertain aircraft systems, such as crewoxygen, could exacerbate a fire inprogress suggest that currentrequirements for conducting systemsafety failure analysis may beinadequate.

Previous RecommendationsJanuary 1999 : FAA is asked to inspect cockpitwiring on all MD-11s.

March 1999 : The Canadian board recommendsflight recorders have independent power sourcesand be able to record up to two hours rather than30 minutes.

August 1999 : Advisory issued that Mylar use bereduced or eliminated. FAA orders metallized Mylarblanket insulation be replaced after it is found to beflammable.

September 1999 : FAA bans the in-flightentertainment system used on Flight 111, calling it"not compatible with the design concept of the MD-11."

April 2000 : FAA orders map-reading lights on MD-11s inspected or shut off. In inspections of about 12aircraft, flammable Mylar blanket insulation wasfound pressed against many of the lights andshowed signs of heat damage.

April 2000 : The Federal Aviation Administrationissues eight safety orders concerning MD-11electrical systems, bringing to over 30 the numberof airworthiness directives released since thecrash.

December 2000 : The Canadian board issues fivesafety recommendations aimed at detecting andsuppressing in-flight fires. Also recommendsrevising cockpit crew's emergency checklist to save


5/20



Safety Data should be

available to all

Is this is thereality?

6

The Futility of Collation in the absence of Coordination

BY Adam Smyth IASA UK The formation of the Wire System SafetyInteragency Working Group (WSSIWG)should see an end to the era oforganisation specific data. Now, those

identified more than two dozenorganizations that collectively spendtens of millions of dollars each year toaddress the aging avionics problem

scrutinising the problemsassociated with electricalsystems in aircraft shouldhave at their disposal dataacquired by other

government agencies notspecifically concerned inaviation. One of thoseagencies is the NuclearRegulatory Commission(NRC).

The NRC experience ofproblems associated withelectrical systems providesus with a wealth ofinformation that directly

Although many of theseprograms are makingsubstantial progress, theyare poorly integrated. Noenterprise wide leadership

is being provided.

So when the FAAsAssociate Director, TomMcSweeny, stated inevidence to acongressional hearing onaircraft wiring held inSeptember 1999 that theFAA did not have seriousconcerns about Kaptonwiring based on in-service

impact aviation. Not only that, it raisesimportant questions regarding datasharing among government agenciesand how lack thereof can lead toduplication of efforts & resources andultimately impact safety. This is one ofthe problems cited in a Report by theCommittee on Aging Avionics in MilitaryAircraft titled Aging Avionics in Military

Aircraft .One of the Committees Findings was: Alarge number of organizations withinDoD, the military services, and industryare attempting to address variousaspects of the aging avionics problem.However, these efforts are poorlycoordinated and often duplicative. TheReport goes on to say: The Committee

data one wonders if their stated positionmight have been different had they seendocuments from the NRC archiveuncovered by IASA.

One of the documents IASA uncoveredis NRC Information Notice No. 88-89titled Degradation of Kapton ElectricalInsulation. Dated November 21, 1988,

this substantial report details what theNRC defined as a generic safetyproblem involving Kapton aromaticpolyimide electrical insulation.

The report refers to a complex hydrolyticKapton degradation process that isalmost fully reversible provided thatactual cracking has not occurred andthe generic lesson is that the


6/20



LINKS1 http://www.nrc.gov/NRC/GENACT/GC/IN/1988/in88089.txt 2 http://www.epri.com/OrderableitemDesc.asp?product_id=NP-7189 3 http://scitech.dot.gov/polplan/wirerpt/index.html 4 http://books.nap.edu/books/0309074495/html/R11.html

performance of numerous Kapton-insulated wires degraded considerablyafter only one year in a quite mildenvironment

Whilst the militarys damningexperience of Kapton aromaticpolyimide electrical insulation was oftendiscounted by reference to a perceivedmore hostile environment than theaverage commercial plane, the quitemild environment referenced in thisNRC document could not have been soeasily discounted.

So when Tom McSweeny said inevidence that he had looked at all theresearch did that include NRCInformation Notice No. 88-89?

Kapton is the registered trademark of

DuPont

Useful Links :

Please note that the InternationalAviation Safety Association (IASA) isnot responsible for the material and/orcontent of the sites to which it providesInternet links.

NRC Information Notice No. 88-89:Link 1

EPRI Report Review of PolyimideInsulated Wire in Nuclear PowerPlants: Link 2

WSSIWG Final Report: Link 3

Committee on Aging Avionics inMilitary Aircraft Report: Link 4

The 2001 Report of the Committee on Aging Avionics in Military

Aircraft speaks of No enterprise wide leadership in dealing with

the aging avionics problem.

Although nearly 13 years have passedsince it was published its importance tothe wider debate is perhaps finally beinggiven the credit it deserves. How? One ofthe non-governmental projects for wiresystem safety cited in the WSSIWGs

Final Report is being undertaken byEPRI who Evaluated the polyimide(Kapton) problems identified in navalaircraft with respect to nuclear plantapplications. Their report, titled Reviewof Polyimide Insulated Wire in NuclearPower Plants, was published onFebruary 1, 1991. In the abstract to thereport reference is made to theProblems due to handling damage ofKapton wire recently led the NRC toissue an Information Notice (No. 88-89).
http://www.nrc.gov/NRC/GENACT/GC/IN/1988/in88089.txthttp://www.epri.com/OrderableitemDesc.asp?product_id=NP-7189http://scitech.dot.gov/polplan/wirerpt/index.htmlhttp://books.nap.edu/books/0309074495/html/R11.htmlhttp://books.nap.edu/books/0309074495/html/R11.htmlhttp://scitech.dot.gov/polplan/wirerpt/index.htmlhttp://www.epri.com/OrderableitemDesc.asp?product_id=NP-7189http://www.nrc.gov/NRC/GENACT/GC/IN/1988/in88089.txt


7/20



With incidents of smoke and or fumesentering into aircraft cabins due toleakage by oils & hydraulic fluidsongoing for at least 20 years, a recentAustralian Senate Inquiry revealedthe problem is a major concern forthe safe operation of aircraft andhealth of crews.

While the focus was on the BAe146,other aircraft including B757, A320 &MD80 have experienced incidents ofcrew exposure, around the world,with varying levels of incapacitation.

Crews inhaling bleed aircontaminants at altitude are exposedto a range of substances includingorganophosphates, hydrocarbons, C0& C02. Mobil Jet Oil II containingTricresyl phosphate (TCP) at 3% wasalways known to include a low levelof the neurotoxic ortho isomer TOCPbut Mobil revealed to the SenateInquiry that it included higherquantities of the isomers MOCP &DOCP having a significantly highertoxicity than TOCP. Industry reliancethat the oil contains low levels of

TOCP underestimates the toxicity bya factor of at least 30,000. The oil canlabel states Prolonged or repeatedbreathing of oil mist, or prolonged orrepeated skin contact can causenervous system effects

New oils being introduced (MJO291)are not phosphate free.

Along with strong evidence of under-reporting, the Inquiry recognised thepresence of fumes and associatedcrew effects conflicted with theRegulations and recommended thatwhen fumes occurred the aircraftshould be immediately withdrawnfrom service until fully rectified.

A range of health effects experiencedby crew and linked to aircraft fumesare sufficiently consistent to indicatethe possibility of a discreteoccupational health condition termedaerotoxic syndrome with numerousflight crew having lost their flightmedicals and no longer able to fly.

The growing list of incidentsdemonstrates there is a significantrisk of a serious incident occurring.Many feel the long term welfare ofcrews and the safety aspects ofpotential crew contamination must betaken more seriously and that a crewtesting procedure be introduced to

assess what crews are beingexposed to, whilst a full andindependent investigation takes placeinto the toxic nature of hydraulic fluidsand oils such as MJOII.

You can learn more about AOPIS.ORG by visiting http://www.aopis.org

Australian Senate Inquiry consider healthimplications of exposure to smoke & Fumes

Contributed by AOPIS.ORG
http://www.aopis.org/http://www.aopis.org/


8/20



Are we investing inPreventionPreventionPreventionPrevention

To THE DETRIMENT ofCureCureCureCure

There was a time when the meremention of flaws in aircraft wiring wouldbe greeted with derision and disbelief.However, now that there is awidespread acceptance that aircraftwiring deserves its place under theproverbial microscope, attention hasnow shifted to methods of inspectionand technological aids in detection ofwiring flaws. But do these apparentadvances in acceptance of the centralproblem herald a more sinisterproblem? Are we investing so heavilyin Prevention that we have abandonedCure?

The Office of the Inspector GeneralAudit Report, Observations On Effortsto Address Concerns About AircraftWiring (Report No. AV-2001-004Issued October 27, 2000), echoes ourconcerns. The report stresses theneed for action by various parties andidentifies three specific areas whereimprovements are needed:

1. Improved MaintenancePractices

2. Better Training for Maintenance

Personnel & FAA Inspectors3. New Technologies for Detecting& Preventing Problems

But the Report also asks, whenimprovements in these areas can bemade and equally critical, has the FAAallocated resources appropriately inaddressing this complex issue?

The FAA requested $22 million for fiscalyear 2001 for aging aircraft research, thebulk of which it spends on methods topredict and detect fatigue cracking andcorrosion of aircraft structures. Accordingto the Office of the Inspector General theFAA needs to rethink its plannedinvestments in aircraft safety research todetermine the correct mix of structural andnon-structural research

The FAA has often been criticised forconcentrating too much of its efforts ondata collation to the detriment of aconcerted effort in the form of action.Even this is now further eroded, by therecognition that even the all-important datais incomplete and unreliable. The Office ofthe Inspector General found thatmeaningful analysis could not beperformed because coding to specificallyidentify wiring problems is not available.

The acceptance of the central problem hasexposed the fundamental flaws in theinfrastructure that is now charged with thetask of solving it. An industry that can beprone not to report a problem, a systemthat cannot as yet properly record an event

for trend analysis, a regulator that does notallocate resources adequately and thatmakes decisions on incomplete andmisleading data.

Is the flying public justified in its concernsthat aircraft wiring is as much acompromise to their safety as those whosemandate it is to make flying safer?


9/20



By

INTOLERABLEDAMAGE

By Martin Aubury

In April, when overdue inspectionsfound cracks in Ansett aircraft andtheir 767 fleet was grounded spindoctors wrangled that the planeswere designed to tolerate damage,

that the cracks were hairline andwere only seven centimeters long.

In reality Damage Tolerance is aspecific way of managing metalfatigue that relies on knowing whenand where to look for cracks. Withouttimely inspections, damage toleranceis a meaningless platitude.

Also, hairline cracks are more

dangerous than gaping ones becausethey are harder to find. And tinycracks can be just as lethal as longones.

So it is worth understanding howdamage tolerance evolved and itslimitations.

Metals fail at a definite stress. They

also fail at lower stress if the stressis applied repeatedly; this is fatigue.But because the number ofrepetitive loads before failure variesenormously, it is impossible toaccurately predict the fatigue life ofan aircraft.

The simplest solution uses analysesand tests to estimate anapproximate life; then cuts it by asafety factor. After that the structureis discarded.

The safety factor is set so that notmore than one aircraft in athousand should fail. Passengersmay fear flying on that one aircraftwhereas operators hate discarding999 prematurely!

Although this safe life approach isrisky and wasteful it is still used forsmall aircraft and helicopters. It wasabandoned for airliners soon aftertwo De Havilland Comet jetscrashed in 1954.

Aviation mythology has it that theComets crashed because fatiguewas overlooked. Not true; anairframe had been tested to 18,000flights but the test was faulty andthe planes burst apart after around1000 real flights.

A better approach was to duplicateall critical structure, so that if onemember fatigued prematurely there

was alternative structure availableto carry the load. This is failsafety. It was the methodologyused to design aircraft throughoutthe 1960s, up to and including theBoeing 747.

Implicitly fail safety depended ondetecting the first failure before theback-up structure also failed. That


10/20



did not always happen. In 1977 a14-year-old Boeing 707 crashed inZambia when its tailplane broke off,because failure of the mainstructure had gone unnoticed.

By then new technology made itpossible to estimate how quickly acrack would grow and how long acrack could be before the structurefailed. Damage tolerance wasachievable by scientificallyscheduling inspections.

Sometimes the critical crack lengthis very short and sophisticatedinspection techniques are needed.Elsewhere cracks can be a meterlong and visual inspections suffice.

The difficulty is knowing where tolook for cracks. Clues are drawnfrom the aircraft design and anairframe is tested to simulateseveral lifetimes and see wherecracks start.

But the best aid is reports fromroutine inspections on hundreds ofaircraft around the world. Findingsare reported back to themanufacturer then notified to alloperators. And that is why Ansettwas remiss in not acting quicklyenough on Boeing advice about thelikelihood of cracks on the 767tailplane and engine attachments.

Although it is possible to predictcrack growth and critical length for asingle crack, a major deficiency withdamage tolerance is the risk ofmany tiny cracks suddenly joiningtogether. That is what happened toan Aloha Airlines Boeing 737 in1988 when six meters of fuselageripped away, most passengers wereinjured and a flight attendant died.

The Aloha accident dramaticallytriggered an unprecedented reviewof aircraft structural maintenance.Defects and complacency were rife.Since then manufacturers,regulators and airlines havecooperated to cut the risk of agingaircraft. Congress has enactedspecific legislation, hundreds ofservice bulletins have been mademandatory, and inspections arebacked up with structuralreinforcement.

Multi-site damage remains adanger. Old airframes are strippedin a hunt for structure susceptible to

it and new inspection techniquesare being developed.

Meanwhile aging aircraft needmeticulously maintenance. Thisbecomes increasingly expensiveand eventually uneconomic.Unfortunately, airlines that cannotafford new planes sometimescannot afford to properly maintainthose they already own.

Abridged by the author from hisarticle published in CanberraTimes 18 April 2001. MartinAubury is a Fellow of the RoyalAeronautical Society and teachesat Australian Defence ForceAcademy


11/20



Limiting Factors for Glass Cockpit Implementation Limiting Factors for Glass Cockpit Implementation

More automatic, pilot-friendly Avionics featuresmean more computingpower is required.

Computer power dependslargely on the clock speedsat which the CPU cyclesare timed. Also a factor isthe level of voltages usedfor the data bus operations.Years ago +28 Volts DirectCurrent (VDC) was and isstill used today. Being adigital circuit, the +28 VDClogic line was either true(+28VDC) or false (0VDC).The voltage toleranceswere very forgiving, oftentrue was considered

anything greater than+24VDC, false wasconsidered anything lessthan +5VDC.

Early Avionics Testsystems of the 1970s used18VDC for logic operations,with correspondinglyreduced thresholds. Anyvoltage in-between the

false and true realm wasa no-operation, i.e.,disregarded. The highervoltage data systemsoffered good and not sogood benefits. A goodbenefit was the noiseimmunity. It was verydifficult for a randomelectrical noise pulse tofalse trigger a true

Also developed during theearly years were the powerdistribution systems we seeon both Military andCommercial aircraft.Evolving gradually fromyears of flight, the systemsbegan as battery systemsusing Direct Current (DC).DC aircraft systemsgenerally used a singlewire to provide power to aload. The airframe wasused as a return currentpath back to the battery.

The maturing need formore sophisticatedAvionics drove the need foran Alternating Current

system. Today, aircraft ACsystems use a groundedWYE, 200 volt three phase400 Hertz generator anddistribution system asspecified by MIL-STD-704.Aircraft AC systems todayare allowed to use theairframe for the return ofAC currents to thegenerator, thus eliminating

the weight and volumerequired for a Neutralconductor. MIL-STD-761authorizes the use of theairframe for AC and DCreturn currents.

Logic system noise marginrequirements and aircraftpower system practicesmeet head-on at the

response. The not so goodwas that the highervoltages andaccompanying higherpower levels mademiniaturization difficult if notimpossible. A secondissue was the speedrestriction imposed by thehigher logic levels. Digitalswitching is notinstantaneous, it takes afinite amount of time for atransistor to slew between

a 0 and a +28VDC level.This limitation served torestrict the system clockspeeds and thusthroughput.

Modern logic levels aremuch lower, some systemsuse +5VDC and even+2.2VDC for extremelyhigh-speed parallelprocessors.

The available noise marginis essentially gone.


12/20



airframe.

As stated, the airframecarries power systemreturn currents. These arecharacterized by wide bandnoise current and voltagetransients below 20 kHz.The logic system iselectrically bonded to theAvionics module chassisand thus to the airframe.The airframe is intended toserve as a 0 voltreference for the many on-board logic processors inthe Avionics system. Yetthe airframe is not a 0 voltreference it is one of thepower system electricalconductors.

Random noise pulses onthe airframe from normalpower system operationscan upset computer

operations by forcing falsecalculation or evendestruction of logic chipscausing system failure.

Successful Implementationof the glass cockpitconcept will requireelimination of powersystem return currents onthe airframe.

The first successfulairplane was built not bydegreed aviationprofessionals, but bicyclemechanics in a woodenshed. Lets take thisproblem back to the shopand apply common sense.

Fig 1: Fourier Transformshowing the of the majornoise elements on thesame airframe. This datawas taken with only around20% of the aircraftloads energized. Mostcannot be fired up with"weight on nosewheel".

Primarily concentratedbelow 5 kHz, they arecapable of creating all sortsof mischief.

Of course, MIL-STD-461REQUIREMENTS FORTHE CONTROL OF EMICHARACTERISTICS OFSUBSYSTEMS ANDEQUIPMENT testing does

not address this area forthe F/A-18. Per CE101,page 28, ConductedEmissions, 30 Hz to 10kHz, this only applies toASW aircraft. Finally, realworld measurements arenot necessary, allqualification tests can bedone in a lab.

Fig 2: Airframe noisemeasured on a DigitalSampling Oscilloscope,using shielded test leads,referenced to the hangarstatic ground. The narrowpositive and negativevoltage spikes are capableof "forcing" a logic low, with

all the possible interestingresults.

It is believed that this is oneof the most commoncauses of the "no faultfound" gremlin.

A false signal forced inflight may cause a very realsystem BITE error. But on

the ground, after a fullsystem reset, the fault doesnot appear.


13/20



FEATURE ARTICLE By John Sampson, IASA Australia

Truth & ReconciliationOne of the aviation safety benefits ofthe Internet is that research can givefresh insights into the past, enablenew perspectives on old accidents

and disclose underlying trendsagainst the backdrop of more recentevents. Ever since the 27 Nov 87crash of an SAA 747 Combi offMauritius, rumour and speculationabout the cause of its onboard firehas been rife. Last year the SouthAfrican Truth and ReconciliationCommission decided to address thisfestering sore with a view to laying itall to rest. Those good intentionsbackfired. On the IASA web site thereare 18 pages packed with the variousfacts and potential fictions about "theHelderberg", including "freshevidence" as to its real cargo (from aMay 2000 scientifically enhancedCVR tape). It's recommended readingbecause there is an underlyinglesson, one that has emergedrepeatedly in accidents such asTWA800, Valujet 592 and AI182 (toname but three). In the aftermath ofthose accidents, certain conclusionscould be drawn from particular facts,but always the proof positive waslacking. VJ592 had a cargo of

flammable (but not inflammatory)oxygen canisters in its hold but it alsohad defective electrics and a type ofwiring (PVC) that is no longer

approved - and for good reason.TWA800 theorists have run the fullgamut of criminal, terrorist andconspiracy /cover-up scenarios yetthe top contender is once again notone of the preferred "usual suspects";it is proven defective wiring. June 85and Air India 182 suffered a suddenexplosive decompression at altitude,the prime suspects automaticallybecoming Sikh Terrorists - simplybecause of the politics of the time,and because Canadian Sikhs couldbe woven into the pre-flight chain ofevents. Although they are two verydistinctly different forensic events (seelater), the "explosive" decompressiongradually found its definitivedevelopment into "there needingtherefore to have been a bomb". TheRCMP doggedly pursued this line ofinquiry for decades and twoindividuals (Sikhs of course) will soonface trial. It is human nature toassume that there is a culprit and thatblame must be laid. Foul play isalways suspected if there's any lack


14/20



of evidence to the contrary (such aswas fortunately available in theSwissair Flt111 accident). It's anatural cynical legacy of thenumerous terrorist hijackings of the60's and 70's. The influence of theplayers in an accident investigationand their preconceived notions,perceptions and even agendas cangive a particular line of inquiry a life o fits own. If you do read into any ofthese accidents looking for logical

conclusions, then there is a furtherpremise that you must entertain.Simply stated, it is that airlinermanufacturers are necessarily part ofthe "party" system of investigation butwill always tend to support alternativetheories - and the more of them thebetter. It is in their interests that thereshould not be any definitive

conclusion about an accident's cause- particularly if it was to mean thatcostly intrinsic design flaws would beunearthed (e.g. 737 rudder), or thespectre of culpability in class-actionlitigation be raised. Remember that amodern airliner is a very costly vehicleto keep parked, hangared formaintenance or modification or, perishthe thought, grounded. Utilisation isthe name of the game and runningfixes on turnaround is the modusoperandi. Insurers are also wont tobelieve their own actuaries, that allthe risks are already factored intotheir premiums. Evidence of non-impartial activity in investigationscame out in the GAO's 1999 inquiry

into allegations of improper conductand unsatisfactory aspects of the 737rudder-caused accidents. But beforewe get to the extracted lesson, let uslook at the Helderberg and AI182accidents in a little more detail.

Because the Helderberg's 30 minuteCVR was in two parts, an earlier 20minute meal-time and the last tenminutes of the flight, the conclusionwas that a fire had broken out earlier

(just about two hours out of Taipei ontheir nine hour flight to Mauritius). Itwas postulated that, because of thesensitivity about the cargo, CaptainUys had strict orders not to divert.Understandably, it was feared that if itwas found, at some divot airfield, thatSAA 747 Combi Freighters hadcontraband Armscor gunrunning

munitions on board, then SAA'sroutes might thereafter be denied tothem (or be subjected to UNInspections or Sanctions). Yet,Armscor's embargo-busting activitieswere vital to the continued security ofSA, which was embroiled in internaldissidence and regional wars. Inparticular the lightly armed SADF wasup against 50,000 Soviet supportedCuban mercenaries in Angola andthey needed an equaliser that wouldstimulate Western intervention. WithIsraeli help, SA had developed seventactical nuclear super-weapons inorder to level the playing field (punintended). Helderberg was widelyrumoured to be carrying at least the


15/20



air-delivery barometrically-actuatedfission trigger of one such fusionweapon but it was also conceded tobe carrying much more dangerousoxidizers, such as ammoniumperchlorate rocket fuels. Shades ofthe convenient oxy-generator theoriesof VJ592, no? However, these wouldhave been well containerised andquite inert (i.e. quite inconsequential,short of an accident or fire occurring -which would then have been another

story). Armscor had been grantedsecret dispensations because it was amatter of national security and the SAmilitary needed weapons - any way itcould get them. Armscor, and notSAA, had the last word on what wasto be carried. Armscor was a law untoitself. Defence Chief Magnus Malanneeded the armaments and that was

the basis of their 007 licence - whichin the culture of the day is not merelya play on idiom. Proponents of the"two fires theory" claim that the crewhad Armscor Standing Orders not todivert but the Pilots Federation poohpooh's this, saying that no sanecaptain would press on into a longoceanic transit with a fire onboard(whether or not it had gone out). Butwhy then was that CVR in two parts?Perhaps there is a middle-groundexplanation that the CVR had beendisabled because the crew hadpartially powered down the aircraftdue to earlier smoke or smell beingdetected (i.e. not an actual fire). If ithad later flared up when power was

reapplied (for a navigational check)ust prior to descent into Mauritius,then that would explain the later re-initiated CVR recording and the logicbeing used throughout by the captain.There would have been no need todisable the CVR because of itrecording their sensitive discussionswith SAA Operations - simplybecause the CVR was a 30 minuteendless loop. So, is it likely that anymunitions could have smouldered for

that length of time and then beenrekindled over seven hours later -coincident with the power beingreapplied to the electrical busses? Notreally. Would the rocket fuel haveplayed any part? Of course - butbefore hopping on the conspiracybandwagon, first apply the chickenand egg part of Ockham's Razor. The

Razor says that in the absence ofevidence to the contrary the mostrational and probable explanation fora train of events is likely toapproximate reality. i.e. the wirestarted the fire. In particular, thismight be so because there wasanother tape, one that recordedaircrew enroute conversations withtheir SAA ops controller inJohannesburg. That tape was neatlydisappeared after the crash, the manwho took it conveniently died and oneend of that vital missing conversationbecame rapidly promoted intoheading up the Miami Office of SAA.At the time, the Margo Inquiry neatlycircumscribed any mention of these


16/20



difficult-to-explain areas andconcentrated on what the deep-sea

dives had managed to dredge up.Boeing sided with the popularfomentation of conspiracy theoriesvarious. Against the violence, intrigueand pre-eminent securityconsiderations of that apartheid era,the vague outcome seems to havebeen inevitable. One reasonableinterpretation of what the crew said(and clearly avoided saying) on theCVR tends to support the abovescenario. But a reasonablydispassionate observer might simplysay: "OK, but all that plot and counter-plot aside, it looks to me like it mighthave been a wiring fault that laterdeveloped into a wiring fire. Theyrestored power in order to get atracking check before top of descentinto Mauritius. That is obvious fromthe CVR. But we would never restorepower to the wiring nowadays - notknowing what we know now." It's notbeen confirmed but it's suspected thatthe Combi's were Kapton-wired, justlike the follow-on 747-400 models.They had very large cargo holds full ofwiring that would have been subject to

lots of wear and tear. Inbound cargocapacity was important to the SA ofthe 80's, although they were restrictedto about 150 odd pax. As the Captainsays, in the enhanced tape, shortlybefore the onboard fire: "Guess whatguys, we've got Boy George 1 aboard".And, as borne out by the heated

discussion that ensued, he wasn'ttalking about the entertainer. So why

was the Margo Inquiry only nowrevealed as having been a cover-up?The simple answer is because theystood to lose 400M rand on the hullloss if the insurers could prove thatthere had been munitions on board.

In comparison with the Helderberg'sonboard fire, the Air India Flt182emergency (Jun 85) was (accordingto its CVR) a sudden loud sound ofabout 5.4 seconds duration in which ascream or cry could be heard. "AIBanalysis indicates that there weredistinct similarities between the soundof the explosive decompression onthe DC-10 and the sound recorded onthe AI 182 CVR. The AIB reportconcluded that the analysis of theCVR and ATC recordings showed noevidence of a high-explosive devicehaving been detonated on AI 182. Itfurther states there is strong evidenceto suggest a sudden explosivedecompression of undeterminedorigin occurred. Although there is noevidence of a high-explosive device,the possibility cannot be ruled out that

1 Hiroshima: Little Boy; Nagasaki: Big Boy;George relates to Operation Greenhouse, the"George" test (Cylinder device) showed that athermonuclear fusion bomb by fusion reactionsof 2H (deuterium) and 3H (tritium) would bepossible to make.(and fusion boosting for atomicbombs was thusly proved possible).


17/20



a detonation occurred in a locationremote from the flight deck and was

not detected on the microphone.However, the AIB report is of theopinion that the device would have tobe small not to be detected as it isconsidered that a large high-explosivedevice could not fail to be detected onthe CVR." Of course the reportdoesn't liken the sound to the muchlater [28 Dec 97] United 811 747'sloss of a cargo-door over the Pacific -but a comparison of the two reportsmakes the similarity apparent. In fact,there were two AI182 reports (seelinks on IASA site). The Indian andCanadian reports describe "anexplosion" in the forward cargo area -however no trace was ever found ofexplosives. So here we can possiblysuspect that UA811's survival of acargo door loss on climb mightindicate how lucky they were - incomparison with Air India 182'spossible loss in cruise flight at FlightLevel 310 (i.e. at a much higherspeed and pressure differential). Whydo cargo doors open in flight? Cargodoors are outward opening, notinward opening plug-doors like the

personnel entrance doors. Plug-doorsare held closed by pressurisation butif a cargo-door's latches fail,pressurisation tears it open, thefuselage is weakened and the cargodoor is sucked into an engine (#3)and can also damage the tail. It's losswill not necessarily be a

straightforward "opening", thefuselage skin surrounds may be torn

away also. and its violentseparation can so weaken thefuselage integrity that, as perTWA800, the nose may separate. Thecargo door-locking mechanisms areelectrical and although they arepowered by the ground buss (which isdeactivated once airborne), the faultmechanism could be similar to theway in which a stray electrical highvoltage current found its way into theTWA800 centre-wing tank's fuelquantity indication system. It hadbeen believed that UA811's door hadbeen improperly latched - until theymuch later recovered the actual doorfrom the Pacific and found that itslatching mechanism had beenelectrically driven open in flight.

It has long been known that faultywiring can cause intermittencies, falseindications, uncommanded actuationand strange symptoms in electrical(and electronic) systems. Arc trackingand shorting can cause fires that canthen propagate courtesy of airconairflows and, beneath the cabin

linings, ably assisted by theflammable thermal/acoustic blanketswith which wiring bundles areentwined. You might well say that thatis simply a hazard that comes with theterritory - the hundreds of kilometresof wire that go to make up the sinewsof a modern airliner. Many wire-faults


18/20



must exist and so, sooner or later, afailure is bound to occur, just as inany other aircraft system. Howeverwiring faults can manifest themselvesin many different ways. In theHelderberg, there was a known fire.CVR evidence (and recorded crewconversations) seems to point to anearly problem that much later recurredwhen power was restored - and it thenspread rapidly. The only logicalexplanation for that is a wiring-

initiated fire. There is much videoevidence of the explosive response ofaromatic polyimide wire (Kapton) to acircuit-breaker being reset after anarc-tracking event has caused it totrip. In the 1985 AI182 accident, Sikhskulduggery was presumed, so itwasn't until after other DC-10 and 747cargo-doors had opened explosively,

that any viable alternativeexplanations could be offered up. TheRCMP are putting a brave face upontheir Oct 2000 arrest of three SIKHindividuals. Upon the release of oneSikh from jail for the 1985 Naritaairport bombing, he was promptly re-arrested and simultaneously two otherCanadian long-term Sikh "suspects"were also arrested and charged with"bombing" AI182. It may yet turn outto be a face-saving RCMP "fishingexpedition". But admittedly: " Althoughluggage made it on board both theaircraft, in both cases, these Sikhtravellers did not fly." As their web-sitesays in explanation of the dearth ofreal proof:

http://www.airindia.istar.ca/

" The RCMP is not prepared to

release any information regarding theindividual involvement of eachaccused in this case. Thatinformation will be presented to thecourts at the appropriate time. Weare also not prepared to discuss anydirect evidence in this case as thismay affect the integrity of theinvestigation. Although arrests have

been made, this does not mark theconclusion of the police investigation.We are continuing to receiveinformation which is being followed upand which we consider beneficial toour case. The Air India Task Forceinvestigators believe there are somepeople who will come forward withinformation now that arrests havebeen made. If your information leadsto an arrest in this investigation youwill qualify for the One million dollarreward. If your information is alreadyknown to the RCMP, you will be sonotified.Well I guess that we shall see aboutall that - in due course.

But as 18 Sikhs were amongst thevictims of AI182 and the Sikh'sgrievances were wholly sectarianissues, you have to wonder why theywould be killing those of their ownbeliefs. And "Pathologicalexamination of 131 recovered bodiesfailed to reveal any injuries indicativeof a fire or explosive residue". Which
http://www.airindia.istar.ca/http://www.airindia.istar.ca/


19/20



all brings me to the point of this long journey through burnt and twistedmetal. When aircraft wiring causes acrash you can be sure that there willnot be much evidence of its infidelityonce everything has burnt out. Evenin the case of Swissair 111, the oceanfloor has failed to yield up any goldennuggets in spite of there being nopost-crash fire. On 28 August 2001the Canadian TSB will be offering upmore of what they have come up with

- and certainly to date there has beenmuch said about onboard fires,fighting them and even preventingthem. And quietly, almostsurreptitiously in the background,there has been an ongoing welter ofMD-11 electrical service bulletins andAirworthiness Directives, mostly to dowith wiring. Boeing refused to endorse

(even as non-mandatory servicebulletins) Swissair's suggested MD-11electrical improvements for the World-wide MD-11 fleet although Swissairhas gone ahead anyway - afterconsiderable pressure from its crews.I guess you would cynically have toopine that Boeing could not acceptthe SR modifications because it wouldhave been a tacit admission that therewas something faulty about their MD-11's original design. The Boeing standhas always been that it's wiringinstallation (and not insulation) that isthe real concern. However, theforthcoming report of the ongoingNTSB investigation into the FAAsairworthiness standards and type

certification might express otheropinions.

The great unspoken has always beenthe issue of that chicken and egggestation of any onboard fire. Boeingwill always insist that even though(perhaps) the wiring was the cause offire and smoke - that it could havebeen something else that firstdamaged that wiring insulation andcooked it off. Portraying the insulation

of a particular wire-type as being theculprit has been simply "not on" -despite a wealth of military and otherin-service knowledge of the failingsand failure-modes of certain types ofwiring insulation. The limitedconcession has lately been that theage of wire is a part of theconsideration in the overall concern

about geriatric airliners. Meanwhilethere are multiple daily instances ofaircrews landing prematurely withsmoke in the cockpit or cabin. Thereis no great crescendo of concernsimply because findings in the VJ592and TWA800 cases were quiteinconclusive, alternative theoriesabounded - and the SR111investigation will soon enter its fourthyear. The length and cost of thesepuzzling crash investigations seem tobe as inconsequential as the fact thattheir conclusions are usuallyindeterminate and inconclusive. Therehas to be a better way to keep track of(or later determine) an airliner's fate -and there is. but what's stopping


20/20


developments in this vital area?

The FAA has grudgingly agreed toswap out the flammable Mylarblankets on a five-year deadline and

concedes that CVR and DFDRtechnology should be enhanced. Butthese improvements are quitedemonstrably far short of what'stechnologically feasible. Firstly thecheapest and easiest solution wouldbe CCTV, simply because CVRanalysis, no matter how clever, canonly tell you so much. There are other

methods of keeping an eye on anaircraft's in-flight progress. It can bedone in real time. Go to the IASA site 1and use the site-search engines tolook for IRIDIAN, ROADSHOW andRAFT. These will tell the story ofsatellite uplink real-time data-monitoring of an aircraft's systemswhilst enroute. Today's technology isquite deterministic and can tell you asearly as this afternoon exactly why anaircraft went down this morning.Under their respective FOQAprograms (Flight Ops QualityAssurance) airlines are alreadysimilarly keeping an eye on theperformance of both aircrews andairplanes via post-flight QAR/DFDR 2analysis. Data-flow upload of thatsame data via satellite uplink istechnically unchallenging and maywell save millions in protracted crashinvestigations 3. It may seem quitecynical but in my opinion, the entity

with most to lose would always be theairliner manufacturers. They arecontent that accident causes shouldremain as probable causes. simplybecause litigation under that regime is

non-punitive and permits them widescope in out-of-court settlementbargaining. If this was not the waythings were, and accident causeswere to be easily nailed down, wellthat would be a whole new litigationball-game, would it not?

So here we have reviewed some old,

some not so old and some morerecent accidents. Why is it all topical?Well the Truth and ReconciliationCommission turned up so much "stuff"that Trevor Abrahams, chief executiveofficer of the Civil Aviation Authority, aman from a somewhat chequeredbackground himself, will soon beadvising the Transport Ministerwhether to hold a further HelderbergInquiry. Air India 182 trials are soon tobegin (unless charges are dropped forlack of evidence of course) and theCanadian TSB is about to surfacefurther SR111 revelations. The FAAand NTSB are also embroiled inTWA800 aftermath - the decisionwhether double-checking the wiring isenough or should inerting of fuel-tanks be mandatory.

But why is it that I strongly suspectthat aircraft wiring will figure in noneof these high profile events? Well ifyou cannot answer that for yourself atthis point, I suggest you go back tothe beginning and re-read - and thenlook at the IASA web site.

2 Quick Access Recorder/Digital Flight DataRecorder

awakenings fall 2001

Documents