Plain English Meaning

When an airplane has two VOR units, the pilot can check their accuracy against each other. Both are set to the same station, and the readings must be within 4 degrees of one another. This counts as a valid VOR accuracy check for instrument flying.

Full Definition

An accuracy check performed on an aircraft equipped with two independent VOR receivers, in which both receivers are tuned to the same VOR ground station and the bearing to that station is read on each. The two indicated bearings must agree within 4 degrees of each other for the system to be considered legal for IFR use. The check must be logged with the date, place, bearing error, and pilot signature.

Context Anchor

Used when verifying VOR receiver accuracy, especially before using VOR for instrument flying.