If GPS is lost, which is NOT listed as a navigation backup method?

If GPS is lost, which is NOT listed as a navigation backup method?

• A. Radar
• B. VOR
• C. DME
• D. INS

Answer: (A)

When GPS is unavailable, pilots switch to non-GNSS navigation methods. VOR and DME are ground-based aids that give angular and distance information to determine your position along airways. INS (inertial navigation system) uses onboard sensors to track movement and compute position without external signals, though it may drift over time. Radar, however, is a surveillance tool used by ATC to see and guide aircraft; it does not provide the pilot with a self-contained method to determine position. Therefore radar is not considered a navigation backup method for the pilot.

When GPS is unavailable, pilots switch to non-GNSS navigation methods. VOR and DME are ground-based aids that give angular and distance information to determine your position along airways. INS (inertial navigation system) uses onboard sensors to track movement and compute position without external signals, though it may drift over time. Radar, however, is a surveillance tool used by ATC to see and guide aircraft; it does not provide the pilot with a self-contained method to determine position. Therefore radar is not considered a navigation backup method for the pilot.