During an RNAV approach, the loss of GPS indicates what necessary action?

When conducting an RNAV approach, the loss of GPS signals means that the aircraft can no longer accurately determine its position or track towards the runway. In such a scenario, the appropriate action is to initiate missed approach procedures. This is crucial because the missed approach is designed to ensure safety by providing a predefined route for the pilot to follow if the approach cannot be completed. It helps prevent potential dangerous situations that could arise from attempting to continue the approach without reliable navigation data.

Maintaining the approach in the absence of GPS could lead to an unsafe landing situation, especially if the pilot is unsure of their exact position relative to the runway. Therefore, following the established missed approach procedures ensures that the pilot has a safe and structured way to handle the situation and return to a safe altitude and navigation track.