FAA Commercial Pilot Airplane (CAX)Aerodynamics and PerformanceEasy
A pilot is planning a high-altitude flight in an unpressurized aircraft. Which physiological effect is a primary concern at altitudes above 10,000 feet without supplemental oxygen?
- AHypoxia.
- BCarbon monoxide poisoning.
- CSpatial disorientation.
- DHyperventilation.
Show answer & explanationAnswer & explanation
Correct answer: A. Hypoxia.
Hypoxia, a deficiency of oxygen in the body's tissues, is the primary physiological concern at higher altitudes due to the decrease in atmospheric pressure and thus partial pressure of oxygen. At altitudes above 10,000 feet, supplemental oxygen is typically required to prevent hypoxia and maintain normal physiological function.
Why the other options are wrong
- B. Carbon monoxide poisoning is due to faulty exhaust systems, not directly related to altitude itself.
- C. Spatial disorientation can be caused by various factors, but hypoxia is a more direct and severe effect of high altitude.
- D. Hyperventilation can occur due to stress or fear, but it's not the primary effect of altitude itself.
Hypoxia at Altitude
A condition in which the body or a region of the body is deprived of adequate oxygen supply. At high altitudes, it's caused by the decreased partial pressure of oxygen in the thinner air.
- Symptoms include impaired judgment, memory, and coordination.
- Onset can be insidious and difficult to self-recognize.
- Requires supplemental oxygen above certain altitudes (e.g., 12,500 ft for longer than 30 min, 14,000 ft at all times for crew).
- Affects vision, particularly night vision, at lower altitudes.
Memory trick: Climb too high without O2, and your brain's goodbye.