What does the completion of a GPS approach require?

The completion of a GPS approach requires valid GPS signals and the aircraft being in the appropriate approach mode. This ensures that the aircraft can accurately navigate to the approach waypoints and execute the descent and landing procedures dictated by the GPS approach.

Valid GPS signals are crucial because they provide the necessary positional information to determine the aircraft's course, distance to the waypoints, and to guide the autopilot or the pilot during the approach. Additionally, being in the correct approach mode activates the aircraft’s navigation systems to follow the predefined lateral and vertical paths of the approach procedure.

While continuous monitoring of WAAS (Wide Area Augmentation System) and other systems might enhance the precision of the GPS approach, the primary requirement for legally and safely completing the approach rests on having valid GPS signals and being in the correct approach mode. Clear visibility and altitude checks, though important for overall situational awareness and safety, are not strictly mandated for the GPS approach itself.