BOAC Flight 781 was a scheduled British Overseas Airways Corporation passenger flight from Singapore to London. On 10 January 1954, a de Havilland Comet passenger jet operating the flight suffered an explosive decompression at altitude and crashed, killing all 35 people on board.
The aircraft, registered G-ALYP, had taken off shortly before from Ciampino Airport in Rome, en route to Heathrow Airport in London, on the final leg of its flight from Singapore. After it exploded, the debris from the explosion fell into the sea near the island of Elba, off the Italian coast.
G-ALYP was the third Comet built. Its loss marked the second in a series of three fatal accidents involving the Comet in less than twelve months, all caused by structural failures; it followed the crash of BOAC Flight 783 near Calcutta, India, in May 1953, and was followed by the loss of South African Airways Flight 201 in April 1954, which crashed in circumstances similar to 781 after departing from Ciampino Airport.
Flight 781 was commanded by Captain Alan Gibson DFC, age 31, one of BOAC's youngest pilots. He had joined BOAC in 1946, after flying in the Royal Air Force during World War II. He had considerable flying experience, having logged more than 6,500 flight hours. He had previously been involved in an accident in 1951, in which a Hermes aircraft was forced to make an emergency landing, and he was later praised for his flying conduct during this accident flight.
The first officer on Flight 781 was William John Bury, age 33. He had flown a total of approximately 4,900 hours. The second officer was Francis Charles Macdonald, age 27, and the radio operator was Luke Patrick McMahon, age 32. They had logged 720 flying hours and close to 3,600 flying hours, respectively.
Ten of the twenty-nine passengers were children. Many of them were students of schools in the United Kingdom and had visited their families that had been residing in Asia. Three employees of BOAC and one employee of British European Airways were passengers on the accident segment. Additionally, six passengers were related to BOAC employees. Among the casualties were Chester Wilmot, a prominent Australian journalist and military historian working for the BBC, and Dorothy Beecher Baker, a Hand of the Cause of God for the Baháʼí Faith. Wilmot first joined the flight in Rangoon, and Baker first joined the flight in Karachi.
On the day of the accident, the Comet went through its routine preflight inspection in Rome, and was checked for "incidental damage"; none was found. The aircraft was therefore released to service. The same team of engineers a few months later examined South African Airways Flight 201 before its final flight.
Flight 781 departed from Rome at 10:31 CET (09:31 UTC) on 10 January 1954, on the final stage of its flight to London. At about 10:50 CEST, a BOAC Argonaut, registration G-ALHJ, piloted by Captain Johnson, which was flying the same route at a lower altitude, was in contact with Captain Gibson. During a radio communication about weather conditions, the conversation was abruptly cut off. The last words heard from Gibson were "George How Jig, from George Yoke Peter, did you get my—". Soon afterwards, witnesses saw wreckage falling into the sea.
Heathrow Airport initially listed Flight 781 as being delayed, but it was removed from the arrivals board at around 1:30 pm.
In its issue dated 11 January 1954, The New York Times published a report stating that a British Comet jet airliner had plunged into the sea near the western coast of Italy, specifically between the islands of Elba and Montecristo. As per the report, it was strongly suspected that the tragic incident had claimed the lives of 35 people. Extensive recovery operations were carried out overnight, yet despite thorough searches in the frigid waters, prospects of finding any survivors were bleak.
The task of finding out what had happened to Flight 781 was difficult at first because the accident had occurred over water. In 1954, there were no cockpit voice recorders or flight data recorders (the so-called "black boxes") to assist crash investigators, and there existed no established protocol for aircraft accident investigation at the time.
An extensive search for the aircraft was organised, which included the Royal Navy ships HMS Barhill and HMS Gambia as well as the Maltese civilian salvage vessel Sea Salvor. The search effort involved the pioneering use of underwater TV cameras, developed by a team at the UK Admiralty Research Laboratory led by George MacNeice, to help to locate and salvage the wreckage in deep water. The wreckage was returned to the United Kingdom by RFA Fort Beauharnois.
Witnesses to the crash were a group of Italian fishermen who rushed to the scene to recover the bodies and to search for possible survivors, of whom there were none. The aircraft wreckage was eventually found on the sea floor; it was subsequently raised and transported to the Royal Aircraft Establishment (RAE) for investigation.
To find more evidence concerning the cause of the crash, the bodies were brought to the coroner for post-mortem. During the examination, pathologist Antonio Fornari found broken and damaged limbs, which had apparently occurred after death. He also discovered in most of the victims a distinct pattern of injuries, consisting of fractured skulls and ruptured and otherwise damaged lungs, which he identified as the actual cause of death. Fornari was confused by the pattern of injuries because he could find no evidence of an explosion.
The ruptured lungs were a sure indicator that the air cabin had depressurised, because the sudden decrease in pressure would have caused the lungs to expand until they ruptured. To support this theory, and also to confirm the cause of the skull fractures, the crash was simulated at the RAE in Farnborough by reproducing the conditions of the actual plane prior to the crash. To make this possible, a model fuselage was constructed that was similar to that of the Comet. Dummies were seated within the fuselage to replicate the possible movements of the passengers during the crash.
In order to simulate the crash, the investigators deliberately ruptured the model fuselage by increasing the air pressure inside until it exploded. The movement of the dummies within the air cabin revealed the cause of the skull fractures: at the moment that the fuselage exploded, they were thrown out of their seats and slammed head-first into the ceiling.
Upon examination of the aircraft wreckage by the RAE, it became evident that the aircraft had broken up in mid-air, and there was initially some speculation that the aircraft might have been brought down by a bomb. Suspicion then shifted to the possibility of an engine turbine explosion, and modifications were instigated in other Comets, where the turbine ring was encased with armour plate to contain a possible disintegration of the turbine disk. The possibility of failure of the pressure cabin was also considered, but this theory was discounted because the Comet's cabin had been designed to a considerably higher strength than was considered necessary at the time.
In the meantime, all Comets were to be grounded until the turbine modifications had been carried out. The New York Times reported on 12 January that BOAC had temporarily withdrawn all of their de Havilland Comet jet airliners from service, as a result of the crash, and that the two French airlines that used the Comet—Air France and Union Aero Maritime des Transports—had also suspended their Comet services. BOAC had confirmed that their Comet routes would be flown with alternative aircraft to minimise the disruption to the service schedule. The airline emphasized that the planes had not been officially grounded by the British government, but that the action was being taken as "a measure of prudence to enable a minute and unhurried technical examination of every aircraft in the Comet fleet to be carried out at maintenance headquarters at London airport."