On a GPS approach, what are the enroute and terminal CDI sensitivities?

• A. +/- 10 NM enroute, +/- 3 NM terminal
• B. +/- 5 NM (+/- 2 NM with RAIM) and +/- 1 NM
• C. +/- 3 NM enroute, +/- 0.5 NM terminal
• D. +/- 7 NM enroute, +/- 2 NM terminal

Answer: (B)

GPS approach CDI sensitivity defines how much lateral deviation the indicator tolerates on different segments. The enroute segment uses a broader sense of tolerance: typically plus or minus 5 nautical miles, and if RAIM (Receiver Autonomous Integrity Monitoring) is available, that tolerance can be narrowed to plus or minus 2 nautical miles. The terminal segment uses a tighter tolerance: plus or minus 1 nautical mile. The other options don’t match these standard values. So the correct combination is plus/minus 5 NM enroute (plus/minus 2 NM with RAIM) and plus/minus 1 NM terminal.