[Pukin Dog]

If the airplane was flying at say 175 KIAS and the pilot moved to maximum deflection of 30 degrees, the flight control system would command 30 degrees and the vertical tail and rudder would be below the maximum allowable loads. If a wind shift occurred during or after this rudder deflection, and the airspeed increased to say 250 knots, the rudder, which is still deflected at 30 degrees, would cause a high yawing moment and the load on the vertical tail might be above the allowable maximum load. The pilot might try to compensate by turning the rudder in the opposite direction which might exacerbate the flight upset. This might cause failure of the rudder and departure of the rudder from the aircraft and subsequent aircraft crash.

No dispute with any of this, but I would suggest (as I often do) that it was not at all smart to depend on composite materials to bear that load. Tests or no tests, that piece should have been metal all around. If weight was the issue, toss a hunk of titanium in there, but don't bet the farm on fabric and glue, right?

[COEXERJ145]

Why is it every time a plane crashes that people crawl out of the wood work to say it was a bomb, missile, terrorism, government conspiracy and cover-up?

[Boot Hill]

"it was not at all smart to depend on composite materials to bear that load."

And the tail of your 777 is made out of...???   J

"You can tell it's swell, it's Matel!"

--Boot Hill

[RandyRep]

I agree with your statement about metal vs. composites -- Boeing still doesn't have much composite material in primary structures like the vertical tail. However, I think the new 7E7 will have more composites, and probably in some primary structure.

I'm sure that the final NTSB report will cover all of these issues - it should be interesting to see what they say about the material choice.