A320
Flight Crew Air Transport Pilot (ATP)
Flight Crew Last 90 Days 180; Flight Crew Total 20000; Flight Crew Type 1100
Aircraft Equipment Problem Critical
Flight Crew Landed in Emergency Condition; Flight Crew Returned To Departure Airport; General Declared Emergency; General Maintenance Action
Aircraft
Climbing out with autopilot engaged.  We notice airplane was flying in a slight left bank.  We analyzed the problem; fuel balanced; engine parameters all normal.  Flight control page showed right aileron full down. Rudder trim indicated 1.5 to 3.5 right.  Stopped climb at FL270 and slowed to 280 knots.  Contacted Dispatch and Maintenance Control.  We concluded the best course of action was to return.  On descent we experienced a jolt as right aileron returned to normal deflection; followed by right aileron returning to full down deflection. Thinking flight controls were in deteriorating situation; we declared emergency and landed safely.
The reporter states that the handling qualities did not seem to be compromised in any way and the aircraft landed normally with full flaps.  He has not heard what actions by maintenance were necessary to return the aircraft to service; but did notice that it was still present 24 hours later.
A320 Captain reports noticing the aircraft is flying with the left wing slightly down during climb and the rudder trim is to the right.  The ECAM flight control page indicates the right aileron is deflected full down.  An emergency is declared and the flight returns safely to the departure airport.  During descent a jolt is felt as the aileron returns to its' normal position and quickly returns to the fully deflected position.