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BOAC Flight 911 (Speedbird 911) was a round-the-world flight operated by British Overseas Airways Corporation that crashed near Mount Fuji, Japan, on 5 March 1966. The Boeing 707-436 on this flight was commanded by Captain Bernard Dobson, 45, from Dorset, an experienced 707 pilot who had been flying these aircraft since November 1960. The aircraft, registered G-APFE, disintegrated and crashed near Mount Fuji, Japan, shortly after departure from Haneda Airport, at the start of the Tokyo-Hong Kong segment. All 113 passengers and 11 crew members were killed in the disaster, including a group of 75 Americans associated with Thermo King of Minneapolis, Minnesota,〔Stone, Richard, "124 die in 2nd Japan air disaster" quote:"A BOAC spokesman said 75 of the Americans aboard were members of a tour sponsored by Thermo King Corp. of Minneapolis, Minn."〕 on a 14-day company sponsored tour of Japan and Southeast Asia. There were 26 couples travelling together in the group, leaving a total of 63 children orphaned. This was the third fatal passenger airline accident in Tokyo in a month, following on the heels of the All Nippon Airways Flight 60 incident 4 February and Canadian Pacific Air Lines Flight 402 the day before Flight 911 crashed. ==Flight and accident investigation results== The aircraft arrived in Haneda at 12:40 hours on the day of the accident from Fukuoka Airport where it had diverted the previous day due to conditions on the ground in Tokyo.〔(【引用サイトリンク】 publisher=Aviation Safety Network )〕 The weather there had since improved behind a cold front with a steep pressure gradient bringing cool dry air from the Asian mainland on a strong west-northwest flow, with crystal clear sky conditions. During their time on the ground, the crew received a weather briefing from a company representative, and filed an instrument flight rules (IFR) flight plan calling for a southbound departure from Haneda via the island of Izu Ōshima, then on airway JG6 to Hong Kong at flight level 310 (31,000 feet).〔 At 13:42 hours the crew contacted air traffic control requesting permission to start engines, and amending their clearance request to a visual meteorological conditions (VMC) climb westbound via the Fuji-Rebel-Kushimoto waypoints, which would take them nearer to Mount Fuji, possibly to give the passengers a better view of the landmark.〔Job, Macaurthur. Air Disaster – Volume 1, p.44〕 The aircraft began taxiing at 13:50 and took off into the northwest wind at 13:58. After takeoff, the aircraft made a continuous climbing right turn over Tokyo Bay, and rolled out on a southwest heading, passing north of Odawara.〔Job, Macaurthur. Air Disaster – Volume 1, p.44-45〕 It then turned right again toward the mountain, flying over Gotemba on a heading of approximately 298°, at an indicated airspeed of 320 to 370 knots, and an altitude of approximately 4,900 m (16,000 ft), well above the 3,776 m (12,388 ft) mountain peak.〔 The aircraft left a debris field 16 km (10 mi) long.〔Job, Macaurthur. Air Disaster – Volume 1, p.45〕 Analysis of the location of wreckage allowed the accident investigators to determine that the vertical stabiliser attachment to the fuselage failed first. It left paint marks indicating that it broke off the port side horizontal stabiliser as it departed to the left and down. A short time later, the ventral fin and all four engine pylons failed due to a leftward over-stress, shortly followed by the remainder of the empennage.〔Job, Macaurthur. Air Disaster – Volume 1, p.47〕 The aircraft then entered a flat spin, with the forward fuselage section and the outer starboard wing breaking off shortly before impact with the ground.〔〔Job, Macaurthur. Air Disaster – Volume 1, p.48-49〕 Although some stress cracking was found in the vertical stabiliser bolt holes, it was determined by subsequent testing that it did not contribute to this accident. Still, it was potentially a significant safety-of-flight issue. Subsequent inspections on Boeing 707 and similar Boeing 720 aircraft as a result of this discovery did reveal this was a common problem, and corrective maintenance actions on the fleet eventually followed. One day after the crash, speculation was that fierce winds above Mount Fuji were responsible. ''The New York Times'' reported: "Despite these reports of a fire and explosion aviation experts said that adverse wind conditions around the volcanic cone about 40 miles south of Tokyo may have caused the crash. The vicinity of the 12,388-foot peak is notorious for tricky air currents. Technicians in New York said that a condition could exist where turbulent air could have caused the aircraft to undergo a drastic manoeuvre that might lead to a crash. Such violent forces, they said, might have caused an engine to disintegrate, possibly setting fire to the wing or fuselage." The probable cause determination was: "The aircraft suddenly encountered abnormally severe turbulence over Gotemba City which imposed a gust load considerably in excess of the design limit."〔 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「BOAC Flight 911」の詳細全文を読む スポンサード リンク
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