What is the maximum allowable difference between field elevation and altimeter display?

The maximum allowable difference between field elevation and altimeter display is 75 feet. This standard is crucial for ensuring safety and accuracy in aviation operations, as discrepancies can lead to improper altitude awareness, which is critical during takeoff, landing, and in-flight navigation.

An altimeter that deviates by more than this maximum limit may indicate a potential malfunction or calibration issue, which can have serious implications in flight operations. Maintaining a strict limit helps pilots and air traffic control to ensure that aircraft are at the correct altitude relative to the ground level, thereby reducing the risk of accidents that could arise from altitude misestimations.

Thus, the established limit of 75 feet serves to facilitate safe operations and provide a clear standard for ensuring that altimeter readings remain reliable and accurate in relation to actual field elevation.