I believe the DC-10 had the same lollypop handle for manually controlling the two outflow valves as the DC-8 and DC-9. Can't speak for the MD-11. The valves were normally electrically actuated and you could see the "lollypop" knob moving as the system operated. In the event, you pulled up on the knob and disengaged the system from the electric actuator and could set the valve openings where desired.