CL-30 flight crew reported fumes from galley area during cruise. Flight crew returned to the departure airport and landed uneventfully.
Synopsis
CL-30 flight crew reported fumes from galley area during cruise. Flight crew returned to the departure airport and landed uneventfully.
Narrative
While passing through approximately FL290 the very strong smell of what appeared smoldering electronics made its way into the cockpit. First Officer and I became aware of it at the same time; and we both turned around to initially investigate when it became clear that it was coming from the galley area (specifically the microwave I observed my Flight Attendant open and close the door and that is when the smell became most pronounced). I instructed First Officer to advise ATC that we needed to make an immediate return to ZZZZ and that we were going to [requested priority handling] to ensure priority handling. Air traffic control accommodated our [request]; instructed us to stop climb and then gave us an initial descent to FL290 ( we were now at approximately at FL320). Additionally; I also requested that speed restrictions on our arrival back into ZZZZ be deleted. During our descent; I elected to de-power the galley area and cabin from DC and AC power; and then we performed the Cabin/Cockpit Fire; Smoke; or Fumes Proc non-EICAS checklist. Due to the fact that we had a near immediate dissipation of the noxious smell; it became clear that performing this checklist might not fully fit the situation since it appeared that removing galley/cabin power appeared to resolve our issue. From that point; we elected to focus on setting up for the approach; perform our briefings; and land. We then briefed our Flight Attendant on our situation and plan and had her relay the pertinent information to our clients since we were making a return to ZZZZ. The flight continued back to ZZZZ without incident and PAX (Passengers) were deplaned. Maintenance control was contacted to advise that we had an overweight landing (approximately 500 lbs overweight). Cause: Unknown. The microwave is the suspected source of the noxious fumes. Suggestions: Cause unknown. Awaiting feedback from Maintenance as to the official cause of the noxious smell of smoke.
Second reporter narrative
While climbing en route at approximately FL300 myself and the crew all noticed a very strong electrical fume smell emanating from the galley which rapidly intensified. Smoke was not observed and after a brief discussion between myself and the Captain we decided to return to ZZZZ and [request priority handling]. We discussed and then turned off the Cabin DC/AC power as we made arrangements with ATC and I prepared the QRH. Our Flight Attendant was feeling and looking for hotspots/potential fires in the galley while this occurred. Once the DC/AC power was cut I noticed an almost immediate relief in fumes with it clearing out in approximately 30 seconds. As we got back on course to return to ZZZZ I notified ATC and I ran the QRH 2 Cabin/Cockpit Fire; Smoke; or Fumes proc to a point where we as a crew felt it was not necessary to proceed further as the fumes had cleared. We also asked to delete speeds on the arrival and ATC accommodated that request. As we got briefed for the arrival/approach I believe the Flight Attendant opened the microwave door to stow loose items and upon doing so another strong fume event occurred; based on this we decided to land about 400lbs overweight on XXR. We asked our Flight Attendant to brief the passengers as to why we would be returning and to remain seated unless we called. The microwave was not in use during the time of both fume events. The landing proceeded smoothly and we did not have any further issues taxiing back to FBO nor getting the pax to their recovery flight. Cause: I personally suspect the microwave; but the cause is unknown; definitely was coming from the galley area. cause unknown; will defer to MX (Maintenance) on future prevention if applicable.
Source: NASA Aviation Safety Reporting System (public domain). Reports are voluntary submissions and are not verified by NASA.