What was found
(CAN) THE PLASTIC COVER UNDER THE PILOT SEAT THAT PROTECTS THE AILERON PULLEY AND CABLE WAS DAMAGED. THE AIRCRAFT HIT SOME TURBULENCE AND A SMALL ROCK CAME OFF THE FLOOR AND DOWN INTO THE PULLEY BETWEEN THE CABLE AND PULLEY JAMMING THE CONTROL. AIRCRAFT MADE A SAFE LANDING WITH AILERON CONTROLS JAMMED IN NEUTRAL POSITION. MAINTENANCE MADE UP AN ALUMINIUM COER TO REPLACE THE PLASTIC ONE. AIRCRAFT RETURNED TO SERVICE.