What was found
ROTORCRAFT EXPERIENCED A PARTIAL CYCLIC CONTROL FAILURE WHILE LANDING. PILOT WAS UNABLE TO ROLL LEFT USING CYCLIC INPUT. INVESTIGATION REVEALED THAT LATERAL TRIM ACTUATOR ASSEMBLY SHAFT, PN C585-1, HAD A STEP WORN IN IT WHICH ALLOWED THE TRIM ACTUATOR TO JAM. THREE ADDITIONAL AIRCRAFT INSPECTED REVEALED THE SAME PROBLEM. LATERAL TRIM ACTUATOR ASSEMBLY WAS REPLACED ON ALL 4 AIRCRAFT. SAFETY RECOMMENDATIONS SUBMITTED. AD 98-04-12 ISSUED TO INSPECT AND CORRECT THIS PROBLEM ON ALL R44 HELICOPTERS.