SDR AOC0701

Service difficulty report · Bearing · Bell 412

Difficulty date
August 16, 2007
Submitted
August 20, 2007
Operation
General aviation
Filed by
R29R029O
Vertex Aerospace LLC
Aircraft
N31893
Make and model
Bell 412
Aircraft serial
33110
Aircraft time
6,758 hours, 11,165 cycles
Engine
Pwa PT6T3B
Part
Bearing
Condition
Damaged
Location
Pitch Link
Stage of operation
IN
How discovered
O
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

DURING A PREFLIGHT INSPECTION OF THE SUBJECT AIRCRAFT, A PITCH CHANGE LINK BEARING (ATTACHED TO THE DRIVER END) APPEARED TO BE WORN. THE PILOT ATTEMPTED TO MOVE THE DRIVER TO CHECK FOR WEAR BUT THE BEARING, BOLT AND DRIVER WERE TIGHT. THE PILOT THEN OBSERVED THE BEARING WHILE THE OTHER PILOT PULLED SLIGHTLY UP ON THE COLLECTIVE CONTROL. AS THIS OCCURRED, THE PILOT FOUND THAT THE BOLT AND BEARING WERE MOVING APPROXIMATELY .1875 INCH. FURTHER INSPECTION REVEALED THAT THE STEEL BUSHING ON THE DRIVER, TRAILING (NUT) SIDE, WAS WORN DOWN CONSIDERABLY (.0001 - .0002 INCH OF STEEL REMAINING). HAD THIS BEEN ALLOWED TO CONTINUE, THE BOLT WOULD HAVE STARTED TO WEAR INTO THE SOFTER METAL OF THE DRIVER, EVENTUALLY CAUSING L

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