Narrative:

After reaching 1;100 feet after takeoff; we got the 'lav smoke' master warning. I notified ATC and leveled off at 2;500 feet. By that time; the warning was gone. A few seconds later; it came back. I called my flight attendant to see if she noticed any smoke or smells from the lavatory. There was no indication of a fire. During takeoff; the lavatory door popped open; so it was easy for her to see. During this entire situation; we continued to verify there was no smoke or fire. The warning continued to go on and off and [we] elected to return to [departure airport]. We did not declare an emergency because there was no evidence of a fire. However; I still requested the fire trucks to meet our aircraft just to be sure there was no indication of a fire near the lavatory; including the baggage compartment. I still ran the 'lav smoke' QRH and pulled the associated breakers as well as the 'overweight landing' nap checklist. After I completed all the QRH checklists; I set up the aircraft for the approach including the overweight landing speeds that was given by ACARS. I advised my flight attendant that the trucks will meet us just to check the aircraft. After the landing; we exited the runway and taxied where the trucks inspected the aircraft. Before the trucks appeared; I notified the passengers of the situation and advised that the trucks were there as an extra set of eyes to make sure the aircraft is ok. After inspection; there was no sign of a fire or smoke and we received a new gate to taxi to. Overall; I believed my crew and myself handled the situation very well.

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Original NASA ASRS Text

Title: EMB-XRJ Captain reported returning to departure airport after receiving a LAV SMOKE master warning that later was found to be a false warning.

Narrative: After reaching 1;100 feet after takeoff; we got the 'LAV SMOKE' master warning. I notified ATC and leveled off at 2;500 feet. By that time; the warning was gone. A few seconds later; it came back. I called my Flight Attendant to see if she noticed any smoke or smells from the lavatory. There was no indication of a fire. During takeoff; the lavatory door popped open; so it was easy for her to see. During this entire situation; we continued to verify there was no smoke or fire. The warning continued to go on and off and [we] elected to return to [departure airport]. We did not declare an emergency because there was no evidence of a fire. However; I still requested the fire trucks to meet our aircraft just to be sure there was no indication of a fire near the lavatory; including the baggage compartment. I still ran the 'lav smoke' QRH and pulled the associated breakers as well as the 'overweight landing' NAP checklist. After I completed all the QRH checklists; I set up the aircraft for the approach including the overweight landing speeds that was given by ACARS. I advised my Flight Attendant that the trucks will meet us just to check the aircraft. After the landing; we exited the runway and taxied where the trucks inspected the aircraft. Before the trucks appeared; I notified the passengers of the situation and advised that the trucks were there as an extra set of eyes to make sure the aircraft is ok. After inspection; there was no sign of a fire or smoke and we received a new gate to taxi to. Overall; I believed my crew and myself handled the situation very well.

Data retrieved from NASA's ASRS site and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.