Service difficulty report · Magneto · Beech C23

Difficulty date
February 13, 2023
Submitted
February 20, 2023
Operation
General aviation
Aircraft
N6632
Make and model
Beech C23
Aircraft serial
M2188
Part
Magneto
Part number
4250
Part serial
88010118
Condition
Damaged
Location
Engine
Component
Magneto · 4250
Component part number
4250
Stage of operation
CR
How discovered
O
Nature of condition
F
Precautionary procedure
A

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

What was found

FOLLOWING A CUSTOMER COMPLAINT ON MONDAY 13/2/23 OF A MAGNETO FAILURE AND EMERGENCY LANDING AT SLEAP AIRFIELD. STRIP AND INSPECT CARRIED OUT 16/2/23 ACCOMPANIED BY NAE QUALITY MANAGER, INITIAL EXTERNAL INSPECTION SHOWS ROTOR SHAFT TO BE BENT AND SEIZED, MARKS AROUND OUTER EDGE OF DRIVE GEAR CONSISTENT WITH BEING IN MESH WITH IDLER GEARS ON SEIZURE, OTHER MARKS ON THE END OF THE GEAR IN A DIRECTION FROM CENTRE TO OUTER EDGE ON GEAR LOOK TO SHOW EVIDENCE OF EXTERNAL IMPACT FROM DROPPAGE OR ROUGH HANDLING. INTERNALLY THE LOWER BEARING (ENGINE END) HAS OVER HEATED AND SEIZED OVERHEATING THE REST OF THE ROTOR TO A POINT OF MELTING PARTS OF THE ROTOR GEAR AND DISTRIBUTOR BLOCK IN THE PROCESS, ROTOR HAS DAMAGED THROUGH THE CENTRE MAGNET SECTION DURING SEIZURE. THIS MAGNETO WAS INSPECTED BY NORVIC ON 01/03/2023 AND BEARINGS WERE FOUND TO BE FREE AND SMOOTH WITH NO EXCESSIVE NOISE ON THE BENCH TEST RIG, THE GENERAL CONDITION WAS GOOD FOR A MAGNETO OF IT’S AGE (35 YEARS). DAMAGE CONSISTENT WITH END ON IMPACT CAUSING THE ROTOR TO SHIFT IN THE BEARINGS LOADING THE LOWER BEARING TO ONE SIDE AND RUNNING WITHOUT THE CORRECT BALL/RACE CLEARANCE. MAGNETO IS BEYOND REPAIR AND WILL BE REPLACED WITH NEW.

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