As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
(CAN) DUE TO PREVIOUS IMPULSE COUPLING FAILURES, WE IMPLEMENTED AN IMPULSE COUPLING INSPECTION EVERY 100 HRS. THIS IMPULSE COUPLING WAS FOUND TO HAVE A LOOSE PAWL RIVET. SLICK SB1-98 WAS CARRIED OUT AND THE PAWL GAPS WERE FOUND TO BE WITHIN LIMITS, AND THE T-155 RIVET GAUGE SHOWED NO WEAR. THE IMPULSE CO UPLING WAS REPLACED WITH A NEW ONE.