What was found
AIRCRAFT WAS GROUNDED: AN EMERGENCY WAS DECLARED DUE TO: AFTER TAKEOFF LOUD NOISE FROM FLOOR THEN UNBEARABLY LOUD AIR BLOWING IN COCKPIT. ACCOMPANIED BY FREEZING TEMPERATURES, UNABLE TO CONTROL COCKPIT TEMP; FLIGHT ATTADNENTS REPORTED FREEZING AIR BLOWING NEAR LAVATORY AND MAIN CABIN DOOR PLUS LOUD AIRFLOW NOISE; AIRCRAFT AIR INTERRUPTED BACK TO AND LANDED SAFELY AT MIA. ACCOMPLISHED FIM 21-51-00-810-802 REMOVED AND REPLACED LEFT PACK CRACKED DUCT ON WATER EXTRACTOR (AALA202502196117), PER AMM 21-51-15. ALSO REMOVED AND REPLACED LEFT PACK CONDENSER (AALA202502192721), PER AMM 21-51-12. OPERTIONAL AND LEAK CHECK GHOOD. CYCLED BOTH AIR CONDITIONING SYSTEMS MULTIPLE TIMES HOT AND COLD NO ICE OR LOUD SOUNDS NOTICED.