B757-200
Flight Crew Air Transport Pilot (ATP)
Flight Crew Type 1180
Communication Breakdown
Flight Deck / Cabin / Aircraft Event Smoke / Fire / Fumes / Odor
Flight Crew Returned To Departure Airport; Flight Crew Landed As Precaution
Aircraft
Climbing through FL220 the EICAS annunciated LAVATORY SMOKE. Flight attendants reported hearing the right aft lavatory smoke detector alarm. Flight attendants did not observe smoke or smell smoke in the lavatories. ATC [was advised] and the flight diverted to [the departure airport].
As the indication of smoke had cleared; and no actual smoke was observed in the cabin; we returned to the gate; where we were met by numerous station personnel and company representatives.In chatting with the passengers while we awaited maintenance to investigate; I was informed that the smoke alarm had sounded (unknown to us) 'shortly after takeoff'; and that the last two rows did indeed smell burning. None of this information had been relayed to us in a timely manner; it seems. Indeed; our first indication was our EICAS message. At no time did I ever smell smoke; or observe any.
B757-200 flight crew reported returning to the departure airport after receiving a lavatory smoke alarm.