1.   When the boat has heeled too far it tries to turn up into the wind and a lot of rudder movement is needed to keep it straight.

2.   Boeing further contends there is no evidence to show that the rudder deflected because of a malfunction in the flight systems that control rudder movement.

3.   Both accidents involved a pre-crash flight path indicating a possible sudden right rudder movement.

4.   Boeing still does not acknowledge that such a rudder movement occurred, and the safety board has not reached a conclusion.

5.   But investigators think jams and reversals occur when an pilot calls for a rudder movement that is large or sudden.

6.   But Ken Higgins, Boeing vice president of flight operations, said recent tests have shown that pilots should have been able to recover from the abrupt rudder movement.

7.   In fact, the rudder movement is a deduction, not an observation, because the flight data recorder was a rudimentary model that did not gather such information.

8.   Investigators are focusing on inadvertent rudder movement as a contributor to the USAir crash.

9.   It converts the rudder pedal movement from the cockpit into hydraulic power to move the rudder.

10.   McGrew said Boeing will conduct further simulated and in-flight tests in an effort to find out what caused the rudder movement.