Also as regards CAT1, our SOPs call for Gear down/F15 at glideslope alive on a CAT3 approach, however our normal approach would be low drag and gear down at 4-5nm. I've heard various reasons, but is there a technical reason why you cant do a low drag approach in a coupled CAT3
Just about all equip. interperates loc/gs at higher sensitivities the closer you get to land/rollout. A high drag approach allows for better capture and loc/gs maintanance to avoid "no autoland" warnings or A/P disconnects. I believe reliability is the bottom line.