Air Bus 300 crash in NY now blamed on co-pilot's improper use of rudder

[Corky Scott]

It was just a news blurb this morning on the local TV news, but they
claimed that investigators now blame the loss of the Air Bus 300's
tail on the improper use of the rudder by the co-pilot.

If true (that the co-pilot is actually being blamed), I find that
difficult to believe. A little research on the net uncovered a bunch
of articles about how the Air Bus encountered wake turbulence from a
preceding airliner and that the rudder experienced some rapid movement
which exceeded it's structural design parameters, and it cleanly
parted the aircraft.

Prior to this accident, were Air Bus 300 pilots specifically told NOT
to use the rudder in flight? Because if they did they might exceed
the design parameters of the rudder? One article claimed that pilots
were taught to counter wake turbulence using ailerons only. It wasn't
clear to me if that applied to Air Buses only, or all airliners.

Or did they learn not to use the rudder during flight because of this
accident?

Either way, I find it difficult to blame the co-pilot for reacting in
what is likely a normal pilot response to turbulence. Surely all
airliners aren't so tempermental when it comes to rudder input are
they?

Corky Scott

[Stefan]

Corky Scott wrote:

> If true (that the co-pilot is actually being blamed), I find that
> difficult to believe. A little research on the net uncovered a bunch
> of articles

I've always been wondering why they do those thorough and long lasting
investigations when all it takes to find the truth is a quick google
search...

Stefan

[G Farris]

Well, throughout the process, Airbus has submitted a large number of documents
in the effort to prove that they've been trying for years to get American
Airlines to wake up and correct their flawed training procedures. Some of
these documents are co-introduced by Boeing, and apply to "Airliners"
indicating efforts on Airbus' behalf to get the spotlight away from their
product.

Some pilots expressed their astonishment at the fact that there would be
instances, in normal operations and within the manoeuvering speed of the
aircraft, where full-amplitude control inputs would have the risk of
destroying the aircraft.

The most surprising thing to me in all of this is that in their never-ending
quarrel over whose "method" is better - the hardcore fly-by-wire method of
Airbus or the "assisted" method of Boeing, Airbus never ceases to stress the
fact that their computers will prevent inadvertent "inappropriate" control
inputs from pilots, such as increasing pitch angle to where the AOA exceeds
stall margin.* Now are we supposed to believe that rudder inputs were simply
"not included" in this guardian angel policy?

Though it may not be fair to the NTSB, it is sometimes hard not to conclude
that placing the blame on a pilot, who is no longer here to defend himself, is
far less "costly" than implicating an airline or major airfarme manufacturer.




*Boeing, it must be said, has not done much better, because they chose to
counter the Airbus argument by saying there could be cases where the
theoretical limits of useful control inputs could (an should) be exceeded
momentarily in an emergency situation. They chose to illustrate this with the
757 accident in Cali. Couldn't they find a more, well, successful,
illustration?

G Faris

[Mike Rapoport]

A tremendous amount of money could be save by eliminating the investigation
in the first place. There would still be articles written about crashes and
we could simply google up the cause.

Mike
MU-2

"Stefan" > wrote in message
...
> Corky Scott wrote:
>
>> If true (that the co-pilot is actually being blamed), I find that
>> difficult to believe. A little research on the net uncovered a bunch
>> of articles
>
> I've always been wondering why they do those thorough and long lasting
> investigations when all it takes to find the truth is a quick google
> search...
>
> Stefan
>

[Ron Natalie]

G Farris wrote:

> Though it may not be fair to the NTSB, it is sometimes hard not to conclude
> that placing the blame on a pilot, who is no longer here to defend himself, is
> far less "costly" than implicating an airline or major airfarme manufacturer.

The NTSB has no interest in what is "costly" or not. It frequently makes
recommendations that the FAA and the airlines decide not to heed for "cost"
reasons.

Obviously we haven't seen the print of the "fimal" report, but I suspect
that the results will be improper control input by the pilot flying with
some blame on the training by the manufacturer or airline on how to deal
with wake turbulance encounters.

[G Farris]

In article >,
says...

>
>The NTSB has no interest in what is "costly" or not. It frequently makes
>recommendations that the FAA and the airlines decide not to heed for "cost"
>reasons.
>


Actually, I meant "costly" more in social terms. With Boeing and Airbus
currently sparring over the subsidy issue, and the European Commission getting
involved, for the NTSB to come out and directly implicate Airbus in the
accident could spark a diplomatic incident.

I am no "conspiracy" theorist, nor do I believe that politics and finance
completely govern the workings of the NTSB, but to suggest they have "no
interest" in the political ramifications of their decisions would be, well,
not very credible.

G Faris

[Corky Scott]

On Tue, 26 Oct 2004 15:36:02 +0200, Stefan >
wrote:

>I've always been wondering why they do those thorough and long lasting
>investigations when all it takes to find the truth is a quick google
>search...
>
>Stefan

You will notice that I was asking a question, not suggesting a
conclusion. I used the internet to refresh my memory of the crash and
the particulars surrounding it, not to second guess the NTSB.

Or maybe you wouldn't notice.

Corky Scott

[PS2727]

Could someone refresh my memory....
what is the definition of maneuvering speed again?

[Stefan]

PS2727 wrote:

> Could someone refresh my memory....
> what is the definition of maneuvering speed again?

That you can fully deflect any control surface without structural
damage. However, this does *not* necessairily imply that you can waggle
from one extrem to the other! Actually, you can't do so with many airliners.

Stefan

[Stefan]

Corky Scott wrote:

> Or maybe you wouldn't notice.

Maybe, I didn't want to? :-P

Stefan

[Ron Natalie]

PS2727 wrote:
> Could someone refresh my memory....
> what is the definition of maneuvering speed again?

Design manouvering speed applies to pitch changes.

[john smith]

Before or after the loss of this aircraft?

PS2727 wrote:
> Could someone refresh my memory....
> what is the definition of maneuvering speed again?

[Peter Duniho]

"Corky Scott" > wrote in message
...
> It was just a news blurb this morning on the local TV news, but they
> claimed that investigators now blame the loss of the Air Bus 300's
> tail on the improper use of the rudder by the co-pilot.
>
> If true (that the co-pilot is actually being blamed), I find that
> difficult to believe.

As Ron says, if you want to know what the NTSB says, you need to read their
report. The news media often corrupts matter of fact into alarmist
finger-pointing.

The truth is that, when there's an aircraft accident, the NTSB almost always
winds up blaming the pilot in their report. They will often assign
additional blame elsewhere, but the truth is that aircraft failures rarely
occur absent pilot input, and so pilot input winds up part of the report.

For example, if an airplane crashes due to an engine failure caused by a
manufacturing defect or maintenance error, followed by poor engine-out
landing, the pilot will be blamed for the poor engine-out landing.

Another crash might be a result of the aircraft stalling and spinning to to
the ground. The accident report will often simply say that the pilot lost
control of the airplane, without offering insight into WHY the pilot lost
control.

If you recall the Alaska Airlines accident in which the elevator trim screw
failed, I would be willing to bet that somewhere in the NTSB report, they
fault the pilots for not landing at the first sign of trouble. Which is not
to say that the maintenance practices involved weren't the primary cause.
(I would have checked the report before posting this, except the NTSB web
site is *really* slow today...possibly related to the Airbus accident report
having just been released; I've been waiting 15 minutes already, have no
idea when my query will come back, and figure there's at least even odds it
will simply time out with an error :( ).

The NTSB simply reports whatever errors they feel they've found. In the
Airbus crash, my understanding is that it's reasonably well-established that
the pilot DID use a control input that led to the failure of the rudder, by
exceeding the design standards for that control.

There may be a host of other reasons why the pilot did so (I am especially
intrigued by the point that Airbus claims that their fly-by-wire system is
supposed to protect against such event), but the fact remains that the pilot
is who made the control input that ultimately caused the accident. There is
nothing fundamentally wrong with the NTSB stating that.

So, seems that what we have here is a clear case of the NTSB reporting
facts, with the media filtering the report to suit whatever agenda they have
at the moment.

> [...]
> Either way, I find it difficult to blame the co-pilot for reacting in
> what is likely a normal pilot response to turbulence. Surely all
> airliners aren't so tempermental when it comes to rudder input are
> they?

For what it's worth, the certification standards do not preclude all
airliners being so temperamental. FAR 25.351 requires only that a single
full-scale deflection be possible, followed by returning the rudder to
center, and an immediate full-scale deflection in the other direction may
well cause failure of the aircraft. Whether any airliners exceed this
design standard, I don't know, but it wouldn't surprise me to find that most
don't.

Pete

[G Farris]

In deference to the NTSB, it has been mentioned here before that, left to
their own devices, they would not have initiated the "probable cause"
reporting that the news media and most of the rest of the world zooms in
on, but would have preferred to keep their report factual. This said, the
"C" and "F" shorthand we have become accustomed to ("C" for causal and "F"
for factor) appear to favor a superficial reading and attribution of
blame.

I agree we find, at times, and almost surreal ability to put the blame on
the shoulders of the flight crew, and this latest incident is an example.
After all, one of the oft-cited criteria for assigning crew responsibility
(or "pilot error"), is the determination of whether the crew acted in
accordance with their training. It is after all unreasonable to expect the
crew to become test pilots and invent hitherto unexplored techniques in
dealing with an emergency, or to consider them at fault for not having
done so. Yet, from the information we have, this would appear to be the
standard being applied to this flight crew. Clearly, nothing in their
basic training, advanced training or type certification indicated they
could not use full rudder deflection for airplane control within
maneuvering speed.

If we accept the arguments submitted by Airbus, who claim they tried for
years to improve the training program at American to reflect this reality,
this further vindicates the flight crew, as we understand that this
training was never implemented. In our world today, had the unfortunate
first officer had the miraculous chance to survive the accident, having
been found at fault, he would certainly be fired, and could even face
involuntary manslaughter charges - a criminal. This smacks of
scapegoating, and one is hard pressed not to see a political expedient at
work here.

G Faris

[Andrew Gideon]

Stefan wrote:

> PS2727 wrote:
>
>> Could someone refresh my memory....
>> what is the definition of maneuvering speed again?
>
> That you can fully deflect any control surface without structural
> damage. However, this does *not* necessairily imply that you can waggle
> from one extrem to the other! Actually, you can't do so with many
> airliners.

I recently read an article on this subject; I just cannot recall where.
It's not just "waggle from one extreme to another" that's not covered by
Va, but also multiple inputs (ie. aeleron and rudder) in directions which
cause opposing (or concurring?) forces.

Anyone recall this article? Otherwise, I'll be digging through some
magazines tonight.

- Andrew

[Andrew Gideon]

Peter Duniho wrote:


> The truth is that, when there's an aircraft accident, the NTSB almost
> always
> winds up blaming the pilot in their report. They will often assign
> additional blame elsewhere, but the truth is that aircraft failures rarely
> occur absent pilot input, and so pilot input winds up part of the report.

In this particular case, though, it appears that the [co]pilot was doing as
he was trained. If he was trained to do the wrong thing, it was the
training at fault and not the pilot.

As I read the article, while it does say that the pilot's actions caused the
crash, it does not appear to afix blame to the pilot.

- Andrew

[Richard Russell]

On Tue, 26 Oct 2004 18:45:08 +0000 (UTC), (G Farris)
wrote:

>
>In deference to the NTSB, it has been mentioned here before that, left to
>their own devices, they would not have initiated the "probable cause"
>reporting that the news media and most of the rest of the world zooms in
>on, but would have preferred to keep their report factual. This said, the
>"C" and "F" shorthand we have become accustomed to ("C" for causal and "F"
>for factor) appear to favor a superficial reading and attribution of
>blame.
>
>I agree we find, at times, and almost surreal ability to put the blame on
>the shoulders of the flight crew, and this latest incident is an example.
>After all, one of the oft-cited criteria for assigning crew responsibility
>(or "pilot error"), is the determination of whether the crew acted in
>accordance with their training. It is after all unreasonable to expect the
>crew to become test pilots and invent hitherto unexplored techniques in
>dealing with an emergency, or to consider them at fault for not having
>done so. Yet, from the information we have, this would appear to be the
>standard being applied to this flight crew. Clearly, nothing in their
>basic training, advanced training or type certification indicated they
>could not use full rudder deflection for airplane control within
>maneuvering speed.
snipped....

That is exactly what struck me when I heard the sound-bite version on
the news. Airbus did provide substantial information showing that
they warned American that there training methods with regard to rudder
control (particularly as it applies to roll correction) was flawed and
dangerous. Given the rudder control idiosyncracies of the aircraft
and the "flawed" training, it seems to me that the co-pilot should be
at least third in line for blame. It is also interesting to note that
there were several internal warnings form people within American
stating that the training was flawed and dangerous. As far as I know,
the training was not revised to reflect correct procedures prior to
the crash. When an aircraft manufacturer and the Airline itself warn
that the training is flawed, and the flawed training continues, how is
that the pilot's fault?
Rich Russell

[Icebound]

"Andrew Gideon" > wrote in message
online.com...

> As I read the article, while it does say that the pilot's actions caused
> the
> crash, it does not appear to afix blame to the pilot.
>


Exactly.

In Canada the TSB tries to make it very clear that they determine the cause,
the do not assign blame... quote from their mandate: it is not the function
of the Board to assign fault or determine civil or criminal liability.
unquote...

I thought it was the same with the NTSB. (Their site does not respond
today, so I cannot refresh my memory on their mandate...)

It seems pretty clear that the "Cause" was the excessive waggling of rudder
by the pilot-flying.

"Blame" will be debated for a long time after the official report.

[Mike Rhodes]

On Tue, 26 Oct 2004 11:15:09 -0400, Ron Natalie >
wrote:

>G Farris wrote:
>
>> Though it may not be fair to the NTSB, it is sometimes hard not to conclude
>> that placing the blame on a pilot, who is no longer here to defend himself, is
>> far less "costly" than implicating an airline or major airfarme manufacturer.
>
>The NTSB has no interest in what is "costly" or not. It frequently makes
>recommendations that the FAA and the airlines decide not to heed for "cost"
>reasons.
>
>Obviously we haven't seen the print of the "fimal" report, but I suspect
>that the results will be improper control input by the pilot flying with
>some blame on the training by the manufacturer or airline on how to deal
>with wake turbulance encounters.

I recall some question concerning a weakness in the design of the
rudder itself, in that the supports to the composite structure were
too few. Not too long after the accident, I saw it was explained on
TV that the manufacturer should have distributed the load over more
points for the sake of the composite material. The known and
understood weakness of composites, compared to metals, is their lesser
ability to handle bearing stress. So Airbus should've known better,
presumably.

I think I heard this on CNN, and their expert (probably Boeing, but I
don't recall) seemed to know what he was talking about; even supplying
drawings of the rudder. From current discussion, I assume this is not
considered valid anymore, and so I may not be valid in bringing it up.
But I thought the problem close to being solved way back when.

If the control inputs are controlled, as I believe Airbus is, then the
pilot cannot be blamed for over-controlling; unless the manufacturer
pointedly states not to do that. So I'm thinking Airbus is really
getting a free one from the NTSB on this. Or the report we are
reading is premature.

Typical structure failure is from stabilizer abuse, not the rudder, I
thought. But now do I need to be concerned with what I do with my
feet?

--Mike

[Peter Duniho]

"Andrew Gideon" > wrote in message
online.com...
> In this particular case, though, it appears that the [co]pilot was doing
> as
> he was trained. If he was trained to do the wrong thing, it was the
> training at fault and not the pilot.

IMHO, that's an oversimplification. For example, some Private pilots are
trained to fly the VASI glideslope, while others are trained to fly a
steeper, power-off gliding approach. A pilot flying the VASI glideslope who
experiences a power failure will wind up crashing short of the airport, but
that doesn't mean that the practice of training pilots to fly the VASI
glideslope is necessarily wrong. Each method has positive and negative
aspects, and it's up to the pilot to make a decision regarding how to apply
their training.

As far as this particular accident goes, are you saying it's the case that
the pilot training specifically *instructed* the pilot to make large back
and forth rudder inputs? I haven't seen any documentation of that claim.
What I have seen are statements that the training neglected to mention that
multiple full deflection rudder inputs were bad; that's an entirely
different claim. After all, flying the airplane into a mountainside is also
bad, but I would be surprised if pilot training spends much time covering
that topic.

One could argue that pilots ought to be familiar with the certification
rules and understand that the rules only grant the pilot a single full
deflection of the rudder in one direction, after which the rudder can be
returned only to the neutral position. Regardless of training.

Now, that's a debate for another time, and I don't even feel that it's a
strictly "either/or" debate anyway. But my point is that ultimately it was
the pilot who over-controlled the aircraft, contrary to the certification
rules that govern the design of the aircraft. To that extent, it is
patently obvious that the pilot shares at least some of the blame.

Beyond all that, it is still factually true that the pilot's control inputs
are what *caused* the accident. My original point is that the NTSB will
state a fact like this, and the media will misinterpret to mean that the
NTSB is assigning blame or fault to the pilot. That's simply not the case.
The pilot can still be the cause of an accident without being to blame,
either partially or wholely. My use of the word "blame" obviously
distracted from what I was really trying to say.

> As I read the article, while it does say that the pilot's actions caused
> the > crash, it does not appear to afix blame to the pilot.

Which article? This thread started with a "news blurb" Corky wrote about.
We were not afforded the opportunity to review the media report Corky wrote
about. If you mean the article that was posted here, that may or may not be
relevant to Corky's post.

In any case, the article to which you refer seems to more accurately convey
the NTSB's likely position (which we'll know once the report is actually
available).

Pete

[Peter Duniho]

"Mike Rhodes" > wrote in message
...
> [...]
> If the control inputs are controlled, as I believe Airbus is, then the
> pilot cannot be blamed for over-controlling; unless the manufacturer
> pointedly states not to do that.

The manual for my airplane (and most, I believe) says nothing about not
pulling too hard on the yoke when recovering from a dive in which the
airspeed exceeds Vne. Does that mean that the manufacturer would be to
blame if I caused the wings to fail by doing so?

I don't think so. I'm curious why it appears that you would.

This vertical stabilizer failure is a more esoteric issue, granted...but
it's essentially the same. All aircraft have their limits, and pilots
should be aware of them.

> Typical structure failure is from stabilizer abuse, not the rudder, I
> thought. But now do I need to be concerned with what I do with my
> feet?

You needed to be before. Though, to be fair, unless you're flying transport
category aircraft, your concerns are defined by different certification
rules than those at issue here.

As far as how structure failure happens, I don't know what you mean by "from
stabilizer abuse, not the rudder". The rudder is the primary way to stress
the vertical stabilizer, it being attached to it and all, as well as using
the vertical stabilizer to transmit forces generated by the control surface
to the airframe.

Pete

[Karl Treier]

I don't think this version was FBW Airbus

[Andrew Gideon]

Peter Duniho wrote:

> Each method has positive and negative
> aspects, and it's up to the pilot to make a decision regarding how to
> apply their training.

This is only possible where the pilot knows that both possibilities exist.
If the training is as described, the pilot was given one way to deal with
the turbulance. There was nothing - of which he knew - with which to
compare it.

>
> As far as this particular accident goes, are you saying it's the case that
> the pilot training specifically *instructed* the pilot to make large back
> and forth rudder inputs? I haven't seen any documentation of that claim.

It certainly sounds like he was instructed to use the rudder to try to
control aircraft in that case, at least from the article in question.
Whether he was ever taught to stop trying this method at a certain point,
I'm in no position to say.

> What I have seen are statements that the training neglected to mention
> that multiple full deflection rudder inputs were bad; that's an entirely
> different claim. After all, flying the airplane into a mountainside is
> also bad, but I would be surprised if pilot training spends much time
> covering that topic.

That's not a fair comparison. One could make a reasonable guess as to the
result of flying into a mountainside. I don't think it reasonable to
believe that futzing with the rudder, even to an extreme, is going to cause
the tail to fall off. If someone told me that, I'd probably assume they
were kidding (at least at first). Who'd build a plane like that??

>
> One could argue that pilots ought to be familiar with the certification
> rules and understand that the rules only grant the pilot a single full
> deflection of the rudder in one direction, after which the rudder can be
> returned only to the neutral position. Regardless of training.
>
> Now, that's a debate for another time,

True, but it is a good point. It's why I was "happy" to read that article
to which I referred earlier: it reminded me that the definition of Va has
certain "limits".

[...]
> Beyond all that, it is still factually true that the pilot's control
> inputs
> are what *caused* the accident. My original point is that the NTSB will
> state a fact like this, and the media will misinterpret to mean that the
> NTSB is assigning blame or fault to the pilot. That's simply not the
> case. The pilot can still be the cause of an accident without being to
> blame,
> either partially or wholely. My use of the word "blame" obviously
> distracted from what I was really trying to say.

Agreed, esp. about the media mangling meaning.

- Andrew

[Andrew Gideon]

Peter Duniho wrote:

> "Mike Rhodes" > wrote in message
> ...
>> [...]
>> If the control inputs are controlled, as I believe Airbus is, then the
>> pilot cannot be blamed for over-controlling; unless the manufacturer
>> pointedly states not to do that.
>
> The manual for my airplane (and most, I believe) says nothing about not
> pulling too hard on the yoke when recovering from a dive in which the
> airspeed exceeds Vne. Does that mean that the manufacturer would be to
> blame if I caused the wings to fail by doing so?
>
> I don't think so. I'm curious why it appears that you would.

The manual does likely say something about the definition of Vne, however.

- Andrew

[Peter Duniho]

"Andrew Gideon" > wrote in message
online.com...
> The manual does likely say something about the definition of Vne, however.

My manual states the value for Vne. It says nothing about how that value
was derived. Again, I believe most aircraft manuals are similar.

[Mike Rhodes]

On Tue, 26 Oct 2004 14:11:41 -0700, "Peter Duniho"
> wrote:

>"Mike Rhodes" > wrote in message
...
>> [...]
>> If the control inputs are controlled, as I believe Airbus is, then the
>> pilot cannot be blamed for over-controlling; unless the manufacturer
>> pointedly states not to do that.
>
>The manual for my airplane (and most, I believe) says nothing about not
>pulling too hard on the yoke when recovering from a dive in which the
>airspeed exceeds Vne. Does that mean that the manufacturer would be to
>blame if I caused the wings to fail by doing so?
>
>I don't think so. I'm curious why it appears that you would.

I'm guessing you're not really curious, for the general nature of you
reply was not one intended to encourage discussion. As for the
paragraph above I'm very surprised you think that makes any point at
all, other than my own. Because it is rhetorical...

--Mike

[Peter Duniho]

"Mike Rhodes" > wrote in message
...
> I'm guessing you're not really curious, for the general nature of you
> reply was not one intended to encourage discussion.

If you have a legitimate justification for your opinion, of course I am
eager to hear it. If you are just blaming Airbus for the sake of blaming
them, then that's stupid and I've got no interest in wasting my time reading
someone trying to justify such a hollow opinion.

So, am I truly curious? Only you can say for sure. For now, it sounds like
you've got bupkis for claiming that the blame rests with Airbus just because
they neglected to mention in the aircraft manual that control inputs outside
the certification standards for the aircraft might damage the aircraft (and
that's assuming that they actually didn't mention that in the manual...I
don't have a copy, do you?)

Pete

[PS2727]

As a multiengine instructor who has witnessed students applying full rudder in
the wrong direction after a simulated engine failure then quickly apply full
opposite rudder in the correct direction am I to understand that I was in
mortal danger from the tail breaking off? Seems that is a little late in
telling pilots how these things are designed....What next, we can't reverse
ailerons when landing in gusty conditions without breaking something there as
well?
Also, maybe someone can explain why the rudder limiter on this Airbus didn't
protect the structure when its sole purpose in life is to prevent damage to the
structure by limiting rudder movement at higher speeds.

[Mike Rapoport]

"PS2727" > wrote in message
...
> As a multiengine instructor who has witnessed students applying full
> rudder in
> the wrong direction after a simulated engine failure then quickly apply
> full
> opposite rudder in the correct direction am I to understand that I was in
> mortal danger from the tail breaking off? Seems that is a little late in
> telling pilots how these things are designed....What next, we can't
> reverse
> ailerons when landing in gusty conditions without breaking something there
> as
> well?
..

No, the limitation applies to transport catagory aircraft.

> Also, maybe someone can explain why the rudder limiter on this Airbus
> didn't
> protect the structure when its sole purpose in life is to prevent damage
> to the
> structure by limiting rudder movement at higher speeds

Good question. It was probably never anticipated that airline pilots would
fly the airplane like your multi students.

Mike
MU-2

[David CL Francis]

On Tue, 26 Oct 2004 at 20:52:36 in message
>, Mike Rhodes
> wrote:
>I recall some question concerning a weakness in the design of the
>rudder itself, in that the supports to the composite structure were
>too few. Not too long after the accident, I saw it was explained on
>TV that the manufacturer should have distributed the load over more
>points for the sake of the composite material. The known and
>understood weakness of composites, compared to metals, is their lesser
>ability to handle bearing stress. So Airbus should've known better,
>presumably.

The original pictures seemed to show clearly that the root attachments
failed at the attachment to the fuselage.

How easy in turbulence is it to develop a pilot induced yaw oscillation?
The fin might well withstand a full deflection but not a few reversals
that built up the maximum yaw oscillation. Fins and rudders are as big
as they are to deal with the engine out case at relatively low speed I
understand. Isn't one of the functions of a yaw damper to restrict and
damp a yaw oscillation?

Do the reports give any indication of the amount of yaw excursion that
took place?

--
David CL Francis

[tony zambon]

"David CL Francis" > wrote in message
...
> On Tue, 26 Oct 2004 at 20:52:36 in message
> >, Mike Rhodes
> > wrote:
>>I recall some question concerning a weakness in the design of the
>>rudder itself, in that the supports to the composite structure were
>>too few. Not too long after the accident, I saw it was explained on
>>TV that the manufacturer should have distributed the load over more
>>points for the sake of the composite material. The known and
>>understood weakness of composites, compared to metals, is their lesser
>>ability to handle bearing stress. So Airbus should've known better,
>>presumably.
>
> The original pictures seemed to show clearly that the root attachments
> failed at the attachment to the fuselage.
>
> How easy in turbulence is it to develop a pilot induced yaw oscillation?
> The fin might well withstand a full deflection but not a few reversals
> that built up the maximum yaw oscillation. Fins and rudders are as big as
> they are to deal with the engine out case at relatively low speed I
> understand. Isn't one of the functions of a yaw damper to restrict and
> damp a yaw oscillation?
>
> Do the reports give any indication of the amount of yaw excursion that
> took place?
>
> --
> David CL Francis

correct me if i am wrong but wasnt it the ntsb that a few years before
aa 587 critized a crew for not using full and complete control deflection
for another accident? i do not remember which one it was but shortly after
some of the airlines started going to those upset recovery courses. sounds
like the ntsb wants it both ways.

tony zambon
grumman 9941L