Accidents happened on Boeing 727 and Tu-154 are more related to mechanical failure/system defect, illustrating that these two types of aircrafts need more careful overhaul to avoid mechanical failure. Deeper investigations are also necessary to detect latent system defect so that experience can be used as reference in new types of aircrafts.
Distinguished factors might bring out accidents in different phases of flight. Accidents happened when taking-off are primarily caused by careless overhaul and mechanical failure/system defect. Bad weather, as well as pilot misoperation, is the main reason for approaching. When it comes to landing process, ground crew miscoordination and runway problem are the critical factors.
Accidents happened on Boeing commercial aviations are closely related to pilot misoperation; accidents happened on McDonnel Douglas(MD) commercial aviations are more related to careless overhaul. This indicated that pilots and maintenance personnel for Boeing and MD should be better trained on the aircraft aviating and overhauling and take more responsibilities on aviation safety.
SUPPLEMENT
Defination:
“Accident” means an occurrence associated with the operation of an aircraft which, in the case of a manned aircraft, takes place between the time any person boards the aircraft with the intention of flight and such time as all such persons have disembarked, or in the case of an unmanned aircraft, takes place between the time the aircraft is ready to move with the purpose of flight until such time it comes to rest at the end of the flight and the primary propulsion system is shut down, in which:
1) a person is fatally or seriously injured
2) the aircraft sustains damage or structural failure
3) the aircraft is missing or is completely inaccessible.
*Defination from Air Accidents Investigation Branch(AAIB)