What was found
FOLLOWING THE ACCIDENT OF A BO105S, AN INVESTIGATION REVEALED THE SUN GEAR (PN 4638-304-001) IN THE MAIN ROTOR TRANSMISSION HAD FAILED. THE EXACT CAUSE OF THE FAILURE TO THIS SUN GEAR HAS NOT BEEN DETERMINED. THIS SAME SUN GEAR HAD BEEN IN THE MAIN ROTOR TRANSMISSION OF AN AIRCRAFT THAT WAS INVOLVED IN A CATASTROPHIC ACCIDENT WHERE THE AIRCRAFT HAD IMPACTED THE GROUND IN AN INVERTED ATTITUDE. PART TOTAL TIME SINCE OVERHAUL, 1,591 HOURS. TRANSMISSION S/N, 1165.