As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
THE ANGLE HAS CRACKED ON ALL OF OUR ACFT. THE ANGLE IS RIVETED AND SCREWED INTO PLACE DIRECTLY BEHIND THE LOWER LT ENGINE MOUNT. CAUSE OF THE CRACK IS UNKNOWN, VIBRATION LEVELS WERE WITHIN ACCEPTABLE LEVELS AND NO UNUSUAL WEAR WAS NOTED. POSSIBLE CAUSE IS THAT THE ALUMINUM USED TO MAKE THE CLIP IS TOO THIN.