For an Instrument Check while stationary, what is the acceptable range for the Altimeter?

The acceptable range for the altimeter during an Instrument Check while stationary is +/- 75 feet of airport elevation. This standard is set to ensure that the altimeter reads with sufficient accuracy, as altimeters are critical for maintaining safe altitudes during flight. An error of up to 75 feet is permissible because it allows for variances in local atmospheric pressure, slight calibration differences, and variations in actual airport elevation.

This margin is important to maintain situational awareness and aircraft safety, particularly considering the tightly regulated environment of IFR operations where precision is key. Recognizing this tolerance helps pilots ensure their altimeter settings are reliable, which is vital during takeoff, landing, and while navigating at altitude.

The other options either set the bar too high or too low for acceptable variance in altimeter readings. A tolerance of +/- 50 feet or +/- 25 feet would be too stringent, while a range of +/- 100 feet would not sufficiently account for the variations typically encountered in atmospheric conditions. Understanding this standard is crucial for pilots to ensure compliance with regulations and to enable effective flight safety management.