G-JECI, a DHC-8-402 (Dash 8) was operating a scheduled passenger flight from Southampton to Belfast. Onboard, 69 passengers, 2 cabin crew, and 2 flight crew.
The aircraft in May 2014 ©BringbackEGDG
After the aircraft had started its descend into Belfast City Airport when descending through FL150 the ‘SMOKE’ caption illuminated shortly on the Caution and Warning Panel and then went off.
This caption indicates Smoke has been detected in either the forward or rear baggage compartment. In an abundance of caution, the captain instructed the First Officer to don his oxygen mask, while he would broadcast a PAN-PAN call to ATC to alert them of their situation. During this time the ‘SMOKE’ warning reappeared. After informing ATC the captain informed the cabin crew of the situation.
Shortly afterward the first officer observed the ‘EXTG’ light had illuminated in the SMOKE/EXT switchlight, indicating the Fire Extinguisher for the cargo compartment had been armed. The crew performed the required Emergency Checklist for an Aft Baggage Compartment checklist. And pressed the SMOKE /EXT switchlight. This discharged the first fire extinguisher bottle into the aft baggage compartment to extinguish the fire in the compartment. Seven minutes later the second bottle was automatically discharged, this discharge is slow to keep the extinguishing agent level high to prevent reignition of the fire.
During this time the commander had issued a MAYDAY call to ATC, requesting a fast routing to the airport. The cabin crew was updated on the developments and they reported that no smoke was present in the passenger cabin.
The ‘SMOKE’ warning extinguished and the captain briefed the cabin crew. The baggage compartment section of the Shortly before the landing, cockpit fire protection panel
the ‘SMOKE’ warning reappeared, (from public source)
again without visible smoke.
After landing the aircraft was stopped on the runway, and ATC informed the crew that there were no external signs of smoke or fire. Due to the consisting ‘SMOKE’ warning, the captain decided to disembark the aircraft quickly via the passenger steps.
Maintenance inspected the aircraft after it was released by the Fire & Rescue services. No signs of fire and/or smoke were found. As a precautionary measure, the smoke detectors in the aft baggage compartment as well as the fire detection system control unit was replaced by the maintenance department after no faults could be found in the system.
A strip examination of the smoke detectors identified corrosion on one of the electrical connector pins. This corrosion on the connector pin was identified as the probable cause of the indications reported by the flight crew.