Plain English Meaning

Before flying on instruments using VOR, the pilot must test the VOR equipment to make sure it is pointing accurately. There are several approved ways to do this, and the result has to be written down with the date, location, error found, and the pilot's signature.

Full Definition

A pre-departure verification of an aircraft's VOR receiver to confirm it is displaying course information within allowable tolerance. Required by 14 CFR 91.171 for flight under IFR using VOR navigation, the check must be performed within the preceding 30 days using one of several approved methods: a VOT (VOR Test Facility), a designated ground or airborne checkpoint, comparison between dual VOR receivers, or a check against a published airway. Permitted error varies by method, generally ±4° for ground checks and ±6° for airborne checks. The date, place, , and 's signature must be entered in the or other reliable record.