Service difficulty report · Yoke · Bell 407

Difficulty date
June 22, 2010
Submitted
January 4, 2011
Operation
General aviation
Make and model
Bell 407
Part
Yoke
Part number
406012102109
Condition
Mismanufactured
Location
Tail Rotor
Stage of operation
IN
How discovered
V
Nature of condition
W
Precautionary procedure
K

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

What was found

TAIL ROTOR YOKE PN 406-012-102-109, SN HBFS821, HAS BEEN MFG INCORRECTLY. THE AREA WHERE THE FLAPPING STOP CONTACTS THE YOKE SHOULD BE MACHINED FLAT. THE YOKE IN QUESTION HAS TOO MUCH MATERIAL REMOVED, CAUSING A RIDGE TO BE FORMED AND RESULTS IN THE FLAPPING STOP NOT MAKING FULL CONTACT WITH THE YOKE. IN ADDITION TO THIS, THE YOKE IS BELOW MINIMUM THICKNESS DUE TO IMPROPER MACHINING. MFG HAS BEEN NOTIFIED AND THE PART HAS BEEN RETURNED FOR WARRANTY.

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