As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
(CAN) AIR CONDITIONER COMPRESSOR PULLEY FAILURE. BOLT STARTED TO BACK OFF CAUSING THE PULLEY TO MIGRATE OFF SHAFT AND MOVE. STEEL WOODRUFF KEY BEGAN TO CHEW UP THE PULLEY. DUE TO THE LOOSENESS, PULLEY FAILED. THERE IS NO LOCKING DEVICES ON THE END BOLT TO PREVENT ITS TURNING.