Definition
A required accuracy check of an aircraft's VOR (Very High Frequency Omnidirectional Range) navigation receiver, performed and logged within the preceding 30 days before any flight under instrument flight rules that uses VOR for navigation. The check confirms the receiver's bearing indication is within allowable tolerance, using one of the FAA-approved methods: a VOT (VOR test facility), a designated ground or airborne checkpoint, a dual-VOR cross-check, or a check over a known landmark on a published airway. Tolerances vary by method (commonly ±4° for ground checks and ±6° for airborne checks). The pilot must record the date, place, bearing error, and signature in the aircraft logbook or other reliable record.
Plain English
A test the pilot does to make sure the aircraft's VOR navigation radio is showing the correct bearing before flying on instruments. It must be done within the last 30 days, and the result must be written down.
Context Anchor
Encountered during instrument preflight planning, especially when the route or approach depends on VOR navigation.
Derivation
VOR stands for Very High Frequency Omnidirectional Range. “Omnidirectional” means the station provides direction information all around it, which helps explain why the check is about whether your receiver shows the correct direction from that station.
Why Pilots Care
Confirms that navigation signals can be trusted, reducing the risk of heading or course errors once airborne in instrument conditions.
Intuition Check
A VOR system check is not just glancing at the instrument to see that it is turned on. It is a specific accuracy check against an approved reference, and the result must be recorded.
Example Sentence 1
Before filing the IFR flight plan, she confirmed the last VOR system check was logged 12 days ago and still valid.
Example Sentence 2
The VOR system check showed an out-of-tolerance error, so the pilot elected to troubleshoot the receiver before accepting the IFR clearance.