Flight Crew Commercial
Time Pressure; Human-Machine Interface; Confusion; Troubleshooting
Aircraft Equipment Problem Critical; Inflight Event / Encounter Fuel Issue; Inflight Event / Encounter Weather / Turbulence
Air Traffic Control Provided Assistance; Flight Crew Executed Go Around / Missed Approach; Flight Crew Diverted; General Declared Emergency; General Maintenance Action
Aircraft; Human Factors; Weather
We were on approach to our destination with the Captain flying; cleared to descend to 7;000 FT. Approach asked the aircraft ahead of us about conditions during their approach. They responded that they started picking up light to moderate rime ice at around 5;500 FT but accumulation stopped at around 3;500 FT. We were still quite a ways from the airport; so we kept our speed at 250 KTS. As we got closer to the airport; we started to pick up moderate amounts of ice on the windshield wipers. We had already configured anti-ice systems with the APU operating; so we continued while monitoring the rate of accumulation. Approach vectored us into a base turn approximately ten miles from the airport; so we began to slow and configure the airplane. As we were vectored onto final; at flaps 20 and 200 KTS; the aircraft began to display unusual airspeed increases; reacted very slowly to control inputs; and a yellow flag began to flash on our MFDs. We realized that we were not in a desired state; so the Captain immediately commanded a go-around and we broke off the approach. We requested and received a climb above the clouds and vectors for another approach. We discussed the possibility of ice accumulation causing the strange handling so we decided to try another approach with a faster descent through the clouds and a more straight in approach. We gave the ice time to melt and then requested another approach clearance. During the second attempt; we had a difficult time slowing using normal configuration procedures; even lowering the gear early to try to slow. As we slowed from 220 to 200 KTS; the yellow flag reappeared and we again began to mush around to control inputs. Approach Control felt that we were getting too close to a preceding arrival so we again broke off the approach and climbed above the clouds. We discussed our options and contacted Dispatch about the possibility of finding an airport with VFR conditions and no icing. The Dispatcher advised ZZZ was probably our best option. We had 3;300 LBS of fuel at the time; so we decided to try one more approach and then divert if the approach was unsuccessful. The Captain performed a few banks and pitches at 250 KTS to check the handling and it felt normal; so we tried a third approach. But the results were the same as before; so we elected to divert. We had [approximately] 3;000 LBS of fuel; which was marginal for the flight to ZZZ; so we declared minimum fuel. We received clearance to the final approach fix for ZZZ. To the best of our knowledge; all the ice had melted from the jet and it was performing normally when we began the approach into ZZZ. We discussed the handling problems again and began to configure early for landing. On approach; however; the aircraft again began to handle erratically; displayed the flag and showed unusual speed variations. We then; due to our low fuel state and concerns about the condition of the aircraft; declared an emergency. We landed and taxied to a gate; where we contacted Maintenance. They advised that the yellow flag indicated an autopilot aileron trim disagree.
While flying approaches in icing conditions the flight crew of a CRJ-200 suffered anomalous flight control response and received a yellow warning flag; the purpose of which they were unaware. Three approaches were abandoned at their destination and; although the symptoms returned again; a final and successful approach and landing were accomplished at a diversion airport.