In the absence of a current altimeter setting, what should a pilot set their altimeter to for local flight?

When a pilot is flying locally and does not have access to a current altimeter setting, the best practice is to set the altimeter to the elevation of the airport. This is important because it allows the pilot to maintain a safe altitude relative to the known terrain and obstacles in the vicinity of the airport. Setting the altimeter to the airport elevation ensures that the pilot is aware of their height above ground level, which is critical during takeoff, landing, and when maneuvering in the traffic pattern.

In areas where barometric pressure changes may not be accurately reflected, using the elevation of the airport serves as a reliable reference point. It helps prevent situations where the aircraft could inadvertently fly too low, especially in hilly or mountainous regions.

Other options may seem practical but do not provide the same level of safety or accuracy. For instance, using the nearest weather station could lead to discrepancies if that station is located far away or in a different altitude setting. Setting to the highest obstacle could create unnecessary restrictions without providing an accurate altitude reference. The lowest permissible altitude is primarily relevant for en route segments and may not correspond to local conditions that affect the actual flight. Thus, using the airport elevation offers a straightforward and effective method for ensuring safe and accurate flight operations