As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DFW - FLT 3829 - AIRCRAFT RETURNED TO GATE WITH LOUD SQUEAL AND ELECTRICAL SMELL FROM LEFT PACK. INSPECTION REVEALED NO EVIDENCE OF SMOKE. MAINTENANCE TIGHTENED THE CLAMPS ON THE PACK VALVE. GROUND RUN REVEALED NO FAULTS. AIRCRAFT RETURNED TO SERVICE. (M)