Air Carrier flight crew reported a fume event during cruise which was caused by Right Recirc Fan failure. After conferring with Dispatch and Maintenance the flight crew executed a diversion followed by a safe landing.
Synopsis
Air Carrier flight crew reported a fume event during cruise which was caused by Right Recirc Fan failure. After conferring with Dispatch and Maintenance the flight crew executed a diversion followed by a safe landing.
Narrative
At XA24z; FL350; approx 80 miles east of position ZZZZZ en route to ZZZ1; we started smelling a strong odor/fumes in cockpit. Shortly thereafter we received a call from the FM that they too smelled the same odor throughout the cabin; but stronger at the mid galley. Immediately we called the FM who confirmed that they too noticed a strange odor; and we awoke the Relief Pilot to further investigate the potential source; and contacted Dispatch via satcom to raise Maintenance Control. The odor very quickly dissipated in the cockpit. Discussing with Dispatch and Maintenance Control the situation and course of action; Maintenance Control commented that due to no indications; there were no checklists for them to reference or follow. At this point we received a call from the Relief Pilot in the cabin; that he had walked the cabin entirely; and that the odor was still present in the cabin but coming from an unknown source. The Relief Pilot then came to the cockpit; and while still on the line with Company and Maintenance Control; we received a Right Recirculating Fan EICAS (Engine Indicating and Crew Alerting System) message. When advising Maintenance Control of the message they commented that that explained the odor. At this point I [requested special handling] and requested Dispatch to change the destination to ZZZZ1; the First Officer as Pilot Flying; [requested special handling] with ZZZZ ATC whilst I continued to coordinate with the Company.I instructed the Relief Pilot to run the QRH for the smoke fire and fumes as necessary although there was no odor at this point. He also ran the Right Recirculating Fan QRH; and placed it to off. I [ended] my call with Dispatch; and called the FM to give him the instructions. I advised him that we would be landing within 20 mins; what the problem was; and at that at this point an evacuation was not necessary. The FM advised me that he would prepare the cabin for our landing in ZZZZ1. I made a PA to the pax; explaining to them the situation and plan and that we would talk to them on the ground with further.ATC descended us to FL330 to avoid traffic; and then turned us left direct ZZZZZ1 a fix adjacent to ZZZZ1. We prepared for an overweight landing and advised ZZZZ ATC that we would be overweight and needing to use the full length of the runway; to avoid high brake temps. ZZZZ1 Tower had emergency equipment standing by; that followed us to the end of the runway after landing. We were able to taxi to stand XX; and brake temps never exceeded 4; which was reached at the gate.Fire dept met us; walked the cabin; as the FAs still smelled an odor in the aft cabin. Fire department checked brake temps and for active fires. We requested them to open cargo doors for them to inspect; which they did. I gathered my entire crew for a debrief after pax had deplaned; and we concluded that everyone had done their due diligence in dealing with the [issue].
Second reporter narrative
Shortly after leveling at FL350; en route to our coast out fix; I was settling into the cruise when the Captain asked me if I could smell anything strange. Up to this point I hadn't; but as I leaned forward I picked up an odor akin to what I had experienced before when a galley oven was turned on or had some plastic debris in it. It was momentarily very noticeable but subsided quite quickly. It was not overpowering or impairing; more just unusual...in fact we thought it may be ozone (something Dispatch also mentioned as a possible cause when the CA (Captain) contacted them). I started to review nearby airport options; which at this point were ZZZZ2 and ZZZZ1; as we were equidistant between them.At this point the purser called us to tell us they also had the same smell; and the CA queried as to the oven status. The purser informed us that they did not think it was coming form an oven. The CA directed me to take the radios; and he then told the purser to have our Relief Pilot awoken; and for the Relief Pilot to go and investigate. The smell had entirely dissipated from the cockpit; but the Relief Pilot shortly thereafter reported that it was still noticeable in the cabin; and that he had opened an equipment locker; and the smell was worse in there. In the meantime the CA had contacted Dispatch and requested to be put on with Maintenance Control; to seek answers and ideas as to what had caused it. We checked all cockpit indications; circuit breakers; and saw nothing unusual. The Relief Pilot returned to the cockpit and said that he felt uncomfortable as the smell was stronger in the back. We knew we had to make a decision very soon; as the coast out point was rapidly approaching. The CA was still online with Dispatch; when we got an EICAS Right Recirc Fan message. At this point the decision was made to divert to ZZZZ1 as it was now nearer; and we already had the weather and notams due to it being our ETOPS alternate. This all happened very quickly. The CA told me to [request special handling] as we didn't know if this was a symptom of a larger problem; and I did so; approximately 80 miles prior to our coast out fix. ZZZZ ATC directed us to descend to FL330 and then to turn left direct to ZZZZZ1; a fix adjacent to ZZZZ1; to avoid traffic. I started the descent whilst the Relief Pilot ran the Recirc fan QRH and then the smoke fire fumes QRH. The smell was intermittently present in the cockpit; but never impairing or to a level where we felt the need to don masks as a crew; as this would hinder the vast amount of communication that is necessary to accomplish an inflight diversion. Nonetheless; I informed the crew that I would put my mask on for the period we could smell the odor; as I was flying and doing the radios with ATC; so that is slightly more straightforward. The CA and Relief Pilot continued with the QRH and coordinating with the cabin crew; whilst I made necessary inputs into the FMC and communicated with ATC. I regularly would inform the CA and Relief Pilot what was occurring and ensured they were happy with what I was inputting. I requested free speed; which was granted; and we were given further descent to FL080 and to expect an ILS XX in VMC conditions. We had already obtained the weather and landing data; and I sent the diversion report to the Company. We were asked if we were to be an overweight landing; and I replied yes. ATC asked if we wished to dump fuel; and we all agreed that would not be needed; given the situation. The Relief Pilot reviewed the overweight landing checklist; and we told ATC that we would use the full runway length to prevent overheating the brakes. The CA asked me if I felt comfortable landing; and I said that I did. We discussed the need for a smooth touchdown; and to use full reverse to prevent overheating. The odor had entirely dissipated by approx FL100; I had my mask off; and the CA and Relief Pilot had completed the various checklists and cabin communications. We had briefed; ran normal checklists; and again discussed the after landing plan. We all regularly ensured we were all comfortable with our decisions and verified we weren't overlooking anything. I felt the CRM and VVM was superior; and never felt out of the loop; or behind the aircraft. I kept the speed up until it was necessary to start slowing for a stabilized approach. I ensured everyone felt comfortable slowing to a normal approach speed. They did; and a normal landing was accomplished. I used full reverse with auto brakes three; and the CA came on the controls around 80 knots. Emergency vehicles followed us down the runway and then to the gate. Brake temps never exceeded 4.Upon arrival at the gate; we were met by fire crews and maintenance. The fire personnel walked the cabin and said they could smell an odor but detected no active fires. Maintenance took a verbal report from us; and then began their investigation. The station issued transit cards to the passengers; and they deplaned with their belongings. The CA conducted a full crew debrief in the cabin and thanked everyone for their professionalism and speedy work preparing the cabin for arrival. In the busy environment after we reached the gate; we all overlooked the need to enter the discrepancy into the log. An innocent oversight; and probably due to the fact maintenance met us and we had spoken to Maintenance Control. However; I shall make a concerted effort to remember to complete clerical duties even when busy; in the future.Ultimately the recirculation fan was found to be the culprit; with bad bearings that caused it to grind when spinning. This was the cause of the odor. No spares were available; and maintenance was unable stop the fan from spinning; even when unpowered. This would have meant that it would continue to grind in flight; thus causing friction and the smell. We felt very uncomfortable with that scenario; and the flight was then canceled and a replacement aircraft sourced.
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Source: NASA Aviation Safety Reporting System (public domain). Reports are voluntary submissions and are not verified by NASA.