The pilots of Singapore Airlines flight SQ321, which was rocked by severe turbulence on May 21, that left one passenger dead and dozens more seriously injured, switched on the seat belt signs just seconds before passengers and crew were flung into the air, according to a preliminary accident report.
The Boeing 777-300, with 211 passengers and 18 crew onboard, was flying at a cruising altitude of 37,000 feet over the south of Myanmar en route to Singapore when the plane experienced a “slight vibration”, the Transport Safety Investigation Bureau of Singapore said on Wednesday.
Just moments later, an updraft caused by ‘developing convective activity’ likely led to an ‘uncommanded increase in aircraft altitude’ to 37,362 feet, at which point the pilots were heard saying that they had switched on the fasten seat belt signs.
Eight seconds later, the aircraft experienced a rapid change in G forces, initially flinging anyone who wasn’t belted in to be thrown into the air and then throwing them back towards the cabin floor.
The turbulence that caused the worst injuries lasted less than five seconds.
“The rapid changes in G over the 4.6 sec duration resulted in an altitude drop of 178 ft, from 37,362 ft to 37,184 ft,” the TSIB report explains. “This sequence of events likely caused the injuries to the crew and passengers.”
Over the next 24 seconds, the aircraft experienced further turbulence before the pilots were able to get the aircraft back to the planned cruising altitude.
Many of the injured passengers and crew sustained serious head, neck and back injuries from where they hit the cabin ceiling and were then thrown back to the floor. 73-year-old Geoff Kitchen died as a result of a suspected heart attack during the incident.
A week after the incident, 28 passengers remain in a hospital in Bangkok, where the aircraft diverted after the pilots declared a medical emergency. One cabin crew member who had to undergo spinal surgery for the injuries she sustained has just been repatriated to Singapore.
In response to the preliminary accident report, Singapore Airlines said in a statement: “SIA is fully cooperating with the relevant authorities in the ongoing investigations into this incident. The safety and well-being of our passengers and staff are our top priorities.”
“We are committed to supporting our passengers and crew members who were on board SQ321 on that day, as well as their families and loved ones. This includes covering their medical and hospital expenses, as well as any additional assistance they may need.”
On Sunday, the 16-year-old aircraft involved in the incident was ferried back to Singapore from Bangkok without any passengers onboard. The aircraft is expected to remain out of service for some time, not only because of the extensive damage within the cabin but because the aircraft is still subject of an ongoing accident investigation.
