As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AIR CONDITIONER BELT SLIPPING, CAUSE, SMOKE IN COCKPIT. IT HAS BEEN NOTED THE BELTS OF THE SAME P/N OCCASIONALLY HAVE A SLIGHT SIZE VARIATION AND WILL NOT ALLOW ADJUSTMENT TO BE MADE FULLY. BETTER QUALITY CONTROL BY THE STC HOLDER, TO PRECLUDE RECURRENCE.