Chapter 8. Techniques of Flight Instruction

Physical Discomfort, Illness, Fatigue, and Dehydration

Physical discomfort, illness, and fatigue will materially slow the rate of learning during both classroom instruction and flight training. Students who are not completely at ease, and whose attention is diverted by discomforts such as the extremes of temperature, poor ventilation, inadequate lighting, or noise and confusion, cannot learn at a normal rate. This is true no matter how diligently they attempt to apply themselves to the learning task.

A minor illness, such as a cold, major illness, or injury, interferes with the normal rate of learning. This is especially important for flight instruction. Most illnesses adversely affect the acuteness of vision, hearing, and feeling, all of which are essential to correct performance.

Airsickness can be a great deterrent to flight instruction. A student who is airsick or bothered with incipient airsickness is incapable of learning at a normal rate. There is no sure cure for airsickness, but resistance or immunity usually can be developed in a relatively short period of time. An instructional flight should be terminated as soon as incipient sickness is experienced. As the student develops immunity, flights can be increased in length until normal flight periods are practicable.

Keeping students interested and occupied during flight is a deterrent to airsickness. They are much less apt to become airsick while operating the controls themselves. Rough air and unexpected abrupt maneuvers tend to increase the chances of airsickness. Tension and apprehension apparently contribute to airsickness and should be avoided.


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). Acute fatigue, a normal occurrence of everyday living, 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 caused by training operations may be physical or mental, or both. It is not necessarily a function of physical robustness or mental acuity. The amount of training any student can absorb without incurring debilitating fatigue varies. Generally speaking, complex operations tend to induce fatigue more rapidly than simpler procedures do, regardless of the physical effort involved. Fatigue is the primary consideration in determining the length and frequency of flight instruction periods and flight instruction should be continued only as long as the student is alert, receptive to instruction, and is performing at a level consistent with experience.

It is important for a CFI to be able to detect fatigue, both in assessing a student’s substandard performance early in a lesson, and also in recognizing the deterioration of performance. If fatigue occurs as a result of application to a learning task, the student should be given a break in instruction and practice.

A CFI who is familiar with the signs indicative to acute fatigue will be more aware if the student is experiencing them. The deficiencies listed below are apparent to others before the individual notices any physical signs of fatigue.

Acute fatigue is characterized by:

  • Inattention
  • Distractibility
  • Errors in timing
  • Neglect of secondary tasks
  • Loss of accuracy and control
  • Lack of awareness of error accumulation
  • Irritability

Another form of fatigue is chronic fatigue which occurs when there is not enough time for a full recovery from repeated episodes of acute fatigue. Chronic fatigue’s underlying cause is generally not “rest-related” and may have deeper points of origin. Therefore, rest alone may not resolve chronic fatigue.

Chronic fatigue is a combination of both physiological problems and psychological issues. Psychological problems such as financial, home life, or job-related stresses cause a lack of qualified rest that is only solved by mitigating the underlying problems before the fatigue is solved. Without resolution, human performance continues to fall off, and judgment becomes impaired so that unwarranted risks may be taken. Recovery from chronic fatigue requires a prolonged and deliberate solution. In either case, unless adequate precautions are taken, personal performance could be impaired and adversely affect pilot judgment and decision-making.

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