In the absence of RAIM when preparing for a GPS approach, what should the pilot do?

When preparing for a GPS approach, the absence of RAIM (Receiver Autonomous Integrity Monitoring) indicates that the GPS system is unable to guarantee the integrity of the navigation information it provides. In this scenario, selecting another type of approach that utilizes a different navigation aid is the most prudent action.

This approach ensures safety by relying on a more established and potentially more reliable navigation method, which could include traditional aids like VOR or NDB, instead of risking an approach based on GPS data that may not be dependable without the integrity checks provided by RAIM.

While continuing to the missed approach point (MAP) or holding while waiting for satellite reception might seem like a reasonable plan to maintain the approach, it does not address the underlying issue of insufficient RAIM availability for the GPS system. Similarly, holding at the Initial Approach Fix (IAF) or changing to a different flight plan may not provide a safe and effective alternative if navigation security is in question. Choosing a different type of approach ensures that the pilot has a viable navigation solution to proceed safely, prioritizing safety and adherence to regulations.