FAA Commercial Pilot Airplane (CAX)RegulationsMedium
A commercial pilot plans an IFR cross-country flight relying on VOR navigation. According to 14 CFR 91.171, the VOR equipment used must have been operationally checked, with results entered in the aircraft's log, within the preceding how many days?
- A14 days
- B30 days
- C90 days
- D60 days
Show answer & explanationAnswer & explanation
Correct answer: B. 30 days
14 CFR 91.171 requires that no person operate a civil aircraft under IFR using the VOR system unless the equipment has been operationally checked within the preceding 30 days and the results logged. Various check methods (VOT, ground checkpoint, airborne checkpoint, or dual VOR comparison) are permitted, each with specified tolerances.
Why the other options are wrong
- A. 14 days is too short and not the regulatory interval
- C. 90 days is far too long and not permitted
- D. 60 days exceeds the allowed interval
VOR Operational Check (91.171)
VOR equipment used for IFR navigation must be operationally checked within the preceding 30 days, with results logged.
- 30-day interval
- Acceptable methods: VOT, ground/airborne checkpoints, dual VOR comparison
- Must log date, place, error, and signature
Memory trick: 'VOR every thirty' keeps your compass true.