Narrative:

While in cruise, left engine began to run rough. Reduced thrust engine ran smooth, all indications normal. Turned around to return to seattle. While on descent to sea (about 45 DME 17000 ft) left engine began to run rough again. Shut engine down. We had declared an emergency. Flight attendants were advised within 2 mins of us turning around. Told them to prepare cabin for a possible emergency landing. All checklists complied with. Landing was uneventful. Callback conversation with reporter revealed the following information: aircraft type MD80. No emergency evacuate/evacuation necessary. During the descent, the engine was operated at 55% N1 and no attempt was made to change thrust lever. When it began running rough it was immediately shut down. Maintenance removed aircraft from service but on initial examination could find no problem. On further investigation, metal filings were found and it was suspected the hot section was the problem. Engine was changed prior to return to service. Callback conversation with reporter acn 373935 revealed the following information: reporter stated the aircraft was an MD80 with P&west JT8D-217 engines. Reporter said the only information available from maintenance was internal failure.

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Original NASA ASRS Text

Title: MD80 CRUISING FL310, L ENG BEGAN TO RUN ROUGH. REDUCED THRUST AND ENG SMOOTHED OUT. ON RETURN TO SEA IN DSCNT, L ENG AGAIN ROUGH. SHUT DOWN AND HAD THE CABIN ATTENDANTS PREPARE THE CABIN FOR EVAC. NO EVAC NECESSARY. MAINT SUSPECTED THE HOT SECTION WAS THE SOURCE OF THE PROB. ACFT TAKEN OTS.

Narrative: WHILE IN CRUISE, L ENG BEGAN TO RUN ROUGH. REDUCED THRUST ENG RAN SMOOTH, ALL INDICATIONS NORMAL. TURNED AROUND TO RETURN TO SEATTLE. WHILE ON DSCNT TO SEA (ABOUT 45 DME 17000 FT) L ENG BEGAN TO RUN ROUGH AGAIN. SHUT ENG DOWN. WE HAD DECLARED AN EMER. FLT ATTENDANTS WERE ADVISED WITHIN 2 MINS OF US TURNING AROUND. TOLD THEM TO PREPARE CABIN FOR A POSSIBLE EMER LNDG. ALL CHKLISTS COMPLIED WITH. LNDG WAS UNEVENTFUL. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: ACFT TYPE MD80. NO EMER EVAC NECESSARY. DURING THE DSCNT, THE ENG WAS OPERATED AT 55% N1 AND NO ATTEMPT WAS MADE TO CHANGE THRUST LEVER. WHEN IT BEGAN RUNNING ROUGH IT WAS IMMEDIATELY SHUT DOWN. MAINT REMOVED ACFT FROM SVC BUT ON INITIAL EXAM COULD FIND NO PROB. ON FURTHER INVESTIGATION, METAL FILINGS WERE FOUND AND IT WAS SUSPECTED THE HOT SECTION WAS THE PROB. ENG WAS CHANGED PRIOR TO RETURN TO SVC. CALLBACK CONVERSATION WITH RPTR ACN 373935 REVEALED THE FOLLOWING INFO: RPTR STATED THE ACFT WAS AN MD80 WITH P&W JT8D-217 ENGS. RPTR SAID THE ONLY INFO AVAILABLE FROM MAINT WAS INTERNAL FAILURE.

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.