As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING INSPECTION OF IMPULSE COUPLINGS AT "500 HR INSPECTION" , IT WAS DISCOVERED THAT BOTH IMPULSE FLYWEIGHT BASE PLATES SHOWED CRACKS NEAT FLYWEIGHT AXLES. CRACKS WERE DISCOVERED USING MAGNETIC PARTICLE NDT METHOD. BOTH IMPULSE COUPLINGS REPLACED WITH NEW.