What was found
DURING POST MAINTENANCE VISIT ACCEPTANCE FLIGHT, DURING FLIGHT CONTROL CHECK IN EXCESS OF 250 KTS, FOUND LT RUDDER HAD NO EFFECT WHEN DEPRESSED FULLY - EITHER WITH POWER ON OR OFF. FULL RUDDER TRIM HAD NO EFFECT DEFLECTED LEFT. RT RUDDER CHECK AND TRIM OPERATED NORMAL. LT RUDDER BECAME FULLY OPERATIONAL WHILE DECELERATING FOR LANDING. ADJUSTED RUDDER HYD POWER PACK PISTON IAW AMM 27-20-08. OPS CK GOOD ON GROUND AND DURING SUBSEQUENT ACCEPTANCE FLIGHT.