How should a crew respond to a GNSS loss of signal warning?

How should a crew respond to a GNSS loss of signal warning?

• A. Continue navigation as if GNSS is present while waiting for reacquisition.
• B. Switch to alternative nav (e.g., INS/IRS, VOR/DME, baro-VNAV) and follow procedures to maintain safe flight while re-acquiring GNSS.
• C. Immediately land at the nearest safe airport.
• D. Disable all avionics to conserve power.

Answer: (B)

When GNSS is lost, you must not rely on satellite navigation anymore and should switch to independent, backup guidance to keep the aircraft safely on course while you wait for GNSS to come back or for a re-check to succeed. The best action is to use alternative navigation sources—such as the inertial system for dead reckoning, VOR/DME for bearing and distance, and baro-VNAV for vertical guidance—and follow the published procedures to maintain safe flight during reacquisition. This approach preserves situational awareness, provides continuous position and path information, and supports ongoing flight planning and ATC separation without depending on GPS. Continuing to navigate as if GNSS is present risks building or following an incorrect position if the signal is degraded or reacquisition is delayed. Landing immediately at the nearest safe airport is not required unless you have no viable backup navigation or a different emergency dictates it. Disabling all avionics would remove critical navigation and safety systems, which is not appropriate during a GNSS loss.

When GNSS is lost, you must not rely on satellite navigation anymore and should switch to independent, backup guidance to keep the aircraft safely on course while you wait for GNSS to come back or for a re-check to succeed. The best action is to use alternative navigation sources—such as the inertial system for dead reckoning, VOR/DME for bearing and distance, and baro-VNAV for vertical guidance—and follow the published procedures to maintain safe flight during reacquisition. This approach preserves situational awareness, provides continuous position and path information, and supports ongoing flight planning and ATC separation without depending on GPS.

Continuing to navigate as if GNSS is present risks building or following an incorrect position if the signal is degraded or reacquisition is delayed. Landing immediately at the nearest safe airport is not required unless you have no viable backup navigation or a different emergency dictates it. Disabling all avionics would remove critical navigation and safety systems, which is not appropriate during a GNSS loss.