Vaughn wrote:
On 1/25/2013 6:17 PM, Transition Zone wrote:
The last time a plane was grounded was what? 1979? That's a big
deal. I remember the A320 had an early scuff-up when it started out,

The A300 was certainly a candidate for grounding after one lost a
vertical stabilizer in 2001 for no apparent reason. Vital parts
failing, falling off, and causing a plane crash with 100% fatalities
sounds a whole lot more difficult to fix that the 787's electrical
problem.


The fact that the NTSB enquiry showed that the fust officer had
overstressed the stabilizer by aggressive alternate full rudder
inputs at a relatively high airspeed was a pretty good candidate
for an 'apparent reason' as was the fact that the A300 had flown
into the wake turbulence of a JAL 747-400

Bottom line is that the pilot overstressed the airframe as
his use of alternate full rudder inputs resulted in large
angle of sideslip which tore off the stabilizer. The loads
imposed by the sideslip were more than double the design
limits.

The FAA airframe engineer stated that for any aircraft

" a maneuver with alternating rudder inputs was an extreme maneuver
and that, if the maneuver were performed, loads would build that
would exceed the current requirements. He further stated that, if two
sets of alternating rudder inputs were performed, a series of
dynamic maneuvers would start that could lead the airplane into
a severe dynamic situation where, at the proper frequency, this continued
application of this surface would allow the motion of the
airplane to build up to the point where the sideslip would become
excessive and overload the airplane "

The flight data recorder and CVR showed exactly such a sequence of
rudder inputs was made.

Keith