Narrative:

Climbing out of FL200; we noticed our left fuel flow indication at zero. I decided to contact maintenance control. However; before I was able to; we noticed the fuel flow indication vary from 0 to 950. At that time; there appeared to be an odor emitting from the left side circuit breaker panel. I asked the first officer if he could verify the odor; and he could not. When reaching FL230; the altitude bell chimed indicating 1;000 ft remained in the climb. Simultaneously we heard an additional tone. To me it sounded similar to a smoke alarm in the lavatory. There were no abnormal indications in the cockpit. Just as I was about to call the cabin crew about the sound; the a flight attendant called on the interphone stating that although there was no indication of smoke or fire; the lavatory smoke detector was activated. I decided to begin a preemptive descent and diversion in case the alarm was not erroneous. We informed ATC of the emergency and decided to return. Next; the a flight attendant called back and stated that there was visible smoke in the cabin. There were still no abnormal indications in the cockpit at this time. I told the flight attendants to don their oxygen masks and inform them that we would be landing in approximately 10 minutes. The first officer and I then donned our oxygen masks. Next; I made an announcement to the passengers informing them to follow the instructions of a uniformed crewmember once on the ground. At this time I transferred the radios to the first officer as he was the pilot flying. As I opened the QRH; we received the smoke master warning. I followed the QRH for smoke. The illuminated smoke/extg switch was the aft cargo and I pressed it as the QRH states. I proceeded with the galley fire smoke checklist so I could dump the cabin as to ensure that the smoke would exit the aircraft. I called the flight attendants at approximately 4;000 ft to ask how the conditions were in the cabin. The flight attendants stated that the visibility was poor. The a flight attendant stated that she couldn't see past the first class cabin. I told them that we would be evacuating on the runway and to wait for my evacuation command. The landing was uneventful. After 60 knots; I took control of the aircraft and brought it to a complete stop. Once the propellers stopped rotating; I initiated the evacuation command to the left side of the aircraft. After the cockpit evacuation duties were completed; I searched the entire cabin and determined that everyone was off of the aircraft safely.

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Original NASA ASRS Text

Title: DHC8-400 Captain reports detecting an electrical odor passing through FL230; along with fuel flow indication malfunctions. This is followed by a lavatory smoke alarm and visible smoke in the cabin. The crew elects to return to the departure airport and QRH procedures are commenced. At this time the Smoke Master Warning is activated indicating smoke in the aft cargo pit. QRH procedures are complied with followed by an emergency landing with an evacuation on the runway.

Narrative: Climbing out of FL200; we noticed our Left Fuel Flow indication at zero. I decided to contact Maintenance Control. However; before I was able to; we noticed the Fuel Flow indication vary from 0 to 950. At that time; there appeared to be an odor emitting from the left side circuit breaker panel. I asked the First Officer if he could verify the odor; and he could not. When reaching FL230; the altitude bell chimed indicating 1;000 FT remained in the climb. Simultaneously we heard an additional tone. To me it sounded similar to a smoke alarm in the lavatory. There were no abnormal indications in the cockpit. Just as I was about to call the cabin crew about the sound; the A Flight Attendant called on the interphone stating that although there was no indication of smoke or fire; the lavatory smoke detector was activated. I decided to begin a preemptive descent and diversion in case the alarm was not erroneous. We informed ATC of the emergency and decided to return. Next; the A Flight Attendant called back and stated that there was visible smoke in the cabin. There were still no abnormal indications in the cockpit at this time. I told the flight attendants to don their oxygen masks and inform them that we would be landing in approximately 10 minutes. The First Officer and I then donned our oxygen masks. Next; I made an announcement to the passengers informing them to follow the instructions of a uniformed crewmember once on the ground. At this time I transferred the radios to the First Officer as he was the pilot flying. As I opened the QRH; we received the SMOKE master warning. I followed the QRH for SMOKE. The illuminated SMOKE/EXTG switch was the AFT Cargo and I pressed it as the QRH states. I proceeded with the Galley Fire Smoke Checklist so I could dump the cabin as to ensure that the smoke would exit the aircraft. I called the flight attendants at approximately 4;000 FT to ask how the conditions were in the cabin. The flight attendants stated that the visibility was poor. The A Flight Attendant stated that she couldn't see past the First Class cabin. I told them that we would be evacuating on the runway and to wait for my evacuation command. The landing was uneventful. After 60 knots; I took control of the aircraft and brought it to a complete stop. Once the propellers stopped rotating; I initiated the evacuation command to the left side of the aircraft. After the cockpit evacuation duties were completed; I searched the entire cabin and determined that everyone was off of the aircraft safely.

Data retrieved from NASA's ASRS site as of July 2013 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.