What must be done during the pre-flight VOR check?

During the pre-flight VOR check, confirming that the VOR (VHF Omnidirectional Range) system is operational and within tolerances is vital for ensuring navigational accuracy. This involves verifying that the VOR receiver is correctly receiving signals and providing accurate information to the pilot. The standard tolerances for a VOR check are that the indicated VOR radial must be within 4 degrees of the ground station radial when checked on the ground, or within 6 degrees when checked in flight. This step is crucial because pilots rely on VOR for course guidance, and any malfunction or misalignment could lead to navigational errors and affect flight safety. The successful completion of this check ensures that the navigation equipment is functioning properly before departure.