Singapore's Ministry of Transport said on Wednesday that severe turbulence on a recent Singapore Airlines flight, which killed one passenger and injured dozens, was caused by a sudden change in altitude and airspeed.
Officials said Flight SQ321 encountered turbulence about 10 hours into a 13-hour flight from London to Singapore last week, with many of the 211 passengers having just finished breakfast.
The Transport Ministry said in a preliminary report on Wednesday that the plane experienced turbulence while flying over southern Myanmar at an altitude of 37,000 feet.
The autopilot lowered the plane when it unexpectedly climbed 362 feet, possibly due to an updraft, the report said. At the same time, the plane's speed also increased unexpectedly, and the pilot responded by manually applying the brakes.
The report said these maneuvers likely caused injuries to passengers and crew and caused the plane to lose altitude about 178 feet in less than five seconds, causing passengers who were not wearing seat belts to become airborne before plummeting back to the ground.
The plane landed safely in Thailand, but authorities later said a 73-year-old British man on board had been killed and 71 people injured.