Under the GPS Approach Overlay Program, which procedures are excluded?

• A. LOC, LDA, and SDF procedures
• B. ILS procedures
• C. VOR procedures
• D. RNAV (GPS) procedures

Answer: (A)

The GPS Approach Overlay Program lets you fly the final approach segment of certain conventional procedures using GPS guidance, while preserving the published path and minimums. Not all procedures are eligible for this overlay, though. Localizer-based approaches—those defined by a localizer signal and labeled as LOC, LDA, or SDF—are excluded from the overlay option. These approaches rely entirely on a ground-based localizer (and, for SDF, a for-warding localizer-type signal), and converting them to a GPS overlay would complicate the procedure design and could risk obstacle clearance. Because of that, they aren’t eligible for GPS overlay. Other procedures, such as those that already involve GPS guidance or are based on non-localizer navaids (like VOR or RNAV/GPS approaches), can be overlaid under the program.