Narrative:

During the boarding process the (lavatory on aircraft left aft) smoke alarm chimes started going off. No one was in that lavatory. After a few mins (no more than 2) it ceased. There didn't seem to be any odor at that time and no smoke was visible. I thought maybe it was set off by a blackberry cell phone's radio signaling but no one in the rear of the aircraft owned up to having a blackberry device. During the demonstration: a few mins later; the chiming of that lavatory smoke detector started again; lasted about a total of 5 mins -- it would stop then start up again for a brief few seconds then stop. I believe; can't remember for sure; that the captain called us about the alarm; but since there was no odor and no visible signs of smoke; we all thought it was malfunctioning. I can't recall how many times this intermittent 'chiming' occurred; but by the time we were starting our beverage service it began again -- this time continuously. The #4 and I looked for the switch to turn off the alarm; but could not find one. This particular aircraft appeared to have been 'revamped' or reconfigured and the original shutoff to the alarm had been disengaged. After looking the location up in our manual we were still not able to find a shutoff. I then decided to check with the captain to see if they knew and he said they didn't have that information or something to that effect but did verify with us that there was no smoke detected by visual or smell. About that time; a furloughed or maybe a 'called back to duty' former pilot of ours who was traveling with his family idented himself as one of our pilots offered to see if he could locate the shutoff and at least keep an eye on the lavatory so we could continue with the service. By this time we had already blocked off the lavatory. Within a few mins he detected what seemed to be an electrical burning odor so he turned the air vent off in the lavatory. When I reported to the captain that this pilot smelled the odor I went back in to check it myself. Not knowing he had turned the air vent off; I turned it back on and then immediately saw a faint puff-like cloud which quickly dissipated. We informed the captain about the strengthening electrical burning odor and smoke-like brief 'puff' and he made the decision to divert for further investigation on the ground. The final consensus on the ground was that the oxygen mask in the lavatory was disengaged/activated which emitted the odor and vapor. We continued on to ZZZZ.

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Original NASA ASRS Text

Title: MD80 FLIGHT ATTENDANT REPORTS THE ACTIVATION OF A LAV SMOKE DETECTOR WHICH RESULTS IN A DIVERSION.

Narrative: DURING THE BOARDING PROCESS THE (LAVATORY ON ACFT L AFT) SMOKE ALARM CHIMES STARTED GOING OFF. NO ONE WAS IN THAT LAVATORY. AFTER A FEW MINS (NO MORE THAN 2) IT CEASED. THERE DIDN'T SEEM TO BE ANY ODOR AT THAT TIME AND NO SMOKE WAS VISIBLE. I THOUGHT MAYBE IT WAS SET OFF BY A BLACKBERRY CELL PHONE'S RADIO SIGNALING BUT NO ONE IN THE REAR OF THE ACFT OWNED UP TO HAVING A BLACKBERRY DEVICE. DURING THE DEMO: A FEW MINS LATER; THE CHIMING OF THAT LAVATORY SMOKE DETECTOR STARTED AGAIN; LASTED ABOUT A TOTAL OF 5 MINS -- IT WOULD STOP THEN START UP AGAIN FOR A BRIEF FEW SECONDS THEN STOP. I BELIEVE; CAN'T REMEMBER FOR SURE; THAT THE CAPT CALLED US ABOUT THE ALARM; BUT SINCE THERE WAS NO ODOR AND NO VISIBLE SIGNS OF SMOKE; WE ALL THOUGHT IT WAS MALFUNCTIONING. I CAN'T RECALL HOW MANY TIMES THIS INTERMITTENT 'CHIMING' OCCURRED; BUT BY THE TIME WE WERE STARTING OUR BEVERAGE SVC IT BEGAN AGAIN -- THIS TIME CONTINUOUSLY. THE #4 AND I LOOKED FOR THE SWITCH TO TURN OFF THE ALARM; BUT COULD NOT FIND ONE. THIS PARTICULAR ACFT APPEARED TO HAVE BEEN 'REVAMPED' OR RECONFIGURED AND THE ORIGINAL SHUTOFF TO THE ALARM HAD BEEN DISENGAGED. AFTER LOOKING THE LOCATION UP IN OUR MANUAL WE WERE STILL NOT ABLE TO FIND A SHUTOFF. I THEN DECIDED TO CHK WITH THE CAPT TO SEE IF THEY KNEW AND HE SAID THEY DIDN'T HAVE THAT INFO OR SOMETHING TO THAT EFFECT BUT DID VERIFY WITH US THAT THERE WAS NO SMOKE DETECTED BY VISUAL OR SMELL. ABOUT THAT TIME; A FURLOUGHED OR MAYBE A 'CALLED BACK TO DUTY' FORMER PLT OF OURS WHO WAS TRAVELING WITH HIS FAMILY IDENTED HIMSELF AS ONE OF OUR PLTS OFFERED TO SEE IF HE COULD LOCATE THE SHUTOFF AND AT LEAST KEEP AN EYE ON THE LAVATORY SO WE COULD CONTINUE WITH THE SVC. BY THIS TIME WE HAD ALREADY BLOCKED OFF THE LAVATORY. WITHIN A FEW MINS HE DETECTED WHAT SEEMED TO BE AN ELECTRICAL BURNING ODOR SO HE TURNED THE AIR VENT OFF IN THE LAVATORY. WHEN I RPTED TO THE CAPT THAT THIS PLT SMELLED THE ODOR I WENT BACK IN TO CHK IT MYSELF. NOT KNOWING HE HAD TURNED THE AIR VENT OFF; I TURNED IT BACK ON AND THEN IMMEDIATELY SAW A FAINT PUFF-LIKE CLOUD WHICH QUICKLY DISSIPATED. WE INFORMED THE CAPT ABOUT THE STRENGTHENING ELECTRICAL BURNING ODOR AND SMOKE-LIKE BRIEF 'PUFF' AND HE MADE THE DECISION TO DIVERT FOR FURTHER INVESTIGATION ON THE GND. THE FINAL CONSENSUS ON THE GND WAS THAT THE OXYGEN MASK IN THE LAVATORY WAS DISENGAGED/ACTIVATED WHICH EMITTED THE ODOR AND VAPOR. WE CONTINUED ON TO ZZZZ.

Data retrieved from NASA's ASRS site as of January 2009 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.