What was found
ON FLIGHT 4359 DURING THE CLIMBOUT PASSING THROUGH 7,000 FEET THE CREW RECEIVED A PACK 1/2 VALVE FAIL MESSAGE FOLLOWED BY A STRONG ELECTRICAL BURNING ODOR. THE CREW ALSO REPORTED HEARING A LOUD NOISE IN THE CABIN. THE ODOR SEEMED TO DISSIPATED WHEN THE PACKS WERE DESELECTED. AN EMERGENCY WAS NOT DECLARED BUT TRUCKS DID ROLL AS A PRECAUTION. THE AIRCRAFT LANDED WITHOUT INCIDENT. THE AIRCRAFT WAS REMOVED FROM SERVICE. RE-SECURED CONNECTION AS REQUIRED. RAN PACK NR 2 ON AUXILIARY POWER UNIT, AND NO LEAKS WERE NOTED. REMOVED AND REPLACED COUPLING BETWEEN THE HEAT EXCHANGER AND AIR CYCLE MACHINE AS REQUIRED. GROUND RAN ENGINES AT TAKEOFF POWER AND TESTED COOLING PACKS. NO DEFECTS NOTED. THE AIRCRAFT WAS RETURNED TO SERVICE.