B757 Undifferentiated or Other Model
Flight Crew Instrument; Flight Crew Air Transport Pilot (ATP); Flight Crew Multiengine
Workload
Flight Deck / Cabin / Aircraft Event Smoke / Fire / Fumes / Odor
Air Traffic Control Provided Assistance; Flight Crew Landed in Emergency Condition; Flight Crew Returned To Departure Airport; General Maintenance Action
Aircraft
While operating Aircraft X from ZZZ-ZZZ1 we departed on schedule at XA55 EDT with over 100 passengers and a weight of about 218;894 LBS. I was the Pilot Flying for this leg and Captain (CA) was Pilot Monitoring. We were off the ground at XB12 EDT. On climbout at approximately 16;000' we received a chime from the aft FA (Flight Attendant). CA answered while I took the radios. As I was trying to listen in I could hear that a loud squeal was coming from what the FAs thought was one of the aft door seals. CA mentioned to have them keep us posted and wait a bit as the aircraft was still pressurizing. A few minutes later we received another chime. This time the aft FA notified the CA that there was smoke coming from the aft ovens and that the loud squeal was actually the aft lavs smoke detectors going off. The FA mentioned to the CA that some passengers in the aft cabin reported a burning smell. At that point the CA and I could actually smell a faint burning smell in the flight deck. We immediately proceeded to do our Smoke; Fire or Fumes Memory Items and proceed with the QRC; QRH. CA directed me to keep flying the plane; notify ATC and get us vectors back to ZZZ as that was the nearest suitable. CA took care of all the appropriate checklists; prepare the FAs and briefing the passengers. We also notified Dispatch; and made sure ATC had the fire equipment standing by on our return to ZZZ. ATC directed us Direct to ZZZZZ on the ZZZ3 Arrival and before reaching ZZZZZ1 gave us vectors just outside of the ILS. Once CA had completed all his tasks we did our arrival briefing; and ran the appropriate checklists. We ended up touching down on 4R at approximately XB52 EDT. We did end up landing about 15;000 LBS overweight at about 213;500 LBS but with a soft touchdown. We were followed to gate X by the fire equipment and upon arrival at the gate; fire personnel boarded the aircraft. After the all clear from the Fire Dept; the passengers were allowed to deplane. CA sent in the write ups for the smoke in the aft ovens as well as the overweight landing. Once all the passengers were off and fire personnel were gone we debriefed as a whole crew.
B757 First Officer reported Flight Attendant notification of aft galley oven emitting smoke which activated lav smoke detector. Crew executed an uneventful return to departure airport.