EMB ERJ 145 ER/LR
Flight Crew Multiengine; Flight Crew Instrument; Flight Crew Air Transport Pilot (ATP)
Workload
Aircraft Equipment Problem Less Severe; Deviation / Discrepancy - Procedural Published Material / Policy; Inflight Event / Encounter Unstabilized Approach; Inflight Event / Encounter Weather / Turbulence
Air Traffic Control Issued New Clearance; Flight Crew Executed Go Around / Missed Approach
Aircraft; Human Factors; Weather
This was our first flight of the day in this airplane. The airplane had an MEL on the engine anti ice valve which required the anti-ice to be on for the duration of the flight. I was PM (Pilot Monitoring); FO (First Officer) was pilot flying. We found out very quickly on the arrival into IAD that the airplane was going to create challenges making crossing restrictions. With the anti-ice on the thrust would not drop below 55% N1; which is normal when anti ice is on; but makes it very difficult to descend and slow when on for the entire descent. We applied speed brakes to assist in slowing but it still didn't help enough. A late descent clearance for the ILS 01C complicated things; and we were too fast and not configured by the FAF in IMC with weather lower than visual minimums. I called for the missed approach; the FO/PF (Pilot Flying) arrested the descent. I advised Tower that we were going missed and the instruction was to follow the localizer inbound and climb to 2;000 feet. During the clearance I realized that TOGA had not been selected yet; I selected TOGA to bring the FD up. I asked Tower for higher as we were already above 2000' when the clearance was called (published missed was 3;000 feet). Tower cleared us for 4;000 feet. Sometime during this exchange the PF had disconnected the autopilot. The airplane began rolling right. I assisted the PF on the controls to arrest the roll and work back toward the localizer; which at this time and proximity to the runway; was full scale deflection to the left. We received a clearance for runway heading; continued climb to 4;000 feet and proceeded with checklists and later a normal landing.During debrief; the PF was unaware that he had disconnected the autopilot. It was this inadvertent disconnect that led to the aircraft rolling right off course. Autopilot should have been used for the missed. Turning the autopilot off greatly increased the workload; causing the momentary loss of situational awareness. The MEL applied to the airplane created an increased workload on every leg we flew this airplane the remainder of the day.
EMB-145 Captain reported executing a go-around following an unstabilized approach related to the high thrust required to compensate for an engine anti-ice valve problem.