Service difficulty report · Bearing · Bell 412

Difficulty date
August 24, 2011
Submitted
September 14, 2015
Operation
General aviation
Make and model
Bell 412
Aircraft time
2,816 hours
Part
Bearing
Part number
412010187101
Condition
Delaminated
Location
M/R Hub
Part time
2,980 hours
Stage of operation
IN
How discovered
9
Nature of condition
O
Precautionary procedure
K

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

What was found

(CAN) DURING A 25 HR/30 DAY SCHEDULED INSPECTION, MAINTENANCE PERSONNEL FOUND THE DAMPER BEARING, LOCATED ON THE INBOARD SIDE OF THE SPINDLE ASSEMBLY TO BE COMPLETELY DELAMINATED AROUND ITS FULL CIRCOMFERENCE. THE BEARING ITSELF WAS DELAMINATED INTERNALLY AS A SMALL PORTION OF THE DAMPER BEARING REMAINED ATTACHED TO THE SPINDLE. SEE ATTACHED PICTURES. THE ENGINEER HAD NOTED A LARGER THAN USUAL GAP BETWEEN THE PORTIONS THAT MAKE UP THE BEARING. A CLOSER VIEW LOOKING FROM THE OUTBOARD OF THE SPINDLE SHOWED THE SMALLER PORTION OF THE DELAMINATED BEARING TO BE INSET FROM THE REST. LOOKING FROM THE INBOARD SIDE, HE HAD NOTED THE SMALLER PORTION TO BE PROTRUDING. THERE WAS NO INDICATION OF THE POWDERY RESIDUE WHICH NORMALLY INDICATES BEARING DELAMINATION. THE AIRCRAFT IS CURRENTLY UNDERGOING MAINTENANCE TO CORRECT THE DEFECT.

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