DUTCH HARBOR, AK, USA
N141EH
AEROSPATIALE AS-350D
APRX 2 MIN AFTER TAKEOFF, THE PLT & PASSENGERS HEARD A LOUD MUFFLED BOOM FROM BEHIND THE FIREWALL, THEN THE ROTOR RPM BEGAN TO DECAY. THE PLT ENTERED AN AUTOROTATION & SELECTED A LANDING AREA. HE NOTED THAT THE ENG WAS NOT DRIVING THE ROTOR SYS, SO HE SHUT IT DOWN TO REDUCE THE POSSIBILITY OF FIRE WHILE LANDING. DURING AN EMERGENCY LANDING ON SLOPING, MOUNTAINOUS TERRAIN, THE HELICOPTER ROLLED OVER, AND SUBSEQUENTLY, IT CAME TO REST IN A RAVINE AT THE BOTTOM OF THE SLOPE. A TEARDOWN OF THE ENG REVEALED THAT THE #3 BEARING, PN 4-301-051-02, HAD FAILED & THAT THE OIL JET FOR THE BEARING WAS CLOGGED. REPORTEDLY, MAINTENANCE PERSONNEL WERE AWARE THAT A DIFFERENTIAL PRESSURE CHECK, TO DETECT CLOGGING TO THE #2 & #3 PACKAGED OIL JETS, WAS 7 TO 8 PSI. THIS WAS 2 TO 3 PSI TOO HIGH & INDICATED CLOGGING OF THE OIL JETS. (THIS PROCEDURE WAS OUTLINED IN LYCOMING SVC BULLETIN LTS101A-17-0014). HOWEVER, THE DISCREPANCY WAS NOT ENTERED IN THE ENG MAINTENANCE LOGS.
Source: NTSB Aviation Accident Database
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