[g-erson]

Was that the final resolution then; that Boeing were ordered to replace the part, and the crashes stopped happening? Was there ever a formal investigation into whether Boeing knew the true cause of the rudder hardover, and chose to ignore it and blame other stuff?

[ams6110]

Without doing any research I'd assume that either there was an investigation and insufficient evidence was found, or that there was not because there was not even probable cause to begin one.

To think otherwise is to believe in a conspiracy between Boeing, NTSB, FAA, and the FBI or whichever law enforcement agency would have jurisdiction.

The FAA has some conflict of interest in its mission, but the NTSB does not and is generally considered to be the premier accident safety investigation group in the world.

[lutorm]

The NTSB is in the business of determining causes of accidents, though, not of assigning blame and certainly not of assigning criminal liability.

[muricula]

From the post: "The NTSB report recommended that the valve be redesigned, and the Federal Aviation Administration mandated that the changes be implemented by November 2002. Since then, no 737s have crashed due to rudder hardover or rudder reversal."