Service difficulty report · Gearshaft · Aviat A1B

Difficulty date
April 11, 2017
Submitted
April 11, 2017
Operation
General aviation
Aircraft
N918HY
Make and model
Aviat A1B
Aircraft serial
2085
Aircraft time
240 hours
Engine
Lyc O360A1P
Engine time
240 hours
Part
Gearshaft
Condition
Broken
Location
Magneto
Part time
240 hours
Component
Magneto · Slick
Component part number
4370
Stage of operation
TO
How discovered
O
Nature of condition
R, P
Precautionary procedure
A

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

What was found

MAGNETO FAILED IN FLIGHT, FLIGHT WAS MADE TO THE AIRPORT ON THE REMAINING MAGNETO. THE AFFECTED MAGNETO, OLD TYPE LONG COIL TAB, NO SPARK LADDER IN BLOCK. THE FAILURE WAS A BROKEN DRIVE GEAR SHAFT AT THE BOTTOM OF THE POINTS CAM SLOT. THIS RESULTED IN THE SMALL DRIVE GEAR FALLING INTO THE POINTS, AND TOTAL LOSS OF MAGNETO FUNCTION. THE BRAKE IN THE STEEL IS RUFF AND HAS A BRITTLE LOOK. THE REST OF THE MAGNETO SHOWS NO RUST AND IS IN FINE SHAPE. THE AIRCRAFT LOST POWER ON THE CLIMB AND THE PILOT RETURNED TO THE AIRPORT. AFTER REMOVING THE MAGNETO FOR REPAIR, THE DAMAGE WAS FOUND TO THE MAIN SHAFT.

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