FAA Aircraft Dispatcher Practice Exam

How is pressure altitude determined?

1. By adjusting altimeter to the local pressure

2. By setting the altimeter to 29.92 inches of mercury

3. By calculating the altitude at which air pressure equals sea level

4. By measuring the height above ground level

The correct answer is: By setting the altimeter to 29.92 inches of mercury

Pressure altitude is determined by setting the altimeter to a standard atmosphere pressure of 29.92 inches of mercury (Hg). This method standardizes altitude readings regardless of local atmospheric conditions. When the altimeter is adjusted to this pressure, the reading reflects the altitude above the standard datum plane, which corresponds to the air pressure that would be observed at sea level under standard atmospheric conditions. This approach is essential for flight planning, navigation, and ensuring safe vertical separation between aircraft. It allows pilots and air traffic control to communicate altitudes that are uniform and comparable across different locations, enabling consistent and effective air traffic management.