Which combination of symptoms from an acute infectious illness can impair aircrew performance and may require grounding or diversion?

• A. Fever, dehydration, malaise
• B. Headache only
• C. Nausea with no fever
• D. Cough without fever

Answer: (A)

Acute infectious illness impairs aircrew performance most when systemic symptoms reflect a true body-wide illness: fever, dehydration, and malaise. Fever increases metabolic demand and can blunt judgment, slow reaction time, and reduce vigilance and decision-making accuracy, all of which are critical for safe flight. Dehydration lowers plasma volume and cerebral perfusion, worsens dizziness, fatigue, and thermoregulatory strain, and makes orthostatic changes more risky during ascent, descent, or maneuvering. Malaise adds a pervasive sense of weakness and reduced concentration, compounding the effects of fever and dehydration. Together, these signs signal a level of impairment that can jeopardize safety and often necessitates grounding or diversion to protect the crew and the mission. A single symptom like a headache, nausea without fever, or a cough without fever may not alone indicate the same level of impairment unless it is severe or accompanied by other signs.