Air Canada A320 near Toronto on Jun 22nd 2014, airframe vibrations

An Air Canada A320-200, registration C-FDSN performing flight AC-696 from Toronto,ON to St. John's,NL (Canada) with 113 people on board, was climbing out of Toronto when the crew noticed unusual airframe vibrations. The crew contacted maintenance, then decided to stop the climb at FL220, declare PAN and return to Toronto, where the aircraft landed safely on runway 23 about 30 minutes after stopping the climb.

The Canadian TSB reported maintenance found the green servo actuator rod end for the rudder had excessive play and replaced the actuator. Subsequent testing also showed the rudder limitation unit centering spring rod was excessively loose, which could not be adjusted. The rudder limitation unit was replaced, too, then testing showed no further faults.