Originally Posted by
vilas
LOC* doesn't activate APP phase but the overflying the D in NAV mode does it and LOC* is also taken as NAV. If flight plan is not sequenced LOC will be captured without activation of approach phase.
That sounds like the proper explanation.
Assuming vectors, i.e. HDG lateral mode: Clear the unnecessary waypoints with or without using the DCT-TO (rad-in), but continue on HDG. Joining LOC* the FMGS starts looking for the DECEL - again - (already past) and APCH phase gets activated.
When I first heard about it, it did not sound quite right. Background memories of LOC* definitely NOT saving me from no APCH phase.