What was found
SHORTLY AFTER TAKEOFF OF A TOUR FLIGHT, AT APPROX 9:40 AM, THE PILOT NOTICED THE ENGINE NG SPEED HUNTING AND THE TORQUE FLUCTUATING (LESS THAN 20 PERCENT), THE AC ALSO EXHIBITED SLIGHT YAWING IN CONJUNCTION WITH THE FLUCTUATING NG AND TORQUE. THE PILOT PERFORMED A LOW POWER PRECAUTIONARY LANDING AT AIRPORT. INSPECTION BY MAINTENANCE REVEALED NO DEFECTS WITH THE FCU RIGGING OR WITH THE FUEL FILTERING AND FUEL DELIVERY SYSTEM. A CHECK OF THE FCU WAS FOUND TO BE DEFECTIVE (THE FCU CHARACTERISTICS CHECKS FAILED). THE DEFECTIVE FCU WAS REMOVED AND SERVICEABLE UNIT INSTALLED. NO FURTHER DEFECTS HAVE OCCURRED. (K)