FAA Ground School Practice Test

At what cabin pressure altitude do civil aircraft operators not need to provide supplemental oxygen?

1. Above 10,000 ft MSL

2. Above 12,500 ft MSL

3. Above 14,000 ft MSL

4. Above 15,000 ft MSL

The correct answer is: Above 14,000 ft MSL

Civil aircraft operators are required to provide supplemental oxygen when the cabin pressure altitude exceeds certain thresholds to ensure the safety and well-being of passengers and crew. For most civil aircraft, pilots are required to provide supplemental oxygen to crew members above 12,500 feet MSL. However, the regulation states that for flights at cabin pressure altitudes above 14,000 feet MSL, oxygen must be provided for all occupants. At cabin pressure altitudes above 15,000 feet MSL, the regulations require that supplemental oxygen be available for all occupants, not just the crew. Therefore, it's correct to identify that aircraft operators do not need to provide supplemental oxygen when the cabin altitude is between 12,500 and 14,000 feet, which is why the correct answer is based on the altitude level of 14,000 feet MSL. This regulation helps mitigate hypoxia risks, which become more significant as altitude increases due to the decrease in available atmospheric oxygen. Understanding these thresholds is critical for flight safety and compliance with FAA guidelines.