Medical Factors

A "go/no-go" decision is made before each flight. The pilot should not only preflight check the aircraft, but also his/ herself before every flight. As a pilot you should ask yourself, "Could I pass my medical examination right now?" If you cannot answer with an absolute "yes," then you should not fly. This is especially true for pilots embarking on flights in IMC. Instrument flying can be much more demanding than flying in VMC, and peak performance is critical for the safety of flight.

Pilot performance can be seriously degraded by both prescribed and over-the-counter medications, as well as by the medical conditions for which they are taken. Many medications, such as tranquilizers, sedatives, strong pain relievers, and cough-suppressants, have primary effects that may impair judgment, memory, alertness, coordination, vision, and the ability to make calculations. Others, such as antihistamines, blood pressure drugs, muscle relaxants, and agents to control diarrhea and motion sickness, have side effects that may impair the same critical functions. Any medication that depresses the nervous system, such as a sedative, tranquilizer, or antihistamine, can make a pilot much more susceptible to hypoxia.

Title 14 of the Code of Federal Regulations (14 CFR) prohibits pilots from performing crewmember duties while using any medication that affects the faculties in any way contrary to safety. The safest rule is not to fly as a crewmember while taking any medication, unless approved to do so by the Federal Aviation Administration (FAA). If there is any doubt regarding the effects of any medication, consult an Aviation Medical Examiner (AME) before flying.

Alcohol
14 CFR part 91 prohibits pilots from performing crewmember duties within 8 hours after drinking any alcoholic beverage or while under the influence. Extensive research has provided a number of facts about the hazards of alcohol consumption and flying. As little as one ounce of liquor, one bottle of beer, or four ounces of wine can impair flying skills and render a pilot much more susceptible to disorientation and hypoxia. Even after the body completely metabolizes a moderate amount of alcohol, a pilot can still be impaired for many hours. There is simply no way of increasing the metabolism of alcohol or alleviating a hangover.

Fatigue
Fatigue is one of the most treacherous hazards to flight safety, as it may not be apparent to a pilot until serious errors are made. Fatigue can be either acute (short-term) or chronic (long-term). 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. Acute fatigue is prevented by adequate rest, regular exercise, and proper nutrition. Chronic fatigue occurs when there is not enough time for a full recovery from repeated episodes of acute fatigue. Recovery from chronic fatigue requires a prolonged period of rest. In either case, unless adequate precautions are taken, personal performance could be impaired and adversely affect pilot judgment and decision making.

IMSAFE Checklist
The following checklist, IMSAFE, is intended for a pilot's personal preflight use. A quick check of the items on this list can help the pilot make a good self-evaluation prior to any flight. If the answer to any of the checklist questions is yes, then the pilot should consider not flying.

Illness—Do I have any symptoms?
Medication—Have I been taking prescription or over-the-counter drugs?
Stress—Am I under psychological pressure from the job? Do I have money, health, or family problems?
Alcohol—Have I been drinking within 8 hours? Within 24 hours?
Fatigue—Am I tired and not adequately rested?
Eating—Have I eaten enough of the proper foods to keep adequately nourished during the entire flight?

Hypoxia: A state of oxygen deficiency in the body sufficient to impair functions of the brain and other organs.