A pilot must continually make decisions about competency,
condition of health, mental and emotional state, level of
fatigue, and many other variables. For example, a pilot may
be called early in the morning to make a long flight. If a pilot
has had only a few hours of sleep and is concerned that the
sinus congestion being experienced could be the onset of a
cold, it would be prudent to consider if the flight could be
accomplished safely.
A pilot had only 4 hours of sleep the night before
being asked by the boss to fly to a meeting in a city
750 miles away. The reported weather was marginal
and not expected to improve. After assessing fitness
as a pilot, it was decided that it would not be wise to
make the flight. The boss was initially unhappy, but
was later convinced by the pilot that the risks
involved were unacceptable.