Which statement about the cabin altimeter indicators is true?

• A. It displays altitude only in feet above mean sea level.
• B. It is composed of three indicators including a cabin altitude meter and a cabin pressure differential meter.
• C. It measures airspeed.
• D. It is composed of two indicators: the cabin altitude meter and the cabin pressure differential meter.

Answer: (D)

The main idea is understanding what the cabin pressurization indicators monitor: two key readings that keep the cabin environment safe and comfortable. One indicator shows cabin altitude, the effective height inside the airplane, so you can verify the pressurization system is maintaining the desired cabin pressure. The other shows the cabin differential pressure, the pressure difference between the inside and outside of the aircraft, which must stay within structural limits.

This pair of indicators is the standard setup, so the correct statement is that the cabin pressurization indicators consist of two indicators: a cabin altitude meter and a cabin pressure differential meter. It doesn’t measure airspeed, and there isn’t a third mandatory indicator in the basic cabin indicator set.