Service difficulty report · Hinge · Cessna 421C

Difficulty date
July 26, 2006
Submitted
August 22, 2006
Operation
General aviation
Aircraft
N485DS
Make and model
Cessna 421C
Aircraft serial
421C0459
Aircraft time
4,783 hours
Engine
Cont GTSIO520*
System (JASC)
5200 · Doors
Part
Hinge
Condition
Corroded
Location
Door
Part time
4,783 hours
Stage of operation
NR
How discovered
9
Nature of condition
O
Precautionary procedure
O

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

What was found

TO FIND USED SERVICEABLE HINGES AND HINGE SUPPORT FITTINGS FROM AC SALVAGE COMPANIES, EVERY HINGE THAT WAS RECEIVED, SAME TYPE OF CORROSION, BEARING AND BUSHINGS WERE RUSTED TO HINGE BOLT. BUSHINGS AND BEARING ARE PRESS FIT INTO HINGE SO AS TO ALLOW HINGE ASSY TO ROTATE ON BOLT. WHEN BOLT FREEZES TO BEARING AND BUSHINGS, BOLT THEN ROTATES IN SOFT ALUMINUM SUPPORT FITTING WHICH ALLOWS HOLES IN FITTING TO ELONGATE. IT WOULD APPEAR THAT THIS IS A CHRONIC PROBLEM. AS NOTED IN ORIGINAL MD PROBLEM SEEMS TO BE RELATED TO FACT THAT SUPPORT FITTINGS CAN RETAIN WATER. THERE IS NO SPECIFIC INSPECTION REQUIREMENT TO CHECK THESE HINGES FOR CORROSION AND SO CONDITION REMAINS UNDETECTED UNTIL BOLTS HAVE TO BE REMOVED.

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