What was found
(CAN) ENGINE NR 1 CHIP DETECTOR CAUTION LIGHT ILLUMINATED WHILE IN CRUISE FLIGHT AND PILOT RETURNED TO BASE. REDUCTION GEARBOX NR 1 SIDE CHIP DETECTOR FOUND WITH SMALL AMOUNT OF METAL. CHIP DETECTOR WAS CLEANED AND AIRCRAFT FLEW ANOTHER 2 HOURS BEFORE SECOND CHIP LIGHT AND RETURNED TO BASE. SLIGHTLY MORE METAL FOUND ON PLUG. OIL WAS CHANGED AND AIRCRAFT WAS GROUND RUN 1 MINUTE BEFORE CHIP LIGHT ILLUMINATED. CHIP DETECTOR AND OIL FILTER CONTAINED MASSIVE AMOUNT OF METAL. REDUCTION GEARBOX WAS REPLACED AND SENT TO MFG FOR INVESTIGATION. NO REPORT HAS BEEN ISSUED AS YET. (TC NR 20070227015)