BAe 146
Having flown "them", I doubt that the air-brake is the problem being referred to: it is an extremely robust and effective system, the chances of it becoming "gummed up" are as close to zero as makes no odds.
The post might be an oblique reference to the fixed tailplane and elevators: one issue was re-hydration and subsequent freezing of de-icing residues, the fix was inspection and removal of residues after the use of type IV fluid.
The second was the accumulation of water in the elevators themselves due blocked drainage paths, this was subject to an AD which increased the number and diameter of drain holes, operators also included a 10 second draining period in the "full and free movement" part of the before takeoff checklist.
Last edited by Jetdriver; 25th Jun 2012 at 17:32.