FMS-based instrument approaches must comply with what?

FMS-based instrument approaches must comply with approved instrument approach procedures from the FMS-3000 database because these procedures are specifically designed to work with the flight management system (FMS). The FMS-3000 database contains information that is essential for properly executing instrument approaches, including waypoints, altitudes, and specific flight paths that are required for safe operations.

This compliance ensures that the pilots are following standardized, reliable procedures that have been validated for use with the FMS, thereby enhancing safety and efficiency during instrument approaches. Using approved procedures also helps prevent navigation errors and misunderstandings that could arise if non-standard approaches were attempted.

In contrast, the other options do not pertain directly to the operational requirements of FMS-based approaches specifically. Standard visual flight rules, altitude restrictions from ATC, and general aviation practices may involve broader parameters for flight operations but do not specifically address the critical need for adherence to the validated procedures in the FMS database.