A319
Flight Crew Air Transport Pilot (ATP)
Flight Crew Last 90 Days 256; Flight Crew Total 15025; Flight Crew Type 5400
Aircraft Equipment Problem Critical; Deviation - Track / Heading All Types
Flight Crew Landed As Precaution; Flight Crew Returned To Departure Airport; General Declared Emergency; General Maintenance Action
Aircraft
Normal taxi out and takeoff.  The First Officer was the flying pilot.  Captain checked in with Departure and read back a turn to heading 230.  Dialed 230 into the MCP heading window.  Heard the First Officer over radio chatter call to take priority.  Did so and locked out side stick on the First Officers side.  Landed safely over weight.  Emergency declared to get the longest runway.
I was flying. On climbout; I engaged AP1 and maintained runway heading. Soon after; we received a vector to heading 230. The heading knob was unresponsive; so I disconnedted the AP and used the stick to turn. The airplane did not turn. I called 'take priority' and the Captain did so; locking me out. We returned for a landing; which was uneventful.
A319 Flight Crew experiences autopilot and side stick controller anomalies during climb out.  The autopilot is unresponsive to MCP heading inputs nor does the First Officer's side stick controller have any effect after the autopilot is disconnected.  Control is passed to the Captain and flight returns to departure airport for an uneventful over weight landing.