What equipment is necessary for filing an alternate airport that only has GPS approaches?

The requirement for filing an alternate airport that has only GPS approaches hinges on the equipment available on the aircraft. In this case, a Wide Area Augmentation System (WAAS) equipped GPS receiver is necessary because WAAS provides improved accuracy, integrity, and availability of GPS signals that are crucial for conducting approaches at airports relying solely on GPS.

WAAS enhances the standard GPS by correcting signal errors and providing better vertical guidance, which is essential when performing an instrument approach. In the case of alternate airports using GPS approaches, regulations stipulate that the aircraft must be equipped with a WAAS capable of meeting the stringent accuracy requirements for the approach procedures. Therefore, pilots planning to use such an airport must ensure their equipment can support the necessary approaches, making the WAAS equipped GPS the correct choice for this scenario.