As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
PILOT REPORTED THAT VIBRATIONS AND GRINDING NOISES WERE FELT IN FLIGHT WITH THE AIR CONDITIONER RUNNING. FOUND THE CONDENSER FAN BLADE HUB BROKEN AWAY FROM THE REST OF THE BLADE ASSEMBLY. IT WAS GRINDING ITSELF UP WHEN RUNNING. INSPECTED T/R DRIVE SYSTEM, TO INCLUDE THE A/C COMPRESSOR & DRIVE, AND FOUND NO PROBLEMS. GROUND RAN THE AIRCRAFT AND ISOLATED THE VIBRATION TO THIS FAN. PULLED AND SECURED AIR CONDITIONER CIRCUIT BREAKER AND DEFERRED THE AIR CONDITIONER PER THE AIR METHODS' BELL HELICOPTER 407 SERIES MEL.