FAA Sport Pilot Airplane (SPA)Human Factors and ADMMedium
A pilot flying at 12,500 feet MSL without supplemental oxygen begins to experience impaired judgment and blue fingertips due to insufficient oxygen in the blood caused by reduced atmospheric pressure. This condition is known as:
- AStagnant hypoxia
- BHypemic hypoxia
- CHypoxic hypoxia
- DHistotoxic hypoxia
Show answer & explanationAnswer & explanation
Correct answer: C. Hypoxic hypoxia
Hypoxic hypoxia results from insufficient oxygen at altitude due to reduced partial pressure of oxygen in the atmosphere, exactly matching the scenario of flying at 12,500 feet without supplemental oxygen.
Why the other options are wrong
- A. Stagnant hypoxia results from poor blood circulation, not altitude.
- B. Hypemic hypoxia is caused by reduced oxygen-carrying capacity of the blood, such as from CO poisoning or blood loss.
- D. Histotoxic hypoxia occurs when cells cannot use oxygen properly, such as from alcohol or drugs.
Hypoxic Hypoxia
A form of hypoxia caused by insufficient oxygen reaching the blood due to reduced atmospheric pressure at altitude.
- Most common form encountered by pilots flying without oxygen at high altitude
- Symptoms include impaired judgment, cyanosis (blue skin), and euphoria
- FAA requires supplemental oxygen for extended flight above 12,500 feet MSL
Memory trick: High altitude, Hemoglobin, Heart flow, Harmful chemicals — the four H's of hypoxia.