What are the VOR check tolerances for Ground VOT/VOR, Dual VOR, and Airborne checks?

What are the VOR check tolerances for Ground VOT/VOR, Dual VOR, and Airborne checks?

• A. Ground VOT/VOR ±4, Dual VOR ±4, Airborne ±6
• B. Ground VOT/VOR ±5, Dual VOR ±5, Airborne ±7
• C. Ground VOT/VOR ±3, Dual VOR ±3, Airborne ±5
• D. Ground VOT/VOR ±6, Dual VOR ±6, Airborne ±8

Answer: (D)

VOR check tolerances are guidelines for how far a measured bearing may deviate from the known reference and still be considered acceptable. The amount of allowable error depends on how the check is performed because different methods have different levels of precision and environmental influence. For a ground check using VOT or VOR, the reference signal is stable and the measurement is made in a controlled, fixed setup. The tolerance is set to six degrees to reflect that level of precision in a ground-based verification. When you perform a dual VOR check, you’re comparing two independent VOR receivers to see how closely their indications line up. The same six-degree allowance applies, as it accounts for typical instrument and installation variances you might encounter with two receivers. In the airborne scenario, the verification happens in flight and must contend with changing aircraft attitude, antenna patterns, multipath, and signal geometry. Because of these practical uncertainties, the tolerance is widened to eight degrees to still guarantee usable navigation guidance while acknowledging the more challenging environment. So, grounded checks and dual-receiver checks are allowed up to six degrees of error, while airborne checks allow up to eight degrees.

VOR check tolerances are guidelines for how far a measured bearing may deviate from the known reference and still be considered acceptable. The amount of allowable error depends on how the check is performed because different methods have different levels of precision and environmental influence.

For a ground check using VOT or VOR, the reference signal is stable and the measurement is made in a controlled, fixed setup. The tolerance is set to six degrees to reflect that level of precision in a ground-based verification.

When you perform a dual VOR check, you’re comparing two independent VOR receivers to see how closely their indications line up. The same six-degree allowance applies, as it accounts for typical instrument and installation variances you might encounter with two receivers.

In the airborne scenario, the verification happens in flight and must contend with changing aircraft attitude, antenna patterns, multipath, and signal geometry. Because of these practical uncertainties, the tolerance is widened to eight degrees to still guarantee usable navigation guidance while acknowledging the more challenging environment.

So, grounded checks and dual-receiver checks are allowed up to six degrees of error, while airborne checks allow up to eight degrees.