"They don't seem to work on landing if I switch them on a long time before landing. What I do is this: I switch the autobrake to #3 once I am on approach. Flaps are at least 15o and speed is 200 KIAS or below."

Ok, have done some flights and sometimes it works and sometimes it doesn't work. Is this a bug? Why i can't switch them? I can brake manually but in bad weather i need the autobrake.  :-?

Chris