Instrument Rating Checkride Practice Test

What is the required oxygen use for flight crew between 12,500' and 14,000' MSL?

1. Oxygen is required for the entire flight

2. Oxygen only if exceeding 30 minutes above

3. No oxygen is required

4. Only passengers require supplemental oxygen

The correct answer is: Oxygen only if exceeding 30 minutes above

For flight crew operating between 12,500 and 14,000 feet MSL, supplemental oxygen is required only if they are flying for more than 30 minutes at that altitude. This regulation is grounded in physiological understanding, as cabin pressure at these altitudes may not provide sufficient oxygen for prolonged exposure, which could lead to hypoxia. The regulation aims to ensure that flight crews can maintain proper cognitive function and situational awareness during flight. The other options do not align with the Federal Aviation Administration (FAA) requirements for oxygen use. For instance, stating that oxygen is required for the entire flight would imply that it is necessary regardless of duration, which is not accurate for this altitude range. Furthermore, indicating that no oxygen is required overlooks the potential risks associated with altitude and the time spent above 12,500 feet. Lastly, the notion that only passengers require supplemental oxygen misrepresents the responsibility of flight crews to ensure they are fit to operate the aircraft at higher altitudes.