If you lose WAAS (Wide Area Augmentation System) capability during a GPS approach, what should you do?

When you lose WAAS capability during a GPS approach, the appropriate action is to hold LNAV minimums and go missed at the missed approach point (MAP). This is correct because WAAS provides enhanced accuracy and is used for approaches with LPV (Localizer Performance with Vertical guidance) minimums. If WAAS loses signal or fails, the approach then reverts to non-WAAS capabilities, which typically means you can only use LNAV (Lateral Navigation) minimums.

By holding LNAV minimums and proceeding to the MAP, you are following the appropriate protocol for handling a loss of WAAS. If you had proceeded to the missed approach point without change or switched to visual flight rules immediately, you'd be disregarding essential safety protocols for non-WAAS equipped approaches. Furthermore, landing without WAAS guidance would not be a safe option, especially if your initial approach was predicated on the precision that WAAS provides.