A B727-200 IN CRUISE AT FL310 DECLARED AN EMER AND DIVERTED DUE TO AFT LOWER BODY OVERHEAT WARNING -- A RECURRING PROB.

Narrative

WHILE AT CRUISE ALT; THE LOWER AFT BODY OVERHEAT LIGHT ILLUMINATED. THE ENG BLEED CONFIGN AT THE TIME WAS #1 ENG BLEED OPEN; L #2 ENG BLEED CLOSED; R #2 ENG BLEED OPEN; AND #3 ENG BLEED CLOSED. THE CHKLIST WAS ACCOMPLISHED. CLOSING THE CARGO HEAT OUTFLOW VALVE DID NOT CHANGE THE SIT. 2 MINS AFTER CLOSING THE #1 ENG BLEED; THE LOWER AFT BODY OVERHEAT LIGHT BEGAN TO FLASH. IT NEVER EXTINGUISHED. THE #1 ENG BLEED WAS SELECTED ON AGAIN AND THE R #2 ENG BLEED WAS MOVED TO THE OFF POS. AFTER 2 MINS; THE LOWER AFT BODY OVERHEAT LIGHT BEGAN TO FLASH. THEREAFTER; THE THROTTLES WERE RETARDED TO START A DSCNT. AFTER RETARDING THE THROTTLES; THE LOWER AFT BODY OVERHEAT LIGHT EXTINGUISHED. AT THIS POINT; THE #1 ENG BLEED WAS OPEN AND THE L PACK WAS OPERATING. THE L PACK WOULD NOT MAINTAIN CABIN PRESSURIZATION AND AS THE CABIN ALT APCHED 10000 FT; THE AFOREMENTIONED DSCNT WAS ACCOMPLISHED. AT 12000 FT; THE CABIN STABILIZED AT 8000 FT. AN EMER WAS DECLARED; AND WE FLEW DIRECT TO SDQ. AN UNEVENTFUL OVERWT LNDG (155000 LBS) WAS MADE AT SDQ. I FLEW THE SAME ACFT (#XYZ) ON AUG/XA/00 AND HAD THE SAME PROB. THE ONLY DIFFERENCE WAS THIS TIME THE LOWER AFT BODY OVERHEAT LIGHT FLASHED; AS OPPOSED TO REMAINING ILLUMINATED UNTIL EXTINGUISHED BY PROPER BLEED SELECTION DURING THE CHKLIST.