Pilot Incapacitation
Pilot Incapacitation
Definition
Pilot Incapacitation is the term used to describe the inability of a pilot, who is part of the operating crew, to carry out their normal duties because of the onset, during flight, of the effects of physiological factors.
Description
Death is the most extreme example of incapacitation, usually as a result of a heart attack. Although most recorded deaths of operating pilots in flight have been found to be due to cardiovascular disease, by far the most common cause of flight crew incapacitation is gastroenteritis.
Incapacitation may occur as a result of:
- The effects of Hypoxia (insufficient oxygen) associated with an absence of normal pressurisation system function at altitudes above 10,000 ft.
- Smoke or Fumes associated with an Fire in the Air or with contamination of the air conditioning system.
- Gastrointestinal problems such as severe Gastroenteritis potentially attributable to Food Poisoning, or to Food Allergy.
- Being asleep.
- A medical condition such as a heart attack, stroke or seizure, or transient mental abnormality.
- A bird strike or other event causing incapacitating physical injury.
- A malicious or hostile act such as assault by an unruly passenger, terrorist action or small arms fire, or possibly malicious targeting of aircraft with high powered lasers by persons on the ground.
Unless the incapacitation occurs on a single pilot operation, incapacitation of one pilot may not be immediately obvious, become only progressively evident, or escape notice altogether until an unexpected absence of response or action occurs.
Effects
Clearly, if the single pilot of a small aircraft becomes incapacitated, the safety of the flight is liable to be severely compromised and Loss of Control may result. However, for the two-pilot case typical of larger transport aircraft, incapacitation of only one of the pilots is unlikely to present a significant risk given the attention which pilot training, especially for low minima precision approaches, is usually required to give to the implications of single pilot incapacitation.
Loss of Separation may be a secondary effect of total crew incapacitation or side effect of the additional workload imposed upon the remaining crew member(s).
Solutions
The key to avoiding serious problems from the incapacitation of one pilot in a multi-crew aircraft is the availability of appropriate SOPs and recurrent training which includes practice in their use.
Correct control of both the aircraft pressurisation system and, if necessary, use of the emergency oxygen supply will both prevent hypoxia and protect the crew from the effects of smoke and fumes. Therapeutic oxygen supplies can also alleviate the condition of a crew member or passenger suffering a medical condition. Staggering crew meal times and ensuring that each pilot eats different meals both prior to and during flight, will usually prevent both pilots becoming incapacitated due to food poisoning and is currently common practice. As a precaution against deliberate poisoning, many airlines have policies against crew members taking any food offered by passengers. Intentional sleep whilst on the flight deck may be relevant on long haul flights but should only take place if an appropriate SOPs exists and is followed.
The first indication that a controller might get of total flight crew incapacitation is Loss of Communication. Having tried all means, without success, to contact the aircraft, it is extremely difficult for a controller to ascertain what is happening on an aircraft. If the aircraft autopilot is engaged then it will be likely to follow the flight plan route towards the destination. Conforming with standard loss of communication procedures, military aircraft can be tasked to intercept the aircraft and inspect it visually but there is little that a controller can do other then ensure the safety of surrounding traffic by maintaining separation.
Accidents & Incidents
Events on the SKYbrary Database which list Incapacitation as a causal factor:
On 21 July 2022, one minute after takeoff from Surabaya, an Airbus A320 first officer acting as pilot flying (PF) saw that the captain was “in a rigid position." A medically qualified passenger was identified but could not find signs of life. A ‘PAN’ was declared and a return to land requested but due to resuscitation attempts, it was over 40 minutes before a landing occurred. The captain was subsequently confirmed deceased. The captain’s most recent medical examination was found not to have included a sufficiently in-depth assessment of his ongoing vascular risk factors before renewal of his medical certification.
On 5 December 2019, the first officer of a Cessna 208 on a scheduled Indonesian domestic passenger flight close to Timor-Leste became physically ill during normal unpressurised cruise at 10,000 feet during conversation about a family health issue. When he briefly lost consciousness, the captain declared a MAYDAY and diverted to Dili. The first officer recovered and when hospital checks were passed, the flight to the intended destination was completed. An in-depth medical investigation found no evidence of physical illness and concluded that unmanaged emotional stress had led to hyperventilation followed by a temporary incapacitation.
On 17 February 2024, an Airbus A321 captain was initially unable to re-enter the flight deck after a short absence in cruise. On succeeding, he discovered that the first officer had become incapacitated with what ICAO classifies as a ‘seizure disorder,’ which was subsequently found to have occurred almost immediately after the captain had left. Once back on the flight deck, an emergency was declared with immediate diversion to Madrid Barajas where the first officer was hospitalised. A safety recommendation to consider further assessment of the risks of one pilot being alone on a secured flight deck was made.
On 25 January 2024, an Airbus A320 first officer inadvertently fell asleep while the captain was already intentionally sleeping en route. Prior approval to temporarily deviate around adverse weather had been given followed by an instruction to join a destination arrival procedure that began 125 nm away. After over 200 nm of further flight and almost half an hour out of ATC contact, the captain woke up, took control and woke up the other pilot. ATC were then contacted for instructions on regaining the arrival route after a significant unapproved deviation from clearance, and the flight was completed without further event.
On 19 May 2016, fire broke out on board an Airbus A320 en route to Cairo at night. The fire spread rapidly from the forward area of the aircraft and rapidly intensified. Loss of control due to conditions on the flight deck resulted in descent and sea impact with all 66 occupants killed. Work for the Investigation (reproduced in the final report) which identified a leak from the flight crew emergency oxygen system as the fire source was eventually discounted. It was concluded that the origin was activation of explosive materials in the forward galley just behind the flight deck.
Further Reading
- ICAO Doc 8984 "Manual of Civil Aviation Medicine", third edition 2012. Part 1, Chapter 3 concerns Flight Crew Incapacitation.
- Flight Crew Incapacitation, BEA France, Incidents in Air Transport No. 12, Feb 2011
- Diabetes mellitus and its effects on pilot performance and flight safety: A review, Australian Transport Safety Bureau (ATSB), June 2005
- AviAtion LAser exposure seLf-Assessment (ALesA), UK CAA
- UK CAA CAP 1703: Aircrew guide to gastroenteritis, August 2018
