Narrative:

On first flight of day, aircraft experienced a 'lower aft body overheat.' the (different) captain retarded #2 throttle and went through abnormal checklist. On landing at dfw, problem was misdiagnosed as a faulty #1 bleed valve. That item was MEL'ed. After takeoff, from dfw-den, we got another 'lower aft body heat.' we went through the abnormal procedures, which call for retarding each throttle in turn, reducing our rate of climb to approximately 400-500 FPM. Our procedures led us to the conclusion that the #2 bleed system was faulty and we continued climb out with #2 throttle retarded. We contacted company maintenance, who requested we return to dfw. We attempted several commercial radio contacts with our dispatch in ind without success. Climbing through approximately 15000-16000 ft, our cabin had reached 8000 ft with nearly 1000 FPM climb. The flight engineer requested permission to open the MEL'ed #1 bleed, in order to stabilize the cabin pressure by operating 2 packs. Operating inoperative'ed items is normally against our company policy, but because we now knew the maintenance signoff to be faulty, we elected to open the bleed. This also prevented us from developing a compound problem: retarded power on #2 and cabin at 10000 ft pressure. During this period, I had been gradually increasing power on #2, to see if the overheat light would recur. At approximately 80-83% N1 on #2, we began to smell a burning 'hot fiberglas' smell in cockpit. I then retarded #2 to idle, declared an emergency, and requested a return to dfw. Company maintenance found the #2 engine's 6TH stage bleed duct had disintegrated, causing an approximately 12 inch by 19 inch hole in the engine's firewall.

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Original NASA ASRS Text

Title: A B727-200 IN CLB AT FL240 DECLARED AN EMER AND DIVERTED DUE TO LOWER BODY OVERHEAT WARNING AND BURNING FIBERGLAS ODOR CAUSED BY A #2 ENG BLEED DUCT FAILURE.

Narrative: ON FIRST FLT OF DAY, ACFT EXPERIENCED A 'LOWER AFT BODY OVERHEAT.' THE (DIFFERENT) CAPT RETARDED #2 THROTTLE AND WENT THROUGH ABNORMAL CHKLIST. ON LNDG AT DFW, PROB WAS MISDIAGNOSED AS A FAULTY #1 BLEED VALVE. THAT ITEM WAS MEL'ED. AFTER TKOF, FROM DFW-DEN, WE GOT ANOTHER 'LOWER AFT BODY HEAT.' WE WENT THROUGH THE ABNORMAL PROCS, WHICH CALL FOR RETARDING EACH THROTTLE IN TURN, REDUCING OUR RATE OF CLB TO APPROX 400-500 FPM. OUR PROCS LED US TO THE CONCLUSION THAT THE #2 BLEED SYS WAS FAULTY AND WE CONTINUED CLBOUT WITH #2 THROTTLE RETARDED. WE CONTACTED COMPANY MAINT, WHO REQUESTED WE RETURN TO DFW. WE ATTEMPTED SEVERAL COMMERCIAL RADIO CONTACTS WITH OUR DISPATCH IN IND WITHOUT SUCCESS. CLBING THROUGH APPROX 15000-16000 FT, OUR CABIN HAD REACHED 8000 FT WITH NEARLY 1000 FPM CLB. THE FE REQUESTED PERMISSION TO OPEN THE MEL'ED #1 BLEED, IN ORDER TO STABILIZE THE CABIN PRESSURE BY OPERATING 2 PACKS. OPERATING INOP'ED ITEMS IS NORMALLY AGAINST OUR COMPANY POLICY, BUT BECAUSE WE NOW KNEW THE MAINT SIGNOFF TO BE FAULTY, WE ELECTED TO OPEN THE BLEED. THIS ALSO PREVENTED US FROM DEVELOPING A COMPOUND PROB: RETARDED PWR ON #2 AND CABIN AT 10000 FT PRESSURE. DURING THIS PERIOD, I HAD BEEN GRADUALLY INCREASING PWR ON #2, TO SEE IF THE OVERHEAT LIGHT WOULD RECUR. AT APPROX 80-83% N1 ON #2, WE BEGAN TO SMELL A BURNING 'HOT FIBERGLAS' SMELL IN COCKPIT. I THEN RETARDED #2 TO IDLE, DECLARED AN EMER, AND REQUESTED A RETURN TO DFW. COMPANY MAINT FOUND THE #2 ENG'S 6TH STAGE BLEED DUCT HAD DISINTEGRATED, CAUSING AN APPROX 12 INCH BY 19 INCH HOLE IN THE ENG'S FIREWALL.

Data retrieved from NASA's ASRS site as of July 2007 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.