FAA Ground School Practice Test

What is the result of altitude changes relative to the altimeter setting during flight?

1. The altimeter shows the absolute altitude

2. The altimeter may show inaccurate altitude

3. The altimeter will never change readings

4. The altimeter solely relies on GPS

The correct answer is: The altimeter may show inaccurate altitude

When an aircraft undergoes changes in altitude relative to the altimeter setting, it can lead to inaccuracies in the altitude display. The altimeter is calibrated to measure pressure changes associated with altitude. Therefore, if the altimeter setting is not adjusted accordingly to the local atmospheric pressure at the new altitude, it can display an incorrect altitude. For example, if a pilot climbs or descends without updating the altimeter setting to reflect the current barometric pressure, the altimeter will not accurately depict the aircraft's true altitude above sea level. This can lead to hazardous situations, particularly when flying in mountainous terrain or during approaches and landings, where precise altitude readings are crucial for safety. This understanding emphasizes the importance of regularly checking and adjusting the altimeter setting to ensure that the altitude displayed is both accurate and reliable.