One person died aboard a Singapore Airlines flight and 30 people were injured, after the aircraft encountered an air pocket and was diverted to Bangkok, the airline said Tuesday.

The aircraft fell into an air pocket over Thai airspace and requested to land at Suvarnabhumi Airport in Bangkok, an airport spokesperson said in a press conference, according to Reuters. The civil aviation department would launch an investigation, the official added.

The flight had left London for Singapore, carrying 211 passengers and 18 crew members. The aircraft “encountered severe turbulence en-route,” according to Singapore Airlines.

“We can confirm that there are injuries and one fatality on board the Boeing 777-300ER,” the company said in an initial update on Facebook. The airport official said that the deceased person is a 73-year-old British national, who likely suffered a heart attack, Reuters reported. Seven people were critically injured with head injuries, the official added.

The airline later added that “18 individuals have been hospitalised. Another 12 are being treated in hospitals. The remaining passengers and crew are being examined and given treatment, where necessary, at Suvarnabhumi International Airport in Bangkok.”

Singapore Airlines said that it was working with local authorities to provide medical assistance and that it would send a support team to Bangkok.

The Aviation Safety Network has recorded seven incidents for Singapore Airlines, last logging fatalities for one of the company’s flights in October 2000, when 83 people were said to have died.

Turbulence-related incidents are the most common type of accident suffered by aircrafts that operate under the Title 14 Code of Federal Regulations Part 121, according to the U.S. National Transportation Safety Board. This covers major U.S. airlines, as well as cargo aircraft and regional carriers.

Data from the Federal Aviation Administration shows that severe injuries from turbulence are rare, with 163 cases recorded between 2009 and 2022.