What was found
THE CREW REPORTED THAT PACK 1 WAS UNUSUALLY LOUD AND SHUTS DOWN ON ITS OWN, AND WHEN OPERATING, A TOXIC ODOR IS PRESENT. MX INSPECTED THE ACFT AND PLACED THE NR 1 PACK ON MEL 21-51-00-2, AND THE ACFT WAS APPROVED FOR RETURN TO SERVICE. MX R & R THE LT DUAL HEAT EXCHANGER, OPS AND LEAK CHECKED WITH NO DEFECTS NOTED, AND THE ACFT WAS APPROVED FOR RETURN TO SERVICE.