SINGAPORE - Investigations have been launched into a Singapore Airlines (SIA) flight that hit sudden, extreme turbulence on May 21, leaving one passenger dead and dozens injured.

The incident on Flight SQ321, which was diverted to Bangkok in Thailand about 10 hours after leaving London, is SIA’s first fatal aviation accident since the SQ006 crash in Taiwan in October 2000, which killed 83.

According to public records, there have been six other times in the last 20 years that Singapore’s Transport Safety Investigation Bureau (TSIB) and its forerunner, the Air Accident Investigation Bureau, have looked into flights hit by turbulence.

The TSIB, a department of the Ministry of Transport, investigates air accidents and incidents in Singapore, as well as those overseas involving Singapore-registered aircraft or aircraft run by a Singapore operator.

All six turbulence cases TSIB investigated involved SIA flights and were classified as aviation accidents, as they each resulted in at least one passenger or crew member suffering a serious injury.

Here is a look at these accidents.

Jan 18, 2019

A female passenger aboard an SIA flight from Melbourne, Australia, to Wellington, New Zealand, broke her right thigh bone after the Boeing 777-200 aircraft momentarily lost altitude during a bout of turbulence.

About an hour and 15 minutes after departure, the plane hit m...