What is the maximum allowable error for VORs in the air?

The maximum allowable error for VORs (VHF Omnidirectional Range) during flight is plus or minus 6 degrees. This standard is established to ensure that pilots receive accurate navigational information while in the air, as VOR systems are a primary means of navigation for IFR (Instrument Flight Rules) operations.

The 6-degree tolerance allows for some margin of error but maintains a level of precision necessary for safe navigation in controlled airspace. This means when a pilot tunes into a VOR, they can expect the bearing indicated by the VOR to be within 6 degrees of the actual magnetic heading to or from the station. If a VOR is found to have an error greater than this threshold during operational checks, it must be corrected or turned off before further use.

This standard helps in flight planning and navigation as pilots can rely on the VOR system to provide reasonably accurate directional data, facilitating safe route navigation and ensuring compliance with air traffic control directives.