Quote:

I switch the autobrake to #3 once I am on approach. Flaps are at least 15o and speed is 200 KIAS or below.

This way works for me every time. It is the only way I have found to get the Autobrakes to work when I land.

Are you using rudder pedals with brakes included (CH or Saitek)? If yes, then maybe you are touching the brakes accidentally, which will turn the autobrakes off. I'll have to check if this can happen in-flight like it does on the the ground.

Mark