What is a critical sign of fatigue that a pilot should monitor during their shift?

Bobbing of the head is a critical sign of fatigue that a pilot should monitor during their shift because it typically indicates that a pilot is struggling to stay awake or maintain focus. This physical symptom occurs when a person falls into micro-sleeps—brief moments of sleep that can happen without the person being fully aware of it. When pilots exhibit head bobbing, it suggests that their alertness is compromised and they may not be fully capable of performing their duties safely. Recognizing and addressing signs of fatigue, including head bobbing, is essential for ensuring flight safety, as it can ultimately impact decision-making and reaction times.

Other signs of fatigue, such as headaches or increased appetite, may be relevant but do not directly indicate a loss of awareness or the need for immediate action like head bobbing does. Enhanced memory would suggest the opposite of fatigue and would not be a sign that a pilot is struggling to maintain their attention and responsiveness. Therefore, monitoring for head bobbing is critical for pilots to stay vigilant and manage their fatigue effectively.