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 (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)---------------
I remember a discussion, several years ago about delamination of
composites materials (AA Airbus accident, New York).
This seems to be adding more fuel to the fire.
As for me, I will avoid flying in these planes until the whole smoke
settles down.
Alfonso
My theory is the water gets in a de-lamination crack and greatly expands
when it freezes at high altitude enlarging the length of the crack until
it fails. This is a process that converts solid rock mountains to sand
over time.
Paul Lamar
Any structure can be damaged by mishandling - leaving control surfaces
disconnected from their actuation hardware. Mishandling means
different things to different designs and materials. I'm not riding
in to the rescue on the side of Airbus - I think they may have a real
problem - but I think it's also not valid to say "You can't build a
safe composite hinge (because Boeing doesn't choose to)."
BTW, B737's have a history of rudder problems too - a control
hydraulics issue. They have lost a few airplanes to this issue. They
put out a fix for it, lost another airplane, and then put out another
fix - if I recall the events correctly. I still like B737's better
than A320 even so.
Paul, you're idea is quite possibly correct, though that seems like a
fairly obvious thing to test for. Might not be able to test on the
line for it very easily, but the lab should be able to see it.
Regards,
Matt-
Guys,
I really do like how people on this forum are considering
all angles when examining this crash.
I guess I want to caution ourselves about jumping to any
conclusions, especially about structures (I canNOT believe I am
writing this about an Airbus! Why was it not ME who found the
Glenn Larson article!?) . Yes, I give full credit to Mr.
Larson's reporting. Yes, I doubt not that the dismantler saw
what he saw. What happened after the storm at his airport
happened. There is no denying these things.
Many more eyes than just French are examining the Air France
wreck, thanks to the Internet. My brother, who is a senior
composites researcher at Boeing (see what I mean about
unbelief?) is watching, too, and he may have some interesting
tidbits to share with us, but not just yet.
I am not putting anybody down. I am just cautioning us against
over-confidence and committing too early to a theory, without
fully considering all the evidence.
Maybe it would be good for us to look again, verrry closely, at
the recovered tail section, in verrrry high-resolution photos?
That's all I can say for now.
Treading lightly,
Les Nordman
So far we got two Airbuses with two tails falling off :)
Paul Lamar
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