Service difficulty report · Rotor · Cessna 177B

Difficulty date
July 16, 2003
Submitted
August 18, 2003
Operation
General aviation
Make and model
Cessna 177B
Aircraft time
3,783 hours
Engine
Lyc O360A1F6
Propeller
Mcauly B2D34C202
Part
Rotor
Part number
ES4145
Condition
Worn
Location
Alternator
Stage of operation
NR
How discovered
O
Nature of condition
H
Precautionary procedure
O

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

What was found

(CAN) ALTERNATOR WAS REMOVED AT 225.9 HRS BECAUSE OF DECREASING OUTPUT & VOLTAGE AS ELECTRICAL LOAD WAS APPLIED. ON DISASSEMBLY, TWO DEFECTS WERE FOUND. THE ROTOR SHAFT BEARING JOURNAL AT THE DRIVE END WAS FOUND LOOSE TO THE BEARING BY ABOUT .080 INCHES, ALLOWING THE ROTOR TO RUB ON THE STATOR STACKS.THE BEARING WAS ALSO SLIGHTLY WORN ON THE INSIDE BORE.ESSENTIALLY THE SHAFT MATERIAL WAS WORN AWAY. OTHER DEFECT LIKELY CAUSED OUTPUT SNAG. THREE POWER OUTPUT WIRES CONNECTING STATOR TO RECTIFIER ASSEMBLY WERE CHAFED & HAD BEEN SHORTING AGAINST INSIDE OF REAR HOUSING. THERE WAS NO SLEEVING OR SILICONE ADHESIVE TO PROTECT AGAINST CHAFING.

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