Fatigue has been blamed in numerous aviation accidents over the years and is a continuing problem facing crew flying aircraft of all sizes. What roles do sleep cycles, dehydration, nutrition and illness play in flight crew fatigue?

There are many documented accidents that can be attributed to pilot fatigue. The most notable is the June 1999 fatal runway accident by American Airlines flight 1420 in which a McDonnell Douglas MD-82 overran the end of the runway, went down an embankment and impacted approach light structures after landing at the Adams Field in Little Rock, Arkansas.

Thunderstorms and heavy rain were reported in the area at the time of the accident. There were 11 fatalities including the aircraft captain and numerous injuries among the 145 passengers and crew on board the flight. In this accident, crew fatigue was listed as a contributing cause.

Fatigue is closely interrelated to other problems in that it can be a symptom of them or it can be the cause. The most common cause of fatigue would be a lack of sleep, but other factors would include stress, anxiety and poor heath. Furthermore, fatigue can be the symptom of other problems such as hypoxia and dehydration.

Some airlines most often stretch their crew rest requirements to the legal limit of flight and duty time restrictions to maximise productivity.
There has always been a conflict of interest between commercial interests and the need to observe the laws and regulations governing duty and flight time limitations in almost every airline from time immemorial. The commercial interest being that every flight should depart on time with little or no disruption whatsoever. Then there are the operational interests in that in the course of these operations, the flight crew might in the process run out of either duty or flight time.

As has been indicated on a number of occasions, the aviation industry is highly regulated and any violation of these rules and regulations invites severe sanctions by the oversight institutions.

This problem of duty and flight time limitations was however overseen by the International Civil Aviation Organisation (ICAO) at the time of formation in Chicago and did come up with provisions for control, regulation and orderly development of aviation. The ICAO, through its various annexes came up with standards and regulations from which the governments can derive the relevant laws to govern duty and flight time limitations.

Here in Zambia, the flight and duty time limitations for flight crew is governed by the aviation Act, Air Navigation Regulations, Operating Crew Part XI, which is the ‘’bible’’ of every aviator. Most of airlines do come up with excerpts from these rules and regulations for distribution to the flight crew. The Act states that ‘’ a member of a flight crew shall be deemed to be performing duty during:

Period commencing not less than 30 minutes before the schedule time of the first take-off of the aeroplane on a flight and ending the period of fifteen minutes immediately following the moment when the engines of the aeroplane are switched off after landing.

Any period spent at an aeroplane or elsewhere in the course of a flight which is not a rest period.

(2) No operator of an air transport undertaking shall cause, permit or schedule any member of a flight crew to perform duty or flying duty and no member of a flight crew shall perform duty or flying duty, otherwise than in accordance with the provisions of this regulation.

(ii) In relation to any flight or flights by an aeroplane with an operating crew of two pilots only or one pilot and one licensed member of an operating crew who is not a pilot:

A pilot shall not perform duty for more than twelve hours or if such duty commences after 6am Local time and ends before 10pm. Local time for more than thirteen hours during twenty-four consecutive hours.

A pilot shall not perform flying duty for more than nine hours or, if such duty commences after 6 am local time and ends before 10 pm. Local time for more than ten hours during any twenty-four consecutive hours unless he has a continuous rest period of not less than eight hours duration at or before the end of nine or ten hours flying duty as the case may be.

A pilot shall have a continuous rest period of not less than thirty-six hours duration once in every seven consecutive days
A pilot shall not perform flying duty for periods exceeding in the aggregate
Thirty-two hours in any seven consecutive days
One hundred hours in any month.
Nine hundred hours in any year.

These duty or flight time limitations should not be exceeded unless under special circumstances and these reasons for making the flight shall be submitted by the pilot in-command (captain) to the operator (the airline) who shall submit the report to the Director of Civil Aviation for further action.
The reasons for this again is: in case of an incident or an accident, the investigators would like to know for how long the flight crew were on duty or flying and if fatigue could have caused the mishap.

Fatigue, from the several researches done by the aviation experts, is often the cause of pilot error and it is therefore often the vital link in the chain of events leading to an accident. It is often the reason that pilots don’t make the right decisions or fly as well as they can.

Further studies indicate that long international flights and automation cause a reduction of mental stimulus and an increase in boredom coupled with the lack of quality sleep. There are other environmental concerns which increase anxiety, stress and restlessness in flight crew such as noise and aircraft vibration, hypoxia (caused by cabin decompression) extreme temperatures and flickering of lights.