ACCIDENT #
ICAO defines accident as “an occurrence associated with the operation of an aircraft which, in the case of a manned aircraft, takes place between the time any person boards the aircraft with the intention of flight until such time as all such persons have disembarked, or in the case of an unmanned aircraft, takes place between the time the aircraft is ready to move with the purpose of flight until such time as it comes to rest at the end of the flight and the primary propulsion system is shut down.”
ICAO goes on to mention the following conditions for an occurrence to qualify as accident:
a) a person is fatally or seriously injured as a result of:
- being in the aircraft,
- having direct contact with any part of the aircraft, including parts which have become detached from the aircraft, or
- having direct exposure to jet blast.
b) the aircraft sustains damage or structural failure which:
- adversely affects the structural strength, performance or flight characteristics of the aircraft,
- would normally require major repair or replacement of the affected component.
c) the aircraft is missing or is completely inaccessible.
The foregoing implies that accidents can be described based on:
I. Level of damage incurred
II. Severity of injury caused
III. Cost of damage to the aircraft
The aircraft could be destroyed and not repairable, could be substantially damaged and require major repair, or just sustain minor damage.
Injuries resulting from an accident could be fatal, serious, or minor.
INCIDENT #
ICAO defines incident as “an occurrence, other than an accident, associated with the operation of an aircraft which affects or could affect the safety of operation.” An incident could be serious, in which case the result determines whether it becomes an accident or not.
A serious incident, according to ICAO, is “an incident involving circumstances indicating that there was a high probability of an accident and associated with the operation of an aircraft which, in the case of a manned aircraft, takes place between the time any person boards the aircraft with the intention of flight until such time as all such persons have disembarked, or in the case of an unmanned aircraft, takes place between the time the aircraft is ready to move with the purpose of flight until such time as it comes to rest at the end of the flight and the primary propulsion system is shut down.”
Simply put, a serious incident involves circumstances indicating that an accident nearly occurred.
Types of aircraft incidents of main Interest to ICAO
- Engine failure.
Failures of more than one engine on the same aircraft and failures which are not confined to the engine, excluding compressor blade and turbine bucket failures. - Fires.
Fires which occur in flight, including those engine fires which are not contained in the engine. - Terrain and obstacle clearance incidents.
Occurrences which result in danger of collision or actual collision with terrain or obstacles. - Flight control and stability problems.
Occurrences which have caused difficulties in controlling the aircraft, e.g. aircraft system failures, weather phenomena, operation outside the approved flight envelope. - Take-off and landing incidents.
Incidents such as undershooting, overrunning, running off the side of runways, wheels-up landing. - Flight crew incapacitation.
Inability of any required flight crew member to perform prescribed flight duties as a result of reduced medical fitness. - Decompression.
Decompression resulting in emergency descent. - Near collisions and other air traffic incidents.
Near collisions and other hazardous air traffic incidents including faulty procedures or equipment failures.
Examples of Serious Incidents as listed by ICAO (The list is not exhaustive, but just for guidance)
- 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.
- Take-offs from a closed or engaged runway with marginal separation from obstacle(s).
- Landings or attempted landings on a closed or engaged runway.
- Gross failures to achieve predicted performance during take-off or initial climb.
- Fires and smoke 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 not classified as an accident.
- Multiple malfunctions of one or more aircraft systems seriously affecting the operation of the aircraft.
- Fuel quantity requiring the declaration of an emergency by the pilot.
- Failures of more than one system in a redundancy system mandatory for flight guidance and navigation.
References #
ICAO Annex 13
ICAO Doc 9156
