Aircraft accident:

An aviation or aircraft accident is nearly defined in the Convention on International Civil Aviation Annex 13 as an incident associated with the operation of an aircraft which takes place between the time any person boards the aircraft with the purpose of flight. An aircraft accident is also defined as a happening other than an accident, connected with the operation of an aircraft, which affects or could affect the safety of operations. An aircraft accident in which the damage to the aircraft is such that it must be written off, or in which the plane is destroyed is called a hull loss accident.

About 80 percent of all aircraft accidents occur shortly before, after, or during takeoff or landing. These aircraft accident are often described as resulting from human error. Mid flight disasters are uncommon but not entirely unheard of. Among other things, the aircraft accidents have been caused by bombs, as in the 1988 Lockerbie incident. These aircraft accident also include mid air collisions such as in the 2002 Uberlingen crash and structural breakdown, as in the 1954 Comet disasters and 1988 Aloha Airlines incident. Aircraft manufacturers are often slow to accept that aspects of design might play a role in the aircraft accident, finding it more suitable to state that human crew members were responsible.

The deadliest aircraft accident related disaster of any kind, considering losses on both the aircraft and the ground, was the destruction of the World Trade Center in New York City on September 11, 2001. The intentional aircraft accident of American Airlines Flight 11 and United Airlines Flight 175 by Alqaeda operatives led to the most deadliest aircraft accident ever known. The aircraft accident killed 2,988, most of them occupants of the World Trade Center towers or emergency personnel responding to the disaster.