When a pilot reports a NAVAID is NOT operating properly, what should a controller do?

When a pilot reports that a NAVAID (Navigational Aid) is not operating properly, the most appropriate action for a controller is to request a second aircraft to monitor the NAVAID. This step is crucial as it provides an additional check on the status of the navigational aid. By getting feedback from another aircraft, the controller can better ascertain the reliability of the NAVAID and take necessary actions, possibly leading to informing other pilots about the issue or adjusting their flight paths accordingly.

Having a second aircraft monitor the NAVAID aids in determining whether the problem is widespread and can significantly enhance safety by preventing further incidents related to navigation errors. This collective information contributes to a more comprehensive understanding of the situation, allowing for informed decision-making regarding the operations of all aircraft in the vicinity.

While adjusting an aircraft's course or telling a pilot to proceed with caution might seem like plausible actions, they do not directly address the need for verification of the NAVAID's status. Additionally, informing the pilot of all NAVAIDs doesn't resolve the immediate issue reported and might overwhelm the pilot with unnecessary information during a critical moment.