- Sir Winston Churchill BOAC DH-106 Comet 1 G-ALYP [6003] - January 10,1954;BOAC DH-106 Comet 1 G-ALYY [6011] - April 8,1954

In any new field of human endeavour, it is often those who blaze a trail into previouslyunknown realms who suffer the consequences of their pioneering efforts. Nowhere wasthis more true than with the development of the world’s first jetliner by Britain's deHavilland Company.

In Britain as the end of World War 2approached, the nation’s aircraft in-dustry was facing a dilemma.Throughout the war, the industryhad properly concentrated on thedevelopment and production of mili-tary aircraft, principally fighters tocounter the might of Germany’sLuftwaffe, and heavy bombers totake the air war into the heartland ofGermany itself. As a result there hadbeen virtually no transport aircraftdevelopment in its own right for sev-eral years. The few transport typesbeing built in Britain were no morethan adaptations of existing twinengined and four engined bomberdesigns.

pressurised aircraft, originally de-signed for TWA as the Constellation.Already Douglas was working on abigger and faster pressurised ver-sion of the DC-4, to be known as theDC-6, while Boeing was developinga two deck transport version of theirhigh altitude B-29 long rangebomber.

be developed as soon as possible af-ter the war, a proposal expected toalmost halve flying times.

With the war’s end, all these air-craft would of course be instantlyadaptable to airline operations. Allin all it looked as though, with thecoming of peace and the anticipatedboom in airline flying the worldover, the British industry would bewell and truly left at the post.

The old established de HavillandCompany, because of its experiencewith the Vampire jet fighter, waskeenly interested in the project, andbegan design work on the world’sfirst jet airliner, to be known as theDH-106 Comet, in 1946.

The Brabazon Committee, a Brit-ish Government body appointed atthe end of 1942 to examine propos-als for the development of postwarairline aircraft, decided that, ratherthan merely design new types ofconventional transport aircraft tocompete with existing American de-signs and their derivatives on theworld market, the British industryshould seek to build civil types thatwould be technologically well aheadof current design practice. Amongthe major recommendations of theBrabazon Committee was that a tur-bojet airliner, capable of operatingon the North Atlantic route, should

It would be powered by four Rolls-Royce Ghost engines, carry 36 pas-sengers in a pressurised cabin, andbe capable of operating up to 40,000feet at a cruising speed of almost500mph (800kph) - nearly twice theperformance of the best existingAmerican piston engined airliners.An ambitious plan indeed!By contrast, in the United States,

the war had provided the stimulusfor the development and construc-tion of large transport aeroplanes ona scale never before envisaged. TheDouglas C-47 Dakota, the militaryversion of the prewar DC-3, hadbeen turned out in thousands, andits four engined long range succes-sor, the C-54 or DC-4, was provingitself as a superb, highly efficient, in-tercontinental military aircraft - theworld’s first true global transport.Meanwhile Lockheed was producingits C-69, an even more advancedhigh speed, long range four engined

A few months later de Havilland’sreceived official backing for theproject when the Ministry of Supplyplaced a contract for the purchase ofseveral Comet aircraft for the gov-ernment overseas airline, BOAC.

Some measure of the magnitude ofthe pioneering design task the deHavilland Company had taken oncan be gained from the fact that itwas not until mid 1949 that the pro-totype Comet made its maiden flight-and it was afurther two and a halfyears before the type - now desig-nated the Comet 1 - received a full

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Certificate of Airworthiness. Afterspecialised crew training by bothBOAC and de Havilland’s, BOAC atlast began scheduled passengerservices with the Comet, initially be-tween London and Johannesburg, onMay 2 1952.

The introduction of the world’sfirst jet airliner to everyday opera-tions, offering passengers entirelynew standards of comfort andspeed, created a furore in the worldairline industry. In one masterlystroke, Britain appeared to have re-gained mastery over the Americancivil aircraft industry, despite thelead the latter had gained during thelong years of war. Orders for theComet and its proposed faster andhigher capacity development, theComet 2, flowed in from other inter-national airlines - Air France andUAT, Canadian Pacific Airlines, Ol-ympic Airways, Middle Eastern Air-lines, United Arab Airlines andIbn-Saud. The Australian based Brit-ish Commonwealth Pacific Airlines,though having reservations aboutthe aircraft’s long range capabilityfor efficient operations on the transPacific service, was keenly inter-ested, while Qantas Empire Airwayswas under considerable pressurefrom its Kangaroo Route partner,BOAC, to also place orders for thetype.

In September 1952, four monthsafter regular Comet services had be-gun, de Havilland’s announced thedevelopment of a longer range vari-ant, the Comet 3, for trans Atlanticservices. The jewel in the crown forthe British aircraft industry followedshortly afterwards - orders for theComet 3 from the long establishedand prestigious Pan American Air-ways. The US domestic operator,

Capitol Airlines, also placed an or-der for Comet 2s soon afterwards. Anew British era in commercial avia-tion was dawning!

But now came the first of a seriesof misfortunes that were ultimatelyto shatter the fulfilment of the Brit-ish dream. On October 26 1952,BOAC’s Comet G-ALYZ was takingoff at night and in rain from Rome’sCiampino Airport with a full load ofpassengers. On the point of becom-ing airborne at 112 knots, CaptainFoote felt a shudder, followed by apronounced buffet - the prelude toan aerodynamic stall. Realising theaircraft was no longer accelerating,he eased the control column for-ward, but the buffet continued andthe aircraft bounced on the runwayFoote immediately cut the powerand abandoned the takeoff, brakingheavily. But too late.

Still travelling at high speed, theComet plunged off the end of therunway into the dark. The undercar-riage was wrenched off as it hit amound of earth, the port wing andtailplane smashed into two of the air-port’s post mounted boundary lights,and the aircraft finally slid to a stopon the muddy ground, damaged be-yond repair. Mercifully, though kero-sine poured from a ruptured fueltank, no fire broke out and the occu-pants, though badly shaken, all es-caped injury.

An investigation carried out by theItalian authorities found that the tailof the Comet had made contact withthe runway several times some dis-tance before its end. The accidentwas attributed to “pilot error” inraising the nose too high, a findingdisputed by the British Airline Pilots’Association. The Italian report wasnot published and the accident itself

was given little publicity, a situationby no means unwelcome to BOACand de Havilland’s.

Subsequent tests by de Havil-land’s chief test pilot, Group CaptainJohn Cunningham, established thatif the nose of a Comet was raised toofar while taking off, the induced dragresulting from the high angle of at-tack would prevent the aircraft fromaccelerating to flying speed andwould bring on a low frequency buf-fet - that which Captain Foote hadexperienced at Rome with such un-fortunate results. Comet pilots wereaccordingly briefed on a revisedtakeoff technique, requiring thenosewheel to be kept in contact withthe runway until the specified take-off speed was reached, when the air-craft was to be “rotated” into theclimb attitude.

Meanwhile the production ofComets continued at de Havilland’sHatfield works and by February,Comet 1 Empress of Hawaii, carry-ing Canadian registration CF-CUN,was ready for delivery to its newowners, Canadian Pacific Airways.A Canadian Pacific delivery crew,led by Captain Charles Pentland, thecompany’s overseas operations man-ager, arrived at Hatfield to undergoendorsement and engineering train-ing, and the delivery flight to Canadawas planned for the end of themonth.

De Havilland now saw the deliveryflight as the opportunity they hadbeen waiting for. Because of the per-ceived reluctance on the part of Brit-ish Commonwealth Pacific Airlines,and particularly Qantas, to actuallyplace orders for the Comet (atti-tudes, it must be said, that werelargely the product of de Havilland’sunwillingness to provide either air-

The prototype de Havilland 106 Comet, flown by de Havilland’s Chief Test Pilot, Group Captain John Cunningham, becomes airborne at Hatfieldfor the first time on July 27, 1949. Keen eyed observers will note the single wheel main undercarriage - in contrast to the bogey type undercarriageof the later production Comets. (Temple

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The future looked bright for BOAC, de Havilland’s and the British aircraft industry when theworld’s first jet passenger from London to Johannesburg opened on May 2 1952.C o m p a n y a n d n a t i o n a l p u b l i c i t y m a d e t h e m o s t o f t h e h i s t o r i c o c c a s i o n . (/PC)

line with a detailed analysis of thetype’s performance), a Comet dem-onstration to Australia had longbeen planned “to help the Austral-ians realise that the Comet is in factan aeroplane and not a pipe dream”,as the Chairman of BOAC, Sir MilesThomas put i t .

If the Canadian Pacific AirwaysComet could be delivered via Aus-tralia and the Pacific instead ofacross the Atlantic, taking time outwhile in Australia to be shown to thepress and public, it could well swingthe balance in favour of Comet or-ders instead of the Lockheed SuperConstellations Qantas were keen toobta in .

A satisfactory arrangement wasnegotiated with Canadian Pacificand it was agreed that the deliveryflight should proceed via Australia,flown by the aircraft’s Canadiancrew under the command of CaptainPentland. A further incentive to helpconvince the potential Australiancustomers was now conceived: if theflight could also smash the elapsedtime record for the England/Aus-tralia route, public acclaim for theComet would be all the greater.

The Comet’s proposed recordbreaking flight was widely reportedin the press and many excited Aus-tralians looked forward to seeingtheir first jet airliner literally withinlittle more than a day after its depar-ture from England. But now fatestruck the whole Comet project amore serious blow.

On March 3 1953, taking off forRangoon in the early hours of themorning after a quick refuelling stop

at Karachi, Pakistan, CF-CUN wasseen to assume an abnormally nose-up attitude early in the takeoff run.After using up the entire length ofthe runway and its overrun withoutbecoming airborne, the Comet’s un-dercarriage struck the culvert of aperimeter drainage ditch. The air-craft swung, lurched, then plungedinto a dry canal bed beyond the air-port boundary, exploding violentlyinto flames on impact. The flightcrew of five, together with their sixpassengers - de Havilland technicalpersonnel on their way to Canada to

assist with the Comet’s introductionto the airline - all died in the crashand fire. It was an almost exact rep-etition of the accident at Rome justover four months previously - ex-cept for the traumatic and tragic out-come.

The weather at the time was fineand calm, with a visibility of somenine kilometres in haze, but thenight was very dark. The Comet wasloaded to its maximum permissibletakeoff weight of 52,150 kilograms,but the 2288 metres of runway avail-able should have been adequate in

the existing conditions. Beyond theend of the paved runway was anoverrun of another 180 metres, andthe runway was equipped with highintensity l ighting and thresholdlights at both ends.

In addition to the evidence ofeyewitnesses who said the aircraft’snose was abnormally high for almostthe whole takeoff run, marks on therunway showed that the Comet’s tailbumper had come in contact withthe ground a number of times. Un-like the Rome accident, there wasnothing to indicate that the crew hadmade any attempt to abandon thetakeoff. But there was evidence thatthe nose high attitude was correctedtowards the end of the runway andthe Comet was about to become air-borne when the undercarriage hitthe culvert.

The Indian invest igat ion con-cluded that the accident resultedfrom the excessive nose-up attitudeof the aircraft during the takeoff run,producing a partly stalled conditionand excessive drag. This prevented

Interior of the comfortable forward passenger cabin of the Comet. Passengers were entrancedb y t h e q u i e t n e s s a n d s m o o t h n e s s o f C o m e t t r a v e l - not t o m e n t i o n i t s s l a s h e d t i m e t a b l e s ! (/PC)

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The production Comet, G-ALYP w h i c h flew the world’s inaugural jet passenger service from London to Johannesburg. This aircraft waslost lust 20 months later when It exploded over the Mediterranean, killing a// on board and casting a heavy shadow over the whole future ofComet operations. (/PC)

normal acceleration to flying speed.Eventually realising the nose wastoo high, the crew took correctiveaction, but too late to prevent theundercarriage striking the culvert.

Contributing to the cause of theaccident was the captain’s very lim-ited experience on Comet aircraft.Though a highly experienced airlinepilot, Captain Pentland had little jetexperience and had not previouslyattempted a night takeoff in aComet. During his conversion train-ing on the Comet, Pentland had beenbriefed on the Rome accident and itsapparent cause. Group Captain Cun-ningham had also demonstrated therevised takeoff technique to him,stressing the need to keep the nose-wheel on the runway until flyingspeed was reached. Even so, as withthe Rome accident, the investigatorsbelieved the steep nose-up attitudeof the aircraft might not have beenapparent to the crew, with no hori-zon visible in the hazy darkness. (Atthat stage of their development,Comet aircraft were not fitted with

accurate attitude indicators withnose attitude calibrated in degrees,their only attitude instruments beingstandard Sperry artificial horizons).

It was also thought that the Com-et’s powered hydraulic flying con-trols, with no “feel” or “feedback” tothe pilot, could easily contribute toover control, especially when no ex-ternal visual reference was available.

The final contributing factor to theaccident was considered to be thepressure on the crew to completethe flight from London to Sydney inthe least possible time. Fatigue hadundoubtedly played some part.

The Karachi accident was a bitterblow to both Canadian Pacific Air-ways and the aircraft manufacturer.Apart from the tragic loss of some ofits key personnel, de Havilland’smuch vaunted public relations exer-cise for the Comet had turned out tobe a disaster of nightmare propor-tions. And its repercussions were byno means limited to the Comet’s fu-ture in Australia: Canadian PacificAirways promptly cancelled orders

they had placed with de Havilland’sfor a further two Comets.

Only two months later anotherComet, operating BOAC’s Singa-pore/London service, became thevictim of an even worse disaster,again on the Indian subcontinent.

On May 2, 1953 - the first anniver-sary of the aircraft type’s inaugura-t ion of jet passenger services -Comet 1 G-ALYV, under the com-mand of Captain Maurice Haddon,landed at Calcutta’s Dum Dum Air-port for refuelling at the conclusionof the leg from Rangoon.

The early summer weather wasfine locally, with three eighths of cu-mulus cloud, but it was the monsoonseason and scattered cumulonimbusbuild ups to 35,000 feet were likely.Following an inflight message froman Indian aircraft operating to thenorth-west of Calcutta, a special air-field weather report had been issueda few minutes before the Cometlanded, warning of a thunderstorm,known locally as the monsoonal“north-wester”, approaching Dum

Comet G-ALM was written off In a takeoff accident at Rome on October 26 1952 - the victim of industry inexperience with large jet powereda i r c r a f t a n d t h e t e c h n i q u e s r e q u i r e d t o h a n d l e t h e m . (/PC)

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Canadian Pacific Airways’ CF-CUN, destroyed in a takeoff accident similar to G-ALZ’s. The accident occurred at Karachi during the Comet’sd e l i v e r y f l i g h t t o C a n a d a v i a A u s t r a l i a . T h i s t i m e all o n b o a r d w e r e k i l l e d i n t h e c r a s h a n d fire. (/PC)

Dum, with squalls reaching 50 knots.The thunderstorm was reported tobe accompanied by “very strong ver-tical updraughts”.

Soon after arriving at Dum Dumfrom Rangoon, Captain Haddonwent to the meteorological office todiscuss the approaching weatherand was personally briefed by theduty forecasting officer. The captainevidently did not consider the ap-proaching storm warranted a majordiversion from track and elected tocontinue the flight on to Delhi asplanned. The terminal forecast forDelhi’s Palam Airport was entirelysatisfactory.

At 4.20pm the Comet taxied outfor takeoff. On board, in addition tothe crew of six, were 37 passengers,most of them Britons resident in theFar East. They included the Leaderof the Opposition in the VictorianState Parliament, Mr Trevor Oldhamand his wife, on their way to Londonto attend the Coronation of QueenElizabeth II. Ten minutes later theaircraft lifted from Dum Dum’s Run-

way 19 and set course to the north-west. The surface wind at the timewas south westerly at 13 knots.

Contacting Calcutta Area Controlat 4.32pm, the Comet reported thatits ETA Delhi was 1850 hours andthat it was “climbing to 32,000 feet”.Three minutes later the Comet washeard calling Delhi, but when Delhi’sCommunications officer told theComet to go ahead with its message,there was no response. All subse-quent attempts to contact the Cometwere unsuccessful.

Around 4.35, workers tilling thesoil in paddy fields near the villageof Jagalgori, some 40 kilometreswest of Calcutta, heard a loud reportduring the passage of an unusuallysevere thunderstorm and saw “ablaze of fire” in the sky. Variouspieces of aircraft wreckage, some ofthem burning, then fell to the groundover a wide area.

An investigation team made up ofthe Indian Department of Civil Avia-tion’s Inspector of Accidents and aSenior Inspector of Accidents from

the Ministry of Civil Aviation in Lon-don, found the main wreckage, con-sisting of the forward fuselage, stubwings and engines, lying inverted ina watercourse 38 kilometres fromDum Dum Airport and right on theaircraft’s planned track. The rear fu-selage lay in a paddy field 250 me-tres away, and a wreckage trail ofsmaller components extended fornearly nine kilometres in a southwesterly direction.

It was clear that the Comet haddisintegrated in the air, the sepa-rated tailplane exhibiting evidenceof having failed under excessivedownloading. A public inquiry con-ducted by an Indian High Courtjudge concluded that the aircraft hadencountered severe gusts duringflight through the thunderstorm,leading to loss of control andoverstressing of the tailplane to thepoint of failure during an attempt torecover.

Components of the wreckagewere afterwards flown to the RoyalAircraft Establishment at Farnbor-

First revenue flight fatality: EJOAC Comet G-ALW broke up in flight during an encounter with a monsoonal thunderstorm, soon after leavingCalcutta en route to Delhi on May 2 1953 - the first anniversary of the commencement of Comet services. (/PC)

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"I h e a r d t h r e e e x p l o s i o n s , ” a f i s h e r m a n t o / d i n v e s t i g a t o r s . “ T h e n , s e v e r a l k i l o m e t r e s a w a y , I s a ws o m e t h i n g s i l v e r f l a s h d o w n o u t o f t h e c l o u d s . B y t h e t i m e I g o t t o w h e r e i t h i t t h e water, all w a sstill again. "

ough for further investigation. Thisconfirmed the determination of theIndian court - an inflight break upafter the aircraft encountered verysevere gusts. The crew’s reaction tothe severe turbulence, resulting inover-control, was probably aggra-vated by the Comet’s non-sensitivepower controls and the fact that thecaptain was a former BOAC flyingboat pilot accustomed to applyingheavy control forces.

Following the failure of the tail-plane under download, the aircraftwould have pitched violently nosedown, breaking the wings off justoutboard of the engines and causingan explosive decompression of thefuselage. The violence of the mon-

soonal thunderstorm was consid-ered to be of such exceptional sever-ity that it could have producedstructural failure in any type of air-craft. There was no reason to sus-pect the integrity of the Cometdesign.

But only eight months later, afteryet another disaster overtook aBOAC Comet en route from Singa-pore to London, the picture began tolook rather different.

At 10.30am GMT on January 10,1954, Comet G-ALYP - the same air-craft that had made history nearlytwo years before by completing theworld’s first scheduled passenger jetflight - took off from Rome’sCiampino Airport for London on the

last leg of its regular service fromSingapore. With its normal crew ofsix - captain and first officer, flightengineer, radio officer and two cabinstaff - it was carrying 29 passengersunder the command of Captain AlanGibson, DFC. The passenger list in-cluded the distinguished Australianwartime radio journalist, ChesterWilmot.

It was a crisp, calm winter’s morn-ing, with only thin and broken layersof middle level cloud which theComet quickly surmounted as itclimbed towards its cruising alti-tude. Tracking via the Ostia NDB onItaly’s west coast, thence north-westup the coast, the Comet reportedpassing through 26,000 feet overOrbetello, 44 nautical miles southeast of the island of Elba, at 0950hours. A minute later, CaptainGibson called Captain J Johnson, thepilot in command of BOAC Argonautaircraft, G-ALHJ, which had takenoff from Rome 10 minutes ahead ofthe Comet, apparently to enquireabout an inflight weather report hehad transmitted a few minutes be-fore. “Did you get my . ...” CaptainGibson began. His message wasnever completed.

At about this time, the crew of afishing trawler off the coast of Elba,and a farmer out shooting on the is-land itself, heard a series of loud ex-plosions, followed by a roaringsound, above the clouds. Soon after-wards they saw aircraft wreckage,some of which was on fire andstreaming smoke, spiral down intothe sea, midway between Elba andthe smaller island of Montecristo, 16nautical miles to the south.

All available vessels from Elba’sPorto Ferrario were dispatched tothe area as soon as the accident was

C o m e t G-ALYY t h e l o s s o f w h i c h o f f N a p l e s o n A p r i l 8 7 9 8 4 w h i l e t h e w r e c k a g e o f G - A L Y P w a s s t i l l b e i n g r a i s e d f r o m t h e s e a b e d , f i n a l l y s e a l e dt h e f a t e o f t h e C o m e t a n d d a s h e d t h e h i g h h o p e s o f t h e B r i t i s h a i r c r a f t i n d u s t r y . ( / P C )

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Diagram showing amount of wreckage of G-ALYP eventually recovered from the seabed off theisland of Elba. -

reported. Assisted by search air-craft, they succeeded five hourslater in recovering various smallitems of floating wreckage - mailbags, cushions, overcoats, a child’steddy bear - and 15 mutilatedbodies.

The Italian Government immedi-ately set up a board of inquiry atwhich the British Ministry of CivilAviation was represented by thesame Senior Inspector of Accidentswho had attended the Comet acci-dent near Calcutta. There was muchpublic and press speculation that theinflight break up was the result ofsabotage - a possibility that even theBritish Government would not ruleout at this stage. But autopsies con-ducted on the recovered bodiesfailed to reveal any telltale signs ofmetallic fragments that could pointto the inflight explosion beingcaused by a bomb. Rather, all thebodies had sustained violent decom-pression injuries and the burns in-flicted on them had occurred afterdeath from this cause. Clearly, an ex-plosive decompression of the pres-surised cabin had occurred,

probably while the Comet wasclimbing through about 27,000 feet.

But why? The aircraft was exactlythree years old the day prior to theaccident and it had flown a total ofonly 3681 hours about 1200 flights.Fatigue testing by de Havilland’s dur-ing the development of the Comet upto twice the cabin’s designed operat-ing pressure differential of 8 1 /4pounds per inch had shown the fa-tigue life of the pressure cabin to beat least of the order of 18,000 flights.

Meanwhile in London, BOAC sus-pended all its scheduled Comet serv-ices for the purpose of completing adetailed examination of its aircraftin collaboration with the Air Regis-tration Board and de Havilland’sSome days later the Italian authori-ties, in view of the complexity of thecase, readily agreed that responsibil-ity for the investigation of the acci-dent should be handed over to theBritish Ministry of Transport andCivil Aviation.

In view of all that was at stake, itwas now essential to recover asmuch of the aircraft’s wreckage aspossible, for detailed technical ex-

amination by experts at the Ministryof Supply’s Royal Aircraft Establish-ment at Farnborough, one of theworld’s most experienced and ad-vanced aviation research organis-ations.

The Royal Navy’s base at Maltawas called upon to assist, and threenavy salvage vessels, one fitted withunderwater television equipmentand carrying a deep sea observationchamber, began their search in the100 fathoms of water into which thewreckage of the Comet had fallen. Itwas the first time television hadbeen used for an underwater search.The navy ships were assisted by sev-eral Italian trawlers, chartered fromPorto Azzurio on Elba.

While the search for the wreckagecontinued, it was decided that pres-surisation fatigue tests to destruc-tion would be carried out on one ofBOAC’s oldest Comets, G-ALYU. Wa-ter instead of air pressure, would beused so the fuselage would not frag-ment when it ultimately failed. Toachieve this, a large water tank wasconstructed around the Comet at theRoyal Aircraft Establishment atFarnborough, completely submerg-ing the fuselage while allowing thewings to protrude through the wallsof tank. A complex loading cycle tosimulate a typical flight, involvingtransfer of loads from undercarriageto wings, pressurisation, depressuri-sation, and finally transfer of loadsback to undercarriage, was devel-oped to achieve the equivalent ofthree hours flying time every 10 min-utes. The test rig then began operat-ing 24 hours a day.

Meanwhile, a committee compris-ing technical representatives ofBOAC, the Air Registration Boardand de Havilland’s, had been set upto consider what modificationsshould be incorporated in the Cometfleet before the resumption ofComet operations could be consid-ered. After examining a number ofpossible explanations for the acci-dent in detail, a large number ofmodifications were carried out. Thecommittee still regarded inflight fire

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as the most likely cause, and all pos-sible sources of fire risk were inves-tigated. To guard against the remotepossibility that an engine failure hadresulted in the loss of a turbineblade which had punctured the pres-sure cabin, armour plate was fittedaround the engine nacelles in theplane of rotation of the turbines. Be-cause of the extensive testing car-ried out by de Havilland’s during thedevelopment of the Comet, it wasthought highly unlikely that the acci-dent was caused by a failure of thepressure cabin itself.

Towards the end of March 1954, 11weeks after the Elba accident, withno real explanation emerging fromthe investigation and still no sign ofstructural weakness apparent in theongoing fatigue testing of the Cometpressure cabin, despite the largenumber of cycles imposed on thetest fuselage, the Air RegistrationBoard could see no reason whyBOAC should not resume Cometservices. This the company did onMarch 23. Meanwhile as a precau-tion, the round-the-clock testing ofthe pressure cabin at Farnboroughwould continue.

Unfortunately the decision was tobe proven premature. Only a fort-night later on the evening of April 8,in good if overcast weather, BOAC

Comet G-ALYY, on charter to SouthAfrican Airways, departed Rome forCairo in the course of a companyservice from London to Johannes-burg. In the hands of an experiencedSouth African Airways crew ofseven under Captain WilhelmMostert, the Comet was carrying 14passengers. Lifting off fromCiampino Airport at 7.32pm, the air-craft reported abeam Naples at7.57pm, climbing to 35,000 feet. At8.05pm the Comet called Cairo topass its ETA for that airport. No fur-ther transmissions were receivedfrom the Comet by any station andall attempts to make radio contactwith it were unsuccessful.

At the time of the aircraft’s disap-pearance, the Royal Navy aircraftcarrier HMS Eagle, accompanied bythe destroyer HMS Daring, were atsea en route from Malta to Naples.The ships were ordered to join thesearch for missing Comet and whenmorning came, Eagle flew off herGrumman Avenger aircraft. Aftersweeping the sea for some time inthe vicinity of the area in which theComet was believed to have gonedown, they succeeded in locatingfloating wreckage close to the vol-canic island of Stromboli, some 20nautical miles to seaward of the Ital-ian west coast and 70nm south east

of Naples. Deformed aircraft seats,personal effects, including a letterbeing written at the time of the acci-dent by one of the passengers, otherfloating wreckage and finally fivebodies, were later picked up by thewarships and taken to Naples. A fur-ther body was later washed up onthe Italian coast.

The fate that had befallen G-ALYYwas clearly a repetition of the Elbaaccident - the aircraft had disinte-grated at approximately the sametime after takeoff and at about thesame height while climbing to cruis-ing level. BOAC again suspended itsComet operations until more wasknown of the accident’s circum-stances. But this time more drasticmeasures were obviously called for- four fatal Comet disasters had nowoccurred within the space of 13months, two of them in highly myste-rious circumstances, and public andmedia confidence in the type hadplummeted.

On April 12, 1954, four days afterthe loss of G-ALYY, the Minister forTransport and Civil Aviation an-nounced to a gloomy House of Com-mons that the Air Registration Boardhad withdrawn the Certificates ofAirworthiness of all British regis-tered Comet aircraft.

It was a bitter blow to the British

Comet G-AlYU, used as a test fuselage, submergedin the specially built water tank at Famborough. The fatigue pressure testing went on 24 hours aday until the pressure cabin failed.

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aircraft industry and to the nation it-self. No other manufacturer in theworld had a jet airliner anywherenear ready for passenger servicesand until this time a huge potentialmarket had been open to the Comet.In Parliament a few days later thePrime Minister, Sir Winston Church-ill, directed that the cost of solvingthe Comet mystery was not to bereckoned in either money or man-power. As a result, the investigationbecame the most intense - desperatewould hardly be too strong a word -the world had ever witnessed into anaircraft accident.

The question of attempting to sal-vage the wreckage of G-ALYY fortechnical examination was consid-ered, but quickly rejected as totallyimpractical. The sea where the flot-sam and bodies were found wasmore than 2000 feet deep, preclud-ing any possibility of recovery withexisting deep sea salvage technol-ogy With no hope of being able toexamine the remains G-ALYY, it thusbecame all the more vital to recoveras much of the airframe of G-ALYPas humanly possible. The two acci-dents would become the subject of ajoint public inquiry, the Governmentdecided. “Exhaustive tests will becarried out as a major national re-search policy”’ it announced.

The Navy search off Elba for theremains of G-ALYP, painstakinglycontinuing in the meantime, hadproved an extraordinarily difficulttask. There was first of all the enor-mous problem of locating the rela-tively small pieces of wreckage in awide area of sea. Descriptions of po-sition by the few witnesses who hadseen the Comet falling into the seavaried by up to 10 nautical mileseach way, making it akin to lookingfor the proverbial needle in a hay-stack. Fortunately, circumstancesnow intervened to the Navy’s advan-tage. It was learned that a surveyaircraft of Skyways Ltd had flownover the disaster area shortly afterthe inflight catastrophe, and hadphotographed vessels picking upwreckage and some of the bodies.In one of the photographs, a cornerof the island of Elba was visible, soproviding a more accurate guide.Even so, more than a month passedbefore the first piece of Cometwreckage was located with the aidof the underwater television camera.Then there was the task of actuallyraising the numerous wreckagepieces from the sea bed, 500 to 600feet below the surface - 300 feet ormore deeper than the maximum atwhich Navy divers could work.

The chartered trawlers systemati-cally swept the sea bed in the hope

Where the pressure cabin ultimately failed in the test tank - at the forward escape hatchand window on the port side. k

of scooping up small items of wreck-age in their nets, the Navy shipsused their Asdic, dropping makerbuoys whenever a significant “ping”was registered, and the salvage ves-sels followed up with the televisioncamera and the deep sea observa-tion chamber, its crew peering outthrough port holes as the sea bottomwas scoured a few metres at a time.As pieces of wreckage were progres-sively recovered, they were broughtinto Porto Azzurio, washed downwith fresh water, then examined andidentified. After being photo-graphed, they were air freighted toFarnborough for detailed examina-tion and inclusion in the Comet "re-construction” which Royal AircraftEstablishment investigators werepiecing together on a wooden “skel-eton” mock-up of the aircraft. Thetedious process dragged on until theend of August, nearly eight monthsafter the loss of G-ALYP

As more and more salvaged piecesof wreckage were placed in theirrelative positions on the fuselageskeleton, the sequence of break upbecame increasing clear, though itsorigin still remained a mystery. Themiddle section of the fuselage hadfailed first, after which the rear fuse-lage, then the nose section, hadseparated as complete enti t ies .Shortly afterwards the outer sec-tions of both wings had broken off.All four pieces of airframe had de-tached in a downward direction,leaving the centre section, includingthe four engines and the remains ofthe centre fuselage, by this time ontire, to plummet into the sea on itsown.

At Farnborough too, the time con-

suming testing of the Comet pres-sure cabin in the water tank went onday and night, surpassing in simu-lated hours, the maximum time sofar flown by any Comet. Meanwhilethe seabed search continued offElba, week after week, without anysignificant progress.

But by late May, when G-ALYP’sbroken off tail assembly was recov-ered from the seabed, the investiga-tion began to take a more dramaticturn. When the tail unit was eventu-ally assembled on the fuselage mockup at Farnborough, it was seen tohave been heavily scored by a metalobject which had left traces of bluepaint. The score marks matchedsimilar ones further forward on theport side of the aft fuselage, indicat-ing that the object had slid along thefuselage before striking the tail andpossibly knocking it off. Chemicalanalysis of the paint showed that theobject responsible for the scoringwas a cabin chair - it had somehowbeen catapulted from the cabin be-fore the tail failed. Embedded in thetail structure itself was further proofthat the cabin had been violently dis-rupted - a piece of carpet from thecabin floor. The only way this couldhave happened was if the carpet hadbeen hurled against the tail beforethe tail assembly broke off.

Now other recovered pieces ofwreckage pointed to an explosivefailure of the fuselage. Score marksand paint were found running acrossthe upper surface of the port wing -and the paint was that used for theheavy blue “cheat line” running thelength of the fuselage! In otherwords the port side of the fuselagehad been violently blown out on to

Air Disaster, Volume 1 1 9

the upper surface of the port wingwhile the wing was still attached. OnJune 16 a piece of the port side ofthe fuselage was recovered from theseabed and sent to Farnborough. Itsscratched blue cheat line paint andjagged edges exactly matched thoseon the portion of port wing!

Even more was to come. At theend of June, as the test fuselage wasbeing pressurised to simulate yet an-other climb to cruising altitude,there was a further dramatic devel-opment - the gauges registering thepressure difference between that ofthe cabin and that in the surroundingtank suddenly dropped to zero. Thefuselage had failed after the equiva-lent of 9000 hours flying!

Draining the tank revealed a mas-sive split in the fuselage skin eightfeet (2.4m) long and three feet(30cm) high, located above the portwing and just below the forwardcabin window and escape hatch. Thefailure had originated from a fatiguecrack at a rivet hole at the lower

rear corner of the escape hatch cutout. Further examination of the fuse-lage then revealed similar hairlinefatigue cracks emanating from rivetholes around the cut out for the ADFantenna in the top of the cabin.

Yet there was not a sign of a simi-lar fatigue failure in the wreckage ofG-ALYP’s fuselage - unless it still layon the bottom of the sea. Certainly agood deal of the fuselage was stillmissing, especially in the vicinity ofthe centre section. The trouble wasthat the Navy search seemed to havescraped the seabed clean.

In desperation, the investigatorsnow turned their attention to thelikely trajectories of G-ALYP’swreckage after the inflight explo-sion, in the hope that this might helplocate the vital still missing sectionsof the fuselage. If there had been aviolent structural failure of the pres-sure cabin, the effect, it was calcu-lated, would be similar to a 500pound bomb exploding inside theaircraft. To simulate what this might

have done to the various sections ofthe airframe, a large number ofwooden scale flying models of theComet were constructed with theirmajor components detachable, butheld in place by sliding pins, towhich lines of varying length wereattached. When the models werelaunched from a tethered balloon,the lines pulled out the pins in a pre-determined sequence to simulate theinflight breakup of G-ALYP. As thecomponents fluttered down, theirtrajectories were recorded by moviecameras. From these experiments, apattern of the way in which the com-ponents scattered was established.This information, scaled-up, wasthen applied to the areas of sea offElba to estimate where the missingsections of fuselage were most likelyto be found.

On July 6 the systematic seasearch off Elba was modified ac-cordingly. The problem now wasdeeper water, confining the work tcthe trawlers. Nothing of significance

Main structural failures of G-ALYP airframe following inflight fracture of pressure cabin. (Matthew Tesch)

2 0 Air Disaster, Volume 1

was found for a month, but on Au-gust 12 the trawl net of one of theItalian fishing vessels at last snaggeda substantial piece of wreckage.When hauled to the surface it provedto be a large piece of the top of thecabin, including the roof “window”for the ADF antenna where the hair-line fatigue crack had been found onthe test fuselage. At a rivet hole inthe corner of the window cut out,not far from the section of fuselagethat had scored the port wing, therewas an unmistakable fatigue crack -marking the origin of the fuselagestructural failure that had destroyedthe aircraft!

The mystery was at last solved. AsG-ALYP climbed to cruising altitudeover the Mediterranean on the morn-ing of January 10, 1954, its pressurecabin had burst like an over inflatedballoon with the force of a bomb,flinging the centre fuselage structureand its contents into space. Somehad hit the wings, others the tail. Im-mediately afterwards, with the integ-rity of the fuselage thus destroyed,the nose and rear sections had sepa-rated, falling relatively intact untilthey hit the water. Aerodynamicforces acting on the tumbling centresection, still with the four enginesattached, had then torn off the outerwings, leaving it to fall, now burningfrom disruption of the fuel lines, intothe sea on its own. For all on board,death would have been instantane-ous as the aircraft exploded.

Had exactly the same thing hap-pened to G-ALYY only three monthslater? All the circumstances cer-tainly pointed to it. But with no ex-amination of the wreckage ofG-ALYY possible to confirm the ori-gin of failure or pattern of break up,how could it be known for certain?

The evidence was provided by theItalian and British pathologists whoexamined the bodies recovered fromthe sea after both disasters. The pat-tern of injuries sustained in the acci-dents was identical in both cases,pointing to a common cause oftrauma. It was the first instance ofaviation pathological evidence con-firming the circumstances of a majorair accident.

So ended what was undoubtedlythe most intense and costly accidentinvestigation in the history of avia-tion. The formal Court of Inquiryinto the two accidents began in Lon-don under a judge of High Court inOctober 1954. The transcript of its

proceedings ran to 800,000 wordsand a document 10 inches (25cms)thick. Its report, published in Febru-ary 1955, found no just cause to criti-cise de Havilland’s: they hadproceeded at all times in accordancewith good engineering practice. Butthey were working at the very fron-tier of technology and had paid ahigh price for their pioneering work.

Did the inquiry’s findings cast anyfurther light on the earlier structuralfailure of Comet G-ALYV after take-off from Calcutta on May 2 1953?The official inquiry report did not re-fer to it, but in retrospect, Senior In-spector of Accidents T R Nelsonwho participated in the Indian inves-tigation privately believed that itsbasic cause was probably similar tothe Elba and Naples accidents.

On the other hand, a distinguishedAustralian aeronautical engineerwho was seconded to the Indian in-vestigation as an observer had an en-tirely different theory which nevercame out in the official report. JohnWatkins, Director of Engineering forTAA and a man with a keen profes-sional interest in the future of theComet at the time, believed the pre-cipitating factor in the Calcutta acci-dent was a lightning strike in thecumulonimbus cloud of the mon-soonal squall line.

At Calcutta when G-ALYV was re-fuelled, the wing tanks were filled tocapacity, but at Captain Haddon’s re-quest only a small amount of fuelwas pumped into the Comet’s emptybelly tank. As i t happened, thetanker vehicle which refuelled theComet had been standing in the hotCalcutta sun for two and a halfhours before the aircraft arrived. Af-ter refuelling, the Comet’s belly tankthus contained a relatively smallquantity of hot kerosine and by thetime of takeoff, a large quantity ofhighly explosive vapour. In these cir-cumstances, John Watkins believed,a lightning strike could have touchedoff the vapour, initiating the struc-tural failure. Watkins examined thewreckage himself and was con-vinced the remains of the belly tankexhibited evidence of such an explo-s ion .

Be that as it may, the findings ofthe massive and definitive British in-vestigation made aviation history. Itseffects were far reaching, other air-craft manufacturers with jet airlinerson the drawing board, particularlythe Boeing and Douglas corpora-

tions in the United States, benefitingenormously from the British indus-try’s costly lessons.

Throughout the world, new designstandards for the structural safety ofjet powered airframes and pressurecabins were adopted, and the spec-tre of metal fatigue became an everpresent consideration in the mindsof designers. Manufacturers werealerted to the fact that even thesmallest fatigue crack resulting fromrepeated pressurisation of a fuselagehad the potential to lead to a disas-trous structural failure.

The Comet investigation alsopointed out the problems inherent indesigning cutouts in pressure cab-ins. The result is that today’s pressu-rised jet airline aircraft fuselageshave heavier skinning and smallerwindows. Their design also incorpo-rates a cross-webbing type of fuse-lage wall structure intended to stopany crack extending unimpededalong the cabin skin. The resultinggain in design knowledge and safetyis plain to see - since the Comet dis-asters, no other airline jet has ex-ploded in flight as a result of apressure cabin fatigue failure.

But none of this could compensatethe aircraft manufacturer and theairline that had blazed the trail intothe unknown realm of high speed jetairliner operations at 40,000 feet -Britain’s de Havilland Company andBOAC. The fleet of five survivingComet 1s remained permanentlygrounded. The RAF’s TransportCommand took delivery of a fewComet 2s with modified fuselages.Only one Comet 3 was completed toflying status and became an airbornetest bed for Rolls-Royce’s new andmore powerful Avon engines.

The general public was not to havethe opportunity to fly again in aComet until BOAC introduced theredesigned and longer fuselageComet 4s to the North Atlantic serv-ice in October 1958. But only threeweeks later Boeing’s new, much big-ger and longer range 707 jetliner, anaircraft developed from the KC-135flying tankers Boeing had developedfor the USAF’s Strategic Air Com-mand, entered the same market - amarket which the Seattle manufac-turer, by the overall excellence of itsproduct, would take by storm.

Britain’s de Havilland Company,the pioneer, has missed the bus.

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