What Is Fatigue?

What is fatigue? One definition states, "fatigue is a period of mental or bodily activity; characterized by a lessened capacity for work and reduced efficiency of accomplishment usually accompanied by a feeling of weariness, sleepiness or irritability." Simply stated, fatigue is the body and mind weakening due to certain factors such as stress, lack of sleep and physical exertion. These by themselves or in combination can diminish a pilot's productivity. In this paper I will focus on the relationship between the causal factors of fatigue and its role in aviation.

Lack of sleep is one significant factor that triggers fatigue in a pilot. Sleep deprivation can affect 47 million adults, or almost a quarter of the American adult population. "Inadequate sleep can affect judgment, reaction-time, hand eye coordination, memory and general wellbeing." (neurology.com) All of these factors must be functioning at their highest levels in order to facilitate an aircraft efficiently. Lack of sleep can influence even the most qualified pilots.

As fatigue levels increase, performance levels can unknowingly decrease. The interpretation of information can be compromised and attention spans can be lowered. This is dangerous because imperative steps can either be ignored or forgotten due to the pilot's exhausted state.

If the pilot is not relieved, their physical state can diminish even further. Their motor skills can worsen, and they may begin to see and hear hallucinations. Severe head or body aches are also common. It also has been proven that the immune system can break down due to a prolonged lack of sleep. Basically, their body is slowly shutting down.

A pilot is affected mentally as well. They are not able to quickly problem solve, which can have serious affects during flight. Unknowingly, they may fall asleep, or taking micro sleeps where they may close their eyes and actually nod off for brief periods of time. Other symptoms also may be apparent. They also may become irritable or may have behavior changes such as jitteriness and paranoia due to the fatigue.

These symptoms will not only affect a fatigued pilot, but also those around them.

When operating an aircraft with a fatigued pilot the entire crew can be affected. The air crew may have to deal with irritability, miscalculations and poor communication. This is a serious safety concern which affects crew resource management.

Common warning signs that a pilot is fatigued are usually quite apparent. They may be stretching and yawning fairly often, shutting and opening their eyes several times and shaking their head to keep themselves awake. They may be constantly rechecking their work and show signs being highly stressed. Slow reaction times may become obvious to other crew members, but not the fatigued individual. The pilot may not think before acting which could endanger the crew, the passengers and anyone in their path. Dark circles may also be apparent, and if the fatigue is severe enough the pilot could be losing weight or become ill fairly easily from a weak immune system.

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