Narrative:

While cruising at FL200 and 40 mi northeast of byp VOR, we had a master caution light and chime go off. We idented the problem as being the right bleed closed light and right bleed fault light. After running the appropriate emergency checklist per the saab 340 aom, volume 1, we determined that the problem was not correctable. We then descended below 14000 ft for precaution on pressurization. After conferring with air carrier dispatch and maintenance, we decided to shut down the right engine, as per the checklist suggestion. We declared an emergency with ATC and were given priority into dfw airport. During the after landing checklist, the right bleed light extinguished itself, but only for around 1 min before it came back on. Callback conversation with reporter revealed the following information: the reporter stated the red bleed overheat light and the master caution warning light came on for the right engine indicating a pneumatic bleed overheat. The reporter said after contacting dispatch and maintenance it was decided to shut down the right engine per the operating manual procedures. The reporter stated that maintenance ran the engine but could not duplicate the problem and replaced the #2 engine pneumatic bleed temperature sensor. Callback conversation with reporter acn 457977 revealed the following information: the reporter stated the aircraft was a saab 340B and the cause of the right engine pneumatic bleed overheat was unknown.

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Original NASA ASRS Text

Title: A SAAB 340B IN CRUISE AT FL200 SHUT DOWN #2 ENG AND DIVERTED DUE TO #2 ENG BLEED OVERHEAT WARNING LIGHT CAUSED BY A FAULTY ENG SENSOR.

Narrative: WHILE CRUISING AT FL200 AND 40 MI NE OF BYP VOR, WE HAD A MASTER CAUTION LIGHT AND CHIME GO OFF. WE IDENTED THE PROB AS BEING THE R BLEED CLOSED LIGHT AND R BLEED FAULT LIGHT. AFTER RUNNING THE APPROPRIATE EMER CHKLIST PER THE SAAB 340 AOM, VOLUME 1, WE DETERMINED THAT THE PROB WAS NOT CORRECTABLE. WE THEN DSNDED BELOW 14000 FT FOR PRECAUTION ON PRESSURIZATION. AFTER CONFERRING WITH ACR DISPATCH AND MAINT, WE DECIDED TO SHUT DOWN THE R ENG, AS PER THE CHKLIST SUGGESTION. WE DECLARED AN EMER WITH ATC AND WERE GIVEN PRIORITY INTO DFW ARPT. DURING THE AFTER LNDG CHKLIST, THE R BLEED LIGHT EXTINGUISHED ITSELF, BUT ONLY FOR AROUND 1 MIN BEFORE IT CAME BACK ON. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: THE RPTR STATED THE RED BLEED OVERHEAT LIGHT AND THE MASTER CAUTION WARNING LIGHT CAME ON FOR THE R ENG INDICATING A PNEUMATIC BLEED OVERHEAT. THE RPTR SAID AFTER CONTACTING DISPATCH AND MAINT IT WAS DECIDED TO SHUT DOWN THE R ENG PER THE OPERATING MANUAL PROCS. THE RPTR STATED THAT MAINT RAN THE ENG BUT COULD NOT DUPLICATE THE PROB AND REPLACED THE #2 ENG PNEUMATIC BLEED TEMP SENSOR. CALLBACK CONVERSATION WITH RPTR ACN 457977 REVEALED THE FOLLOWING INFO: THE RPTR STATED THE ACFT WAS A SAAB 340B AND THE CAUSE OF THE R ENG PNEUMATIC BLEED OVERHEAT WAS UNKNOWN.

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.