What happened
On March 5, 2009, an Air France Boeing 777-200, registration FGSPD, was conducting a scheduled flight from Paris Charles de Gaulle to Narita International Airport. While descending through approximately 30,600 feet, about 21km southeast of Niigata Airport, the aircraft encountered sudden and violent turbulence.
The aircraft's descent had begun following instructions from Tokyo Control to descend to FL 280. During this phase, the aircraft entered an area of rapidly changing wind conditions. As the aircraft moved through a significant shift in wind velocity, the airspeed increased rapidly, approaching the maximum operating limit. In an attempt to manage the increasing speed, the pilot flying applied significant force to the control column. This maneuver, combined with the atmospheric instability, caused the autopilot to disengage and resulted in a sharp nose-up pitch and a vertical acceleration of approximately +2.3G.
In the aft galley, the sudden movement threw several crew members into the air. A purser and a steward were seriously injured when they were thrown against the floor and galley structures. The aircraft remained undamaged and eventually landed safely at Narita International Airport.
The investigation
The Japan Transport Safety Board (JTSB) examined flight data from the Digital Flight Data Recorder (DFDR) and Cockpit Voice Recorder (CVR), alongside air traffic control communications and interviews with the flight crew and cabin attendants.
Investigators analyzed meteorological data, including satellite imagery and upper-air charts, which revealed that the aircraft was flying near the strong wind axis of the jet stream. The investigation specifically looked at the flight's descent profile, the changes in wind direction and velocity, and the physical forces applied to the control column during the event. The study also reviewed the physical layout of the aft galley to understand how the crew members were positioned during the impact.