If GPS fails and RNAV-only approaches are available at the destination, what should the pilot consider?

If GPS fails and RNAV-only approaches are available at the destination, what should the pilot consider?

• A. Diversion
• B. Continue to destination with RNAV-only approach
• C. Switch to VOR approach
• D. Delay until GPS returns

Answer: (A)

The key idea is that RNAV approaches rely on GNSS, typically GPS, to provide the required lateral navigation guidance and to define the final approach path. If GPS fails, you cannot fly RNAV-only procedures. In this scenario the destination airport has RNAV-only approaches published, which means there isn’t a conventional non-GNSS approach (like a VOR/DME or NDB approach) available to land there. With the GPS outage, those RNAV procedures cannot be used, so continuing to land at that airport isn’t feasible. Given that limitation, the prudent and safe option is to divert to a suitable alternate where a non-GNSS approach is available or where a conventional procedure can be used without GPS. Delaying until GPS returns isn’t reliable or timely, and attempting to press on to land using an RNAV procedure would not be permitted without GNSS. Switching to a VOR approach at the destination isn’t applicable here if the RNAV-only approaches are the published option and no non-GNSS approach exists. Diversion, therefore, is the appropriate course of action.

The key idea is that RNAV approaches rely on GNSS, typically GPS, to provide the required lateral navigation guidance and to define the final approach path. If GPS fails, you cannot fly RNAV-only procedures. In this scenario the destination airport has RNAV-only approaches published, which means there isn’t a conventional non-GNSS approach (like a VOR/DME or NDB approach) available to land there. With the GPS outage, those RNAV procedures cannot be used, so continuing to land at that airport isn’t feasible.

Given that limitation, the prudent and safe option is to divert to a suitable alternate where a non-GNSS approach is available or where a conventional procedure can be used without GPS. Delaying until GPS returns isn’t reliable or timely, and attempting to press on to land using an RNAV procedure would not be permitted without GNSS. Switching to a VOR approach at the destination isn’t applicable here if the RNAV-only approaches are the published option and no non-GNSS approach exists. Diversion, therefore, is the appropriate course of action.