What was found
TWO MINUTES AFTER TAKEOFF, POWER DECREASED TO 20 - 40 PERCENT OF NORMAL ON NR 1 ENGINE. RETURNED FOR PRECAUTIONARY LANDING. ENGINE APPEARED TO FUNCTION NORMALLY BELOW 50 PERCENT TORQUE, ABOVE 50 PERCENT, TORQUE WOULD DECREASE. NO FURTHER INCIDENT OCCURRED. AIRCRAFT SHUT DOWN. ELECTRICAL CONNECTIONS CHECKED. OPERATIONAL CHECK FLIGHT PERFORMED AND RETURNED TO SERVICE.