What is the direct cause of Dalian 5.7 air crash?

The arson in Zhang Pilin caused the plane to go out of control.

To analyze such an air crash caused by fire, we must first find the origin of combustion. Look at the fire on the plane. Through investigation, it was found that Zhang's seat was burned the most seriously. Based on other studies, it can be concluded that this is the origin of combustion.

Incident investigation

Through the investigation of Dalian Zhoushuizi International Airport, it is confirmed that the navigation and radar equipment of the airport were completely normal at the time of the accident. The captain of the crashed passenger plane was born in 1967 and had 1 1000 hours of flying experience before the accident. The co-pilot was born in 1973 with a flying time of 3300 hours. Both driver's license and physical examination license are valid, and they have passed the routine physical examination before taking off;

As for the aircraft, from March 27th to April 2nd, 2002, the aircraft received routine 5A maintenance. In addition, by looking at the relevant warehouse receipts and fuel lists, it is confirmed that the weight and stowage of the aircraft when taking off from Beijing Capital International Airport meet the standards. After the above-mentioned series of investigations and careful reasoning, the air crash handling team concluded that the "5.7" air crash was a sabotage incident caused by passenger Zhang Pilin's arson.

Refer to the above? Baidu Encyclopedia-Dalian 5.7 air crash, China News Network-Southern Weekend: Why is it so simple to announce the conclusion of the 5.7 air crash?