Dash 8 Series Undifferentiated or Other Model
Flight Crew Air Transport Pilot (ATP)
Aircraft Equipment Problem Less Severe; Flight Deck / Cabin / Aircraft Event Smoke / Fire / Fumes / Odor
Flight Crew Became Reoriented; Flight Crew Overcame Equipment Problem; General Maintenance Action
Aircraft; Procedure
We were on initial descent when I noticed smoke in the flight deck. I looked down and saw smoke coming from the SAHS switch control panel on the center console. We previously had the SAHS MEL'd due to a popped c/b that caused that panel to not have power. The MEL was cleared before we departed. I directed the First Officer to pull that c/b and to suit up. We donned the masks and the First Officer informed me that that same c/b had popped again on its own. I vented the smoke out of the forward pressure valve. We completed the smoke on the flight deck known source emergency check list and landed without any further incident. I guess the SAHS switch controller had an electrical short of some sort.Maybe Maintenance should have continued the SAHS MEL with the popped c/b collared until they could further determine the cause. Instead the c/b was reset and OPS CHECK OK to clear the MEL.
DHC8 Captain reported seeing smoke coming from the SAHS switch control panel on the center console. The circuit breaker that powers the panel had already tripped on its own. The circuit breaker had been written up previously and signed off by Maintenance.