A 320 Flight Management Function

[Boyington]

In the Limitations section of the FCOM, it is stated that FMGS Lateral and Vertical guidance is certified for Instrument Approach procedures except ILS, LOC , LOC BC , GLS etc. What does this mean?

[Flaps0]

In the Limitations section of the FCOM, it is stated that FMGS Lateral and Vertical guidance is certified for Instrument Approach procedures except ILS, LOC , LOC BC , GLS etc. What does this mean?


It is certified for RNAV/RNP approaches, and VOR and NDB Overlay approaches.

[pattern_is_full]

Put another way, the "FMGS lateral and Vertical guidance" is non-precision. You can use it for published RNAV/RNP approaches, you can use it to program/simulate/overlay with other published non-precision approaches (VOR and NDB).

But you cannot (or should not) use it for published precision approaches (ILS, LOC, etc.) - not accurate enough (yet). Skip the RNAV/VNAV, fly the real radio guidance beams (NAV 1 radio).

[FE Hoppy]

You can't fly an "overlay" on a localiser approach. Primary nav source has to be the localiser. And it can't do GBAS.