Bangkok, Thai Airways clarified the case of flight TG 121, Chiang Mai-Bangkok route, on Feb. 7, saying that a passenger opened the plane door while the hoist was approaching the runway.
On February 7, the flight was operated by an Airbus A320 while the aircraft was lined up and waiting to take off on the runway. A passenger opened the plane door. After the technicians had inspected and corrected according to safety standards, it was able to depart at 12:34 a.m. on February 8, with all passengers, pilots, and crew safe.
Source: Thai News Agency