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Aviation History
1954
1954 - 2949.PDF
638 FLIGHT THE COMET INQUIRY The First Week's Evidence: Pressure-cabin Fatigue Failure In G-AL YP THE conclusion that the accident to Comet G-ALYP near Elba in January this year was caused by structural failure of the pressure cabin brought about by fatigue was put forward by the Crown in the opening stages of the Comet inquiry in London last week. This conclusion was based on a detailed investigation by the staff of the Royal Aircraft Establishment into all possible causes of the disaster, using evidence from the wreck age, practical tests and theoretical analyses. In the absence of wreckage from the accident to G-ALYY near Naples in April, no definite cause could be suggested, although the same explanation' appeared to be applicable. The inquiry opened in Church House, Westminster, on Tuesday, October 19th, before Lord Cohen, Commissioner, with Sir William Farren, C.B., M.B.E., F.R.S., Professor W. J. Duncan, C.B.E., D.Sc, F.R.S., and A. Cdre. A. H. Wheeler, O.B.E., as his assessors. Sir Lionel Heald, Q.C., Mr. J. P. Graham, Q.C., and Mr. P. J. Stuart Bevan appeared on behalf of H.M. Attorney-General, while the Ministry of Transport and Civil Aviation, the Ministry of Supply, the British Air Line Pilots' Association, British Overseas Airways Corporation, South African Airways, the Air Registration Board, the de Havilland Aircraft Co., Aero Research, Ltd., British Thomson-Houston Co., Ltd., the Navigators and Engineer Officers' Union, Normalair, and the personal representatives of a number of the deceased crew-members and pas sengers, as interested parties, were represented by counsel. Accredited representatives of the Governments of Italy and of the Union of South Africa were also present, and a watching brief was held on behalf of Union Aeromaritime de Transport. The explanation of what was believed to have happened to Comet G-ALYP was given to the court by Sir Lionel Heald in his opening for the Crown. (This opening is summarized extensively on pages 652-654 of this issue.) He traced the history of the accidents and of the events which followed them, with particular reference to the technical investigation performed by the R.A.E. The lines of approach and the techniques used were detailed, and also the process of elimination which led to the opinion that metal fatigue was the only possible cause, consistent with all the facts, of the Elba accident. The first witness to be called was Mr. Eric Newton, chief investigating officer of the Accident Investigation Branch (Civil Aviation), M.T.C.A., who produced formal aircraft documents relating to G-ALYP. Mr. C. M. Mack and Mr. M. R. Ovenden, B.O.A.C. inspectors, then gave evidence in turn, confirming that they had signed the airframe and engines sections respectively on the aircraft's Certificate of Maintenance. The next witness, Mr. A. A. Elliott of the M.T.C.A., stated that all the aircrew licences of the crews concerned in the accident were valid at that time, with the exception of that of the flight engineer, which had expired on December 11th, 1953. Capt. E. E. Rodley, a Flight Captain of the B.O.A.C. Comet 2 fleet, gave evidence concerning the flight experience of the crew of G-ALYP. Capt. Alan Gibson, he said, "was above average as a pilot and as a commander and had shown himself extremely capable of dealing with any emergencies that might arise." The other crew-members were 1st Off. Bury, R/Off. Macmahon, Flt/Eng. F. C. Macdonald, Steward F. L. Saunders, and Stewardess Jean Evelyn Clark. The Fleet Engineer Officer, B.O.A.C. Comet fleet, Mr. W. L. Bennett, was the next witness, and he described Eng/Off. Macdonald as com petent and conscientious, experienced on Comet aircraft, and having successfully completed a periodical check on all aspects of flight engineer ing on December 11th, 1953. He continued, "I can see no reason why he should not have renewed his licence at the appropriate date." Wednesday, October 20th: Second Day.—The picture of what happened to G-ALYP before and after the accident was gradually built up by the spoken evidence of flight crews and ground personnel based at Ciampino, and by the written affidavits of eye-witnesses on the Isle of Elba. Those referring to the Comet and its crew before take-off from Rome pointed to the absence of any prior indication whatsoever of any mishap likely during the flight, while a broken-off R.T. message—and what was seen from Elba—confirmed the suddenness of the disaster. The first witness to be examined was Capt. A. Meagher, of B.O.A.C., who was in command of Comet YP on its flight from Karachi to Rome on January 9th-10th. He said that the aircraft behaved perfectly normally on the flight, but that it was delayed at Beirut due to an unserviceable port-wing refuelling valve actuator. Two other minor unserviceabilities had arisen, but neither affected the safety of the aircraft. Details of these items were given to Capt. Gibson by the witness on handing over the aircraft at Rome. Mr. G. C. Stuart, flight engineer on the Karachi-Rome flight of YP, next gave further details of the refuelling actuator's unserviceability. The actuator, he said, was removed, checked and replaced at Beirut following refuelling difficulty, and the fact was entered in the "B snag" section of the Technical Log. At Rome, Flt/Eng. Macdonald—who was taking over for the Rome-London flight—was told of what had happened. Four affidavits were next read to the court, those of B.E.A. and B.O.A.C. operations personnel who were on.duty at Ciampino on the day of the accident. Their statements were to the effect that nothing unusual occurred in the normal preparation for the flight of YP from Rome. This was confirmed by Mr. W. G. T. Latimer (B.E.A. station officer), who supervised the unloading and loading of the Comet, and by Mr. G. A. Bull (B.O.A.C. maintenance engineer), who carried out a refuelling check and departure check on it. Mr. B. J. Folliard (B.O.A.C. assistant inspector of accidents) disclosed that there was a small loading discrepancy of 27 kg between the trim-sheet figures and the total obtained from cargo manifests and passenger sheets, in hold 2A. This, he thought, was an arithmetical error. The B.E.A. station superintendent at Ciampino, Mr. P. C. Pinfield, was the next witness. He said that the situation as regards access to B.E.A. and B.O.A.C. aircraft by unauthorized persons at the time of the accident was satisfactory, although there had been occasions when members of the public had gained access to the apron area. R/T. messages to and from the Comet were described to the court by Mr. L. Lippera (B.O.A.C. operations assistant), who on the day of the accident had been on duty, noting such messages in the Flight Progress Log at Ciampino. The messages from YP after its take-off at 0931 included : 0932, "Departed Ciampino heading for Ostia Beacon climbing 2,500ft now"; 0934, "Over Ostia Beacon at 6,500ft climbing"; further messages at 0936 and 0941; 0942, "Abeam Civitavecchia Beacon 19,000ft"; 0946, "Visual flight above clouds at 23,000ft"; 0950, "Over Orbetello Beacon now." At 1005 a background transmission was heard, which might have been either the Comet or Air Traffic Control; no further message from YP was received. The pilot of the Argonaut G-ALHJ which took off from Rome at 0919 hr that morning, Capt. J. R. Johnson, gave details of his R/T. con versations with the captafn of YP, whom he had asked for the cloud-top height. After the Comet had reported over Orbetello, Capt. Johnson said, "Immediately his transmission stcrpped I called Rome Control. . . . This call to Rome must have reminded the captain of YP that he had promised to give me the top of the cloud, and he called: 'George How Jig from George Yoke Peter. Did you get my—" and the transmission stopped at 'my.'" An estimated position of G-ALYP at 0951 was given by Mr. C. Evans (until recently B.O.A.C. Fleet Navigation Officer, Comet Fleet), who said that the Comet was just about crossing the coast on its way from Orbetello to Elba at that time. Its height, he thought, would be approaching 27,000ft. This was followed by an account of the meteoro logical aspects of the accident by Mr. P. J. Meade, senior meteorological officer at London Airport, who reported that there was no evidence of severe turbulence being encountered, although the Comet was flying in an area in which, due to the relative position of a northerly jet stream, severe turbulence was a possibility. The events at Elba at the time of the accident were next outlined, by means of affidavits by eye-witnesses. Extracts from these include: —- Ninuccio Geri: "I am a sailor ... I was busy working when suddenly heard a heavy roaring noise like thunder. I turned in tlv direction of the noise and saw a globe of fire rotating as it came dow into the sea. ..." Vasco Nomellini: "I am a farmer ... I heard the noise of an air craft . . . but I did not pay any attention to it. Suddenly, howeye., my attention was caught by a roaring sound in the air in the directio" from which the noise of the aircraft was coming, and I distinctly notices in that direction, two pieces of an aircraft, the smaller in flames, fallirK in almost parallel lines into the sea. . . ." Probable source of the pressure-cabin failure on G-ALYP was trace among the recovered wreckage, to this corner of the rear A.D.F. windov-" where signs of high-level fatigue were found.
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