Refer to figures.
Final approach segment (FAS). That segment of an instrument approach procedure in which alignment and descent for landing are accomplished. The final approach segment begins at the Final Approach Point (FAP) for precision approaches, or at the Final Approach Fix (FAF) for non-precision approaches.

LNAV only is a non-precision approach (similar to a VOR approach) using GNSS. The final segment of such approach begins at the Final Approach Fix (FAF). Jeppesen charts use the symbol shown on the figure to idicate the FAF. At the specified approach procedure, the FAF is the AI locator.