FAA Instrument Rating Airplane (IRA)Aeromedical and ADMMedium
During an unpressurized cross-country flight at 14,000 feet MSL without supplemental oxygen, a pilot begins to feel unusually cheerful and self-assured, believes their performance is excellent, and does not notice their own slowed reaction times or degraded judgment. This scenario best illustrates a hazard of which physiological condition?
- AMiddle ear barotrauma
- BHypoxia
- CCarbon monoxide poisoning
- DHyperventilation
Show answer & explanationAnswer & explanation
Correct answer: B. Hypoxia
Hypoxia (specifically hypoxic hypoxia from reduced oxygen at altitude) often produces euphoria and a false sense of well-being, along with impaired judgment and slowed reaction time, without the pilot recognizing their own degraded performance. This insidious nature makes hypoxia especially dangerous.
Why the other options are wrong
- A. Middle ear barotrauma causes pain and pressure sensations, not cognitive/mood changes.
- C. Carbon monoxide poisoning causes headache, confusion, and cherry-red skin tone, generally without the euphoric symptom pattern.
- D. Hyperventilation typically causes tingling, dizziness, and anxiety from excessive CO2 loss, not euphoria from lack of oxygen.
Hypoxia (Hypoxic Hypoxia)
A physiological condition caused by insufficient oxygen reaching body tissues, often at altitude, characterized by early symptoms of euphoria, impaired judgment, and lack of self-awareness of the impairment.
- Time of useful consciousness decreases rapidly above 25,000 ft
- Symptoms are insidious—pilot often feels fine while performance degrades
- 14 CFR 91.211 requires supplemental oxygen for flight crew above 12,500 ft MSL for more than 30 minutes and continuously above 14,000 ft
Memory trick: High and happy but hazardously hindered