Accident Summary
A flight attendant sustained serious injuries during an in-flight encounter with unforecast moderate to severe turbulence. The international air carrier flight was in cruise flight at the time of the accident, operating at flight level 340. The fasten seat belt sign was illuminated because the flight had encountered light chop after leveling off at cruise altitude. The captain reported that the ride had been smooth for approximately 10 minutes prior to the turbulence event.
Crew Reports
The captain stated that the flight "encountered a brief (2-3 second) but very intense moderate-to-severe turbulence event" at flight level 340. He noted that continuous moderate turbulence continued for approximately 30 seconds, followed by periods of occasional-to-continuous moderate chop lasting about 10 minutes after the initial encounter. The captain added that there were no returns on the weather radar, and no pilot reports or adverse ride reports were received from air traffic control.
The injured flight attendant reported that she was working in the aft galley when the turbulence began. She stated that she hit her head on the ceiling and landed on the galley floor with her leg bent under her, resulting in her serious injury.
Flight Data
The Flight Data Recorder (FDR) revealed that the airplane encountered vertical acceleration ranging from 0.245 G to 1.246 G. The data also indicated that the autopilot was engaged and that no pitch inputs were made from the cockpit at the time of the encounter.
Post-Inspection
Postaccident inspections did not reveal any damage to the airplane.