When an aircraft altimeter is set at 29.92 inHg on the ground, the altimeter will read

When an aircraft altimeter is set at 29.92 inHg on the ground, the altimeter will read

• A. Indicated altitude
• B. Pressure altitude
• C. Density altitude
• D. True altitude

Answer: (B)

Using the standard pressure setting (29.92 inHg) makes the altimeter show pressure altitude. The altimeter converts ambient pressure to height, and the standard setting is defined as the height above the standard datum plane where the pressure is 29.92 inHg. On the ground, dialing 29.92 removes local pressure variations, so the instrument reads the altitude relative to that standard plane—i.e., the pressure altitude. The other quantities require different settings or conditions: indicated altitude needs the local QNH, density altitude adds temperature effects, and true altitude is the actual height above mean sea level.

Using the standard pressure setting (29.92 inHg) makes the altimeter show pressure altitude. The altimeter converts ambient pressure to height, and the standard setting is defined as the height above the standard datum plane where the pressure is 29.92 inHg. On the ground, dialing 29.92 removes local pressure variations, so the instrument reads the altitude relative to that standard plane—i.e., the pressure altitude. The other quantities require different settings or conditions: indicated altitude needs the local QNH, density altitude adds temperature effects, and true altitude is the actual height above mean sea level.