among the damage discovered after the accident, investigators found the #7 slat missing from the leading edge of the right wing. ntsb investigators requested the aircraft manufacturer, boeing, inspect the remainder of the slat assembly, including a portion of the "slat actuator cylinder" (the motor that moves the slat and holds it in position). boeing determined that the #7 slat had failed because the slats had been extended while the aircraft was flying at cruising speed. they also determined that it was "impossible" for the flaps to extend without manipulating the controls.