What was found
UPON DEPARTURE FROM OKC, AT APPROXIMATELY 5000 FEET, CAPTAIN STARTED TO SMELL A HOT BURNING ODOR COMING FROM THE AIR VENTS. HE TURNED THE PACKS OFF, AND THE SMELL WENT AWAY. NO WARNING INDICATIONS WERE RECEIVED FROM THE AIR CONDITIONING SYSTEM. AIRCRAFT LANDED IN DFW WITHOUT INCIDENT. MAINTENANCE RAN ENGINES AND OPERATED PACKS BUT COULD NOT DUPLICATE THE SMELL. ENGINE AND PACKS BOTH OPERATED NORMALLY. AIRCRAFT RETURNED TO SERVICE. (M)