Service difficulty report · Hub · Beech 35C33

Difficulty date
January 19, 2010
Submitted
January 19, 2010
Operation
General aviation
Aircraft
N1310A
Make and model
Beech 35C33
Aircraft time
9,280 hours
Engine
Cont IO470L
Propeller
Mcauly 3A36C434
Part
Hub
Part number
3A36C434A
Part serial
991694
Condition
Mismanufactured
Location
Propeller
Part time
2,200 hours
Component
Propeller · Mcauly
Component part number
3A36C434A80VEA0
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

PROPELLER FACTORY NEW IN 12/10/99. PROPELLER HUB FOUND AT O/H TO BE UNAIRWORTHY DUE TO CYLINDER HOLES DEPTH DRILLED BY FACTORY TOO DEEP. 3 SMALL DIMPLES NOTED ON UNDERSIDE OF HUB ON INSPECTION. MFG HAS REJECTED HUB. FACTORY HAD TO HAVE IMPROPERLY DRILLED HUB AS THEY ARE THE ONLY ONE THAT HANDLES THE MACHINING IN THIS AREA. SUBSEQUENT CONVERSATIONS STATE REPAIR STATIONS HAVE ALSO SEEN THIS IN OTHER HUBS. IMPROPER DEPTH OF DRILLING AT MACHINING PROCESS OF NEW HUB IS THE ONLY WAY THIS HUB COULD HAVE BEEN DAMAGE. POSSIBLE NOT TO FIND IN INSP UNTIL WHICH TIME PROPELLER CYLINDER HAD BEEN OFF AND ON ENOUGH. FEEL THERE MAY BE MANY MORE THAT WERE DRILLED THE SAME DAY OUT IN THE FIELD THAT HAVE NOT BEEN FOUND.

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