As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
(CAN) AS A RESULT OF PREVIOUS IMPULSE COUPLING FAILURES, WE IMPLEMENTED AN IMPULSE COUPLING INSPECTION EVERY 100 HRS. UPON INSPECTION OF THIS IMPULSE COUPLING WE FOUND THE HUB VERY LOOSE, BOTH PAWL RIVETS LOOSE, AND THE PAWL GAPS EXCEEDED THE MAXIMUM ALLOWED BY SLICK SB1-98. PAWL GAPS WERE IN EXCESS OF .170 INCH. MAX ALLOWABLE IS .150 INCH. HAD THIS IMPULSE COUPLING FAILED IT WOULD HAVE DAMAGED AND CONTAMINATED THE ENGINE.