When is the use of RAIM generally recommended?

The use of RAIM, or Receiver Autonomous Integrity Monitoring, is generally recommended during any IFR flight using GPS. RAIM is a critical feature in GPS navigation that helps ensure the integrity of the GPS signals being received. It monitors the satellite signals to detect and alert the pilot to any potential errors in positional information that could jeopardize the safety of the navigation.

When flying under IFR (Instrument Flight Rules), the reliability and accuracy of navigation systems are paramount, especially in controlled airspace where precise tracking and location are required for safety and compliance with air traffic control. GPS can be a reliable source of navigation during IFR flights, but its integrity must be verified, which is where RAIM comes into play.

RAIM checks the consistency of the signals received from multiple satellites to determine whether the GPS position is trustworthy. If a fault is detected, RAIM will provide an alert to the pilot, allowing them to take appropriate action, such as switching to an alternative navigation source. This ensures that pilots can have confidence in the navigation data they rely on when flying in challenging conditions where maintaining situational awareness is critical.

Other options, while they may mention circumstances concerning vertical separation, controlled airspace, or visual flight rules, do not capture the comprehensive necessity of RAIM