Boeing 737 Safety Record

The pilots' failure to use available reverse thrust in a timely manner to safely slow or stop the airplane after landing, which resulted in a runway overrun. This failure occurred because the pilots' first experience and lack of familiarity with the airplane's autobrake system distracted them from thrust reverser usage during the challenging landing. Contributing to the accident were Southwest Airline's 1) failure to provide its pilots with clear and consistent guidance and training regarding company policies and procedures related to arrival landing distance calculations; 2) programming and design of its onboard performance computer, which did not present inherent assumptions in the program critical to pilot decision making; 3) plan to implement new autobrake procedures without a familiarization period; and 4) failure to include a margin of safety in the arrival assessment to account for operational uncertainties. Also contributing to the accident was the pilots' failure to divert to another airport given reports that included poor braking action and a tailwind component greater than 5 knots. Contributing to the severity of the accident was the absence of an engineering materials arresting system, which was needed because of the limited runway safety area beyond the departure end of runway 31C.

A LACK OF ADEQUATE CLEARANCE BETWEEN THE WALKER AND TUG WHICH RESULTED IN THE WALKER BEING STRUCK BY THE TUG WHEN HE FELL FOR UNKNOWN REASON(S). A FACTOR RELATED TO THE ACCIDENT WAS THE LACK OF A POLICY TO STAY CLEAR OF THE TUG, TOWBAR, AND NOSEWHEEL OF THE AIRPLANE, WHILE PUSHBACK OPERATIONS ARE IN MOTION.

A loss of control of the airplane resulting from the movement of the rudder surface to its blowdown limit. The rudder surface most likely deflected in a direction opposite to that commanded by the pilots as a result of a jam of the main rudder power control unit servo valve secondary slide to the servo valve housing offset from its neutral position and overtravel of the primary slide.

THE CAPTAIN'S FAILURE TO EXERCISE HIS COMMAND AUTHORITY IN A TIMELY MANNER TO REJECT THE TAKEOFF OR TAKE SUFFICIENT CONTROL TO CONTINUE THE TAKEOFF, WHICH WAS INITIATED WITH A MISTRIMMED RUDDER. ALSO CAUSAL WAS THE CAPTAIN'S FAILURE TO DETECT THE MISTRIMMED RUDDER BEFORE THE TAKEOFF WAS ATTEMPTED.