Editing Korean Air Lines Flight 007 (section)

=====Hydraulics=====
KAL&nbsp;007 had four [[Redundancy (engineering)|redundant]] hydraulic systems of which systems one, two, and three were damaged or destroyed. There was no evidence of damage to system four.<ref name="ICAO93-54" /> The hydraulics provided actuation of all primary and secondary flight controls (except leading edge slats in the latter) as well as landing gear retraction, extension, gear steering, and wheel braking. Each primary flight control axis received power from all four hydraulic systems.<ref>Norris and Wagner, ''Boeing''</ref> Upon missile detonation, the jumbo jet began to experience oscillations (yawing) as the dual channel yaw damper was damaged. Yawing would not have occurred if hydraulic systems one or two were fully operational. The result is that the control column did not thrust forward after missile detonation (it should have done so as the plane was on autopilot) to bring the plane down to its former altitude of {{convert|35000|ft|m}}. This failure of the autopilot to correct the rise in altitude indicates that hydraulic system number three, which operates the autopilot actuator, a system controlling the plane's elevators, was damaged or out. KAL&nbsp;007's airspeed and acceleration rate both began to decrease as the plane began to climb. At twenty seconds after the missile detonation, a click was heard in the cabin, which is identified as the "automatic pilot disconnect warning" sound. Either the pilot or co-pilot had disconnected the autopilot and was manually thrusting the control column forward to bring the plane lower. Though the autopilot had been turned off, manual mode did not begin functioning for another twenty seconds. This failure of the manual system to engage upon command indicates failure in hydraulic systems one and two. With wing flaps up, "control was reduced to the right inboard [[aileron]] and the innermost of spoiler section of each side".<ref name="ICAO93-54" />