If RAIM capability is lost in flight, what is the pilot's assurance of GPS position?

• A. The pilot has assurance of GPS position accuracy
• B. The GPS position is guaranteed to be correct
• C. The pilot has no assurance of the accuracy of GPS position
• D. RAIM loss triggers GPS automatic correction

Answer: (C)

RAIM provides integrity monitoring for GPS by checking that the satellite signals and the navigation solution are trustworthy. When RAIM capability is lost, you can’t verify the GPS position’s accuracy, so there’s no assurance that the position you’re seeing is correct. In that situation you should not rely on GPS for navigation decisions that depend on precise position; instead, fall back to other navigation methods (dead reckoning, pilotage, known ground fixes, VOR/DME if available) and cross-check with those sources until RAIM becomes available again.