Service difficulty report · Impulse Coupling

Difficulty date
May 9, 2014
Submitted
May 25, 2014
Operation
General aviation
Aircraft
N614WM
Engine
Lyc IO540A1A5
Engine time
196 hours
Part
Impulse Coupling
Part number
6351
Part serial
121017101210172
Condition
Damaged
Location
Magneto
Part time
196 hours
Component
Magneto · Slick
Component part number
6351
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

DURING UNSCHEDUALED MAINTENANCE OF THE MAGNETOS TO RESET DIRFTED INTERNAL TIMMING, THE INPULSE COUPLING WAS VISUALY INSPECTED IT WAS FOUND THAT THE COUPLING SHELL SHOWED IMPACT DAMAGE ON THE BEVELED EDGE ABOVE THE TWO PAWLES. WHEN THE MAGNETO IS TURNING SLOW DURING START UP, THE APARENT CAUSE IS THE FIXED PORTION OF THE CAM ASSEMBLY IS CONTACTING THE SHELL. IN TIME THIS COULD CAUSE THE EAR OF THE COUPLING BODY TO BREAK OFF AND POSSIBLY JAM THE GEAR TRAIN. NO AD'S OR AVAILABLE SB'S COVERED THIS TYPE OF WEAR. THE MFG REPRESENTATIVE WAS CONTACTED. HE DID NOT NEED ANY PICTURES AND SAID NOT REINSTALL THE MAGNETOS. THEY WOULD REPLACE UNDER WARRANTY. MAGNETO, SN 12101710 AND 12101720. BOTH MAGNETOS SHOWED THE SAME DEFECT. THESE MAGNETOS WERE INSTALLED BY ENGINE MFG NEW ON A NEW ENGINE.