I have posted here before because I like to get answers from experts
about aviation. I have been interested in the media reporting on the
Air France Flight 447 crash. More to the point, I'm curious if you
all think they are missing a bigger story.

The Airbus planes employ something called fly-by-wire technology. As
I understand it, that means the actuators that move the control
surfaces of the aircraft are triggered solely by electrical wiring.
They don't rely on a hydrolic system to move the surfaces based on the
moves of the control stick.

So as I'm hearing about flight 447, the thought crosses my mind that
if lightning hit the plane just right, would it be possible for that
to send the wrong signals to the control actuators? Perhaps pushing
them in different directions and locking them there as the electric
connections failed due to the lightning strike? Or at the very least
severing the electric connections by frying the wires and making it
impossible for the crew to control the airplane. I know it has
redundant systems and lots of insulation on the wires, but it seems to
me that such an all-electric system makes a problem like this possible
where a hydrolic system does not.

I keep hearing aviation experts saying that a lightning strike
wouldn't bring down a plane of this size. I also seem to recall NASA
declaring that foam strikes wouldn't damage the shuttle enough to
cause it to break up on re-entry. I'm just wondering if fly-by-wire
has an undocumented (or unannounced) fatal flaw.

What do you think?

wrote:

> I have posted here before because I like to get answers from experts
> about aviation. I have been interested in the media reporting on the
> Air France Flight 447 crash. More to the point, I'm curious if you
> all think they are missing a bigger story.
>
> The Airbus planes employ something called fly-by-wire technology. As
> I understand it, that means the actuators that move the control
> surfaces of the aircraft are triggered solely by electrical wiring.
> They don't rely on a hydrolic system to move the surfaces based on the
> moves of the control stick.

The system still uses hydraulics to move the control surfaces.

> So as I'm hearing about flight 447, the thought crosses my mind that
> if lightning hit the plane just right, would it be possible for that
> to send the wrong signals to the control actuators? Perhaps pushing
> them in different directions and locking them there as the electric
> connections failed due to the lightning strike? Or at the very least
> severing the electric connections by frying the wires and making it
> impossible for the crew to control the airplane. I know it has
> redundant systems and lots of insulation on the wires, but it seems to
> me that such an all-electric system makes a problem like this possible
> where a hydrolic system does not.

Anything's possible, however nothing like that has ever shown up so far
on thousands of FBW aircraft that have been flying for over 20 years. It
has about a much credence as the plane being hit by falling debris from
space.

> I keep hearing aviation experts saying that a lightning strike
> wouldn't bring down a plane of this size. I also seem to recall NASA
> declaring that foam strikes wouldn't damage the shuttle enough to
> cause it to break up on re-entry. I'm just wondering if fly-by-wire
> has an undocumented (or unannounced) fatal flaw.

Don't think so.

> wrote in message
...
..
>
> What do you think?

I think that you are engaging in meaningless speculation.

Vaughn

> wrote in message
...
>I have posted here before because I like to get answers from experts
> about aviation. I have been interested in the media reporting on the
> Air France Flight 447 crash. More to the point, I'm curious if you
> all think they are missing a bigger story.
>
> The Airbus planes employ something called fly-by-wire technology. As
> I understand it, that means the actuators that move the control
> surfaces of the aircraft are triggered solely by electrical wiring.
> They don't rely on a hydrolic system to move the surfaces based on the
> moves of the control stick.
>
> So as I'm hearing about flight 447, the thought crosses my mind that
> if lightning hit the plane just right, would it be possible for that
> to send the wrong signals to the control actuators? Perhaps pushing
> them in different directions and locking them there as the electric
> connections failed due to the lightning strike? Or at the very least
> severing the electric connections by frying the wires and making it
> impossible for the crew to control the airplane. I know it has
> redundant systems and lots of insulation on the wires, but it seems to
> me that such an all-electric system makes a problem like this possible
> where a hydrolic system does not.
>
> I keep hearing aviation experts saying that a lightning strike
> wouldn't bring down a plane of this size. I also seem to recall NASA
> declaring that foam strikes wouldn't damage the shuttle enough to
> cause it to break up on re-entry. I'm just wondering if fly-by-wire
> has an undocumented (or unannounced) fatal flaw.
>
> What do you think?

I have been wondering the same thing. I know our history with FBW seems
golden with respect to lightening strikes, but they were flying near a large
thunder storm. Seems regardless of our success with FBW, perhaps they were
the victim of some kind of mega strike that overwhelmed their systems. Our
experience with lightening has documented some very powerful and bizarre
behavior, this might be a first.

But even if true, it wouldn't necessarily suggest a fatal flaw in FBW. A
possible loss of control or structural integrity could be unrelated to the
FBW system, and perhaps a supposed mega strike could have condemned a
conventionally controlled aircraft just as easily.

"Tim" > wrote:
>
> I have been wondering the same thing. I know our history with FBW
> seems golden with respect to lightening strikes, but they were flying
> near a large thunder storm.

According to two separate sources that track lightning, there was none
within something like 100 miles of their planned course, so it isn't clear
that they were anywhere near lightning. It's simply speculation on the
part of some pundits.

James Robinson wrote:
> "Tim" > wrote:
>> I have been wondering the same thing. I know our history with FBW
>> seems golden with respect to lightening strikes, but they were flying
>> near a large thunder storm.
>
> According to two separate sources that track lightning, there was none
> within something like 100 miles of their planned course, so it isn't clear
> that they were anywhere near lightning. It's simply speculation on the
> part of some pundits.

And those same two separate sources admit they don't have great coverage
in the Atlantic in that area, so I don't think that data point is any
more useful than the Air Comet flight that claimed they saw an "intense
flash of bright light." Their flight path was no closer than 2000 km
from the likely crash area of AF 447.

Given the actual data of satellite pics showing the continuous
convective buildups in that area, lightning in the area is certainly
plausible. Whether it actually touched the airplane, and if so whether
it led to a unrecoverable situation is certainly very questionable.

Clark > wrote:

> James Robinson > wrote in
> news:Xns9C20C3311F8C9wascana212com@ 94.75.244.46:
>
>> "Tim" > wrote:
>>>
>>> I have been wondering the same thing. I know our history with FBW
>>> seems golden with respect to lightening strikes, but they were
>>> flying near a large thunder storm.
>>
>> According to two separate sources that track lightning, there was
>> none within something like 100 miles of their planned course, so it
>> isn't clear that they were anywhere near lightning. It's simply
>> speculation on the part of some pundits.
>>
>
> Do those sources track air-to-air or air-to-ground lightning? If they
> are ground based then they only track air-to-ground and they will miss
> all the air-to-air stuff. That might make just a wee bit of
> difference...

They use satellites.

While that is a possibility the timing might suggest otherwise. The
malfunction reports that reported electrical and pressurization failures
came several minutes AFTER other serious malfunction reports. It is
possible the electrical and pressurization failures report was a RESULT of
an aircraft breakup.

> wrote in message
...
>I have posted here before because I like to get answers from experts
> about aviation. I have been interested in the media reporting on the
> Air France Flight 447 crash. More to the point, I'm curious if you
> all think they are missing a bigger story.
>
> The Airbus planes employ something called fly-by-wire technology. As
> I understand it, that means the actuators that move the control
> surfaces of the aircraft are triggered solely by electrical wiring.
> They don't rely on a hydrolic system to move the surfaces based on the
> moves of the control stick.
>
> So as I'm hearing about flight 447, the thought crosses my mind that
> if lightning hit the plane just right, would it be possible for that
> to send the wrong signals to the control actuators? Perhaps pushing
> them in different directions and locking them there as the electric
> connections failed due to the lightning strike? Or at the very least
> severing the electric connections by frying the wires and making it
> impossible for the crew to control the airplane. I know it has
> redundant systems and lots of insulation on the wires, but it seems to
> me that such an all-electric system makes a problem like this possible
> where a hydrolic system does not.
>
> I keep hearing aviation experts saying that a lightning strike
> wouldn't bring down a plane of this size. I also seem to recall NASA
> declaring that foam strikes wouldn't damage the shuttle enough to
> cause it to break up on re-entry. I'm just wondering if fly-by-wire
> has an undocumented (or unannounced) fatal flaw.
>
> What do you think?

> ...
> .
>>
>> What do you think?
>

Here is something I found interesting:
http://www.weathergraphics.com/tim/af447/

Kobra

Panic wrote:
> While that is a possibility the timing might suggest otherwise. The
> malfunction reports that reported electrical and pressurization failures
> came several minutes AFTER other serious malfunction reports. It is
> possible the electrical and pressurization failures report was a RESULT of
> an aircraft breakup.

ACARS did not report a "pressurization failure." ACARS reported a cabin
altitude alarm. Although loss of pressurization could be one reason for
this alarm, another would be a fast descent and "catching the cabin" or
the outside altitude getting too close too fast to the cabin altitude.

Beware what you read in the press, they are taking raw data and either
misinterpreting it or trying to "simplify" it for their impression of
their reader's intelligence.

Exhibit A for this is the NY Times:

"A loss of cabin pressure could suggest a break in the fuselage, but
planes are built to withstand buffeting from a storm’s updrafts and
downdrafts. It could also be a consequence of an electrical failure, if
the plane’s air compressors stop working."

As if the A300 has electric air compressors! No western transport plane
flying today does, although the Boeing 787 will change that. Perhaps
the "reporters" should do a little fact checking and research about what
they are writing about.

One has no idea how true this is, but for what it's worth, read on:.

More chilling information about the use and
misuse of composite materials. The risks look bad. Nick

Subject: Air France Accident: Smoking Gun Found

>
>A Brazilian Naval unit reportedly found the complete vertical
>fin/rudder assembly of the doomed aircraft floating some 30 miles
>from the main debris field. The search for the flight recorders goes
>on, but given the failure history of the vertical fins on
>A300-series aircraft, an analysis of its structure at the point of
>failure will likely yield the primary cause factor in the breakup of
>the aircraft, with the flight recorder data (if found) providing
>only secondary contributing phenomena.
>
>The fin-failure-leading-to-breakup sequence is strongly suggested in
>the attached (below) narrative report by George Larson, Editor
>emeritus of Smithsonian Air & Space Magazine.
>
>It's regrettable that these aircraft are permitted to continue in
>routine flight operations with this known structural defect. It
>appears that safety finishes last within Airbus Industries, behind
>national pride and economics. Hopefully, this accident will force
>the issue to be addressed, requiring at a minimum restricted
>operations of selected platforms, and grounding of some high-time
>aircraft until a re-engineered (strengthened) vertical fin/rudder
>attachment structure can be incorporated.
>
>Les
>
>

WHAT FOLLOWS HAS NOT BEEN INDEPENDENTLY VERIFIED

--------------------------(George Larson's Report)----------------
>
>This is an account of a discussion I had recently with a maintenance
>professional
>who salvages airliner airframes for a living. He has been at it for
>a while, dba BMI
>Salvage at Opa Locka Airport in Florida. In the process of stripping
>parts, he sees
>things few others are able to see. His observations confirm prior
>assessments of
>Airbus structural deficiencies within our flight test and aero
>structures communities
>by those who have seen the closely held reports of A3XX-series
>vertical fin failures.
>
>His observations:
>
>"I have scrapped just about every type of transport aircraft from A-310,
>A-320, B-747, 727, 737, 707, DC-3, 4, 6, 7, 8, 9, 10, MD-80, L-188, L1011
>and various Martin, Convair and KC-97 aircraft.
>
>Over a hundred of them.
>
>Airbus products are the flimsiest and most poorly designed as far as
>airframe structure is concerned by an almost obsession to utilize composite
>materials.
>
>I have one A310 vertical fin on the premises from a demonstration I just
>performed. It was pathetic to see the composite structure shatter as it did,
>something a Boeing product will not do.
>
>The vertical fin along with the composite hinges on rudder and elevators is
>the worst example of structural use of composites I have ever seen and I am
>not surprised by the current pictures of rescue crews recovering the
>complete Vertical fin and rudder assembly at some distance from the crash
>site.
>
>The Airbus line has a history of both multiple rudder losses and a vertical
>fin and rudder separation from the airframe as was the case in NY with AA.
>
>As an old non-radar equipped DC4 pilot who flew through many a thunderstorm
>in Africa along the equator, I am quite familiar with their
>ferocity. It is not
>difficult to understand how such a storm might have stressed an aircraft
>structure to failure at its weakest point, and especially so in the
>presence of
>instrumentation problems.
>
>I replied with this:
>
>"I'm watching very carefully the orchestration of the inquiry by French
>officials and Airbus. I think I can smell a concerted effort to steer
>discussion away from structural issues and onto sensors, etc. Now Air France, at the behest of their pilots' union, is replacing all the air data
>sensors on the Airbus fleet, which creates a distraction and shifts the
>media's focus away from the real problem.
>
>It's difficult to delve into the structural issue without wading into the
>Boeing vs. Airbus swamp, where any observation is instantly tainted by its
>origin. Americans noting any Airbus structural issues (A380 early failure
>of wing in static test; loss of vertical surfaces in Canadian fleet prior to
>AA A300, e.g.) will be attacked by the other side as partisan, biased, etc. "
>
>His follow-up:
>
>One gets a really unique insight into structural issues when one has
>first-hand experience in the dismantling process.
>
>I am an A&P, FEJ and an ATP with 7000 flight hours and I was absolutely
>stunned, flabbergasted when I realized that the majority of internal
>airframe structural supports on the A 310 which appear to be aluminum are actually rolled composite material with aluminum rod ends. They shattered.
>
>Three years ago we had a storm come through, with gusts up to 60-70 kts.,
>catching several A320s tied down on the line, out in the open.
>
>The A320 elevators and rudder hinges whose actuators had been
>removed shattered and the rudder and elevators came off.
>
>Upon closer inspection I realized that not only were the rear spars
>composite but so were the hinges. While Boeing also uses composite
>material in its airfoil structures, the actual attach fittings for
>the elevators, rudder, vertical and horizontal stabilizers are all of machined aluminum."
>-----------------(end of narrative)---------------

a > wrote:
> One has no idea how true this is, but for what it's worth, read on:.
>
> More chilling information about the use and
> misuse of composite materials. The risks look bad. Nick
[ Elided ]

Since the "report" is devoid of numbers, it is absolutely worthless. Yes,
composites can shatter. Metals bend, fatigue, and break. The issue isn't in
so much as how these different materials fail, but the values of the
stresses that they fail at.

The "report" relies on subjective claims of "flimsiest" and "poorly
designed" and appeals to authority as a substitute for objective stress
measurements.

a > wrote:

> One has no idea how true this is, but for what it's worth, read on:.

It's sensationalist garbage.

The fact that the maintenance system transmitted for four minutes says that
not only was the aircraft more or less in one piece during that time, but
that the electrical systems were still functioning. If the tail snapped
off as suggested, the aircraft wouldn't have lasted more than a few seconds
at that altitude and speed.

Indications are stronger that the failure of the vertical stabilizer was a
consequence rather than a cause of the accident.

Jim Logajan wrote:
> a > wrote:
>> One has no idea how true this is, but for what it's worth, read on:.
>>
>> More chilling information about the use and
>> misuse of composite materials. The risks look bad. Nick
> [ Elided ]
>
> Since the "report" is devoid of numbers, it is absolutely worthless. Yes,
> composites can shatter. Metals bend, fatigue, and break. The issue isn't in
> so much as how these different materials fail, but the values of the
> stresses that they fail at.
>
> The "report" relies on subjective claims of "flimsiest" and "poorly
> designed" and appeals to authority as a substitute for objective stress
> measurements.


It's not that composites CAN shatter when overstressed - they certainly
WILL shatter. Hence design factors are increased for these materials.
Apart from that quibble, I'm with Jim on this one

Brian W

James Robinson wrote:
> a > wrote:
>
>> One has no idea how true this is, but for what it's worth, read on:.
>
> It's sensationalist garbage.
>
> The fact that the maintenance system transmitted for four minutes says that
> not only was the aircraft more or less in one piece during that time, but
> that the electrical systems were still functioning. If the tail snapped
> off as suggested, the aircraft wouldn't have lasted more than a few seconds
> at that altitude and speed.
>
> Indications are stronger that the failure of the vertical stabilizer was a
> consequence rather than a cause of the accident.

Would it be possible that four minutes is how long it took the aircraft
(or the remains of hit) to hit the water? That would be a 8750 feet per
minute vertical speed, which seems a realist figure to me. Furthermore I
am on the impression that the system is autonomous, thus could still
function once the aircraft was broken apart (if so was the case).

Tom Duhamel > wrote:

> James Robinson wrote:
>
>> a > wrote:
>>
>>> One has no idea how true this is, but for what it's worth, read on:.
>>
>> It's sensationalist garbage.
>>
>> The fact that the maintenance system transmitted for four minutes
>> says that not only was the aircraft more or less in one piece during
>> that time, but that the electrical systems were still functioning.
>> If the tail snapped off as suggested, the aircraft wouldn't have
>> lasted more than a few seconds at that altitude and speed.
>>
>> Indications are stronger that the failure of the vertical stabilizer
>> was a consequence rather than a cause of the accident.
>
> Would it be possible that four minutes is how long it took the
> aircraft (or the remains of hit) to hit the water? That would be a
> 8750 feet per minute vertical speed, which seems a realist figure to
> me. Furthermore I am on the impression that the system is autonomous,
> thus could still function once the aircraft was broken apart (if so
> was the case).

Anything is possible, however, the communication link depends on a
relatively stable aircraft, since the satcom antennas mounted on the top
of the fuselage have to be directed at the satellites. If the aircraft
is banked more than something like 70 degrees, or pitching or rolling
wildly, the communication link would be broken. It certainly wouldn't
work if the aircraft wasn't in one piece.

Further, the messages indicate that while many things were going wrong on
the aircraft, the fact that the communication took place at all suggests
that electrical system was more or less functional for the four minute
period.

"a" > wrote in message
...
> One has no idea how true this is, but for what it's worth, read on:.
>
snip

More at

http://www.globalresearch.ca/index.php?context=va&aid=14025

Happy landings,

Private wrote:
> "a" > wrote in message
> ...
>> One has no idea how true this is, but for what it's worth, read on:.
>>
> snip
>
> More at
>
> http://www.globalresearch.ca/index.php?context=va&aid=14025
>
> Happy landings,
>
>
>
Dear Anonymous Poster,

the level of engineering insight of this URL is typified by this
paragraph:
"We do not know if Air France Flight 447 was brought down by a
lightning storm, a failure of speed sensors, rudder problems or pilot
error. What we do know is that its plastic tail fin fell off and the
plane fell almost seven miles into the ocean killing everyone aboard."

If you don't realize the level of insight offered in this paragraph,
should you be spreading it?

Brian Whatcott
Altus OK
(Real Name at Real Place.)

In article >,
Brian Whatcott > wrote:

> Private wrote:
> > "a" > wrote in message
> > ...
> >> One has no idea how true this is, but for what it's worth, read on:.
> >>
> > snip
> >
> > More at
> >
> > http://www.globalresearch.ca/index.php?context=va&aid=14025
> >
> > Happy landings,
> >
> >
> >
> Dear Anonymous Poster,
>
> the level of engineering insight of this URL is typified by this
> paragraph:
> "We do not know if Air France Flight 447 was brought down by a
> lightning storm, a failure of speed sensors, rudder problems or pilot
> error. What we do know is that its plastic tail fin fell off and the
> plane fell almost seven miles into the ocean killing everyone aboard."
>
> If you don't realize the level of insight offered in this paragraph,
> should you be spreading it?

That is indeed ridiculous.

I particularly enjoy the derisive use of the word "plastic" to describe
the vertical stabilizer. As an owner of a composite aircraft, I can tell
you that I much prefer "plastic" to metal when given the choice. Yeah,
when you exceed its strength it fails in a completely unforgiving
manner, but composites make it a *lot* harder to get to that point in
the first place.

Perhaps there really is an engineering deficiency here, but to think
that it's the fault of the material itself and that airliner engineering
should just ignore new materials technology and stick to good ol'
aluminum forever is silly. Glider makers figured out how great
composites were forty years ago, it's about time for the rest to catch
up too.

(And yes, I realize that there are certain differences between building
a 600-pound glider and a 200,000-pound airliner, and between engineering
something to be safe enough to carry a single dare-devilish pilot and
carrying hundreds of paying passengers. But four decades ought to be
enough to figure out how it works for the latter, and indeed things are
moving that way.)

--
Mike Ash
Radio Free Earth
Broadcasting from our climate-controlled studios deep inside the Moon

Mike Ash wrote:

> That is indeed ridiculous.

Even more funny is that those Airbus bashers don't seem to realize that
a certain Boeing Dreamliner, should it ever fly, is built with a much
higher percentage of plastic parts than any Airbus.

In article >,
John Smith > wrote:

> Mike Ash wrote:
>
> > That is indeed ridiculous.
>
> Even more funny is that those Airbus bashers don't seem to realize that
> a certain Boeing Dreamliner, should it ever fly, is built with a much
> higher percentage of plastic parts than any Airbus.

It didn't occur to me that they would be Boeing partisans. I just
figured they were anti-composites. If they are Boeing fans then that
does indeed make it that much funnier.

--
Mike Ash
Radio Free Earth
Broadcasting from our climate-controlled studios deep inside the Moon

"Brian Whatcott" > wrote in message
...
> Private wrote:
>> "a" > wrote in message
>> ...
>>> One has no idea how true this is, but for what it's worth, read on:.
>>>
>> snip
>>
>> More at
>>
>> http://www.globalresearch.ca/index.php?context=va&aid=14025
>>
>> Happy landings,
>>
>>
>>
> Dear Anonymous Poster,
>
> the level of engineering insight of this URL is typified by this
> paragraph:
> "We do not know if Air France Flight 447 was brought down by a lightning
> storm, a failure of speed sensors, rudder problems or pilot error. What
> we do know is that its plastic tail fin fell off and the plane fell almost
> seven miles into the ocean killing everyone aboard."
>
> If you don't realize the level of insight offered in this paragraph,
> should you be spreading it?
>

IMHO the quoted passage is a fair statement of what we currently suspect,
hopefully further investigation will reveal more complete information.

The link was offered to stimulate thought and discussion and with the
qualifier "One has no idea how true this is, but for what it's worth, read
on:"

All pilots are (as always) encouraged to apply their own knowledge and
experience to form their own conclusions.

Happy landings,

"Mike Ash" > wrote in message
...
> In article >,
> Brian Whatcott > wrote:
>
>> Private wrote:
>> > "a" > wrote in message
>> > ...
>> >> One has no idea how true this is, but for what it's worth, read on:.
>> >>
>> > snip
>> >
>> > More at
>> >
>> > http://www.globalresearch.ca/index.php?context=va&aid=14025
>> >
>> > Happy landings,
>> >
snip
> (And yes, I realize that there are certain differences between building
> a 600-pound glider and a 200,000-pound airliner, and between engineering
> something to be safe enough to carry a single dare-devilish pilot and
> carrying hundreds of paying passengers. But four decades ought to be
> enough to figure out how it works for the latter, and indeed things are
> moving that way.)
>
snip

I do not disagree with much of your post, and also have personally enjoyed
many happy hours flying glass gliders and powered aircraft, but feel
compelled to submit that in addition to the obvious weight differences, most
gliders live in a (UV free) trailer or hanger, and IMHE few have accumulated
over 5000 hours (500-2000 hrs is more average) vs. >50,000 hours for
airliners. (I once flew in a 737-200 that had >70,000 hrs and a similar
number of cycles.) On most small powered and glider glass aircraft the
vertical stab is formed as an integral part of the fuselage vs. the airliner
where the weak point of the assembly seems to be the point of attachment to
the fuselage. I suspect you will also agree that in addition to the
increased loading and much higher speeds, the consequence of structural
failure of a commercial aircraft carrying large numbers of passengers is
greater than that of a much slower glider carrying 1 or 2 flyers who are
probably also wearing parachutes.

The real point of the article was that the materials technology, service
expectations and proper inspection procedures seem to still be under
development and that we still have much to learn. Older glass gliders often
display obvious deterioration of at least the gel coat and crashes have been
caused by structural failure or lightning strikes.

Happy landings,

Mike Ash wrote:

> It didn't occur to me that they would be Boeing partisans.

Look at the subject ;-)

While I certainly distance myself from any of this sensationalist
speculation, and do not in any way join the Airbus detractors, I do think
the apparent similarity of the vertical stabilizer separation in the two
accidents is worthy of investigation. I am also fully confident that it
will be investigated, and determined as to whether the similarity is only
an apparent one or not. This is significant even if we never determine
what its contribution may have been in the causality of the Air France
accident.

In article >,
"Private" > wrote:

> "Mike Ash" > wrote in message
> ...
> > In article >,
> > Brian Whatcott > wrote:
> >
> >> Private wrote:
> >> > "a" > wrote in message
> >> > ...
> >> >> One has no idea how true this is, but for what it's worth, read on:.
> >> >>
> >> > snip
> >> >
> >> > More at
> >> >
> >> > http://www.globalresearch.ca/index.php?context=va&aid=14025
> >> >
> >> > Happy landings,
> >> >
> snip
> > (And yes, I realize that there are certain differences between building
> > a 600-pound glider and a 200,000-pound airliner, and between engineering
> > something to be safe enough to carry a single dare-devilish pilot and
> > carrying hundreds of paying passengers. But four decades ought to be
> > enough to figure out how it works for the latter, and indeed things are
> > moving that way.)
> >
> snip
>
> I do not disagree with much of your post, and also have personally enjoyed
> many happy hours flying glass gliders and powered aircraft, but feel
> compelled to submit that in addition to the obvious weight differences, most
> gliders live in a (UV free) trailer or hanger, and IMHE few have accumulated
> over 5000 hours (500-2000 hrs is more average) vs. >50,000 hours for
> airliners. (I once flew in a 737-200 that had >70,000 hrs and a similar
> number of cycles.) On most small powered and glider glass aircraft the
> vertical stab is formed as an integral part of the fuselage vs. the airliner
> where the weak point of the assembly seems to be the point of attachment to
> the fuselage. I suspect you will also agree that in addition to the
> increased loading and much higher speeds, the consequence of structural
> failure of a commercial aircraft carrying large numbers of passengers is
> greater than that of a much slower glider carrying 1 or 2 flyers who are
> probably also wearing parachutes.

All fine points. I understand that the circumstances are greatly
different (thus my parenthetical above), but it seems that 40 years
ought to be enough to move from the one to the other. And indeed, it
seems that both Airbus and Boeing think this way as well.

> The real point of the article was that the materials technology, service
> expectations and proper inspection procedures seem to still be under
> development and that we still have much to learn. Older glass gliders often
> display obvious deterioration of at least the gel coat and crashes have been
> caused by structural failure or lightning strikes.

Gel coat deterioration is largely inconsequential, as it's not
structural and can be easily replaced. (Obviously it's not
"inconsequential" for the poor glider owner who has to pay five figures
for a refinish, but in terms of maintenance it's easy to spot and a
known quantity for repair.)

The lightning strike angle is an interesting one. I assume you're
referring to that ASK-21 which exploded over the UK a few years back,
and which we've seen some posts about from the passenger recently. I'm
not aware of another such incident, but that's probably more because
gliders are fair-weather beasts, not because they're usually immune to
lightning. Are there any other incidents you know of?

As for the structural failure angle, my (admittedly highly limited)
understanding is that there basically isn't any other than that
resulting from exceeding design limits or from manufacturing defects. My
club has an Open Cirrus which is over 40 years old and it's built like a
tank, and by all indications every bit as strong right now as it was
when it was built. My understanding is that this is the norm for
composite construction, as long as it's properly protected from the
elements. An important thing is that it doesn't really fatigue the way
metal does. Let's not forget that metal fatigue killed a bunch of
airline passengers in the 50s and remains a significant (and
occasionally deadly) concern today.

No doubt there is much to learn, and maybe the Airbus was improperly
designed, but my point is simply that a knee-jerk rejection of all
composites (which is what the article seemed to be trying to do with its
pejorative use of the word "plastic") is not the way to go.

Again, my knowledge on the subject is quite limited, so if I'm wrong
about any of the above, or just missing further important information, I
would very much appreciate any correction!

--
Mike Ash
Radio Free Earth
Broadcasting from our climate-controlled studios deep inside the Moon

Mike Ash wrote:
> I particularly enjoy the derisive use of the word "plastic" to describe
> the vertical stabilizer. As an owner of a composite aircraft, I can tell
> you that I much prefer "plastic" to metal when given the choice. Yeah,
> when you exceed its strength it fails in a completely unforgiving
> manner, but composites make it a *lot* harder to get to that point in
> the first place.
>
> Perhaps there really is an engineering deficiency here, but to think
> that it's the fault of the material itself and that airliner engineering
> should just ignore new materials technology and stick to good ol'
> aluminum forever is silly. Glider makers figured out how great
> composites were forty years ago, it's about time for the rest to catch
> up too.
>
> (And yes, I realize that there are certain differences between building
> a 600-pound glider and a 200,000-pound airliner, and between engineering
> something to be safe enough to carry a single dare-devilish pilot and
> carrying hundreds of paying passengers. But four decades ought to be
> enough to figure out how it works for the latter, and indeed things are
> moving that way.)
>

Gliders fly at lower altitudes, at lower speeds, in good weather
conditions...

Airliners fly in high altitude, high speed, low temperature, in
thunderstorms...

How good is composite when lightning strikes? Doesn't is explode or
something? I don't think it will conduct electricity, does it?

Please see that as questions, I really don't know much and I'm
wondering. I'm not trying to reduce your opinion in anyway.

Tom :)

"Mike Ash" > wrote in message
...
>> snip
>> > something to be safe enough to carry a single dare-devilish pilot and
snip
> Gel coat deterioration is largely inconsequential, as it's not >
> structural

How do we know for sure?

snip
> As for the structural failure angle, my (admittedly highly limited)
> understanding is that there basically isn't any other than that
> resulting from exceeding design limits or from manufacturing defects.

EXACTLY my point.

snip
> No doubt there is much to learn, and maybe the Airbus was improperly
> designed, but my point is simply that a knee-jerk rejection of all
> composites (which is what the article seemed to be trying to do with its
> pejorative use of the word "plastic") is not the way to go.
>
> Again, my knowledge on the subject is quite limited, so if I'm wrong
> about any of the above, or just missing further important information, I
> would very much appreciate any correction!


I think we are in substantial agreement, I particularly liked your original
reference to "a single dare-devilish pilot" and am reminded of the final
words (and on his gravestone) of Otto Lilienthal.
http://en.wikipedia.org/wiki/Otto_Lilienthal
His statement "Sacrifices must be made" pretty much sums up the history of
all aviation development, during which most advances have been accompanied
by the loss of (lots of) both blood and money.

IMHO, The use of the term 'plastic' is probably improper and certainly
overly general but it is common usage, and while I do agree that precise
language is an important goal, I try not to get too fixated on semantics.

Composites offer significant opportunities for improved aircraft
performance, but the use of these materials is complicated by the
variability of the materials and difficulty of quality control.in both
manufacturing and maintenance. It seems that better inspection procedures
for QC need to be developed and implemented and this will be of increased
importance as composite use increases and the fleet ages. We went through a
similar period in the development of metal airframes.

Happy landings,

In article >,
"Private" > wrote:

> I think we are in substantial agreement, I particularly liked your original
> reference to "a single dare-devilish pilot" and am reminded of the final
> words (and on his gravestone) of Otto Lilienthal.
> http://en.wikipedia.org/wiki/Otto_Lilienthal
> His statement "Sacrifices must be made" pretty much sums up the history of
> all aviation development, during which most advances have been accompanied
> by the loss of (lots of) both blood and money.

Yes, it seems to me that we are in agreement as well. How unusual. :)

> IMHO, The use of the term 'plastic' is probably improper and certainly
> overly general but it is common usage, and while I do agree that precise
> language is an important goal, I try not to get too fixated on semantics.

Normally I would consider it to be completely unimportant. However in
this particular case, it's clearly being used as a pejorative. I don't
care all that much about his use of the word "plastic", it's merely
indicative of the overall attitude that composites are bad and people
who use them are stupid. In other words, "plastic" is a symptom, not the
disease. I've heard glider people refer to composite aircraft as
"plastic" from time to time and that doesn't bother me at all, because
the intent is not the same.

> Composites offer significant opportunities for improved aircraft
> performance, but the use of these materials is complicated by the
> variability of the materials and difficulty of quality control.in both
> manufacturing and maintenance. It seems that better inspection procedures
> for QC need to be developed and implemented and this will be of increased
> importance as composite use increases and the fleet ages. We went through a
> similar period in the development of metal airframes.

The incremental use of composites in airliners, starting with small bits
here and there and working up, seems like the proper way to do things
here. I don't expect, or want, the airline industry to drop aluminum and
start doing everything in composites. An evolutionary approach as is
being done now will get us there in the end with a minimum of surprises.

--
Mike Ash
Radio Free Earth
Broadcasting from our climate-controlled studios deep inside the Moon

In article >,
Tom Duhamel > wrote:

> Gliders fly at lower altitudes, at lower speeds, in good weather
> conditions...
>
> Airliners fly in high altitude, high speed, low temperature, in
> thunderstorms...

Don't think airliners fly higher. It's true that *on average* they do,
and they certainly collect *vastly* more time at FL360 than gliders do,
but gliders *do* collect time there. The current glider altitude record,
set in a composite glider, is over 50,000ft. I don't think low
temperatures or pressures have been seen to do anything bad to the
structure. A fellow did tell me once that a rapid descent can do bad
things to the gelcoat due to the temperature change, but that's a
separate issue, and I don't know if an airliner would even use that sort
of coating.

For speeds, that's really just a matter of increased structural strength
and stiffness, which means using more stuff or different shapes. The
question is how the composites tolerate load, which is well known. They
won't change their characteristics suddenly just because they're moving.

> How good is composite when lightning strikes? Doesn't is explode or
> something? I don't think it will conduct electricity, does it?

This one is a completely open question to me. No, they don't conduct
electricity as far as I know. In the one famous case of a glider getting
hit by lightning, the lightning traveled along metal control rods. The
rods superheated the air inside the wings, blowing the glider to bits.
Obviously this is not a desirable outcome for an airliner carrying 300
people and no parachutes. I can only assume that the smart engineers
working on this stuff have figured out a way to stop this from
happening, but I have no idea at all what that way would be.

--
Mike Ash
Radio Free Earth
Broadcasting from our climate-controlled studios deep inside the Moon

Mike Ash > wrote:
> In article >,
> Tom Duhamel > wrote:
>
>> Gliders fly at lower altitudes, at lower speeds, in good weather
>> conditions...
>>
>> Airliners fly in high altitude, high speed, low temperature, in
>> thunderstorms...
>
> Don't think airliners fly higher. It's true that *on average* they do,
> and they certainly collect *vastly* more time at FL360 than gliders do,
> but gliders *do* collect time there. The current glider altitude record,
> set in a composite glider, is over 50,000ft. I don't think low
> temperatures or pressures have been seen to do anything bad to the
> structure. A fellow did tell me once that a rapid descent can do bad
> things to the gelcoat due to the temperature change, but that's a
> separate issue, and I don't know if an airliner would even use that sort
> of coating.
>
> For speeds, that's really just a matter of increased structural strength
> and stiffness, which means using more stuff or different shapes. The
> question is how the composites tolerate load, which is well known. They
> won't change their characteristics suddenly just because they're moving.
>
>> How good is composite when lightning strikes? Doesn't is explode or
>> something? I don't think it will conduct electricity, does it?
>
> This one is a completely open question to me. No, they don't conduct
> electricity as far as I know. In the one famous case of a glider getting
> hit by lightning, the lightning traveled along metal control rods. The
> rods superheated the air inside the wings, blowing the glider to bits.
> Obviously this is not a desirable outcome for an airliner carrying 300
> people and no parachutes. I can only assume that the smart engineers
> working on this stuff have figured out a way to stop this from
> happening, but I have no idea at all what that way would be.
>

Embedded conductive layers.

http://www.lightningtech.com/d~ta/faq1.html

--
Jim Pennino

Remove .spam.sux to reply.

Tom Duhamel > wrote:
> How good is composite when lightning strikes?

The following article titled "Building the 787: When lightning strikes"
may provide some background:

http://seattletimes.nwsource.com/html/businesstechnology/2002844619_boeing05.html

> Doesn't is explode or something?

Probably depends on its electrical conductivity, which in turn depends
on the composition and construction of the fiber. (With enough current
you can even explode a conductor; something of interest to scientists
studying plasmas - and people who like to blow things up:

http://tesladownunder.com/Pulse_Power.htm
http://etd.caltech.edu/etd/available/etd-08022006-104759/
http://www.plasmacenter.cornell.edu/ExplodingWires.html )

> I don't think it will conduct electricity, does it?

Depends on the composite. If it is carbon fiber, then it can be made to
conduct electricity:

"The fiber also finds use in filtration of high-temperature gasses, as
an electrode with high surface area and impeccable corrosion resistance,
and as an anti-static component." From:
http://en.wikipedia.org/wiki/Carbon_fiber

In article >,
says...
> Tom Duhamel > wrote:
> > How good is composite when lightning strikes?
>
> The following article titled "Building the 787: When lightning strikes"
> may provide some background:
>
> http://seattletimes.nwsource.com/html/businesstechnology/2002844619_boeing05.html
>
> > Doesn't is explode or something?
>
> Probably depends on its electrical conductivity, which in turn depends
> on the composition and construction of the fiber. (With enough current
> you can even explode a conductor; something of interest to scientists
> studying plasmas - and people who like to blow things up:
>
> http://tesladownunder.com/Pulse_Power.htm
> http://etd.caltech.edu/etd/available/etd-08022006-104759/
> http://www.plasmacenter.cornell.edu/ExplodingWires.html )
>
> > I don't think it will conduct electricity, does it?
>
> Depends on the composite. If it is carbon fiber, then it can be made to
> conduct electricity:
>
> "The fiber also finds use in filtration of high-temperature gasses, as
> an electrode with high surface area and impeccable corrosion resistance,
> and as an anti-static component." From:
> http://en.wikipedia.org/wiki/Carbon_fiber

Humans seem to conduct quite well, check out this Indian (meeting his
maker) on top of a train. Warning, some might find it a bit graphic, so
don't watch it...

http://www.liveleak.com/view?i=fc0_1243424473

--
Duncan

In article >,
wrote:

> >> How good is composite when lightning strikes? Doesn't is explode or
> >> something? I don't think it will conduct electricity, does it?
> >
> > This one is a completely open question to me. No, they don't conduct
> > electricity as far as I know. In the one famous case of a glider getting
> > hit by lightning, the lightning traveled along metal control rods. The
> > rods superheated the air inside the wings, blowing the glider to bits.
> > Obviously this is not a desirable outcome for an airliner carrying 300
> > people and no parachutes. I can only assume that the smart engineers
> > working on this stuff have figured out a way to stop this from
> > happening, but I have no idea at all what that way would be.
>
> Embedded conductive layers.
>
> http://www.lightningtech.com/d~ta/faq1.html

Cool stuff. Thanks!

--
Mike Ash
Radio Free Earth
Broadcasting from our climate-controlled studios deep inside the Moon

On Jun 23, 9:39*am, Tom Duhamel > wrote:

> Gliders fly at lower altitudes, at lower speeds, in good weather
> conditions...

Up until you start flying in wave and get intimate with rotor.
And they (generally) have to be rigged every time you want to go
flying and there are some rough handlers out there !

george wrote:

>> Gliders fly at lower altitudes, at lower speeds, in good weather
>> conditions...
>
> Up until you start flying in wave and get intimate with rotor.

Or within a cumulus congestus.

But agreed, they don't have a pressurized cabin and are usually stored
in shelter.

Dave Doe wrote:
> Humans seem to conduct quite well, check out this Indian (meeting his
> maker) on top of a train. Warning, some might find it a bit graphic, so
> don't watch it...
>
> http://www.liveleak.com/view?i=fc0_1243424473
>

On the contrary, it's actually because we don't conduct electricity well
that we suffer from it. Since we resist current, we burn (not mentioning
the effect on some of our organs).

Nice video, but not to be shown to children!

wrote:
> Embedded conductive layers.
>
> http://www.lightningtech.com/d~ta/faq1.html
>

Really good article. Summed up some of my interrogations. Thanks for the
link, Jim :)