What is required for GPS instrument approaches?

In GPS instrument approaches, one significant requirement is the availability of RAIM (Receiver Autonomous Integrity Monitoring) by the Final Approach Fix. RAIM is a critical function that ensures the integrity and accuracy of the GPS signal being used to navigate. It performs checks on the satellite signal to confirm that the user is receiving reliable data before proceeding with the approach. This is vital for maintaining safety during the approach, especially since GPS systems rely heavily on satellite signals for navigation.

Without RAIM availability, pilots may face risks of navigating with unreliable information, which can lead to incorrect positioning and hazardous situations during critical phases of flight like the approach and landing. Therefore, having RAIM monitoring confirmed before reaching the Final Approach Fix is essential to ensure that the GPS system can be trusted for the precision required during these phases of flight.

The other options do not encapsulate the necessary requirements for conducting a GPS instrument approach with the same level of rigor and safety. For example, while manual verification of waypoints and standard GPS tracking might seem important, they do not directly ensure the integrity of the navigation information being used at critical points in the approach. Additionally, needing a special authorization from the FAA is not a standard requirement for all GPS approaches, further highlighting the significance of RAIM as