As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AFTER LAST FLIGHT OF THE DAY, ENGINEERING REVIEWED THE HUMS DATA AND NOTICED A SPIKE IN THE SHAFT INFORMATION. THE A/C ENGINE WAS REMOVED THE SHAFT REMOVED FROM THE ENGINE AND INSPECTED, AND A CRACK WAS DISCOVERED IN BETWEEN THE TWO FRANGIBLE DISCS. ANOTHER SHAFT WAS INSTALLED AND ALL NECESSARY GROUND RUNS AND VIBRATION CHECK WERE CARRIED OUT SATISFACTORY. A/C WAS RETURNED TO SERVICE.