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.
Plain English
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.
Context Anchor
Used when verifying VOR receiver accuracy, especially before using VOR navigation for instrument flying.
Derivation
Dual comes from the Latin duo, meaning two. That helps here because the check depends on comparing two separate VOR receivers against the same signal.
Why Pilots Care
Confirms navigation data is reliable so the aircraft stays on the intended course and avoids position errors that could compromise safety.
Intuition Check
A dual VOR receiver check is not just confirming that two receivers are installed. It means comparing their actual navigation indications and making sure they are within the allowed 4-degree difference.
Example Sentence 1
Before the IFR flight, the pilot tuned both VOR receivers to the same station, compared the bearings, and logged the dual VOR receiver check showing 2 degrees of difference.
Example Sentence 2
Both receivers agreed within four degrees, satisfying the dual VOR receiver check requirement for the IFR flight.