Wasn't aware I had to advise the passengers whenever I decide to use a flight control system for speed or height control. Typically when speed brakes are deployed it's a busy time in the cockpit and talking to the cabin can cause an unnecessary distraction to the pilots. In addition most airlines do not allow PA's from the cockpit below 10000', again a safety issue. So for those of you who are alarmed by the use of speed brakes be glad they are not used all the time and remember if there is a problem we will let you know.
