Chinese investigators have determined that the pilots of a Henan Airlines Embraer 190 continued an approach in fog, despite loss of visual ground references, before the twinjet crashed short of the runway at Yichun.
Forty-four of the 96 occupants were killed in the accident involving flight VD8387 from Harbin.
Henan had only been operating the Harbin-Yichun connection for two weeks before the night-time crash on 24 August 2010. It had conducted seven flights on the route.
The Chinese state administration for work safety, in its inquiry report, says that Yichun was susceptible to fog and that visibility over the course of the evening had deteriorated to 2,800m.
After briefing for an approach to the 2,300m (7,550ft) runway 30, and being informed by air traffic control that horizontal visibility was poor, the crew executed a procedural turn and reported seeing the runway.
The crew was cleared to continue the approach and air traffic control reminded the pilots of a 440m minimum descent altitude.
About three minutes later, having entered the fog, the crew turned off the autopilot. The jet descended through the minimum altitude but, says the inquiry, the aircraft was still in fog and the captain could not see the runway.
Some 15s before impact the captain queried the aircraft's position. While the co-pilot's response appeared to suggest the jet was 1nm (1.85km) from the runway threshold, the inquiry found that it was actually 1.6nm away and flying below the normal glidepath.
There followed a series of automatic height call-outs, from 50ft to 10ft, but the inquiry does not indicate any attempt to abort the approach. The Embraer flew through the fog "until ground impact", it says, while the pilots were "unable to see the runway" and "did not establish the necessary visual references".
The aircraft struck trees 1,110m from the threshold, the main landing-gear touching down 30m further on. It began to break up, the engines contacting the ground 870m before the runway while the fuselage slid another 180m before coming to rest.
Fuel from the ruptured tanks ignited. The inquiry sharply criticises the captain for not taking control of the evacuation, and adds that there were problems opening the emergency exits.
The administration identifies several individuals as bearing various degrees of responsibility in a list headed by the captain, who survived the crash, and the co-pilot, who did not. It recommends harsh penalties for the captain - including revocation of his licence and a possible criminal investigation - and various other disciplinary measures for other personnel.
Henan Airlines, it adds, should receive a CNY5 million ($790,000) fine. The 98-seat aircraft (B-3130) had accumulated 5,110h in 4,712 cycles.
Source: Air Transport Intelligence news