Narrative:

During the conduct of the originating checklist in ZZZ before the first flight of the day, our aircraft's #2 baggage compartment smoke detector test was giving an abnormal indication until a company mechanic made an adjustment to the smoke detector unit in the baggage compartment. Then the test was ok. The first flight of the day from ZZZ to bwi was uneventful. On the second flight of the day (bwi-bdl) a smoke warning was received in the cockpit while we were in cruise flight. I suspected the problem was the faulty warning test earlier in the day. I became the PF and sent the first officer to the rear of the cabin to inspect the baggage compartment. He returned to the cockpit and reported no signs of smoke or fire. I called maintenance in ZZZ on the radio and they agreed with me that we did not need to divert to a closer airport. The smoke warning stayed on for 5-10 mins and then went out. The first officer inspected the baggage compartment a second time before landing and found no signs of smoke or fire. The flight attendant was 'on alert' to detect any sign of smoke in the cabin. After landing in bdl a mechanic disconnected the #2 smoke alarm. (Our aircraft are authority/authorized per the MEL to operate with only 1 baggage compartment smoke alarm working.) callback conversation with reporter revealed the following information: the reporter stated the aircraft was a dehavilland 8 model 100. The reporter said the cause of the false compartment smoke warning was a defective smoke sensor module. The reporter said this is the second false warning event he has experienced with this type aircraft. The reporter stated the previous event occurred on the ground with the cargo door open and the compartment empty and was caused by ground equipment exhaust. The reporter said 2 sensor modules are located in the compartment and each sensor module is protected by a screen to prevent damage from thrown baggage.

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Original NASA ASRS Text

Title: A DEHAVILLAND 8 IN CRUISE AT 17000 FT EXPERIENCED A BAGGAGE COMPARTMENT SMOKE WARNING CAUSED BY A FAILED SENSOR.

Narrative: DURING THE CONDUCT OF THE ORIGINATING CHKLIST IN ZZZ BEFORE THE FIRST FLT OF THE DAY, OUR ACFT'S #2 BAGGAGE COMPARTMENT SMOKE DETECTOR TEST WAS GIVING AN ABNORMAL INDICATION UNTIL A COMPANY MECH MADE AN ADJUSTMENT TO THE SMOKE DETECTOR UNIT IN THE BAGGAGE COMPARTMENT. THEN THE TEST WAS OK. THE FIRST FLT OF THE DAY FROM ZZZ TO BWI WAS UNEVENTFUL. ON THE SECOND FLT OF THE DAY (BWI-BDL) A SMOKE WARNING WAS RECEIVED IN THE COCKPIT WHILE WE WERE IN CRUISE FLT. I SUSPECTED THE PROB WAS THE FAULTY WARNING TEST EARLIER IN THE DAY. I BECAME THE PF AND SENT THE FO TO THE REAR OF THE CABIN TO INSPECT THE BAGGAGE COMPARTMENT. HE RETURNED TO THE COCKPIT AND RPTED NO SIGNS OF SMOKE OR FIRE. I CALLED MAINT IN ZZZ ON THE RADIO AND THEY AGREED WITH ME THAT WE DID NOT NEED TO DIVERT TO A CLOSER ARPT. THE SMOKE WARNING STAYED ON FOR 5-10 MINS AND THEN WENT OUT. THE FO INSPECTED THE BAGGAGE COMPARTMENT A SECOND TIME BEFORE LNDG AND FOUND NO SIGNS OF SMOKE OR FIRE. THE FLT ATTENDANT WAS 'ON ALERT' TO DETECT ANY SIGN OF SMOKE IN THE CABIN. AFTER LNDG IN BDL A MECH DISCONNECTED THE #2 SMOKE ALARM. (OUR ACFT ARE AUTH PER THE MEL TO OPERATE WITH ONLY 1 BAGGAGE COMPARTMENT SMOKE ALARM WORKING.) CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: THE RPTR STATED THE ACFT WAS A DEHAVILLAND 8 MODEL 100. THE RPTR SAID THE CAUSE OF THE FALSE COMPARTMENT SMOKE WARNING WAS A DEFECTIVE SMOKE SENSOR MODULE. THE RPTR SAID THIS IS THE SECOND FALSE WARNING EVENT HE HAS EXPERIENCED WITH THIS TYPE ACFT. THE RPTR STATED THE PREVIOUS EVENT OCCURRED ON THE GND WITH THE CARGO DOOR OPEN AND THE COMPARTMENT EMPTY AND WAS CAUSED BY GND EQUIP EXHAUST. THE RPTR SAID 2 SENSOR MODULES ARE LOCATED IN THE COMPARTMENT AND EACH SENSOR MODULE IS PROTECTED BY A SCREEN TO PREVENT DAMAGE FROM THROWN BAGGAGE.

Data retrieved from NASA's ASRS site as of July 2007 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.