Service difficulty report · Tube · Bell 407

Difficulty date
March 5, 2009
Submitted
June 16, 2009
Operation
General aviation
Make and model
Bell 407
Aircraft time
1,639 hours
Engine
Allsn 250C47B
Part
Tube
Part number
406012118101
Condition
Failed
Location
Tail Rotor
Part time
2,074 hours
Stage of operation
IN
How discovered
V
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) RECEIVED TAIL ROTOR GEARBOX FOR A 60 MONTH INSP WITH PITCH CHANGE MECHANISM ATTACHED. WHEN PITCH MECHANISM WAS REMOVED, NOTICED A RAISED SLIVER OF MATERIAL THE ENTIRE DIAMETER OF THE PITCH TUBE IN THE AREA OF THE BRG SLEEVE AND PITCH TUBE BRG SHOULDER. THE SLIVER OF MATERIAL TURNED OUT TO BE METAL FROM THE PITCH TUBE WHICH WAS POUNDED OUT. THIS WAS GOING ON FOR A WHILE BECAUSE IT MANAGED TO CREATE A GAP OF .035 INCHES WHERE THERE SHOULD NOT BE A GAP. THE CUSTOMER DID REMEMBER THAT HE HAD TO RE-TORQUE THE NUT WHICH RETAINS THE BALL BRG, BRG SLEEVE AND TUBE TOGETHER A COUPLE OF YEARS AGO. THE PITCH TUBE AND SLEEVE WERE DEEMED NOT REPAIREABLE AND RETURNED TO MFG FOR FURTHER INVESTIGATION.

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