AAIB are generally only involved in reportable occurances as defined in the ANO:
17 (1) For the purposes of article 94(1), the following reportable occurrences are hereby
prescribed, that is to say those –
(a) involving damage to an aircraft;
(b) involving injury to a person;
(c) involving the impairment during a flight of the capacity of a member of the flight
crew of an aircraft to undertake the functions to which his licence relates;
(d) involving the use in flight of any procedures taken for the purpose of overcoming
an emergency;
(e) involving the failure of an aircraft system or of any equipment of an aircraft;
(f) arising from the control of an aircraft in flight by its flight crew;
(g) arising from failure or inadequacy of facilities or services on the ground used or
intended to be used for the purposes of or in connection with the operation of
aircraft;
(h) arising from the loading or the carriage of passengers, cargo (including mail) or
fuel;.