Serious Incidents

“Serious incident” means an incident that ———

(a) is associated with the operation of an aircraft involving circumstances indicating that there was a high probability of an accident; and

(b) takes place after the time any person boards the aircraft with the intention of flight and no later than the time all persons who boarded.

2. There may be a high probability of an accident if there are few or no safety defences remaining to prevent the incident from progressing to an accident. To determine this, AAIA will perform an event risk-based analysis - takes into account the most credible scenario had the incident escalated and the effectiveness of the remaining defences between the incident and the potential accident - as follows:

(a) consider whether there is a credible scenario by which this incident could have escalated to an accident; and

(b) assess the remaining defences between the incident and the potential accident as:

- effective, if several defences remained and needed to coincidently fail; or
- limited, if few or no defences remained, or when the accident was only avoided due to providence.

3. AAIA will consider both the number and robustness of the remaining defences between the incident and the potential accident. Ignore defences that failed, and consider only those that worked and any subsequent defences still in place.

Note 1.— The most credible scenario refers to the realistic assessment of injury and/or damage resulting from the potential accident.

Note 2.— Defences include crew, their training and procedures, ATC, alerts (within and outside the aircraft), aircraft systems and redundancies, structural design of the aircraft and aerodrome infrastructure.

4. The combination of these two assessments helps to determine which incidents are serious incidents:

		(b) Remaining defences between the incident and the potential accident
		Effective	Limited
(a) Most credible scenario	Accident	Incident	Serious Incident
	No accident	Incident

5. The incidents listed are examples of what may be serious incidents. However, the list is not exhaustive and, depending on the context, items on the list may not be classified as serious incidents if effective defences remained between the incident and the credible scenario.

• Near collisions requiring an avoidance manoeuvre to avoid a collision or an unsafe situation or when an avoidance action would have been appropriate.

• Collisions not classified as accidents.

• Controlled flight into terrain only marginally avoided.

• Aborted take-offs on a closed or engaged runway, on a taxiway¹ or unassigned runway.

• Take-offs from a closed or engaged runway, from a taxiway¹ or unassigned runway.

• Landings or attempted landings on a closed or engaged runway, on a taxiway¹ , on an unassigned runway or on unintended landing locations such as roadways.

• Retraction of a landing gear leg or a wheels-up landing not classified as an accident.

• Dragging during landing of a wing tip, an engine pod or any other part of the aircraft, when not classified as an accident.

• Gross failures to achieve predicted performance during take-off or initial climb.

• Fires and/or smoke in the cockpit, in the passenger compartment, in cargo compartments or engine fires, even though such fires were extinguished by the use of extinguishing agents.

• Events requiring the emergency use of oxygen by the flight crew.

• Aircraft structural failures or engine disintegrations, including uncontained turbine engine failures, not classified as an accident.

• Multiple malfunctions of one or more aircraft systems seriously affecting the operation of the aircraft.

• Flight crew incapacitation in flight:

• for single pilot operations; or

• for multi-pilot operations for which flight safety was compromised because of a significant increase in workload for the remaining crew.

• Fuel quantity level or distribution situations requiring the declaration of an emergency by the pilot, such as insufficient fuel, fuel exhaustion, fuel starvation, or inability to use all usable fuel on board.

• Runway incursions classified with severity A. The Manual on the Prevention of Runway Incursions (Doc 9870) contains information on the severity classifications.

• Take-off or landing incidents. Incidents such as under-shooting, overrunning or running off the side of runways.

• System failures (including loss of power or thrust), weather phenomena, operations outside the approved flight envelope or other occurrences which caused or could have caused difficulties controlling the aircraft.

• Failures of more than one system in a redundancy system mandatory for flight guidance and navigation.

• The unintentional or, as an emergency measure, the intentional release of a slung load or any other load carried external to the aircraft.

Source : with reference to Annex 13 to the CONVENTION ON INTERNATIONAL CIVIL AVIATION - AIRCRAFT ACCIDENT AND INCIDENT INVESTIGATION. The document can be purchased from the website of International Civil Aviation Organization.

¹ Excluding authorized operations by helicopters.