Interesting Airbus / Air France read
 

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."




Sorry for some of the syntax errors, it didn't transfer over well. I hadn't even thought to correlate this crash with the AA in 2001. Any airbus drivers wanna chime in on this?

I don't drive the airbus, but I agree with this scenario being fairly likely. Extreme turbulence, loss of vertical stab and resulting loss of control/ breakup. I believe the very first message transmitted was a rudder limit fault.

The history of vert stab/rudder failures is on the A300/310 series, not the A320. Different airplanes, although I'm sure some design philosophy bleed over.

In an extreme turbulence situation, the vert stab is probably the most likely thing to fail first on any aircraft. It has a large lever arm.

Also the wings/ailerons and horiz stab/elevators are designed to take large loads in normal flight regime.

The vertical structure normally only needs to handle large control deflections in a low-speed, engine out scenario. It is designed with a lot of area to generate needed counter-yaw at low airspeed.

But there is certainly suspicion that airbus takes a minimalist approach to vert stab strength, as compared to other manufacturers.

There's no such thing as a minimalist approach to certification of an airframe in this day and age!

The Aircraft are certified under JAR-21 Certification Procedures for Aircraft, products and related parts.

Under the JAA board, there is a JAA Committee and Joint Steering Assembly that is heavily involved with JAA/FAA Harmonisation. This also drives requirements for JAA/FAA certification.


Al

Airbus isnt alone in its rudder issues if you recall the RPCU issues on the 737.

Could've been a rudder failure due to a rudder limiter failure...

June 14, 2009, (Sawf News) - The spate of automatic messages sent by Air France Flight 447 Airbus A330 minutes before it disappeared included one that indicated that a rudder safety device had disengaged.

"The message tells us that the rudder limiter was inoperative," Jack Casey, an aviation safety consultant in Washington, D.C., told AP. "It does not give you any reason why it is not working or what caused it, or what came afterward."

The rudder limiter regulates the extent to which rudder can be applied at a given air speed to preclude structural damage to the aircraft.

With the limiter inoperative, excessive rudder inputs at high speed could cause the vertical stabilizer of the aircraft to shear off.

The vertical stabilizer was recovered nearly intact by Brazilian searchers prompting experts to theorize that it may have sheared off.

According to industry sources the rudder limiter locked itself in place because of conflicting air speed indications caused by icing on airspeed sensing pitot tubes.

Meanwhile, Airbus’ parent company, EADS, officials have emphasized the importance of locating the flight data and cockpit voice recorders (Black boxes) for accurately determining the cause of the crash.

"In such an accident, there is not one cause," EADS CEO Louis Gallois said on Sunday. "It's the convergence of different causes creating such an accident."

"It's essential for everybody to know what happened and we know that it's not easy. I hope we will find the black box," he added.

While the exact sequence of events will only be determined if the Black boxes are located there is little doubt the sequence was triggered by the aircraft’s entry into severe thunderstorms, points an Airbus pilot that Sawf News spoke to.

Air France Flight 447, carrying 228 people from Rio de Janeiro to Paris on May 31, crashed after running into fierce thunderstorms.

Brazilian authorities have so far retrieved 44 bodies from the Atlantic ocean; French ships have recovered another six.

When I saw the AF447 rudder I noticed one thing. The Forward Attach Point (nut) was still on the rudder and the aft one was missing.
I am not a accident investigator but studied it extensively in college, and what I deduce is this:
The forward attach point would have sheared on impact with the water if if was attached to the fuselage. Because the back one was missing I think it is reasonable to suspect large rudder or vertical stabilizer oscillations that caused the Afterword Attach Point to shear.

Now granted this is just off the new photos, but it was in very good shape.

I Agree
 

I concluded the same thing and noticed that the photographs indicate a good possibility that the vertical stabilizer/rudder actually sheared off in flight. If that did occur, then obviously the remaining fuselage would likely break up in flight. It makes sense that several of the bodies recovered to date had their clothing torn off, hurling through the atmosphere, especially considering the number of broken bones. Remember these folks didn't drown according to preliminary reports.

IF this scenario plays out and the final ruling is that this was the root cause of the accident, it will be interesting to see whether the NTSB actually has the guts to address this issue head on. I know the political and economic ramifications are huge but then again, so is the potential loss of life with operating aircraft with a known design flaw. Remember, if this scenario plays out, it will be the second major accident in which a vertical stabilizer/rudder structural failure of an Airbus aircraft was the cause.

Y'All be careful out there:rolleyes:...yes, I know. We don't jump to conclusions and wait patiently until the accident investigators have completed their jobs.

G'Day:)

Agreed. Simply do not wag the rudder.

This is true, but the 737 entire vert. assembly did not break of the aircraft. That was due to a PCU servo value that jammed, not the design of vert stab unit itself.

I would deduce that once the rudder limiter disengaged, the rudder travel exceeded those "limits" and was sheered completely off the aircraft at altitude. Because of its shape, it would have fallen relatively gently to the water, which is why it remains intact, unlike the rest of the aircraft which would have had a catastrophic collision with the water, hence the small pieces they are finding.

Airbus really needs to take their pride and shove it where the sun does not shine. Fix the flippin' issue.