Flight attendants often remind passengers to keep their seatbelts fastened even when the fasten seatbelt sign is extinguished, and this is why.

China Southern Airlines flight CZ-3235 from Guangzhou Baiyun Airport to Shanghai Hongqiao hit severe turbulence about 20 minutes after takeoff yesterday (May 10), even though the fasten seatbelt sign was turned off.

Some of those who weren’t wearing their seatbelts hit the ceiling, with nine of the passengers taken to hospital once the plane arrived in Shanghai.

The Aviation Herald says a female passenger fractured her right arm, one guy fractured his nose and neck and seven others had minor injuries.

Photos of the flight circulated on Weibo yesterday, with one showing coffee spilled on the ceiling.

The captain said he had not ever experienced turbulence of that magnitude in his 20 year career.