Service difficulty report · Lock Plate · Cessna 421B

Difficulty date
November 20, 2007
Submitted
December 4, 2007
Operation
Air carrier
Aircraft
N707DT
Make and model
Cessna 421B
Aircraft serial
421B0468
Engine
Cont GTSIO520H
Part
Lock Plate
Part number
641909
Condition
Destroyed
Location
Crankshaft
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

THIS ENGINE WAS REMOVED ON AUG 31, 2007, HOBBS TIME 1523.9 DUE TO A CRACKED ENGINE CASE. THE ENGINE WAS SENT FOR REPAIR. REPAIRED THE ENGINE ON SEPT 20, 2007. THIS ENGINE WAS REINSTALLED ON AIRCRAFT. DURING A NIGHT FLIGHT ON NOV 20, 2007 THE PILOT HAD AN ALTERNATOR FAILURE. REPORTED PROBLEM THE NEXT DAY. UPON INSPECTION OF THE ALTERNATOR, IT WAS FOUND IN PIECES, WITH THE MOUNT HOUSING STILL ATTACHED TO THE ENGINE. THE INSIDE OF THE ALTERNATOR INSTALLATION HOLE WAS INSPECTED. THE INSPECTION REVEALED THAT THE ATTACH BOLTS ON THE ALTERNATOR FACE GEAR HAD NO TAB LOCK PLATES INSTALLED. THE ATTACH BOLTS CAME LOOSE AND DAMAGED THE ENGINE AND ALTERNATOR. RAM AC WAS NOTIFIED OF THE PROBLEM. IT IS RECOMMENDED THAT BEFORE ENGINE INSTALLATION, INSPECT FOR MISSING PARTS IN THE ALTERNATOR ATTACH HOLE. THE ENGINE HAD 65.6 HOURS SINCE PREVIOUS INSTALLATION. (K)

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