Challenger Jet Undifferentiated or Other Model
Flight Crew Air Transport Pilot (ATP)
Human-Machine Interface; Other / Unknown; Troubleshooting
Aircraft Equipment Problem Critical; Inflight Event / Encounter Loss Of Aircraft Control
Flight Crew Overcame Equipment Problem; Flight Crew Regained Aircraft Control; General Maintenance Action
Aircraft
After landing we got a Spoilerons Fault Status message for the left out board spoileron. We contacted Maintenance Control and they sent Contract Maintenance out. After some trouble shooting it was deferred. We departed and ran the appropriate check per the MEL on the Taxi way. Just prior to that we got a Yaw Damper One Inoperative status message which we reset; we made sure everything was reset for takeoff and departed.Accelerating above 10;000 FT MSL the plane yawed hard. The First Officer and I looked at each other and neither one had accidentally stepped on the rudder. I was the flying pilot. The slip skid indicator was three quarters deflected to the left. I stepped on the left rudder and simultaneously disconnected the auto pilot. This resolved the yaw problem; but the aircraft kept wanting to roll left with a quick jerk which would stop but would then repeat the sequence. I had the First Officer declare an emergency and coordinate our return to our departure airport.We looked at the flight control page and it was not indicating anything abnormal. The only message was the Yaw Damper One Inoperative status message. We briefed the flight attendants and the passengers and got set up for Runway 34 as it was most suitable and the winds were directly down it. Once we got below 10;000 MSL the problem seemed to get a little better with a slower speed and more dense air. As the aircraft slowed to get configured to landing; it seemed to get sluggish and the flight controls a little less responsive. Concerned about possible [controllability issues] at slow speed I kept and extra 20 KTS above ref until about 200 FT above the runway. The day was VFR we could pick up the airport 40 miles out. The Flight Attendant described the event as like a two year old was flying. The deadheading crew described it like someone who was just learning to fly having difficulty keeping the wings level.I don't know if the MEL had anything to do with this problem or not but if so then a review of the MEL and possibly no longer allowing it to be deferred. Or follow up with any other issue to correct the problem.
Dispatched with a deferred Spoileron Fault Message and faced with a Yaw Damper Inop CAS status message -- which cleared during taxi as required -- the flight crew of a CL-600 encountered repeated abrupt roll inputs during acceleration above 10;000 FT that forced a return to their departure airport. They declared an emergency; added additional airspeed for the approach and landed safely despite aircraft oscillations described by their Flight Attendant; '...as though the aircraft was being flown by a two year old!'