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, but is not necessarily the most hazardous. 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.
- Gastro-intestinal 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 then 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 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 and it was concluded that the origin was activation of explosive materials in the forward galley just behind the flight deck.
On 19 October 2022, an Embraer E175-200 had just departed Dublin when the First Officer, who was acting as ‘Pilot Flying’, became incapacitated. The Captain immediately took over all flying duties, requested assistance for the First Officer from the cabin crew and declared a MAYDAY. The aircraft then returned to land without further significant event although a bird strike occurred on approach. The 35 year-old First Officer was medically assessed and the conclusion was that he had “low blood pressure (and) a possible lack of water and food” which would have been exacerbated by the rising cabin altitude after departure.
On 6 June 2023, a Boeing 717-200 was on base leg about 10 nm from Hobart, Australia, when chlorine fumes became evident on the flight deck. As the aircraft became fully established on final approach, the captain recognised signs of cognitive impairment and handed control to the initially unaffected first officer. Just before touchdown, the first officer was similarly affected but was able to safely complete the landing and taxi in. The same aircraft had experienced a similar event two days earlier with no fault found. The Investigation determined that the operator’s procedures for responding to crew incapacitation in flight had been inadequate.
On 17 January 2022, about 30 minutes after takeoff from Fort-de-France, Martinique, on an Extended Operations (ETOPS) flight, an Airbus A330-900 was approaching its initial cruise altitude when the apparently unconscious captain appeared initially unresponsive. On being more aggressively roused, he seemed normal, and a doctor on board initially assessed him as fit to continue. However, about two hours into the flight, his condition subsequently deteriorated. The first officer called the chief purser to take his seat to assist. A PAN, later upgraded to a MAYDAY, was declared and a diversion was made to the Azores where the captain was hospitalised.
On 21 February 2019, the Captain of an Airbus A350-900 in the cruise en-route to Hong Kong became and remained incapacitated. The First Officer took over control and completed the flight as planned without further event. The Cabin Crew Manager was called to the flight deck and advised and a doctor on board provided medical assistance to the Captain who remained conscious but with slurred speech and was hospitalised on arrival. It was concluded that the response to the situation had been effectively handled and the remainder of the flight was completed in accordance with all applicable procedures and training.
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
