FAA Aviation Mechanic Airframe (AMA)Fuel, Cabin and Ice Control SystemsMedium
During a functional test of a transport-category aircraft's pressurization warning system, a technician confirms that a warning horn and light activate when cabin altitude reaches a specific value. At approximately what cabin altitude does the cabin altitude warning system typically activate?
- A5,000 feet
- B8,000 feet
- C14,000 feet
- D10,000 feet
Show answer & explanationAnswer & explanation
Correct answer: D. 10,000 feet
Most transport-category cabin altitude warning systems are set to activate at approximately 10,000 feet cabin altitude, alerting the flight crew that supplemental oxygen may become necessary and that a pressurization malfunction may exist.
Why the other options are wrong
- A. 5,000 feet is well below the typical cruise cabin altitude and would cause nuisance warnings.
- B. 8,000 feet is the normal maximum cabin altitude during pressurized cruise, not the warning threshold.
- C. 14,000 feet is far above the safe threshold and would delay crew awareness too long.
Cabin Altitude Warning System
A pressurization safety system that activates a horn and light when cabin altitude reaches approximately 10,000 feet, alerting the crew to a possible pressurization failure.
- Activates near 10,000 ft cabin altitude
- Normal cruise cabin altitude is ~8,000 ft or less
- Alerts crew before oxygen becomes critical
Memory trick: 'Ten grand, sound the horn'