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:
- Errors in timing
- Neglect of secondary tasks
- Loss of accuracy and control
- Lack of awareness of error accumulation
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.
Dehydration and Heatstroke
Dehydration is the term given to a critical loss of water from the body. Dehydration reduces a pilot’s level of alertness, producing a subsequent slowing of decision-making processes or even the inability to control the aircraft. The first noticeable effect of dehydration is fatigue, which in turn makes top physical and mental performance difficult, if not impossible. Flying for long periods in hot summer temperatures or at high altitudes increases susceptibility to dehydration since dry air at high altitudes tends to increase the rate of water loss from the body. If this fluid is not replaced, fatigue progresses to dizziness, weakness, nausea, tingling of hands and feet, abdominal cramps, and extreme thirst.
Heatstroke is a condition caused by any inability of the body to control its temperature. Onset of this condition may be recognized by the symptoms of dehydration, but also has been known to be recognized only by complete collapse. To prevent these symptoms, it is recommended that an ample supply of water be carried and used at frequent intervals on any long flight, whether the pilot is thirsty or not. If the airplane has a canopy or roof window, wearing light-colored, porous clothing and a hat helps provide protection from the sun. Keeping the flight deck well ventilated aids in dissipating excess heat.
Apathy Due to Inadequate Instruction
Students can become apathetic when they recognize that the instructor has made inadequate preparations for the instruction being given, or when the instruction appears to be deficient, contradictory, or insincere. To hold the student’s interest and to maintain the motivation necessary for efficient learning, well-planned, appropriate, and accurate instruction must be provided. Nothing destroys a student’s interest as quickly as a poorly organized period of instruction. Even an inexperienced student realizes immediately when the instructor has failed to prepare a lesson. [Figure 8-3]
Instruction may be overly explicit and so elementary it fails to hold student interest, or it may be so general or complicated that it fails to evoke the interest necessary for effective learning. To be effective, the instructor must teach for the level of the student. The presentation must be adjusted to be meaningful to the person for whom it is intended. For example, instruction in the preflight inspection of an aircraft should be presented quite differently for a student who is a skilled aircraft maintenance technician (AMT) compared to the instruction on the same operation for a student with no previous aeronautical experience. The instruction needed in each case is the same, but a presentation meaningful to one of these students might not be appropriate for the other.
Poor instructional presentations may result not only from poor preparation, but also from distracting mannerisms, personal untidiness, or the appearance of irritation with the student. Creating the impression of talking down to the student is one of the fastest ways for an instructor to lose student confidence and attention. Once the instructor loses student confidence, it is difficult to regain, and the learning rate is unnecessarily diminished.
Student anxiety may place additional burdens on the instructor. This frequently limits the student’s perceptive ability and retards the development of insights. The student must be comfortable, confident in the instructor and the aircraft, and at ease if effective learning is to occur. Providing this atmosphere for learning is one of the first and most important tasks of the instructor. Although doing so may be difficult at first, successive accomplishment of recognizable goals and the avoidance of alarming occurrences or situations will rapidly ease the student’s mind. This is true of all flight students, but special handling by the instructor may be required for students who are obviously anxious or uncomfortable.