FAA Ground School Practice Test

Prior to takeoff, the altimeter should be set to which altitude or altimeter setting?

1. The current local altimeter setting, if available

2. Standard pressure of 29.92 inHg

3. The elevation of the runway

4. The elevation of the nearest VOR

The correct answer is: The current local altimeter setting, if available

Setting the altimeter to the current local altimeter setting before takeoff is essential for ensuring accurate altitude readings. This local setting is a representation of the atmospheric pressure at sea level, adjusted for the current weather conditions. Every airport and area has a specific altimeter setting that accounts for temperature, air pressure, and other factors that can vary throughout the day. Using the local altimeter setting allows pilots to accurately gauge their altitude relative to the ground, which is crucial for maintaining safe separation from terrain and obstacles during departure. Furthermore, it assures that all aircraft operating in the vicinity are communicating and reporting their altitudes based on the same reference, enhancing situational awareness and safety. In contrast, while the standard pressure setting might be used in some circumstances, flying with the local altimeter setting is often preferred closer to takeoff. The elevation of the runway or a nearby VOR would not provide a dynamic altitude reference that accounts for changing atmospheric conditions, which can lead to potential navigation errors or altitude misjudgments.