What was found
DURING CLIMBOUT AFTER 10 MINUTES OF FLIGHT, THE LOWER AFT BODY HEAT LIGHT CAME ON. CONFIGURATION WAS 1 AND 3 BLEEDS OPEN. PER RED TABS SECTION 2-7-14, NR 1 PACK AND BLEED WERE TURNED OFF. BEFORE NR 1 ENGINE COULD BE RETARDED THE LIGHT WENT OUT. THE OVERHEAT SYSTEM TESTED NORMAL. FLIGHT CONTINUED WITH NR 1 PACK AND NR 1 AND 2 BLEEDS OFF. FOUND LEAK AT A CLAMP ON PNEUMATIC DUCT IN LOWER AFT CARGO BEHIND FORWARD BULKHEAD. RESECURED CLAMP, DUCT LEAK CHECKED GOOD.