Date: 201910
Local time of day: 1201-1800
Location: ZZZ.Airport, US
Flight conditions: VMC
Light: Daylight
Aircraft: Dash 8-400
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Mission: Passenger
Flight phase: Parked
Airspace: Class D ZZZ
ATC / advisory: Ground ZZZ
Aircraft component: Ground Spoiler
Component problem: Malfunctioning
Reporter organization: Air Carrier
Reporter function: Captain; Pilot Flying
Reporter qualification: Flight Crew Air Transport Pilot (ATP); Flight Crew Multiengine; Flight Crew Instrument
Anomaly: Aircraft Equipment Problem Critical; Deviation / Discrepancy - Procedural Published Material / Policy; Deviation / Discrepancy - Procedural Clearance
Detector: Person Flight Crew
When detected: Taxi
Result: General Flight Cancelled / Delayed; General Maintenance Action
Contributing factors: Aircraft; Procedure
Primary problem: Procedure

Narrative: Both engines were started at the gate with the GPU. We were pushed out of the gate and during the disconnect and after start flow; the Flight Taxi switch failed with the audible 'click' to the Flight position while I disengaged the control lock. Although the switch was in the Flight position; the PFCS (Primary Flight Control System) showed that the spoilers were stowed; verified by looking at the wings. The roll inboard roll outboard advisory light was dark; the improper configuration while in ground mode.Maintenance Control was contacted through Dispatch. It was determined that the switch could not be deferred under MEL 27-XX-X due to not meeting the conditions of line 'a' of the MEL and item 2 of the operating procedure. As we were returning to the gate; when I advanced the power levers with the Flight Taxi switch still in the Flight position; the spoilers deployed and the advisory lights illuminated. We parked and deplaned.Maintenance Control asked us to do a full power down/power up cycle of the aircraft. Under the direction of Maintenance Control we assisted Contract Maintenance with the running of the engines and system operation as per the task card. Engines were again started at the gate and at the tug disconnect/after start point; the same exact failure occurred. As soon as I disengaged the control lock the Flight Taxi switch failed a second time with the audible 'click' to the Flight position and the PFCS showed that the spoilers were stowed; verified by looking at the wings. The roll inboard roll outboard advisory light were dark.At this point it was my understanding that we had reproduced the same system failure after a full power down and reset of the aircraft and that the task had failed. Maintenance Control asked if we would help pinpoint which power lever's micro switch might be the culprit. During this procedure it could not be determined which lever was the issue. Through a lengthy process the spoiler system and switch started operating normally. Maintenance Control authorized Contract Maintenance to sign it off.After two identical failures of the spoiler controls; reproduced after a hard reset that did not have MEL relief; I had safety concerns about the stability of the system. I conferred with a Duty Officer. With the information at hand; I felt that the issue had not been resolved and did not feel comfortable operating the aircraft. I made the difficult decision of refusing the aircraft.After what had been a cooperative and professional operation with the Maintenance Control Technician; a frustrated Maintenance Manager or Director came on the phone and proceeded to attempt to undermine 'Ready Safe Go' by belittling; berating and shaming me for my decision.




Synopsis: DH8-400 Captain reported refusing the aircraft after maintenance improperly complied with MEL procedures.