Incident Overview
Date: Wednesday 11 September 1985
Aircraft Type: Boeing 747-146
Owner/operator: Japan Air Lines
Registration Number: JA8101
Location: 565 km WNW of Midway –
ÿ Pacific Ocean
Phase of Flight: En route
Casualties: Fatalities: 0 / Occupants: 353
Component Affected: AircraftAircraft
Investigating Agency: JTSBJTSB
Category: Accident
An aircraft experienced severe turbulence while cruising at FL350 due to a cumulonimbus cloud. The turbulence resulted in a significant acceleration and deceleration of the aircraft, causing injuries to two passengers and four crew members. The lack of ‘fasten seat belt’ activation contributed to the incident.An aircraft experienced severe turbulence while cruising at FL350 due to a cumulonimbus cloud. The turbulence resulted in a significant acceleration and deceleration of the aircraft, causing injuries to two passengers and four crew members. The lack of ‘fasten seat belt’ activation contributed to the incident.
Description
While cruising at FL350, the aircraft encountered severe turbulence. Two pax were seriously injured, and 45 pax and 4 cabin crew were slightly injured. The “fasten seat belt” sign had not been turned on. DGDR analysis revealed that the aircraft encountered turbulence causing plus 2.04 g to minus 0.30 g of about 8 sec duration. The aircraft climbed about 220 ft then descended about 320 ft. Cause: The cause of this accident is that while the aircraft was flying at an altitude of 35,000 feet, it suddenly encountered turbulence related to a cumulonimbus cloud that was 20 to 30 nautical miles to the left, or turbulence caused by an ongoing cumulonimbus cloud that could not be detected by radar.
Primary Cause
Cumulonimbus cloud turbulence encountered during flight.Cumulonimbus cloud turbulence encountered during flight.Share on:
