Probably an a.net topic but I thought one of you might be able to shed some light on this. On UA 205 IAD-SFO last night our pilot asked approach to relay to tower that we would be on "auto-land". Both approach and later the tower noted that "ILS critical areas are not protected".

I assume the former just means something along of the lines of that we landed on autopilot (which was close to perfect, by the way). What's the deal with 'critical areas' though? And why might a pilot choose to autoland? Thanks.

D