As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING TRANSIT CHECK SMOKE IN CABIN WAS REPORTED WHEN GROUND PNEUMATIC UNIT WAS CONNECTED AND LT AIR CONDITIONING SYSTEM WAS ACTIVATED. THE SYSTEM WAS CHECKED AND NO SMOKE EVIDENCE WAS DETECTED. BOTH AIR COOLING TURBINES WERE CHECKED AND LT AIR CONDITIONING SYSTEM WAS DEFERRED IAW MEL 21-1. DURING OVERNIGHT SERVICE AT GDL, LT TURBINE COOLING WAS REPLACED IAW MM 21-51-1, TEST CORRECT.