As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
WHILE INVESTIGATING AN OIL LEAK AND SUBSEQUENT REMOVAL OF THE MAIN GEARBOX, THE MAST WAS FOUND CRACKED ALMOST HALFWAY AROUND ITS CIRCUMFERENCE. THE CRACK IS LOCATED BELOW THE LOWER MAIN ROTOR HUB MOUNTING FLANGE. THE CRACK MEASURES ALMOST HALFWAY AROUND THE MAST. THE MAJORITY OF THE CRACK WAS HIDDEN BY THE SWASHPLATE GUIDE SHIELD RUBBER SEAL. MAIN GEARBOX SENT FOR EVALUATION. (X)