In less than a second, gravitational force aboard Singapore Airlines flight SQ321 changed so violently that unbelted passengers became airborne. Within four seconds, another rapid G-force shift sent them crashing down. The final report by Singapore's Transport Safety Investigation Bureau details the events.
At 7:30am UTC, the plane cruised at 37,000ft near southwest Myanmar. Cabin crew prepared breakfast as passengers woke. Weather radar showed no returns, and the flight path appeared clear.
By 7:49am, turbulence began. Vertical accelerations ranged from +0.44G to +1.57G over 17 seconds. The crew deployed speed brakes, reduced speed, and switched on the seat belt sign-no time for a cabin announcement.
Severe turbulence struck at 7:49:40am UTC. Vertical acceleration dropped from +1.35G to -1.5G in 0.6 seconds, then surged to +1.5G in four seconds. A stall warning briefly activated. The crew disengaged autopilot and flew manually for 21 seconds to stabilize the aircraft.
The pilot-in-command expressed surprise, removing a sunshade to look outside. Both pilots reported clear skies, yet the aircraft had hit something. Cabin crew reported multiple injuries.
At 8:01am, the crew declared Mayday and diverted to Bangkok. The aircraft landed at Suvarnabhumi Airport at 8:45am, where medical personnel treated the injured.