What was found
M/R MAST WAS REPLACED 4 HOURS PREVIOUSLY. PILOT HAD A TRANSMISSION CHIP LIGHT AND NOTIFIED TOWER OF LANDING DUE TO A MX PROBLEM. ENGINEER INSPECTED F/W, TRANSMISSION, AND MAST CHIP DETECTORS. FOUND HAIR LIKE SLIVER ON THE UPPER MAST BRG CHIP DETECTOR AND ON THE TRANSMISSION OIL MONITOR, AS PER BELL 206L-1 CHIP DETECTOR GUIDE C/O INSPECTION AS REQUIRED, C/O OPERATIONAL CHECK AND 20 MIN GROUND RUN AS PER BELL 206L-1 MM. CHECK CHIP DETECTORS, OIL REPLACED, FILTER INSPECTED AND REPLACED AND ANOTHER OPERATIONAL CHECK C/O. SLIVERS MAY HAVE BEEN FROM MAST INSPECTION OR OIL CANS? SOURCE UNKNOWN. AIRCRAFT RETURNED TO SERVICE WITH A SATISFACTORY TEST FLIGHT.