What is the response required by a pilot once they lose GPS signal during an RNAV approach?

When a pilot loses GPS signal during an RNAV approach, the appropriate response is to immediately follow the missed approach procedure. This is crucial because RNAV approaches rely on GPS for lateral guidance and precise navigation to the runway. Loss of GPS signal means the aircraft could deviate from the intended flight path, increasing the risk of a collision with obstacles or failing to reach the runway safely.

Executing the missed approach procedure provides a structured and safe method for the pilot to navigate away from the approach path and reposition for a subsequent approach or alternative landing. This procedure is designed to ensure safety and maintain operational integrity, allowing the pilot to safely manage the flight under unexpected circumstances caused by the loss of navigation data.

In this context, performing a go-around is not necessarily correct since a go-around involves executing a climb to a safe altitude and circling back to approach again, but does not directly address the need to navigate away safely when GPS becomes unavailable. Similarly, flying to the next waypoint or attempting to re-establish GPS signal may not be viable or safe options when the aircraft is already in an approach phase without appropriate lateral guidance. The missed approach procedure provides clear guidelines on how to handle the situation safely and effectively, which is why that response is the correct one.