Introduction

Crew incapacitation is a situation where one or more crew members (or the entire flight crew) are no longer able to perform their job to the required level. It may range from one person being dizzy to the entire crew becoming unconscious. This is a special type of onboard medical emergency because the impact of the incapacitation may not be limited solely to the person(s) affected. Crew incapacitation can potentially hamper the ability to control the aircraft thus become a major safety hazard. On a number of occasions, flight crew incapacitation has lead to an incident or an accident.

Incapacitation Types

Generally speaking, there are two categories of incapacitation: obvious and subtle. The former is usually easy to recognize and its implications are fairly obvious. However the latter is often the more dangerous of the two due to the fact that the problem could remain unnoticed (even by the incapacitated person themselves). This easily prevents any corrective action being taken in time.

Obvious (complete) incapacitation

• The first indication of illness may be loss of consciousness, seizures, severe pain or paralysis.
• Onset may be sudden.
• The victim may interfere with aircraft controls, by e.g.:
  • Gripping controls during a seizure;
  • Slumping forward on the controls;
  • Behaving in a violent or aggressive manner;
• The victim's condition may deteriorate rapidly and they may be in distress.

Subtle (incomplete) incapacitation

• Skills or judgement may be lost with little or no outward sign.
• The victim may not respond to stimulus, may make illogical decisions, or may appear to be manipulating controls in an ineffective or hazardous manner.
• Symptoms may be evident only in moments of high stress or workload.
• The victim's condition may lead to more dramatic or complete incapacitation.

Causes of Incapacitation

In order to determine the most appropriate course of action to be taken by controllers, it is imperative they understand incapacitation cause(s) and potential effect(s). This understanding will provide the controller with reasonable expectations in terms of aircraft behaviour and allow them to determine the best ways to provide assistance. Some of the more common scenarios are:

• Medical problems (e.g. heart attack, food poisoning etc.) – usually affect only one crew member. The effects of administered medication could also affect the judgement and the response. That risk is substantial, particularly in cases of self-medication and treatment (e.g. self administered treatment with sleeping pills, anti-depressants or anti-allergy medicine, etc.) ;
• Depressurisation – the exposure to an oxygen-poor environment may affect the entire flight crew to the point that they are no longer capable of taking normal, corrective or protective actions. The depressurisation could be slow and undetected (also known as ‘gradual or insidious depressurisation’), rapid or explosive. (e.g. due to an explosion or a broken windshield). In any of these cases it may cause hypoxia and, potentially, death.
• Laser blinding;
• Injury; it can be:
  • accidental (e.g. due to turbulence, explosion, fire, etc)
  • deliberate (e.g. due to unlawful interference, unruly passenger, etc)

Controller’s Actions

The advice in this section is derived from best practices and is not considered exhaustive nor is it intended to replace local procedures.

There is little that a controller can do about recognizing the state of incapacitation or in terms of assistance in flying the aircraft. After the situation has been positively identified (e.g. by a flight crew report), the controller should take some (or all) of the following actions, as appropriate:

• Determine flight crew’s intentions; most likely they would elect to land at the nearest suitable aerodrome;
• Provide room for manoeuvring (e.g. emergency descent, most appropriate route to the aerodrome chosen, etc.) by clearing the way of other aircraft;
• Inform the supervisor as soon as practicable; they are usually expected to notify other authorities and may assist in the coordination activities with other units/the aerodrome/etc.;
• Inform other appropriate authorities, e.g. law enforcement in case of laser blinding or of an unruly passenger;
• Coordinate emergency response services at the aerodrome chosen;
• Determine crew intentions after landing; it is possible that the aircraft would remain on the runway;
• Determine whether the crew are in full control of the airplane;
• Any runway operations should be stopped at a reasonable time before the expected landing; if there is only one runway at the aerodrome cancelling the start-ups should be considered;

Related Articles

• Pilot Incapacitation
• Food Poisoning
• Fainting
• Hypoxia
• Time of Useful Consciousness (TUC)
• Pressurisation Problems: Guidance for Controllers

Further Reading

EUROCONTROL

• Guidelines for Controller Training in the Handling of Unusual/Emergency Situations
• ATC Refresher Training Manual, ed.1.0, March 2015

UK CAA

• CAP 745, Aircraft Emergencies, Considerations for air traffic controllers

FAA

• Safety Recommendation Report - Emergency Training for Air Traffic Controllers

Others

• In-Flight Incapacitation – Flight Crew Training, IFALPA, 8 August 2013
• TP 11629 - Pilot Incapacitation, Transport Canada
• ICAO Doc 8984 "Manual of Civil Aviation Medicine", third edition 2012. Part 1, Chapter 3 Flight Crew Incapacitation
• Diabetes mellitus and its effects on pilot performance and flight safety, Aviation Research report, ATSB, June 2005