What was found
FLIGHT DECK AIR TEMPERATURE IS TOO HOT, NO AIRFLOW ON GROUND. SAMC TEXT: WITH CABIN TEMP IN MANUAL COLD, LOW AIR FLOW FROM ALL OUTLETS, IT TOOK 2 HRS TO COOL THE FLT DECK, PER CREW. PLZ CHK FLT DECK DUCTING FOR ANY BLOCKAGE. CHECKED FLOW IN LEFT TUNNEL BEFORE DUCT SPLIT, FOUND FLOW LOW. CHECKED BOTH MUFFLERS, BOTH CLEAR. FOUND LARGE AMOUNT OF DEBRIS AT 1ST FLT DECK SUPPLY DUCT ORIFICE AT STA 525. REMOVED DEBRIS, FLIGHT DECK AIRFLOW RETURNED TO NORMAL. ** NEED TO CANCEL LM1429.