What is required for an alternate airport when using GPS for navigation and instrument approaches?

When planning to use GPS for navigation and instrument approaches, it is necessary to have an alternate airport that has an approved operational instrument approach procedure that is not solely reliant on GPS. This requirement ensures that in the event of an emergency or if conditions deteriorate at the primary airport, the aircraft can safely divert to an alternate that offers a reliable means of approach, especially in weather conditions that warrant instrument flight rules.

Using an approved alternative approach procedure—such as an instrument landing system (ILS), VOR, or other radar-based systems—provides assurance that pilots have multiple navigational aids to help them safely land even if GPS reception is compromised. This redundancy is critical for maintaining safety in flight operations, particularly when navigating under instrument flight rules.

In contrast, the other options either suggest inadequate safety measures or do not align with the regulatory requirements for flight planning. Reliance on a singular GPS approach, VFR procedures, or the absence of specific approach requirements would not provide the necessary safety protocol for instrument navigation and could lead to unsafe situations.