What happened
On 8 July 2017, a Boeing 757-28A, registration G-OOBC, was operating a commercial passenger flight from Manchester to Girona, Spain. Approximately 15 minutes after departure, a cabin crew member activated the ovens in the forward galley to prepare for the in-flight service. Shortly thereafter, smoke began emitting from both ovens.
In response, the crew pulled the relevant circuit breakers and requested assistance from colleagues in the rear galley. The crew discharged a Halon (BCF) extinguisher into the ovens, but the smoke persisted. A second extinguisher was also used without success. Following these unsuccessful attempts to clear the smoke, the commander decided to divert the aircraft to London Gatwick.
Upon arrival at Gatwick, the aircraft taxied to a stand where airport fire services (AFRS) inspected the galley and confirmed there was no ongoing fire hazard. While there were no passenger injuries, three members of the cabin crew required medical assessment and were subsequently taken to the hospital for checks.
The investigation
Investigators examined the ovens in both the forward and rear galleys, discovering that the interiors of both units were contaminated with a specific fluid. The ovens were removed from the aircraft for further testing and cleaning.
Analysis revealed that the substance was a degreasing fluid typically used for removing chewing gum from carpets, rather than an approved aviation-grade oven cleaner. The aircraft had undergone a 'deep clean' 48 hours before the flight, marking its first operation since that maintenance. While the cleaning company's investigation suggested that the approved cleaning protocols were followed and the correct fluids were used during the scheduled deep clean, it remained impossible to determine exactly how the non-approved degreaser entered the oven units.