As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
IN CRUISE FLIGHT OVER THE GULF OF MEXICO, THE AIRCRAFT DEVELOPED A SEVERE VIBRATION. THE PILOT MADE AN IMMEDIATE PRECAUTIONARY LANDING TO AN OFFSHORE DRILLING PLATFORM. EXAMINATION OF THE AIRCRAFT REVEALED THE LOWER EROSION SHIELD ON A MAIN ROTOR BLADE HAD SEPARATED FROM THE BLADE.