Summary In-flight break-up Passengers 113 Survivors 0 Date 5 March 1966 Survivor 0 | Crew 11 Total fatalities 124 (all) Passenger count 113 | |
 | ||
Similar Canadian Pacific Air Lines Flig, All Nippon Airways Flight 60, BOAC Flight 781, All Nippon Airways Flight 58, Cathay Pacific Flight 700 | ||
BOAC Flight 911 (Speedbird 911) was a round-the-world flight operated by British Overseas Airways Corporation that crashed as a result of an encounter with severe clear-air turbulence near Mount Fuji in 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.
Contents
The aircraft, registered G-APFE, disintegrated and crashed near Mount Fuji in 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, 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.
Boac flight 911 last takeoff
Flight and accident
The aircraft arrived in Haneda at 12:40 on the day of the accident from Fukuoka Airport where it had diverted the previous day due to conditions on the ground in Tokyo. 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 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. 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. 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 then encounted strong winds, causing it to break up in flight, and crash into a forest near the mountain.
Investigation
The aircraft left a debris field 16 km (10 mi) long. 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. 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.
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 60 km (37 mi) south of Tokyo may have caused the crash. The vicinity of the 3,776 m (12,388 ft)-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."
Related information
This accident was one of five fatal aircraft disasters—four commercial and one military—in Japan in 1966, and occurred less than 24 hours after Canadian Pacific Airlines Flight 402 crashed and burned on landing at Haneda. Indeed, Flight 911 had taxied past the still smouldering wreckage of that Douglas DC-8 immediately before taking off on the flight that would shortly lead to its own accident.
Several booked passengers cancelled their tickets at the last moment to see a ninja demonstration. These passengers, Cubby Broccoli, Harry Saltzman, Ken Adam, Lewis Gilbert, and Freddie Young, were in Japan scouting locations for the fifth James Bond film, You Only Live Twice.