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Old June 29th 09, 03:36 AM posted to rec.aviation.piloting
James Robinson
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Posts: 180
Default Airbus Story (FWIW)

spanky wrote:



Why would they be using rudder at cruising speed? *Further, according
to the discussion in some of the other groups, the rudder limiter is
still effective in alternate law. It supposedly clamps the limit at
where it was when the shift was made from normal to alternate law.


...look at the first line in the ACARS messages: RUD TRV LIM FAULT...
in other words, the rudder travel limiter not doing what it was
supposed to do, i.e., limit the rudder travel.


My understanding from the pros in other groups, is that message simply
says that the autolimiter disconnected, and as mentioned, the limits are
clamped at what they were prior to the disconnect. It is supposedly
part of the change from normal to alternate law.

This was followed in fairly short order by a TCAS fault, an
autothrottle disconnect, a/p disconnect and institution of alternate
flight law algorithms.


Look at the failure point of the 447 vertical
stab and compare that with the failure point of the AA 300 that went
down in 2001 on departure from JFK.


They are different. Not at all the same type of attachment or type of
failure.

Despite having a rudder travel limiter in place and working,


The A300 was not a FBW aircraft.

the 2001 incident proved rather markedly that it is entirely possible,
even at climb speeds, to overstress the vertical attach points of the
structure. ...at cruise, in what may have been beyond extreme
turbulence, that possibility may indeed be a probability in this case.


Why would an experienced pilot be using the rudder at all at cruising
speed and at that altitude?

We'll never know until the FDRs and CVRs are found and the data
downloaded, but on that subject I have no faith that they will be
found and, given Airbus's shenanigans with black boxes from earlier
incidents, I have no faith that the company wants them to be found.


So they will just hope no other aircraft decide to disappear while in
cruise flight? Or do you think they already know what went wrong, and are
correcting it behind the curtain?