Cause of midflight pressure loss probed

An investigation has been launched after an Air China flight on Tuesday suddenly lost altitude between Hong Kong and Dalian, Liaoning province, causing oxygen masks to fall from their compartments before the aircraft climbed again to cruising altitude.

Flight CA106 eventually landed safely in Dalian, but investigators want to know what happened, the Northeast Regional Administration of Civil Aviation Administration of China said on Thursday.

There were 153 passengers and nine crew aboard the plane, which landed at Dalian Zhoushuizi International Airport at about 10:30 pm - about an hour late. No injuries were reported, and the aircraft continued to operate normally, the administration said in a statement released on Thursday.