If Receiver Autonomous Integrity Monitoring (RAIM) is not available prior to beginning a GPS approach, what should the pilot do?

Using a navigation system other than GPS is the correct approach when Receiver Autonomous Integrity Monitoring (RAIM) is not available prior to beginning a GPS approach. RAIM is essential for ensuring that the GPS signals being used are reliable and accurate. Without RAIM, the integrity of the GPS solution is compromised, posing risks during the approach and landing phases. By utilizing a different navigation system, the pilot ensures that they have access to reliable and verifiable route information, which is critical for safe operation, particularly in situations where precision is required.

In this scenario, relying solely on GPS without integrity monitoring could lead to navigation errors. Alternative systems such as VOR (VHF Omnidirectional Range) or NDB (Non-Directional Beacon) can provide an additional level of assurance and safety. This decision safeguards the pilot's ability to navigate accurately and safely in conditions that demand precise navigation capabilities.