B767-300 and 300 ER
Flight Crew Air Transport Pilot (ATP)
Workload; Distraction; Troubleshooting
Aircraft Equipment Problem Critical; Flight Deck / Cabin / Aircraft Event Smoke / Fire / Fumes / Odor
Flight Crew Took Evasive Action; Flight Crew Landed in Emergency Condition; Flight Crew Returned To Departure Airport; General Declared Emergency; General Maintenance Action
Aircraft
While preparing for takeoff; the First Officer; Relief Pilot; and myself noticed a smell in the cockpit. It had an electrical burning nature to it and we stopped the aircraft to investigate. Shortly thereafter the smell dissipated and we could find nothing abnormal in the cabin or in the cockpit. The flight attendants from both the front and rear smelled nothing abnormal and the ovens were off. No circuit popped circuit breakers were found. After takeoff; approximately 22 minutes into the flight I noticed the electrical burning smell again and it seemed to come from under the glare shield. It was not a strong odor; however I turned off the florescent lighting and asked the First Officer and Relief Pilot if they smelled it and even switched seats with the Relief Pilot to verify if he smelled it. They both acknowledged that while not strong; there was a distinct odor of something electrical burning. Out of caution; we made the decision to return to the departure airport to have Maintenance investigate. We declared an emergency and we received ATC clearance to return directly to the airport. I notified the flight attendants of our return and; while expecting a normal landing; I let them know the reason for the return. We ran the overweight landing procedure in the QRH and with Airfield Rescue and Fire Fighting (ARFF) equipment standing by we made an overweight landing. Touchdown at less than 300 FT/minutes; at 326;000 LBS; braking was not required until turn off. We had the ARFF follow us to the gate as a precaution. Maintenance found the forward EE Equipment Cooling fan seized with a popped circuit breaker. After compliance with all the maintenance procedures we were re-released and on our way.
A B767 crew detected an electrical burning odor taxing out but could not verify it. After leveling at cruise; the odor returned so an emergency was declared and the flight returned to the departure airport where Maintenance found the Forward EE Compartment fan had failed.