What was found
PILOT HEARD AN UNUSUAL GROWLING NOISE FROM THE NR 1 INPUT AT REDUCED POWER. A FEW HOURS LATER, A SLIGHT VIBRATION AT REDUCED POWER WAS FELT IN THE AIRFRAME. THE CHIP PLUG AND SCREEN WERE CHECKED AND A FEW SMALL SLIVERS WERE FOUND ON THE CHIP PLUG AND 12 SMALL FLAKES OF MAGNESIUM IN THE SCREEN. ON DISASSEMBLY OF GEAR BOX INPUT SECTION, NR 1 CAMSHAFT WAS FOUND BROKEN. INPUT CAMSHAFT IS BEING SENT TO A LAB FOR FRACTURE ANALYSIS. REF: OPER CONTROL NR JYER5329.