9.G said
Alright M2002, now tell me which distance do take in case there's only LDA beyond the GS published? Plenty of those around.
Well, as I-2021 said, according to Jepp, threshold distance is depicted only if it there is a restriction (displaced threshold and the like, I assume). So I will use the full distance shown in 10-9 in those cases where there is no restriction. Someone here also pointed out that in their OM it is specified to do it that way.
In any case, I can only compare performance calculated from 50 ft with LDA from the threshold (and again, still remains the question of those extra feet of the TCH above 50 ft?).
My FCOM, as most of FCOMs, gives me distances from 50 ft. Beyond glide slope distances are simply useless for me. Its like mixing ēK and ēC. They are the same but referred to different datums.
By the way, 9G, How do you calculate if your landing distance is OK for a given runway? What do you use?