What should you do to check dual VOR receivers without a test facility?

Setting both VOR receivers to the same VOR facility is the correct method for checking dual VOR receivers without a test facility. This approach allows you to compare the outputs of the two receivers directly against each other. Since both receivers are tuned to the same VOR, you can easily observe whether they are providing the same bearing indication. If the readings differ significantly, it indicates that one of the receivers may be malfunctioning, thus requiring further investigation or maintenance.

This method is essential because VOR systems have specific tolerances, and ensuring that both receivers agree within those tolerances confirms that they are functioning properly. The practice helps pilots maintain situational awareness and ensures that navigational equipment is reliable and accurate during flight.

Other methods, such as using different VOR facilities or checking one receiver at a time, do not provide the same level of direct comparison needed to assess the accuracy and reliability of dual VOR systems. Using a handheld VOR receiver could add unnecessary complexity and isn't considered a standard method for this specific check.