When using GPS for navigation and instrument approaches, what requirement must be met regarding alternate airports?

When utilizing GPS for navigation and instrument approaches, the key requirement for alternate airports is that they must have an approved operational instrument approach procedure that is not dependent solely on GPS. This is crucial because GPS can be susceptible to various factors such as signal degradation or unavailability due to atmospheric conditions, interference, or system outages. Therefore, having an alternative approach method ensures that, in case of GPS failure, the aircraft can still safely execute an approach and landing at the alternate airport using conventional navigational aids.

The necessity of having other instrument approach procedures bolsters the safety of the flight, ensuring redundancy in navigation options. This requirement highlights the importance of a reliable backup navigation system in the event of a technology-dependent failure.