MD-80 Series (DC-9-80) Undifferentiated or Other Model
Flight Crew Air Transport Pilot (ATP)
Aircraft Equipment Problem Critical; Deviation / Discrepancy - Procedural Published Material / Policy; Flight Deck / Cabin / Aircraft Event Smoke / Fire / Fumes / Odor
Flight Crew Diverted; Flight Crew Landed As Precaution; General Maintenance Action
Aircraft
We were level in cruise at FL300 after a normal and uneventful departure and climb. Approximately an hour into the flight the Inflight crew notified the flight deck that they had turned on the oven to heat up items and began smelling an odd and possibly burning smell. They informed us that they had immediately turned the oven off. In response to this report; the Captain elected to turn off the Galley Power switch. I recall discussing the issue with the Captain and the possible procedures we may get into; since prior to departure it was noted in the maintenance log that there had been an electrical burning smell on this aircraft the previous day. Maintenance technicians had replaced a ballast and signed off the discrepancy. The inflight crew reported that the smell cleared out upon turning the oven off. The Captain and I discussed the fact that we would put a write up in the maintenance log regarding the oven upon landing. Approximately 30 minutes later the front flight attendants called the flight deck and began reporting again a burning electrical smell and while they were making this report the aft flight attendants came on the line and in a very concerned voice reported a heavy acrid electrical burning smell. I handed the phone to the Captain so he could hear this report directly. I inspected the circuit breaker panels that I could see and there were no circuit breakers tripped. Upon hearing this report and evaluating our situation the decision was made to [advise ATC] and divert immediately to [a nearby airport]. We ran the QRH for Electrical smoke of unknown origin. During the descent and running the QRH; it took a couple minutes to determine if the smell/fumes were increasing; decreasing or remaining constant. With the both engine driven generators off; normal communication with the inflight crew was not possible so I unlocked the door and waved one of the FAs into the cockpit. I briefed her through my oxygen mask about our diversion plan; time available; I told her they would have to brief the passengers by voice as the PA would be inop for a while and that any other decisions would be made and communicated later. I asked about the status of the smell/fumes and she advised that it was continuing. This led us to turn on the Left Generator; Left APU switch and land as soon as practicable. We landed and stopped the plane on the runway and requested [ARFF] crews to carefully inspect the exterior of the aircraft. We asked the inflight crew for a status on the smell/fumes and they reported it had mostly cleared. We reported this to the [ARFF] and later declined their offer to do an aircraft entry. [ARFF] informed us that the exterior of the aircraft appeared to be normal. We taxied off the runway and to the ramp where we waited for about 25 or 30 minutes while the company tried to find us an appropriate gate. The [ARFF] crews and airport ops crews stayed near and communicated with us often as to any needs we may have had. Upon reaching a gate; the passengers were deplaned; [ARFF] and airport ops visited the crew to be sure no further assistance was needed. Upon [Company] mechanics arrival; they began troubleshooting. It took only about 2 minutes to determine that when the ground shift breakers were pulled by them that only seconds later all three phase breakers for the Recirc Fan tripped. They repeated the process several time to confirm. Later; they inspected the Recirc Fan and determined that it emitted an acrid burning smell. The flight crew was released to rest at a hotel. The MD80; like any large mechanical machine with many systems that interact so closely is a complicated aircraft to maintain and especially to troubleshoot when a problem occurs. I think the Recirc fan motor was failing on the previous day. When the maintenance technicians found a 'hot ballast' it is perfectly reasonably to conclude that that was the issue. Replacing the ballast is a perfectly logical solution to the write up. But; considering what a complex machine this aircraft is and understanding how systems interact; it would have been prudent to inspect the air conditioning and pressurization systems as these are both reasonable sources for the smell reported. I know time is of the essence when attempting to turn an aircraft green on the maintenance board; but in this case just a few minutes of 'hand over hand' inspection of the air conditioning system may have caught the failing Recirc fan and prevented this event.
MD-80 First Officer reported diverting to an alternate airport after experiencing burning smell and fumes from a malfunctioning recirculation fan.