An aviation accident is defined by the Convention on International Civil Aviation Annex 13 as an occurrence associated with the operation of an aircraft, which takes place from the time any person boards the aircraft with the intention of flight until all such persons have disembarked, and in which (a) a person is fatally or seriously injured, (b) the aircraft sustains significant damage or structural failure, or (c) the aircraft goes missing or becomes completely inaccessible. Annex 13 defines an aviation incident as an occurrence, other than an accident, associated with the operation of an aircraft that affects or could affect the safety of operation.
A hull loss occurs if an aircraft is damaged beyond repair, lost, or becomes completely inaccessible.
The first fatal aviation accident occurred on 10 May 1785, when a hot air balloon crashed in the town of Tullamore, Co. Offaly, Ireland. The town was seriously damaged from the resultant fire that burned down over 130 homes. The first involving a powered aircraft was the crash of a Wright Model A aircraft at Fort Myer, Virginia, in the United States on September 17, 1908, injuring its co-inventor and pilot, Orville Wright, and killing the passenger, Signal Corps lieutenant Thomas Selfridge.
Source: Wikipedia
In the early morning hours of Sunday, October 31, 1999, EgyptAir 990, a Boeing 767-300ER (Extended Range) aircraft, plunged into the Atlantic Ocean shortly after taking off from Kennedy Airport, killing 217 people. This was the third such accident in recent years, following TWA Flight 800, a Boeing 747-100 that crashed July 1, 1996, killing 230 people; and Swissair Flight 111, a McDonnell-Douglas MD-11 that crashed on September 2, 1998, killing 229 people.
Earlier major air disasters include: Paris 1974 (346 killed) Tenerife 1977 (582), Chicago 1979 (273), Riyadh 1980 (301), Korean 1983 (269), Japan 1985 (520), Arab Gulf 1988 (290), Lockerbie 1988 (270), Nagoya 1994 (262).
In 1992, an Israeli El Al cargo jet plowed into a low-income housing complex near Amsterdam in 1992, killing 43 people and injuring dozens. The cause of the crash was established fairly quickly: fatigue in a "fuse pin" on the engine mount. But only in 1998 it was revealed that apart from electronics, flowers and perfume, as originally claimed, the aircraft carried also DMMP (part of a combination of elements used to make sarin nerve gas) and 270 kilograms of depleted uranium, used for ballast in the tail section of the older aircraft.