What is the identification protocol when a VORTAC is undergoing routine maintenance and is considered unreliable?

The identification protocol for a VORTAC that is undergoing routine maintenance and is deemed unreliable involves the removal of the identifier. When a VORTAC is not operational or is undergoing maintenance, it is essential to eliminate any potential confusion for pilots and air traffic controllers who rely on that navigation signal. By removing the identifier, it becomes clear that the station is not providing valid navigation information, helping to ensure safety in the airspace.

This approach prevents any possibility of misinterpretation where pilots might think they are receiving navigational guidance from that VORTAC, thus reducing the risk of navigation errors. It is important for operational integrity that facilities clearly indicate when a navigational aid is not usable, which is why removing the identifier is the optimal protocol in such cases.

The other options suggest various signals or indications that might lead to confusion or miscommunication, which would be counterproductive when a VORTAC is not reliable for navigation.