As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
BOTH FLIGHT ATTENDANT'S AND PASSENGERS SITTING AT ROW 2DE SMELLED A BURNING ODOR FROM THE GASPER VENTS IN 2DE. F/A REPORTED THAT IT SMELLED LIKE A GRINDING METAL. GROUND RAN ACFT, HAD PACKS UP HOT, NO ODOR IN AC, NO OTHER DEFECTS NOTED. COULD NOT DUPLICATE PROBLEM. RETURNED TO SERVICE. NO PARTS REPLACED.