What was found
AIRCRAFT LEVEL FLIGHT - FL 350. ON ITS OWN, ENGINE WENT TO AN OVERSPEED CONDITION OF 105 PERCENT (103 PERCENT MAX ALLOWABLE). THROTTLE MOVEMENT HAD NO AFFECT. NORMAL THROTTLE CONTROL REGAINED ON DESCENT OUT OF FL 300. LANDING UNEVENTFUL. MANDATORY ENGINE OVERHAUL REQUIRED BY MFG. SUSPECTED ENGINE COMPUTER (DEEC). NO EVALUATION OR CAUSE IDENTIFIED. LOANER ENGINE WITH REPLACEMENT DEEC HAS WORKED NORMALLY.