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Not a Tiring Matter

Fatigue is a major contributor to accidents and lost productivity

September 28, 2007  By Tarek M. Sardana MD


On August 6, 1997, Korean Air flight 801, a Boeing 747-300, crashed at
Nimitz Hill in Guam. Flight 801 departed Kimpo International Airport,
Seoul, with two pilots, a flight engineer, 14 flight attendants and 237
passengers. The airplane had been cleared to land on runway 6 Left at
A.B. Won Guam International Airport, but crashed into high terrain
about three miles southwest of the airport. Of the 254 persons on
board, 228 were killed; 23 passengers and three flight attendants
survived with serious injuries.

National Transportation Safety Board (NTSB) determined that the
probable cause of the accident was the captain’s failure to adequately
brief and execute the non-precision approach and the first officer’s
and flight engineer’s failure to effectively monitor and crosscheck the
captain’s execution of the approach. Contributing to these failures was
the captain’s fatigue.

The NTSB examined several fatiguerelated
factors, including time of day, recent sleeping patterns and the number
of hours since awakening, to determine whether fatigue was a factor in
the captain’s performance. On the basis of the time of day, statements
recorded on the CVR, as well as sleep and fatigue research, it was
concluded that the captain was fatigued, which degraded his performance
and contributed to his failure to properly execute the approach.

is the state of tiredness associated with prolonged work/activity,
and/or prolonged wakefulness. Sleep deprivation and circadian factors
are major components of the entire fatigue equation.


studies within international aviation safety reporting systems indicate
that over 7% of aviation accidents are identified as fatigue-related,
and this is likely just the tip of the iceberg. The NHTSA (National
Highway Traffic Safety Administration) attributes 100,000 accidents,
1,500 fatalities, 71,000 injuries, and US$12.5 billion a year in losses
to fatigue in the US alone!

Since 1893, the electric light bulb
changed night into day, extending work time, which has led to a 20%
reduction in sleep time over the last century and as well, aviation
improvements have enabled the crossing of one time zone per hour rather
than one time zone per day. It is clear that society has become an
increasingly 24/7 operation and it is anticipated that fatigue will
become an increasingly concerning issue.

have indicated through various studies that fatigue is an issue of
concern. Nearly 75% of military pilots say fatigue is a widespread
problem, and 89% of regional airline pilots say fatigue is a moderate
or serious concern. Between 50-89% of pilots have admitted to having
fallen asleep in the cockpit depending on which type of study is
reviewed. Pilots are not only susceptible to fatigue due to lack of
sleep, they are also subject to the effects of circadian
shift-adjustment problems (more commonly known as jet lag). This
situation may be exacerbated with the advent of Ultra Long Range (ULR)
aviation operations with flight times often exceeding 18 hours. Not
only will aircrew have to function for long periods of time, but they
will often be crossing 12 time zones twice a week. Fatigue is certainly
not an issue specific only to pilots; schedulers and maintenance
personnel, among others who do shift work, are also particularly
susceptible to the effects of fatigue.

decrements are similar to those caused by alcohol. A significantly
fatigued individual will more commonly miss checklist items, not
recognize emergency situations and not respond as crisply to an urgent
scenario, etc. It is interesting that we would never allow a
pilot/technician under the influence of alcohol to operate complex
machinery, but we as an aviation system are much more accepting of
allowing a fatigued individual to continue to function. A paradigm
shift in the aviation culture of fatigue is required.

1. Light or melatonin to adjust to new schedules
2. Ensuring sufficient daily sleep (i.e., more than 8 hours)
3. Strategic Naps
4. Stimulants
5. Rest Breaks
6. Posture
7. Exercise
8. Environmental Stimulation
9. Positive General Health

the fatigue reducing strategies listed above can be useful in aviation
operations. But remember, each operation is unique and in any gven
situation an examination of particular circumstances will be necessary

naps of less than 30 minutes have proven effective in decreasing the
effects of fatigue and improving task functioning. Regular exercise at
least four hours prior to scheduled sleep improves quality and length
of sleep. Being in good general health is also beneficial in countering
the effects of fatigue. Small amounts of caffeine (less than three
regular cups) have definite performance benefits.

is a major contributor to accidents, lost productivity and poor quality
of life in many facets of our modern society. It is important to
recognize the impact that fatigue has; especially as demand for 24/7
aviation operations increases, the potential for fatigue-related
problems will only become more significant. However, safety,
performance, and general well-being can be preserved by adhering to
well planned work-scheduling practices, implementing proven fatigue
countermeasures, ensuring that off-duty workers have sufficient sleep
opportunities and making adequate daily sleep a top priority. Remember,
sleep is a physical necessity – not a luxury, and there is simply no
substitute for sleep. I encourage you to review your personal and
professional environment and assess if fatigue is a concern within your

The author would like to thank Caldwell & Caldwell (2005) for allowing the use of some of their research data and charts.

Sardana is a pilot, a civil aviation medicine examiner (CAME) and
president of Aviation Medicine International (AMI) Inc.; Comments on this article or future topic
suggestions gladly appreciated at aviationmedintl@


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