Fatigue

From SKYbrary Wiki

Article Information
Category:	Aeromedical
Content source:	SKYbrary
Content control:	EUROCONTROL

Contents 1 Description 2 Hazards 3 Typical Scenarios 4 Contributory Factors 5 Solutions 6 Related Articles 7 Related OGHFA Material 8 Accidents & Incidents 9 Further Reading

Description

Fatigue is the general term used to describe physical and/or mental weariness which extends beyond normal tiredness.

Physical fatigue concerns the inability to exert force with ones muscles to the degree that would be expected. It may be an overall tiredness of the whole body, or be confined to particular muscle groups. Physical fatigue most commonly results from physical exercise or loss of sleep. Physical fatigue often leads to mental fatigue.

Mental fatigue, which may include sleepiness, concerns a general decrease of attention and ability to perform complex, or even quite simple tasks with customary efficiency. Mental fatigue often results from loss or interruption of the normal sleep pattern and is therefore of great concern to pilots and ATCOs, who are frequently required to work early in the morning or at night.

Sleep patterns are naturally associated with the body's circadian rhythms. Shift patterns and transit across time zones can interrupt circadian rhythms so that, for example, it may be difficult for flight crew or pilots on duty in the early hours of the morning or flight crew operating long-haul routes through multiple time zones to achieve satisfactory rest prior to commencing duty.

Hazards

Fatigue usually results in impaired standards of operation with increased likeliness of error. For example:

• Increased reaction time;

• Reduced attentiveness;

• Impaired memory; and,

• Withdrawn mood.

Typical Scenarios

In a pilot, fatigue may manifest itself by:

• Inaccurate flying;

• Missed radio calls;

• Symptoms of equipment malfunctions being missed;

• Routine tasks being performed inaccurately or even forgotten; and, in extreme cases,

• Falling asleep - either a short "micro-sleep" or for a longer period.

In an ATCO, fatigue may result in:

• Poor decision making;

• Slow reaction to changing situation;

• Failure to notice an impending confliction;

• Loss of situational awareness;

• Forgetfulness.

Contributory Factors

• Length of previous rest period;

• Time on duty;

• Physical conditions (temperature, airlessness, noise, comfort, etc.);

• Workload (high or low);

• Emotional stress (in family life or at work);

• Lifestyle (including sleeping, eating, drinking and smoking habits) and fitness; and,

• Health.

Solutions

Employers:

• Ensure that work schedules, including consecutive shift-working patterns, are constructed so as to have the least possible impact on off duty - and if applicable on duty) rest.

• Seek to provide optimum working conditions;

• Use Crew Resource Management or Team Resource Management training to promote awareness to fatigue and sleep issues.

Pilots and ATCOs

Adopt personal strategies which are likelt to decrease the effects of fatigue such as the following:

• Planning activities, meals, rest and sleep patterns during off-duty periods;

• Making the most of permitted rest breaks, including naps;

• Advising colleagues if one detects feeling drowsy;

• Alerting colleagues if they appear to be becoming drowsy.

Related Articles

• Pilot Workload
• Controller Workload

Related OGHFA Material

Briefing Notes

• Fatigue Manifestations (OGHFA BN)
• Sleep (OGHFA BN)
• Circadian Rhythms (OGHFA BN)
• Key Training Topics About Managing Jet Lag (OGHFA BN)

Visuals

• Fatigue and Alertness Management in Aviation
• Being Prepared for the Outbound Flight - Checklist
• Being Prepared for the Return Flight in Eastward Rotations - Checklist
• Being Prepared for the Return Flight in North and South Rotations - Checklist
• Being Prepared for the Return Flight in Westward Rotations - Checklist

Situational Examples

• Fuel Starvation, Stress, Fatigue and Nonstandard Phraseology (OGHFA SE)
• Impaired Judgment, Decision Making and Flying Skills due to Fatigue (OGHFA SE)
• Takeoff Weight Entry Error and Fatigue (OGHFA SE)

Accidents & Incidents

Events in the SKYbrary database which include fatigue as a contributory factor:

• MD82, Little Rock USA, 1999 (WX RE FIRE HF) (On 1 June 1999, an MD82 belonging to American Airlines, overran the end of the runway during landing. The captain and 10 passengers were killed.)
• B738, En route, south west of Beirut Lebanon, 2010 (LOC HF) (On 25 January 2010, a Boeing 737-800 being operated by Ethiopian Airlines on a scheduled passenger flight from Beirut to Addis Ababa in night IMC disappeared from ATC radar soon after departure from Runway 21 and was subsequently found to have impacted the sea in an unintentional out of control condition some five miles south west of the airport less than five minutes after getting airborne Impact resulted in the destruction of the aircraft and the death of all 90 occupants.)
• FA20, vicinity Narsarsuaq Greenland, 2001 (CFIT HF) (On 5 August 2001, a Dassault Falcon 20, operated by Naske Air, on a non-scheduled international cargo flight, crashed on the final approach to runway 07 at Narsarsuaq, Greenland (BGBW), the aircraft impacting mountainous terrain 4.5 NM SW of the aerodrome.)
• RJ1H, vicinity Zurich Switzerland, 2001 (CFIT FIRE HF) (On 24 November 2001, while performing a standard VOR/DME approach to runway 28 at Zurich, the pilot in command of a an AVRO 146 RJ 100 decided to continue below the minimum descent altitude. The aircraft collided with treetops and subsequently crashed impacted the ground - 24 persons died, 9 survived the accident.)
• SF34, New York JFK USA, 1999 (HF RE) (An SF34 overan New York JFK 04R after an unstabilised ILS approach in IMC was continued to a deep landing at excessive speed and the aircraft overan into the installed EMAS.)
• … further results

Further Reading

EASA

• Moebus Aviation Final Report: Scientific and Medical Evaluation of Flight Time Limitations;

EUROCONTROL

• Fatigue and Sleep Management Brochure;
• Personal Strategies for Decreasing the Effects of Fatigue in Air Traffic Control;

UK CAA

• Aircrew Fatigue: A Review of Research Undertaken on Behalf of the UK Civil Aviation Authority.