BOAC Flight 781 DeHavilland Comet 'Mid Air Explosion'
On Sunday 10 January 1954, British Overseas Airways Corporation Flight 781, a de Havilland DH.106 Comet 1 registered G-ALYP, took off from Ciampino Airport in Rome, Italy, en route to Heathrow Airport in London, England, on the final leg of its flight from Singapore. At about 10:51 GMT, the aircraft suffered an explosive decompression at altitude and crashed into the Mediterranean Sea, killing everyone on board. The accident aircraft G-ALYP was the third Comet built.
Official findings concerning BOAC Flight 781 and South African Airways Flight 201 were released jointly on 1 February 1955, in Civil Aircraft Accident Report of the Court of Inquiry into the Accidents to Comet G-ALYP on 10 January 1954 and Comet G-ALYY on 8 April 1954. After the equivalent of 3,000 flights simulated with G-ALYU, investigators at the RAE were able to conclude that the crash of G-ALYP had been due to failure of the pressure cabin at the forward ADF window in the roof. This window was one of two apertures for the aerials of an electronic navigation system in which opaque fiberglass panels took the place of the window glass. The failure was a result of metal fatigue caused by the repeated pressurization and de-pressurization of the aircraft cabin. Another fact was that the supports around the windows were riveted, not glued, as the original specifications for the aircraft had called for. The problem was exacerbated by the punch rivet construction technique employed. Unlike drill riveting, the imperfect nature of the hole created by punch riveting caused manufacturing defect cracks, which may have caused fatigue cracks to start around the rivet. The investigators examined the final piece of wreckage with a microscope.
Japan Airlines JAL Flight 123 'Explosive Decompression'
Japan Airlines Flight 123 (日本航空123便墜落事故 Nihonkōkū 123 Bin Tsuirakujiko) was a scheduled domestic Japan Airlines passenger flight from Haneda Airport (Tokyo International Airport) to Osaka International Airport, Japan. On Monday, August 12, 1985, a Boeing 747SR operating this route suffered mechanical failure 12 minutes into the flight and, 32 minutes later, crashed into two ridges of Mount Takamagahara in Ueno, Gunma Prefecture, 100 kilometres (62 miles) from Tokyo. The crash site was on Osutaka Ridge (御巣鷹の尾根 Osutaka-no-One), near Mount Osutaka. All 15 crew members and 505 of the 509 passengers on board died.