SIA turbulence incident leaves crew member with fractured ankle

About 11 minutes later, air traffic control instructed the pilots to descend from 40,000ft to 34,000ft.

The pilots started descending at 700ft per minute instead of the usual rate of 1,000ft per minute, to allow the aircraft to fly at an altitude of about 37,000ft – more than 5,000ft above the storm clouds.

At 7.53pm, the plane encountered turbulence while descending at about 38,450 feet.

The report said the vertical acceleration of the plane dropped from plus 1G to plus 0.7G in 1.34 seconds, before rising to plus 1.89G in 0.34 second.

It then fluctuated between plus 1.89G and plus 1.5G for the next 1¼ seconds, before reaching plus 1.66G. It then dropped to plus 0.24G in 1¼ seconds. The aircraft returned to stable flight after another two seconds.

Gravitational force, or G-force, measures acceleration or deceleration compared with the normal pull of gravity on earth. The baseline is set at plus 1G, which means that at plus 1.89G, a person would feel as if they were 1.89 times their body weight.

The pilot said the plane was not flying through storm clouds when the turbulence hit, the report added.

The plane landed in Singapore at 8.41pm.

The TSIB report said the pilots reviewed pre-flight briefing materials before the flight, including a forecast of occasional storm clouds that could reach a height of 51,000ft.

Despite the precautions the pilots took – such as switching on the seat belt signs and opting for a shallower descent – they could not avoid the turbulence, the report added.

The incident, the report said, highlighted how the effects of thunderstorms and other weather phenomena can spill beyond the top of storm clouds detected on weather radars, and how they can have a harmful effect even if planes maintain the recommended vertical distance of 5,000ft from the clouds.

In response to queries, SIA said it acknowledged the report’s findings. It added that its pilots and cabin crew receive regular training, guidance and updates on safety precautions, including measures to manage turbulence.

The airline also said the cabin crew member who suffered a fractured ankle has since returned to flying duties.

SIA has, in the past, reminded its pilots to switch on the seat belt signs to ensure that passengers and cabin crew remain seated whenever weather conditions pose a safety risk.

The carrier has also discussed case studies of turbulence-related incidents with cabin crew members.

At least 11 turbulence incidents involving Singapore-registered aircraft were recorded from 2004 to 2025, based on TSIB air safety investigation reports.