Narrative:

During cruise at FL390 approximately 60 NM east of denver (den), we noticed a smell in the cockpit like that produced by burning electrical components. We had, 10 mins or so prior, an EICAS message 'right recirculation fan, accompanied by an 'off' light in the right recirculation fan switch. We placed the right recirculation fan switch in the 'off' position. About 10 mins later, we noticed the smell. The flight attendants notified us they had a similar odor in the cabin, so we notified ZDV that we would land at denver international and declared an emergency. Descent and landing at den were uneventful. The fire department inspected the aircraft externally and told us there was no sign of fire, so we taxied to the gate and parked the aircraft. The crew on the flight 2 legs prior to this one had a problem with the right recirculation fan and had written it up in the logbook at a non-maintenance station. The company maintenance personnel telephonically instructed the crew that the item would be deferred. The crew on the next leg operated the fan normally. We started our leg with the fan operating normally for the first 2 hours of the flight, then had the EICAS message. To prevent a recurrence, do not operate a component that has been deferred as inoperative by maintenance even if it appears to be operating normally.

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Original NASA ASRS Text

Title: ACR FLC DECLARES EMER AND LANDS SHORT OF DEST DUE TO MALFUNCTION OF A HIGH ELECTRICAL DRAW COMPONENT WHICH IS FOLLOWED BY SMELL OF ELECTRICAL FUMES IN BOTH COCKPIT AND PAX CABIN.

Narrative: DURING CRUISE AT FL390 APPROX 60 NM E OF DENVER (DEN), WE NOTICED A SMELL IN THE COCKPIT LIKE THAT PRODUCED BY BURNING ELECTRICAL COMPONENTS. WE HAD, 10 MINS OR SO PRIOR, AN EICAS MESSAGE 'R RECIRCULATION FAN, ACCOMPANIED BY AN 'OFF' LIGHT IN THE R RECIRCULATION FAN SWITCH. WE PLACED THE R RECIRCULATION FAN SWITCH IN THE 'OFF' POS. ABOUT 10 MINS LATER, WE NOTICED THE SMELL. THE FLT ATTENDANTS NOTIFIED US THEY HAD A SIMILAR ODOR IN THE CABIN, SO WE NOTIFIED ZDV THAT WE WOULD LAND AT DENVER INTL AND DECLARED AN EMER. DSCNT AND LNDG AT DEN WERE UNEVENTFUL. THE FIRE DEPT INSPECTED THE ACFT EXTERNALLY AND TOLD US THERE WAS NO SIGN OF FIRE, SO WE TAXIED TO THE GATE AND PARKED THE ACFT. THE CREW ON THE FLT 2 LEGS PRIOR TO THIS ONE HAD A PROB WITH THE R RECIRCULATION FAN AND HAD WRITTEN IT UP IN THE LOGBOOK AT A NON-MAINT STATION. THE COMPANY MAINT PERSONNEL TELEPHONICALLY INSTRUCTED THE CREW THAT THE ITEM WOULD BE DEFERRED. THE CREW ON THE NEXT LEG OPERATED THE FAN NORMALLY. WE STARTED OUR LEG WITH THE FAN OPERATING NORMALLY FOR THE FIRST 2 HRS OF THE FLT, THEN HAD THE EICAS MESSAGE. TO PREVENT A RECURRENCE, DO NOT OPERATE A COMPONENT THAT HAS BEEN DEFERRED AS INOP BY MAINT EVEN IF IT APPEARS TO BE OPERATING NORMALLY.

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.