DC-10 Undifferentiated or Other Model
Flight Crew Air Transport Pilot (ATP)
Human-Machine Interface; Troubleshooting
Aircraft Equipment Problem Critical; Deviation - Track / Heading All Types; Deviation / Discrepancy - Procedural Clearance
Flight Crew Overcame Equipment Problem; General Maintenance Action
Aircraft
While descending through approximately 14;000 MSL; to ensure that the aircraft remained on the proper descent profile; the pilot flying extended the speedbrakes. Immediately after extending the speedbrakes; the aircraft went into an uncommanded right turn at approximately a 45 degree bank angle causing the aircraft to depart our cleared track by approximately one half mile. The Captain immediately disconnected the autopilot and had to apply full left aileron to maintain wings level. He then attempted to retract the speedbrake handle; but due to the friction on the handle; was unable to do so. He then directed me to retract the speedbrakes while he flew the aircraft. I was able to retract the speed brakes; and the pilot flying was immediately able to regain full control of the aircraft. Montreal Control noticed our heading deviate from course; and asked us to confirm that we were proceeding as previously cleared. I advised that the autopilot made an uncommanded input and that we were correcting back to course. After confirming that full aircraft control was maintained; we attempted to analyze the malfunction. We concluded that there was binding in the spoiler handle and that extension of the speedbrakes was the cause of the asymmetric flight control malfunction. After a full analysis of the malfunction; the landing runway; landing data; and possible solutions we decided to perform an ILS approach to Runway 24 using flaps 50; and no spoilers. After an uneventful landing; we taxied to parking; made the appropriate write-up in the logbook; and debriefed the aircraft mechanic as to the details of the malfunction.
When a DC10 flight crew extended spoilers to assist compliance with their planned descent profile the aircraft abruptly banked 45 degrees and deviated from their cleared track. The pilot flying was unable to retract the spoilers while resisting the bank and directed the First Officer to do so. Normal flight was recovered and the landing was made without deploying spoilers as a precaution.