Smoke and fumes in cockpit prompt a diversion to nearest suitable airport.

Attributes
ACN	483507
Time
Date	200008
Day	Sun
Local Time Of Day	0601 To 1200
Place
Locale Reference	airport : fsd.airport
State Reference	SD
Altitude	msl single value : 31000
Environment
Flight Conditions	Mixed
Light	Daylight
Aircraft 1
Controlling Facilities	artcc : zmp.artcc
Operator	common carrier : air carrier
Make Model Name	B757 Undifferentiated or Other Model
Operating Under FAR Part	Part 121
Navigation In Use	other
Flight Phase	cruise : level
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : flight engineer pilot : atp pilot : commercial pilot : instrument
Experience	flight time last 90 days : 200 flight time total : 3600 flight time type : 600
ASRS Report	483507
Person 2
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Events
Anomaly	aircraft equipment problem : critical other anomaly other anomaly
Independent Detector	other flight crewa other flight crewb other other : cab 3
Resolutory Action	flight crew : diverted to another airport
Consequence	other
Factors
Maintenance	performance deficiency : scheduled maintenance
Supplementary
Problem Areas	Maintenance Human Performance Aircraft
Primary Problem	Aircraft

Narrative:

Detected a burning smell in the cockpit at FL310 in cruise. Had flight attendant check cabin/galleys. Upon returning, she stated odor was coming from cockpit. Smoke/fumesecond officerdor checklist was run, which called for landing at nearest suitable airport if source could not be determined. Elected to divert to fsd. Landing was uneventful. While a faint odor was detected in cabin by flight attendants, it seemed to be confined to the cockpit. After rollout, smell was still strong in cockpit. Cockpit windows were opened and we taxied to the ramp. Maintenance found no obvious cause. Possible cause was a partially blocked lint screen on a piece of navigation equipment (first officer's FMC). Same FMC had periodically failed earlier in flight. Possibly heat related. I don't believe any FARS were violated during this diversion. The company emergency procedures used, while adequate, should probably contain some troubleshooting though. Had this occurred far from an airport, there could be serious problems with smoke/fumesecond officerdors depending on the severity.

Original NASA ASRS Text

Title: SMOKE AND FUMES IN COCKPIT PROMPT A DIVERSION TO NEAREST SUITABLE ARPT.

Narrative: DETECTED A BURNING SMELL IN THE COCKPIT AT FL310 IN CRUISE. HAD FLT ATTENDANT CHK CABIN/GALLEYS. UPON RETURNING, SHE STATED ODOR WAS COMING FROM COCKPIT. SMOKE/FUMES/ODOR CHKLIST WAS RUN, WHICH CALLED FOR LNDG AT NEAREST SUITABLE ARPT IF SOURCE COULD NOT BE DETERMINED. ELECTED TO DIVERT TO FSD. LNDG WAS UNEVENTFUL. WHILE A FAINT ODOR WAS DETECTED IN CABIN BY FLT ATTENDANTS, IT SEEMED TO BE CONFINED TO THE COCKPIT. AFTER ROLLOUT, SMELL WAS STILL STRONG IN COCKPIT. COCKPIT WINDOWS WERE OPENED AND WE TAXIED TO THE RAMP. MAINT FOUND NO OBVIOUS CAUSE. POSSIBLE CAUSE WAS A PARTIALLY BLOCKED LINT SCREEN ON A PIECE OF NAV EQUIP (FO'S FMC). SAME FMC HAD PERIODICALLY FAILED EARLIER IN FLT. POSSIBLY HEAT RELATED. I DON'T BELIEVE ANY FARS WERE VIOLATED DURING THIS DIVERSION. THE COMPANY EMER PROCS USED, WHILE ADEQUATE, SHOULD PROBABLY CONTAIN SOME TROUBLESHOOTING THOUGH. HAD THIS OCCURRED FAR FROM AN ARPT, THERE COULD BE SERIOUS PROBS WITH SMOKE/FUMES/ODORS DEPENDING ON THE SEVERITY.

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.