As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AFTER PILOT COMPLAINED OF NO AIR CONDITIONING, TROUBLESHOT AND FOUND QUILL SHAFT FOR COMPRESSOR DRIVE ON RT ENGINE HAD THE AFT SPLINES ON SHAFT WORN OFF AND SPLINES ON PULLEY WORN DOWN. THERE WAS NO EVIDENCE OF BEARINGS AT PULLEY DRIVE SEIZING OR WORN OUT. SPLINES AT ACCESSORY CASE END WERE GOOD. THIS IS THE SECOND TIME IN 250 HOURS THAT THIS HAS HAPPENED.