What was found
DURING FLIGHT, PILOT HEARD INCREASING "RUMBLING" NOISE. PILOT LANDED TO THE NEAREST LANDABLE SIDE APPROX 2 MIN AFTER THE NOISE STARTED. RUMBLING DECREASED SIMULTANEOUSLY WITH ENGINE LOAD. ENGINE CHIP CAUTION ILLUMINATED AT THE END. ENGINE HAS NOT BEEN RUN SINCE HELICOPTER LANDING. BOTH ENGINE MAGNETIC PLUGS WERE CHECKED. PASTE AND SMALL SILVER PARTICLES, NOT EXCEEDING .79 MM WERE FOUND ON UPPER AND LOWER PLUGS, R & R AND MM 72-00-00 11.G. OIL FILTER BOWL FOUND SEVERAL SILVER FLAKES AND SLIVERS EXCEEDING SIZE OF .79 MM LIMIT AND AMOUNT OF 4.