Following the death of a Singapore Airlines passenger and injury to several others in an episode of severe turbulence, industry experts are advising passengers to do one thing on their next flight: buckle up.

SQ321 from London to Singapore made an unscheduled landing at Bangkok’s airport after declaring an emergency over the Andaman Sea last night.

Hitting a pocket of severe clear air turbulence, the conditions were unexpected and caught passengers and cabin crew off guard. Many of them were reportedly not wearing seatbelts.

Reuters cited passengers who said several travellers were thrown from their seats, hitting their heads on the cabin.

“It is a matter of life and death,” says Sara Nelson, international president of flight attendants association CWA.

The association, which represents 50,000 cabin crew around the world, says last night’s flight encountered a pocket of clear air turbulence, which Nelson called the “most dangerous type” because it provides pilots and crew little warning.

“As our climate changes, severe and clear air turbulence instances are on the rise. Always follow crew instructions and wear your seatbelt whenever seated,” said Nelson.

“Turbulence is a serious workplace safety issue for flight attendants, and today we are sadly reminded it can be deadly.”

A report into turbulence-related injuries by the United States Federal Aviation Administration showed 80 per cent are to crew. That’s mainly because they are most likely to be out of their jumpseats, carrying out their duties in the cabin.

New Zealand Air Line Pilots’ Association (NZALPA) president Andrew McKeen told the Herald, there was not enough warning for the passengers and crew to be seated.

• Deadly turbulence: 2 Kiwis hospitalised after Singapore Airlines flight
• Plane drops seven thousand feet, dozens left injured

“Unfortunately, incidents occur where passengers and crew are injured due to severe turbulence. Our advice is to always keep your seatbelt fastened while you are seated even if the seatbelt sign is off,” said McKeen.

McKeen, a Boeing 787-rated pilot, says today planes are provided with detailed live forecasts, not all turbulence can be detected.

“While equipment on the flightdeck assists in real time to avoid turbulence associated with certain cloud formations, weather forecasting in general has limitations.”

Even in predictably calm flights, passengers are advised to wear seatbelts when seated.

Fifteen passengers were seriously injured this year on Latam flight LA800 into Auckland. While investigations revealed this sudden plunge was not turbulence related, experts say some injuries could have been avoided if passengers had been buckled up.

Professor Rico Merkert said LA800 was a valuable reminder to “listen to the safety advice and instruction of your airline and wear your seatbelt”.

The aviation expert at the University of Sydney told the Sydney Morning Herald that, although rapid changes in altitude are rare, wearing a seatbelt could be a lifesaver.