Air France A330 Down

[conehead]

Why don't you just admit that you have no idea of what happened instead of concluding that they encountered hail.

Easy there Woxof, I've made no conclusions, and of course I don't know what happened. I'm only trying to point out that most systems have redundant alternates, and the failure of one or two pitot probes shouldn't cause a total failure of pitot-static information. However, the PHC does control the heating for all the probes; thus could be the cause of all the probes failing. This is just speculation, based on my experience as an Avionics Technician, and knowing that there was a fault message for the PHC sent just prior to the crash.

[handyman]

Should they ground the Airbus?

Airbus

[Don Hudson]

woxof, conehead;

I think it's important to bear in mind that loss of pitot-static data does not disable any of the five flight control computers. The loss of the Birgenair and Aeroperu 757's demonstrated the need for the "unreliable airspeed" drills with the memorized items. We know of at least four cases, two recent ones, on the A330 in which these procedures worked.

The 330 is under full pilot control in alternate and direct laws - any one of the three PRIMs or two SECs will fly the aircraft.

We know by the ACARS messages that there was a loss of pitot data, (and possibly a loss of static data), which resulted in a number of sub-system faults beginning with the ADRs.

Loss of the IRSs is far more serious but this fault is not known in any of the other incidents.

The common thread appears to be the Thales pitot probe. Many of these messages seen here have occured in the other incidents; - as a matter of record, these cautions have been announced by AB in previous bulletins to airlines since mid-2008. The Rosemount installation does not appear to have the same issues.

We still do not know what information would have been presented, if at all, by the ISIS. The ISIS as independant IRS-type "gyros"/accelerometers but the ACARS shows data problems with the ISIS as well.

I wouldn't expect a call for, nor do I think there is a need to ground the 330.

A more detailed ACARS summary:

[Don Hudson]

I agree Rich - the story is full of half-truths, outright false information, unfounded speculaton and emotional hyperbole. It isn't worth reading, certainly not to gain reliable information on the issue.

Your comment about the 787 came to mind as I was reading. Add hypocritical to hyperbole to describe this bit of hack writing.

[handyman]

That may be but why have there been issues with Airbus tail-fins?

We don't know all the details of the AF accident but they do know the tail came off in-flight. Why is that? Why is it possible to overstress a component to a catastrophic conclusion with simple control inputs? Are we setting ourselves up for more loss of life with composite tails?

I guess if your conclusion is a loss of pitot static information was the cause and building a first-class pitot static system is the fix...so be it. But I'm a little more suspect of what happened after the failure!

[Don Hudson]

First, how do we know the rudder came off "in-flight"? Other scenarios have been posited, and while I think the rudder came off in a high-altitude breakup, I have nothing to base that upon bt a hunch - we cannot say "we know".

I guess if your conclusion is a loss of pitot static information was the cause and building a first-class pitot static system is the fix...so be it. But I'm a little more suspect of what happened after the failure!

Well, let's focus a bit - the pattern seems to be the Thales pitot probe not the entire pitot-static system.

To focus on the vertical stabilizer as a root cause of the problem and a reason to "ground the world-wide Airbus fleet", as the article poses as a rhetorical question, would be a significant mistake in investigation.

The vertical stabilizer in this accident was torn out by the roots. The carbon-fibre structure held together - it was the titanium/alu fuselage structue that failed, a substantially different failure mode than AA587. A large section of the upper fuselage structure came off with the vertical stabilizer as can be seen in the photograph below. This kind of damage is due to forces which exceeded the design limits of the airframe. That is a factor in any airframe, not just this one.

Without wishing to resurrect the AA587 discussion, the rudder on that aircraft was rapidly taken from stop to stop by the crew, likely the flying pilot, exposing the vertical stabilizer to loads which were 1.93 times expected loads and far exceeding the 1.5x design specifications.

The rudder delamination issues are a red herring in examining this accident.

[Don Hudson]

My curiosity was piqued so I took a look at some other writing by this author.

The following is a brief quotation from another article about Airbus.

It is abundantly apparent that he knows nothing about the Airbus and nothing about the accidents he is describing but isn't letting that get in the way of a clear anti-Airbus sentiment:

. . . .

Both Boeing and Airbus depend upon FBW technology in aircraft design; however, there are fundamental differences. Basically, a pilot can override the computer in a Boeing aircraft, while Airbus pilots are not allowed to second guess the flight control computer. Boeing pilots also receive greater visual feedback from control surfaces by relying upon a conventional control yoke, while Airbus pilots use a small joystick.

A Boeing pilot can turn the airplane upside down, release the controls and the plane will right itself. If an Airbus pilot wants to lose lift and stall to avoid a midair crash and the computer decides that acceleration and a climb is better, the pilot simply hangs on for the ride. Only if all electronic systems fail does the Airbus default into a "manual backup" mode allowing limited use of basic mechanical systems while the pilots attempt to determine the cause of the electrical and computer failure.

Although airplanes equipped with FBW systems are reportedly easier to fly, the very efficiency can conceal defects that might be otherwise discovered by hands-on mechanical operations and may allow a plane to be operated under conditions where a human operator would fail.

The accident rates for Boeing and Airbus are similar: however, there have been some unusual Airbus accidents apparently caused by computer malfunctions. One of the first occurred in 1988 shortly after the Airbus was placed in service. During a flyover at a French air show, the computer assumed that the plane was supposed to land since it was close to the ground and the landing gear was down. Although the pilot attempted to accelerate and climb, the computer ignored his input and landed the plane in an adjacent forest killing three passengers. Airbus attempted to blame the accident on pilot error.

Another incongruous accident more recently occurred during the testing of a brand new 472-passenger Airbus A-340-600 being delivered to Etihad Airlines in 2007 at the Toulouse airport. As the flight crew ramped up the four engines to takeoff power with the brakes on, a takeoff warning horn sounded because the computer sensed that the plane was not properly configured for takeoff. When the crew silenced the alarm, the computer apparently decided the plane was flying and trying to land with its brakes on. The computer released the brakes and the plane accelerated into a crash barrier at full power.

The spectacular televised landing of a JetBlue Airbus at the Los Angeles airport in 2005 with its nosewheel locked in place crosswise to the fuselage brought to light at least 67 earlier "nosewheel failures" on a variety of Airbus aircraft that were usually repaired by the replacement or "reprogramming" of the Brake Steering Control Unit computer.

A rudder design implemented by Airbus in 1988 increased the sensitivity of actual rudder movement to the pilot's movement of the pedals by slightly more than one inch and allowed for a wider degree of rudder travel per pound of force on the pedal. Rudder movement is necessarily restricted at cruising speeds; however, the Airbus computer did not impose a limit at lower speeds, such as during takeoff.

These rudder changes contributed to the crash of American Airlines Flight 587 on November 12, 2001 shortly after takeoff from Kennedy Airport in New York City when the aircraft encountered wake vortices from the preceding aircraft. As the copilot attempted to maintain the Airbus' steady-state left turn, he sought to correct an unexpected, vortex-caused "overbank" by using the rudder attached to the back of the tail fin. The copilot commanded rapid left-right rudder movements that exceeded the design loads of the vertical stabilizer, and the computer was not programmed to limit the command at low speeds. The all-composite stabilizer was ripped from the fuselage and the aircraft became uncontrollable. Its crash killed nine crew members, 251 passengers and five people on the ground. The relatively intact tail fin was found floating in the waters of Jamaica Bay.

Although several catastrophic Airbus crashes into the ocean with major loss of life have been blamed on pilot error, including the 2000 losses of Kenya Airways Flight 431 and Gulf Air Flight 072, the crash of an Airbus belonging to Air New Zealand on November 27, 2008 into the Mediterranean Sea has raised new questions about Airbus safety. Seven crew members engaged in a test maintenance flight died in the crash, and the tail section was found floating where the plane went down. No official cause for the accident has been reported.

. . . .

Let's take a quick look at two statements in the article:

"Both Boeing and Airbus depend upon FBW technology in aircraft design; however, there are fundamental differences. Basically, a pilot can override the computer in a Boeing aircraft, while Airbus pilots are not allowed to second guess the flight control computer. "

and,

"As the copilot attempted to maintain the Airbus' steady-state left turn, he sought to correct an unexpected, vortex-caused "overbank" by using the rudder attached to the back of the tail fin. The copilot commanded rapid left-right rudder movements that exceeded the design loads of the vertical stabilizer, and the computer was not programmed to limit the command at low speeds. "

Mr. Cox apparently wants it both ways; "the computer gets in the way of what the pilot wants", and "the computer failed to limit the pilot's aggressive inputs". Makes one dizzy.

His writing is entirely selective, cherry-picking examples to bolster an otherwise flimsy argument about a subject of which he demonstrably knows nothing, (as evidenced by his statement, "If an Airbus pilot wants to lose lift and stall to avoid a midair crash and the computer decides that acceleration and a climb is better, the pilot simply hangs on for the ride."). Wow..."stall to avoid a mid-air crash". I am very happy he is a writer and not a pilot.

So far as aviation writing goes, he has no credibility whatsoever, but for anti-Airbus writers not seeking truth that probably doesn't matter.

[handyman]

I'm not saying he is an authority on this issue, but aren't you the least bit curious why Airbus has issues with the tail? There are many more Boeings flying...why don't we hear of these issues with them? The only Boeing tail issue I can recall is the JAL 747 and we know how maintenance was the cause of that accident.

Rich,

Are you serious? Do you actually believe the fuselage could have failed causing the tail to break?

As for composite airframes...maybe we will be having a discussion like this in about 5 years time...who knows?

[Don Hudson]

You cited the article so I have to assume you thought he had something important to say about Airbus and groundings. He doesn't.

No, I'm not "curious" about "why Airbus has issues with the tail" because, while delamination has occured, the cause is known and one expects, fixed, and there is exactly one accident in which we know the vertical stabilizer failed due to overstressing by pilot input - a stress far in exceedance of even the highest expected loads under the greatest control abuse. We don't know yet what happened to AF447. The other vertical stabilizer separations I can think of occurred during high-speed impact with the sea, (Perpignan); as for the AF447 accident, we don't know the point of failure of the VS and may never know.

What I am curious about is the propensity to use the rudder inappropriately in jet upset circumstances. AA587 wasn't the last time this was done.

As far back as I can recall there was never any sense that one should use the rudder in a swept-wing transport category aircraft - it is just never done. Design philosphy with Boeing and Airbus alike, restricts rudder use at high speed while permitting full use at low speeds so that certification standards in yaw control for engine failure can be demonstrated. Rapid rudder reversals to both the stops was never contemplated as a legitimate control technique for an airliner nor should it have been. It's like justifying pulling enough 'g' such that either the wings break or the engine pods are thrown off - at what point do the designers stop adding weight and cost to what is, as you must know, a structural compromise from the laying of the keel beam, on.

This just reinforces the widely held understanding that the strongest critics of the Airbus design are those who have never flown it or don't know the systems.

Boeing has issues which seem curiously to be accepted; to be sure, Airbus will have to answer for pushing the envelope twenty years ago but the millions of hours of unremarkable flying is the measure of success to go by, not the opinions of those who have never flown it or engineered it. Nor am I defending it blindly - there are lots of traps for young and experienced players alike and the Boeing design is, up until the 787, pretty bread-and-butter, although the 777 remains a fly-by-wire design, (no cable-and-pulley backup...it's wires and electronics all the way to the servos despite the fact that "the Big Switch" can be used to by-pass the flight control computers taking the 777 into Direct 'law').

FWIW, I think the 787 is a brilliant airplane and we'll forget about it's delivery issues once it begins flying. I'd love to have flown it and I hope you get the chance to.

[handyman]

You cited the article so I have to assume you thought he had something important to say about Airbus and groundings. He doesn't.

No, I'm not "curious" about "why Airbus has issues with the tail" because, while delamination has occured, the cause is known and one expects, fixed, and there is exactly one accident in which we know the vertical stabilizer failed due to overstressing by pilot input - a stress far in exceedance of even the highest expected loads under the greatest control abuse. We don't know yet what happened to AF447. The other vertical stabilizer separations I can think of occurred during high-speed impact with the sea, (Perpignan); as for the AF447 accident, we don't know the point of failure of the VS and may never know.

What I am curious about is the propensity to use the rudder inappropriately in jet upset circumstances. AA587 wasn't the last time this was done.

As far back as I can recall there was never any sense that one should use the rudder in a swept-wing transport category aircraft - it is just never done. Design philosphy with Boeing and Airbus alike, restricts rudder use at high speed while permitting full use at low speeds so that certification standards in yaw control for engine failure can be demonstrated. Rapid rudder reversals to both the stops was never contemplated as a legitimate control technique for an airliner nor should it have been. It's like justifying pulling enough 'g' such that either the wings break or the engine pods are thrown off - at what point do the designers stop adding weight and cost to what is, as you must know, a structural compromise from the laying of the keel beam, on.

This just reinforces the widely held understanding that the strongest critics of the Airbus design are those who have never flown it or don't know the systems.

Boeing has issues which seem curiously to be accepted; to be sure, Airbus will have to answer for pushing the envelope twenty years ago but the millions of hours of unremarkable flying is the measure of success to go by, not the opinions of those who have never flown it or engineered it. Nor am I defending it blindly - there are lots of traps for young and experienced players alike and the Boeing design is, up until the 787, pretty bread-and-butter, although the 777 remains a fly-by-wire design, (no cable-and-pulley backup...it's wires and electronics all the way to the servos despite the fact that "the Big Switch" can be used to by-pass the flight control computers taking the 777 into Direct 'law').

FWIW, I think the 787 is a brilliant airplane and we'll forget about it's delivery issues once it begins flying. I'd love to have flown it and I hope you get the chance to.

I appreciate your candid response Don but just because I cited the article doesn't mean I fully endorse it either. I may not fully endorse it but I don't entirely discount it either!

I read the fin was found 18 miles from the rest of the majority of wreckage found. I have to ask why?

Yes we know of one accident with a tail failure...but how many others have possible (unproven or discounted) tail failures? Why is it Boeings are not included in this list of possible failures?

Do you think AA587 was the only case of a Pilot inappropriately handling rudders and it just happened to be on an Airbus? All I can say to that is...I hope you're right!

As for the 787, time will tell if it's as good as they say it will be. Sure I would like to fly it but I know I won't as it's too small for us. I do look forward to being a passenger on one with the improved environmental conditions.

[Don Hudson]

I appreciate your candid response Don but just because I cited the article doesn't mean I fully endorse it either. I may not fully endorse it but I don't entirely discount it either!

Fair enough. For me, the article contains enough half-baked notions and partial truths to sound viable and even intelligent but in truth it does not withstand tough scrutiny. After all, we're trying to find out what happened to an airliner; both the author and the article are wholly inadequate and badly uninformed about Airbus autoflight matters when discussing the many factors concerning this accident and the larger issues surrounding autoflight. It is an article for conspiracy theorists and those who paint devils on the wall.

Though there are a number of viable theories and some very good work done regarding ocean currents, we don't know why the fin was found that distance away. Some superb ocean current work has been done regarding location of both wreckage and bodies found; the presentations are widely available. There are some excellent theories on the possibility of a turn-back for example. But the data is simply too granular to be conclusive.

Yes we know of one accident with a tail failure...but how many others have possible (unproven or discounted) tail failures? Why is it Boeings are not included in this list of possible failures?

Well,...how many angels can dance on the head of a pin? How do you prove an unknown? Who knows why Boeings aren't included? The Airbus numbers are miniscule and certainly cannot be called a trend let alone a chronic design/structural fault.

I can only think of two cases, both Boeings - the BOAC 707 over Fuji and the PanAm 707 over Elkton, MD likely brought down by a thunderstorm but the VS was not part of the story to my recollection. I can think of one rudder/yaw damper induced rollover and that occurred in 1961 to an AA B707 off 22L at Idlewild into Jamaica Bay - shorted yaw damper wiring (careless use of pliers) was the determined cause. The vertical stab stayed on but we don't know the strength of the rudder deflection. It is sideslip, not actual yaw rate that places the greatest lateral stress on the vs.

I would be interested in learning what lateral loads were placed on the Gimli Glider as it was side-slipped to lose altitude.

Why not Boeings? See above. I could say, "because no pilot has ever pushed the rudders like they did in the A300" and it would be the same question you're asking about how many possible but unproven events have occurred. How is such a question even addressed; absence of data, and being unable to answer proves nothing.

I believe the Boeing design in terms of how the (carbon fibre) vertical stab is fastened, is the same as Airbus - tabs and lugs. The limiters would have the same intention and be close in the numbers.

The industry (meaning us, in this case) shouldn't need a reminder to "stay off the rudder". But for engine failure, the rudder should never be used.

[RFL]

I'm not saying he is an authority on this issue, but aren't you the least bit curious why Airbus has issues with the tail?  There are many more Boeings flying...why don't we hear of these issues with them?  The only Boeing tail issue I can recall is the JAL 747 and we know how maintenance was the cause of that accident.

I agree handyman. No theory should be discounted casually. There are fully documented and thoroughly investigated cases of rudder hardover on the B737 due to defective early model PCU's. Two of the cases resulted in fatal accidents but none resulted in fin separation.

[Say Again, Over!]

Interestingly enough, the BOAC crash at mount Fuji involved separation of the VS at "only 110% its design limit gust load".

It was a Boeing...

BOAC 911

Felix

[handyman]

Personally, I don't care if it's a Boeing or an Airbus...if it's suspect, it should be discussed and dealt with without politics or prejudice. So whether it's a 777 or an Airbus, composite tails and housings are breaking and they should be aggressively studied regardless of who made them!

[mo32a]

Why not Boeings? See above. I could say, "because no pilot has ever pushed the rudders like they did in the A300" and it would be the same question you're asking about how many possible but unproven events have occurred. How is such a question even addressed; absence of data, and being unable to answer proves nothing.

Do you think it is possible that some pilots are so used to the computer protecting them from doing something wrong they get complacent about their inputs to the controls, especially in a catastrophic emergency?

[Don Hudson]

RFL;

No theory should be discounted casually. There are fully documented and thoroughly investigated cases of rudder hardover on the B737 due to defective early model PCU's. Two of the cases resulted in fatal accidents but none resulted in fin separation.

If I may respond, I don't think it can be said that the "theory" that Airbus "has problems with vertical stabilizers" is being discounted casually. It's just that there is no basis for the theory to even exist because the evidence simply isn't there.

Aside from AA587, fin loss is the result of crash forces, not aerodynamic side loads, turbulence, pilot-induced forces or lightning, (all of which have been stated as causes of the loss of AF447's vertical stabilizer. In 447's case we just don't know yet.

Stating that there is such evidence for such a theory is the same as saying that engines coming off wings in an accident is evidence that the manufacturer has a problem with engine mounts. Engines come off in a crash, so do wings and everything else.

What I do think is of interest is the APA Report on AA587 which can be found here. This report cites what is termed APC - Aircraft Pilot Coupling in which it is stated that the A300 rudder system is the most sensitive of all types tested. The A330/A340 types were not among those cited however. From the report:

“APC events are collaborations between the pilot and the aircraft in that they occur only when the pilot attempts to control what the aircraft does. For this reason, pilot error is often listed as the cause of accidents and incidents that include an APC event. However, the [NRC] committee believes that the most severe APC events attributed to pilot error are the result of adverse APC that misleads the pilot into taking actions that contribute to the severity of the event. In these situations, it is often possible, after the fact, to analyze the event carefully and identify a sequence of actions the pilot could have taken to overcome the aircraft design deficiencies and avoid the event. However, it is typically not feasible for the pilot to identify and execute the required actions in real time” (161). National Research Council

With reference to the B737 example cited, the following is from the NTSB Recommendations document of the report on the AA587 accident.

This safety recommendation letter addresses an industry-wide safety issue involving omissions in pilot training on transport-category airplanes. Specifically, the National Transportation Safety Board has learned that many pilot training programs do not include information about the structural certification requirements for the rudder and vertical stabilizer on transport-category airplanes. Further, the Safety Board has learned that sequential full opposite rudder inputs (sometimes colloquially referred to as “rudder reversals”)—even at speeds below the design maneuvering speed1—may result in structural loads that exceed those

addressed by the requirements. In fact, pilots may have the impression that the rudder limiter systems installed on most transport-category airplanes, which limit rudder travel as airspeed increases to prevent a single full rudder input from overloading the structure, also prevent sequential full opposite rudder deflections from damaging the structure. However, the structural certification requirements for transport-category airplanes do not take such maneuvers into account; therefore, such sequential opposite rudder inputs, even when a rudder limiter is in effect, can produce loads higher than those required for certification and that may exceed the structural capabilities of the aircraft.

No fins came off 737 aircraft as a result of rudder hardovers because the sideslip loads were within structural tolerances. The vs came off the A300 due to extreme loads caused by a rapid reversal of the rudder.

The "rudder hardover-fin staying on" case does not support a theory that Airbus has vertical stab problems while Boeing does not.

handyman;

Personally, I don't care if it's a Boeing or an Airbus...if it's suspect, it should be discussed and dealt with without politics or prejudice. So whether it's a 777 or an Airbus, composite tails and housings are breaking and they should be aggressively studied regardless of who made them!

Delamination issues are a known entity and are being dealt with.

If you still believe there is a problem with vertical stabilizers however, cite the evidence in which fins are coming off airplanes or where there are problems with the design.

mo32a;

Do you think it is possible that some pilots are so used to the computer protecting them from doing something wrong they get complacent about their inputs to the controls, especially in a catastrophic emergency?

\

Yes, I think something of that nature is possible but I don't think it is possible to say why - I don't think it's the "4-wheel drive in winter" syndrome where, because of over-confidence, more four-wheel drive vehicles are towed out of ditches than two-wheel drive ones.

There is no training whatsoever for handling jet upsets or extreme turbulence. We cannot therefore state beforehand what aircrews will do in an extreme upset. I'm not even sure such is possible to do realistically. Upsets are controlled with aileron to get the wings level, then elevator to control any dive. The one thing all transport pilots knew before AA587 and know even more strongly today is, the rudder is never used except to control yaw in an engine failure and to kick off a bit of drift in heavy crosswind landings.

[boestar]

The one thing all transport pilots knew before AA587 and know even more strongly today is, the rudder is never used except to control yaw in an engine failure and to kick off a bit of drift in heavy crosswind landings.

While I wholeheartedly agree with this I do have one thing to say. If, in a catastrauphic (sp?) situation, you are trying to regain control of an aircraft that, for whatever reason, has become "uncontrolable", would one not attempt to use EVERY control available to accomplisht that task? Including rudder inputs.

A situation could arise where rudder input would be warranted or at least considered when in an unusual attitude or situation when all else has failed.

That being said rapid application of the rudder or rapid reversals would definately be a bad thing in almost any situation.

[Guest woxof]

Just to clarify about the poorly written article....the A-340-600 that crashed into a barrier during an engine run was the fault of the guy doing the engine run with all four engines at high power and when the aircraft unsurprisingly started moving, he tried to stop it with brakes and avoid the barrier with nosewheel steering(which affects brake pressure) instead of.....Reducing Power.

You can read an english translation of the report on page 26 of this thread...

http://www.pprune.org/rumours-news/300539-...wounded-26.html

[anonymous]

Remember that the Boeing 737 model has had some issues with rudder "hard overs". No one is immune to imperfect human design and manufacturing.

[handyman]

Yes, I am serious. All aircraft have a maximum structural speed. At high altitude, in challenging weather conditions, at night, with (possibly) erroneous speed indications, it would not be difficult to exceed the Mne with catastrophic results.

In my company, we regularly practice "erroneous speed" situations in the simulator. It can certainly be bewildering; especially when you get overspeed warnings and stall warnings simultaneously. Most guys intuitively respect the stall warning rather than the overspeed warning. Result... the nose gets lowered and the thrust gets increased.

In an A330, if you have a zero-degree pitch angle & TOGA thrust, you're going to accelerate fairly quickly. Add a little turbulence and the Mach number could increase rapidly, easily exceeding Mne (M0.93 for the A330 if I remember correctly). And that situation isn't all that implausible given the conditions being speculated in this case.

My point being... we simply don't know the sequence of events. IMHO, the stab failing first or the fuselage/wings failing first are equally possible situations. At this point, the only thing we can deduce from the floating stab is that it has buoyancy.

Rich,

First of all, aircraft manufacturers use Mmo not Mne. It's a max operating speed and not a never exceed speed. This is because it's NOT UNSAFE to exceed this speed but should not be a common practice.

2. The A330 has a Mmo of .86 and protection that will kick in at .87 (never flown an Airbus but this is my understanding). It is possible I understand to force an overspeed with full forward deflection up to .92-.93 and with release of pressure the speed will stabilize back to around .89-.90. Structural limits would not come into play here unless the aircraft was grossly out of control (like a vertical dive) exceeding mach 1.0.

3. I can assure you that the weakest part of any commercial aircraft is the tail and excessive speeds combined with high lateral forces would tend to exceed the structural limits of the tail-plane prior to the wing-spar.

4. Any commercial AC at 0 degrees and TOGA/Max thrust will accelerate as this attitude is not a level attitude and is actually descending by a 2-3degree vertical bearing.

5. If we were part of the Flight Safety Board, then your deduction of a conclusion is sound. We don't know for an absolute...that is true! Be we do have several interesting facts that should keep our eyes OPEN for the strong possibility that the dots do in fact line up!

[handyman]

I do understand the difference between Mne and Mmo. Mne is a very hard number to find! Probably with good reason.

Maybe because Airbus doesn't publish one!

[Guest rattler]

I wonder if we will ever really know what caused the crash

French investigators say speed sensors not cause of Flight 447 crash, plane hit water intact

--------------------------------------------------------------------------------

at 11:36 on July 2, 2009, EDT.

By Emma Vandore,Greg Keller, THE ASSOCIATED PRESS

LE BOURGET, France - An intact Air France Flight 447 slammed belly first into the Atlantic Ocean at a very high speed, a top French investigator said Thursday, adding that problems with the plane's speed sensors were not the direct cause of the crash.

Alain Bouillard, who is leading the investigation into the June 1 crash for the French accident agency BEA, says the speed sensors, called Pitot tubes, were "a factor but not the only one."

"It is an element but not the cause," Bouillard told a news conference in Le Bourget outside Paris. "Today we are very far from establishing the causes of the accident."

The Airbus A330-200 plane was flying from Rio de Janeiro to Paris when it went down with 228 people on board in a remote area of the Atlantic, 930 miles (1,500 kilometres) off Brazil's mainland and far from radar coverage.

The BEA released its first preliminary findings on the crash Thursday, calling it one of history's most challenging plane crash investigations. Yet the probe, which has operated without access to the plane's flight data and voice recorders, appears to have unveiled little about what really caused the accident.

"Between the surface of the water and 35,000 feet, we don't know what happened," Bouillard admitted. "In the absence of the flight recorders, it is extremely difficult to draw conclusions."

One of the automatic messages emitted by the Air France plane indicates it was receiving incorrect speed information from the external monitoring instruments, which could destabilize the plane's control systems. Experts have suggested those external instruments might have iced over.

The Pitots have not been "excluded form the chain that led to the accident," he said.

Bouillard said the plane "was not destroyed in flight" and appeared to have hit "belly first," gathering speed as it dropped thousands of feet through the air.

He said investigators have found "neither traces of fire nor traces of explosives."

Bouillard said life vests found among the wreckage were not inflated, suggesting that passengers were not prepared for a crash landing in the water. The pilots apparently also did not send any mayday calls.

He said there was "no information" suggesting a need to ground the world's fleet of more than 600 A330 planes as a result of the crash.

"As far as I'm concerned there's no problem flying these aircraft," he said.

A burst of automated messages emitted by the plane before it fell gave rescuers only a vague location to begin their search, which has failed to locate the plane's black boxes in the vast ocean expanse. The chances of finding the flight recorders are falling daily as the signals they emit fade. Without them, the full causes of the tragic accident may never be known.

The black boxes - which are in reality bright orange - are resting somewhere on an underwater mountain range filled with crevasses and rough, uneven terrain. Bouillard said the search for the plane's black boxes has been extended by 10 days and will continue through July 10.

The remote location, combined with the mystery of what happened to the plane - the pilots had either no time or no radio frequency to make a mayday call - makes the inquiry exceptionally challenging.

Bouillard said French investigators have yet to receive any information from Brazilian authorities about the results of the autopsies on the 51 bodies recovered from the site.

Families of the victims met with officials from BEA, Air France and the French transport ministry before the report was released Thursday. An association of families addressed a letter to the CEO of Air France, Pierre-Henri Gourgeon, demanding answers to several questions about the plane.

Investigators should have an easier time recovering debris and black boxes in the crash of a Yemeni Airbus 310 with 153 people on board that went down Tuesday just nine miles (14.5 kilometres) north of the Indian Ocean island-nation of Comoros.

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[handyman]

I hope this latest report is not politically motivated! It almost sounds like an Airbus press release.

[DEFCON]

" Most guys intuitively respect the stall warning rather than the overspeed warning. Result... the nose gets lowered and the thrust gets increased."

I've seen this in the sim as well. I don't understand the thought process entirely? Why does someone react to stimulus without first considering all the available info, i.e.; attitude, engine power, etc?

[handyman]

" Most guys intuitively respect the stall warning rather than the overspeed warning. Result... the nose gets lowered and the thrust gets increased."

I've seen this in the sim as well. I don't understand the thought process entirely? Why does someone react to stimulus without first considering all the available info, i.e.; attitude, engine power, etc?

Totally agree and have had stall warnings before on take-off. Luckily they were false but would you really want to push the nose over at 100'?

Airbus must have an "unreliable airspeed checklist" on the Boeing we just set an attitude and power setting which is rather accurate. Can they not do this with the Airbus thrust levers in a manual mode?