Flight History
The aircraft, a Boeing 777-200 registered FGSPD, operated Air France flight 276 from Paris Charles de Gaulle to Tokyo Narita. Departing at 21:55 JST on March 4, 2009, the flight proceeded under instrument flight rules. On March 5, at approximately 08:14 JST, Tokyo Area Control instructed the crew to descend to FL 280 with an altitude restriction. The autopilot altitude was set to 28,000 ft, and the descent began at 08:15:47.
As the aircraft descended from FL 370, wind conditions changed: direction shifted from about 270 to 300 degrees, and wind speed initially decreased by about 15 kt over 50 seconds, then increased by about 45 kt over the next 40 seconds, stabilizing near 125–128 kt. At 08:18:37, at an altitude of about 30,600 ft and approximately 21 km southeast of Niigata Airport, the autopilot disengaged, the master warning activated, and the aircraft pitched up rapidly, recording a vertical acceleration of +2.3G. Control column forces of up to 101 pounds were recorded. The airspeed was near 320 kt, close to the maximum operating limit.
The flight crew reported feeling a weak, slow turbulence reminiscent of a mountain wave, lasting 3–5 seconds. No prior turbulence forecasts or visible weather indications were noted; the seat belt sign was not illuminated. After the event, the autopilot was re-engaged at 08:18:54. At 08:20:30, the cockpit learned of injured flight attendants via interphone. The aircraft landed at Narita International Airport at about 08:51.
Injuries and Damage
Two flight attendants in the aft galley—a purser and a steward—were seriously injured. Another chief purser and a steward in the area were not injured. No other crew members or passengers were injured. The aircraft was not damaged.
Investigation
The Japan Transport Safety Board (JTSB) investigated the event, with accredited representatives from France (as the state of registry and operator) and the United States (as the state of design and manufacture). The investigation included analysis of the digital flight data recorder, cockpit voice recorder, air traffic control communications, and interviews with crew members. No probable cause was determined in the report.