Air Accidents Investigation Branch
Summary
Approximately 1 hour 50 minutes after departing Singapore en route London, G-STBL encountered severe turbulence over the Bay of Bengal and unsecured cabin crew were thrown around in the cabin. Two crew members were seriously injured and three sustained minor injuries. The aircraft returned to Singapore.
In a similar event, G-YMML encountered what the commander described as moderate chop around 15 minutes before landing at Beijing Daxing Airport and while manoeuvring to avoid convective weather seen on radar. The commander was informed after landing of a serious injury to one of the crew that had been sustained during the turbulence.
In both cases, the pilots took action to avoid areas of poor weather and turbulence but, nevertheless, their aircraft encountered turbulence of sufficient severity to injure unsecured crew. When route weather forecasts cover large areas and contain general predictions of the likelihood of encountering turbulence, pilots may not be able to identify specific areas in flight where it will actually be encountered.