David CL Francis
:

On Thu, 17 Mar 2005 at 03:47:12 in message
, Ralph Nesbitt
wrote:
So did the airframe meet design requirements for gust loading, yaw
deflections and angles, control movements, negative and positive 'g'
etc? If it did not, then why not? Are the design requirements wrong
or did the airframe fail to meet them? Another factor is to what
extent are safeguards against excessively loads built in to
airliners and to their requirements?
--
David CL Francis

IRC the rudder went stop to stop several times in ~ 10 seconds. IMHO a
question which was not adequately addressed by the investigation was
why the rudder went stop to stop not once but several times. The
rudder travel is supposed to be limited at the speed the A/C was
moving at the time the rudder went stop to stop several times.

So that was more than enough to develop a pilot induced oscillation
that could easily drive the aircraft beyond its yaw limits. Time your
reversals so that they do the opposite of a yaw damper and you could
well go beyond any normal load case.

the yaw damper only makes tiny inputs. Couple of degrees. IOW it had nothng
whatsoever todo with it.


I was also told that the yaw damper was not switched on even though it
is a check list item?

Bull****, and evenit it wasn't switched on it would have had nothing to do
with, well, anything. Low altitude, it's strictly for comfort, and igh
altitude it prevents reversal problems asociatied mach compications brought
on by dutch roll.


Bertie