Service difficulty report · Bearing · Bell 407

Difficulty date
June 4, 2008
Submitted
July 16, 2008
Operation
General aviation
Aircraft
N3WV
Make and model
Bell 407
Aircraft serial
53713
Engine
Allsn 250C47B
Part
Bearing
Part number
23009670
Part serial
MP000604
Condition
Failed
Location
Compressor
Component
Compressor
Component part number
250C47B
Stage of operation
NR
How discovered
O
Nature of condition
J
Precautionary procedure
O

As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.

What was found

PILOT REPORTED ENGINE CHIP LIGHT PRECAUTIONARY LANDING MADE TO INVESTIGATE. A CONSIDERABLE AMOUNT OF FERROUS MATERIAL WAS ON THE TOP AND BOTTOM CHIP DETECTORS. NO PENALTY RUNS WERE PERFORMED. AIRCRAFT WAS PLACED ONTO A TRAILER AND MOVED BACK TO BASE WHERE THE ENGINE WAS REMOVED AND FORWARDED TO THE ENGINE SHOP FOR INVESTIGATION. THE DISMANTLE AND INVESTIGATION REVEALED THE NR 2 BEARING THAT SUPPORTS THE REAR OF THE IMPELLER HAD FAILED. THE BALL BEARING KEEPER HAD FRACTURED COMPLETELY ACROSS THE SURFACE. AT LEAST ONE OF THE BALLS HAD SPALLED AND ALSO THE OUTER RACE HAD SEVERAL AREAS OF SPALLING. THE FAILED BEARING WAS REPLACED, THE REMAINDER OF THE ENGINE OIL SYSTEM WAS FLUSHED WITH NO DISCREPANCIES NOTED. ENGINE WAS REASSEMBLED AND RETURNED TO SERVICE. (K)

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