What should a pilot do if they experience a vertical outage during a WAAS approach?

In the situation of a vertical outage during a WAAS approach, switching to a conventional approach procedure is the appropriate action. WAAS (Wide Area Augmentation System) enhances GPS signals to improve accuracy and integrity, which is critical during precision approaches. If a vertical outage occurs, this indicates a loss of the reliable vertical guidance that WAAS provides.

By transitioning to a conventional approach procedure, a pilot can utilize other navigation aids, such as VOR (VHF Omnidirectional Range) or ILS (Instrument Landing System), which do not rely on the GPS system. This ensures that the pilot can continue their approach with a known navigation system that is not affected by the WAAS outage.

The other responses, while they may seem valid under certain circumstances, do not provide the safest or most effective immediate action in response to a vertical outage. Continuing the approach as planned would be inappropriate because it assumes the guidance is still reliable. Alerting air traffic control or referring to the emergency procedures checklist could be important later, but the first step should naturally be transitioning to a standard procedure that doesn't depend on WAAS vertical guidance to maintain operational safety.