About accident and incident investigation

According to Annex 13 of the Convention on International Civil Aviation (Chicago, 1944) the investigation of air accidents and serious incidents has to be performed under the responsibility of the state where the accident or incident happened (State of Occurrence).A state may delegate the whole or any part of the conducting of such investigation to another State. In all cases, the investigation shall be conducted by an independent investigation authority.


In accordance with Annex 13 of the Convention on International Civil Aviation, it is not the purpose of aircraft accident investigation to apportion blame or liability. The sole objective of the investigation and the Final Report is the determination of the causes, and define recommendations in order to prevent future accidents and incidents.


For this purpose, the Air Accident Investigation Unit of Belgium, abbreviated as AAIU(Be), was established in accordance with the Royal Decree of 8 December 1998. This unit is directly under the jurisdiction of the Federal Public Service Mobility and Transport and is functional independent, in particular of the Belgian Civil Aviation Authority. This unit is actively involved in maintaining and improving safety in civil aviation.


Since the European Regulation (EU) 996/2010, this cell is also part of the European Network of Civil Aviation Safety Investigation Authorities (ENCASIA).


In principle, the investigation unit is required to investigate all accidents and serious incidents that have occurred with an aircraft


What are aircraft?

Any machine that can derive support in the atmosphere from the reactions of the air other than reactions of the air against the earth’s surface.

Annex II to Regulation (EC) No 216/2008 contains a list of categories of aircraft which are excluded from the obligation to investigate. It refers to, amongst others, ultralight aircraft (ULM). Anyhow, for a particular reason it can be interesting to conduct an investigation in the case of an accident with these kinds of aircraft.



What is an accident?

An occurrence associated with the operation of an aircraft which might take place between the time any person boards the aircraft with the intention of flight and such time as all persons have disembarked, in which:

a) a person is fatally or seriously injured as a result of:

  • being in the aircraft, or
  • direct contact with any part of the aircraft, including parts which have become detached from the aircraft, or
  • direct exposure to jet blast,

except when the injuries are from natural causes, self-inflicted or inflicted by other persons, or when the injuries are to stowaways hiding outside the areas normally available to the passengers and crew; or

b) the aircraft sustains damage or structural failure which:

  • adversely affects the structural strength, performance or flight characteristics of the aircraft, and
  • would normally require major repair or replacement of the affected component,

except for engine failure or damage, when the damage is limited to the engine, its cowlings or accessories; or for damagelimited to propellers, wing tips, antennas, tires, brakes, fairings, small dents or puncture holes in the aircraft skin; or

c) the aircraft is missing or is completely inaccessible.


What is an incident?

An occurrence, other than an accident, associated with the operation of an aircraft which affects or could affect the safety of operation.


What is a serious incident?

An incident involving circumstances indicating that an accident nearly occurred.



More information and definitions can be found in the legislation and regulation section