What is the maximum allowable deviation for magnetic compasses?

The maximum allowable deviation for magnetic compasses is 5 degrees. This standard is based on the critical need for accuracy and reliability in navigation, particularly in aviation. Deviation refers to the difference between the magnetic heading indicated by the compass and the true magnetic heading.

A deviation limit of 5 degrees ensures that pilots are provided with sufficiently precise information to maintain safe operations, particularly in dynamic flight environments where even minor discrepancies can lead to significant navigational errors. Under this standard, if a compass shows a deviation greater than 5 degrees, it would typically necessitate further inspection or calibration to ensure it meets the necessary performance requirements for accurate navigation.

Understanding this limit is essential for pilots, as it helps maintain situational awareness and safety during flight.