Private Pilot Private Exam

Prior to takeoff, what should the altimeter be set to?

1. The elevation of the departure airport

2. The highest obstacle in the vicinity

3. The current local altimeter setting

4. Both the departure airport elevation and current local setting

The correct answer is: Both the departure airport elevation and current local setting

The altimeter should always be set to the current local altimeter setting prior to takeoff. This ensures that the aircraft is calibrated to accurately reflect the altitude relative to sea level and maintain proper vertical navigation. Setting the altimeter correctly is crucial for maintaining safety and avoiding terrain. While it may be useful to know the elevation of the departure airport for planning purposes, the primary concern before takeoff is to align with the local atmospheric conditions, which can change due to weather variations. Thus, having the altimeter set to the current local altimeter setting provides the most accurate reference for flying in the area immediately surrounding the departure airport. Knowing the current local altimeter setting ensures that, upon takeoff, the pilot is aware of the true altitude of the aircraft above mean sea level, facilitating safer navigation and avoiding obstacles. This local setting is typically provided by air traffic control or can be obtained from automated weather stations at airports. In situations where both the departure airport's elevation and the local altimeter setting are considered, it’s essential to prioritize the local altimeter setting for takeoff to ensure the aircraft is behaving correctly relative to the actual atmospheric pressure conditions at that site.