Seatbelts, safety and spotting air pockets: Lessons of Singapore turbulence death flight

Experts say incident is a reminder that passengers need to keep seatbelts on during flights

The interior of Singapore Airlines flight SQ321 after an emergency landing at Bangkok's Suvarnabhumi International Airport, Thailand. Reuters

The death of a passenger and dozens of injuries on a flight from London’s Heathrow Airport to Singapore when the plane hit severe turbulence has put a focus on safety rules on board, particularly surrounding the use of seatbelts.

Twenty people remained in intensive care on Wednesday after a Singapore Airlines plane hit an air pocket causing it to plunge, tossing passengers from their seats and throwing the crew, who were in the middle of serving breakfast, around the cabin.

Flight SQ321 hit the turbulence on Tuesday over the Andaman Sea.

The Boeing 777, which carried 211 passengers and 18 crew members, descended 6,000 feet in about three minutes, the carrier said.

Investigation

Chris Hammond, a retired British Airways and easyJet pilot, told The National the incident will be the subject of a full aircraft accident investigation, which will examine everything that happened before, during and after the flight.

That may result in changes to regulations, he said, but they are unlikely to involve making seatbelts mandatory at all times.

“You can’t make people wear seatbelts, unless the seatbelt sign is on. In America occasionally they have been known to leave the seatbelt sign on all the time. Then you can enforce it, because the seatbelt sign is on. But then people have problems going to the toilet,” said Mr Hammond, who advised his passengers to keep their seatbelts on while in their seats.

“This is a passenger industry. It’s paid for by the passengers. You can’t inconvenience them too much.”

Training

Any lessons from the inquiry are more likely to come from how pilots can better spot clear air turbulence, which is suspected of causing the sudden drop.

The incident will likely also feature in pilots' regular simulator training sessions as “the topic of the moment”, he said.

“[They will likely talk about ]how to look for subtle signs you might be starting to get into an area of clear air turbulence, which is two air masses rubbing up against each other.

“Often they have different temperatures and there is no alarm for that. You have to be looking at the outside air temperature gauge to spot it.”

Aviation expert John Strickland told The National passengers need to adhere to the advice of keeping seatbelts on during flights.

“Incidents of this kind are fortunately rare in the context of millions of flights operated annually,” he said.

“It underlines the need to respect the advice of always keeping seat belts fastened loosely throughout a flight.”

Aviation investigators arrived in Bangkok on Wednesday to find out how and why the incident happened.

Samitivej Srinakarin Hospital, where most of the injured were taken, said 20 people were being treated in intensive care while 27 others have been discharged.

The patients include six Britons, six Malaysians, three Australians, two Singaporeans and one person each from Hong Kong, New Zealand and the Philippines, it said.

The hospital said nine people underwent surgery on Tuesday and five more operations were expected to be completed on Wednesday. It said it had provided 104 people with medical care, including 19 at its clinic at the airport.

British passenger Andrew Davies told Sky News that the seatbelt sign was illuminated but crew members did not have time to take their seats.

“Every single cabin crew person I saw was injured in some way or another, maybe with a gash on their head,” he said. “One had a bad back, who was in obvious pain.”

British man Geoffrey Kitchen, 73, who was going on a six-week holiday with his wife, died during the incident.

Officers from Singapore’s Transport Safety Investigation Bureau arrived in Bangkok late on Tuesday.

Most people associate turbulence with heavy storms, but the most dangerous type is so-called clear air turbulence.

Wind shear can occur in wispy cirrus clouds or even in clear air near thunderstorms, as differences in temperature and pressure create powerful currents of fast-moving air.

Bumpy flights

Professor Paul Williams, an atmospheric scientist at the University of Reading, told The National climate change will lead to turbulence trebling in the future.

“Turbulence fatalities on commercial flights are fortunately very rare,” Prof Williams said.

“Turbulence on flights can be caused by storms, mountains, and strong air currents called jet streams. In this last case, it is called clear-air turbulence, and it can be difficult to avoid because it doesn't show up on the weather radar in the flight deck. A detailed analysis of the meteorological circumstances and the particular type of turbulence that caused today's fatality will take some time.

“We now have strong evidence that turbulence is increasing because of climate change. We recently discovered that severe clear-air turbulence in the North Atlantic has increased by 55 per cent since 1979. Our latest future projections indicate a doubling or trebling of severe turbulence in the jet streams in the coming decades, if the climate continues to change as we expect.”

According to a 2021 report by the US National Transportation Safety Board, turbulence accounted for 37.6 per cent of all accidents on larger commercial airlines between 2009 and 2018.

The Federal Aviation Administration has said there were 146 serious injuries from turbulence from 2009 to 2021.

“For flight attendants and passengers alike, the dangerous, shaky feeling in mid-air called turbulence comes from air currents shifting,” the US based Association of Flight Attendants said.

“While details of Singapore Flight 321 are still developing, initial reports seem to indicate clear air turbulence, which is the most dangerous type of turbulence. It cannot be seen and is virtually undetectable with current technology. One second, you’re cruising smoothly; the next, passengers, crew and unsecured carts or other items are being thrown around the cabin.

“Always follow crew instructions and wear your seatbelt whenever seated.

“It is a matter of life and death.”