What was found
AFTER TAKEOFF LEFT AC SUPPLY PRESSURE DROPS TO ZERO, QRH FAILS TO RESTORE SUPPLY PRESSURE, LEFT PACK IS INOPERATIVE. UPON ENTERING ICING CONDITIONS A 2ND ATTEMPT TO RESET THE PACK RESULTED IN A TEMP RESTORATION OF LEFT PACK, SUBSEQUENT OPERATION OF ENGINE AND AIRFOIL ANTI-ICE SYSTEMS CAUSED AN ABNORMAL SURGE IN LEFT SUPPLY PRESSURE, AIRFOIL ICE PRESSURE ABNORMAL LIGHT ILLUMINATED, PACK FAILED, DIVERTED INTO MYR. FOUND CONNECTOR PERI-SEAL LEAKING ON DUCTING AT SECONDARY HEAT EXCHANGER. REMOVED AND REPLACED PERI-SEALS AT LEFT HEAT EXCHANGER. OPS AND LEAK CHECK GOOD. NO OTHER DEFECTS NOTED. (M)