Narrative:

At cruise at FL370, ATC asked for a reduced airspeed. We retarded throttles (autothrottles on) to comply. After reducing airspeed, the throttles advanced to maintain speed. The right engine accelerated normally, the left engine remained at idle EPR even though the throttle itself advanced along with the right throttle. The autothrottles disconnected. We began a descent and contacted dispatch and maintenance controller. The left engine was unresponsive to throttle movement. We turned on engine anti-ice but that was no help. Maintenance controller could not offer any remedies, so we declared an emergency through dispatch and landed uneventfully. Cabin advisory only was given to the flight attendants. Maintenance was debriefed and a loss of thrust report was submitted. Callback conversation with reporter revealed the following information: the reporter stated no information on the corrective action taken by maintenance was available. The reporter said prior to departing from the diversion station, two ideas were tossed around, both speculation. One, the electronic engine control failed and second, the fuel filter iced up caused by the failure of the automatic fuel heat system. The reporter stated maintenance has a poor record of reporting maintenance faults to flight crews.

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Original NASA ASRS Text

Title: A B767-200 IN CRUISE AT FL370 DECLARED AN EMER AND DIVERTED DUE TO LOSS OF L ENG CTL. CAUSE UNKNOWN.

Narrative: AT CRUISE AT FL370, ATC ASKED FOR A REDUCED AIRSPD. WE RETARDED THROTTLES (AUTOTHROTTLES ON) TO COMPLY. AFTER REDUCING AIRSPD, THE THROTTLES ADVANCED TO MAINTAIN SPD. THE R ENG ACCELERATED NORMALLY, THE L ENG REMAINED AT IDLE EPR EVEN THOUGH THE THROTTLE ITSELF ADVANCED ALONG WITH THE R THROTTLE. THE AUTOTHROTTLES DISCONNECTED. WE BEGAN A DSCNT AND CONTACTED DISPATCH AND MAINT CTLR. THE L ENG WAS UNRESPONSIVE TO THROTTLE MOVEMENT. WE TURNED ON ENG ANTI-ICE BUT THAT WAS NO HELP. MAINT CTLR COULD NOT OFFER ANY REMEDIES, SO WE DECLARED AN EMER THROUGH DISPATCH AND LANDED UNEVENTFULLY. CABIN ADVISORY ONLY WAS GIVEN TO THE FLT ATTENDANTS. MAINT WAS DEBRIEFED AND A LOSS OF THRUST RPT WAS SUBMITTED. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: THE RPTR STATED NO INFO ON THE CORRECTIVE ACTION TAKEN BY MAINT WAS AVAILABLE. THE RPTR SAID PRIOR TO DEPARTING FROM THE DIVERSION STATION, TWO IDEAS WERE TOSSED AROUND, BOTH SPECULATION. ONE, THE ELECTRONIC ENG CTL FAILED AND SECOND, THE FUEL FILTER ICED UP CAUSED BY THE FAILURE OF THE AUTO FUEL HEAT SYS. THE RPTR STATED MAINT HAS A POOR RECORD OF RPTING MAINT FAULTS TO FLT CREWS.

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.