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AIM 

6/17/21 

impaired for many hours by hangover. There is 
simply no way of increasing the destruction of 
alcohol or alleviating a hangover. Alcohol also 
renders a pilot much more susceptible to disorienta-
tion and hypoxia. 

2. 

A consistently high alcohol related fatal 

aircraft accident rate serves to emphasize that alcohol 
and flying are a potentially lethal combination. The 
CFRs prohibit pilots from performing crewmember 
duties within 8 hours after drinking any alcoholic 
beverage or while under the influence of alcohol. 
However, due to the slow destruction of alcohol, a 
pilot may still be under influence 8 hours after 
drinking a moderate amount of alcohol. Therefore, an 
excellent rule is to allow at least 12 to 24 hours 
between “bottle and throttle,” depending on the 
amount of alcoholic beverage consumed. 

e.  Fatigue. 

1. 

Fatigue continues to be one of the most 

treacherous hazards to flight safety, as it may not be 
apparent to a pilot until serious errors are made. 
Fatigue is best described as either acute (short-term) 
or chronic (long-term). 

2. 

A normal occurrence of everyday living, 

acute fatigue is the tiredness felt after long periods of 
physical and mental strain, including strenuous 
muscular effort, immobility, heavy mental workload, 
strong emotional pressure, monotony, and lack of 
sleep. Consequently, coordination and alertness, so 
vital to safe pilot performance, can be reduced. Acute 
fatigue is prevented by adequate rest and sleep, as 
well as by regular exercise and proper nutrition. 

3. 

Chronic fatigue occurs when there is not 

enough time for full recovery between episodes of 
acute fatigue. Performance continues to fall off, and 
judgment becomes impaired so that unwarranted 
risks may be taken. Recovery from chronic fatigue 
requires a prolonged period of rest. 

4. 

OBSTRUCTIVE SLEEP APNEA (OSA). 

OSA is now recognized as an important preventable 
factor identified in transportation accidents. OSA 
interrupts the normal restorative sleep necessary for 
normal functioning and is associated with chronic 
illnesses such as hypertension, heart attack, stroke, 
obesity, and diabetes. Symptoms include snoring, 
excessive daytime sleepiness, intermittent prolonged 
breathing pauses while sleeping, memory impair-

ment and lack of concentration. There are many 
available treatments which can reverse the day time 
symptoms and reduce the chance of an accident. OSA 
can be easily treated. Most treatments are acceptable 
for medical certification upon demonstrating effect-
ive treatment. If you have any symptoms described 
above, or neck size over 17 inches in men or 16 inches 
in women, or a body mass index greater than 30 you 
should be evaluated for sleep apnea by a sleep 
medicine specialist. 
(

https://www.cdc.gov/healthyweight/assessing/ 

bmi/adult_bmi/english_bmi_calculator/bmi_calc 
ulator.html

) With treatment you can avoid or delay 

the onset of these chronic illnesses and prolong a 
quality life. 

f.  Stress. 

1. 

Stress from the pressures of everyday living 

can impair pilot performance, often in very subtle 
ways. Difficulties, particularly at work, can occupy 
thought processes enough to markedly decrease 
alertness. Distraction can so interfere with judgment 
that unwarranted risks are taken, such as flying into 
deteriorating weather conditions to keep on schedule. 
Stress and fatigue (see above) can be an extremely 
hazardous combination. 

2. 

Most pilots do not leave stress “on the 

ground.” Therefore, when more than usual difficul-
ties are being experienced, a pilot should consider 
delaying flight until these difficulties are satisfac-
torily resolved. 

g.  Emotion. 

Certain emotionally upsetting events, including a 
serious argument, death of a family member, 
separation or divorce, loss of job, and financial 
catastrophe, can render a pilot unable to fly an aircraft 
safely. The emotions of anger, depression, and 
anxiety from such events not only decrease alertness 
but also may lead to taking risks that border on 
self-destruction. Any pilot who experiences an 
emotionally upsetting event should not fly until 
satisfactorily recovered from it. 

h. Personal Checklist. 

Aircraft accident statis-

tics show that pilots should be conducting preflight 
checklists on themselves as well as their aircraft for 
pilot impairment contributes to many more accidents 
than failures of aircraft systems. A personal checklist, 
which includes all of the categories of pilot 
impairment as discussed in this section, that can be 

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Fitness for Flight