Private Pilot Private Exam

What is pressure altitude?

1. The altitude shown on an aircraft's altimeter

2. The altitude indicated when the barometric pressure scale is set to 29.92 inches of mercury

3. Altitude corrected for temperature variance

4. Altitude referenced to mean sea level

The correct answer is: The altitude indicated when the barometric pressure scale is set to 29.92 inches of mercury

Pressure altitude is defined as the altitude indicated on an altimeter when it is calibrated to a standard atmospheric pressure setting of 29.92 inches of mercury (inHg). This setting is used to standardize aircraft altimeters, ensuring that they provide consistent altitude readings across different atmospheric conditions, which is critical for safe navigation and separation between aircraft. When the altimeter is set to this standard pressure, it allows pilots to determine their height above a zero reference point known as the National Standard Atmosphere. This point correlates to sea level under standard conditions. Pressure altitude is particularly important for flight planning and operations, as it directly correlates with aircraft performance, engine efficiency, and safety margins during ascent, cruise, and descent through different air layers. Understanding pressure altitude is essential for pilots, as it helps them interpret altimeter readings during flight and adhere to airspace regulations, particularly in regions where altitude reporting is dictated by pressure instead of geographic elevation.