Air France plane missing?

[Evan]

(due to evidence of yaw rotation)

What evidence of yaw rotation?

[Leightman]

We don't even know if the wings were attached at that point. Do we?

No, you are strictly correct, nor do we know for certain if any of the empennage or other control or lifting surfaces were compromised. However a wings level and nose up attitude, and the relatively low sink rate that you point out, together with the very large debris pieces, are all highly suggestive that the plane was pretty much intact.

[Leightman]

What evidence of yaw rotation?

Multiple items in the interim report including twisted brackets, assymetrical deformation, of panels, and early conclusions based on study of the vertical stab mount deformations. If the report had not also specified (for unmentioned reasons) that the wings appear to have been level, one could say an alternate possibilty for deformations indicating a small yaw rotation could have resulted from a small bank angle at impact.

[Evan]

Multiple items in the interim report including twisted brackets, assymetrical deformation, of panels, and early conclusions based on study of the vertical stab mount deformations. If the report had not also specified (for unmentioned reasons) that the wings appear to have been level, one could say an alternate possibilty for deformations indicating a small yaw rotation could have resulted from a small bank angle at impact.

The bank angle would be my guess for the vstab deformation, gravity and not load factor. The slightest amount would cause it to fail to one direction vs. the other. I wasn't aware of the other evidence. I'll have to reread the report more carefully. I appreciate the thinking you put into this, but I think you might be forcing some conclusions upon the evidence. But that's the definition of speculation and I have no problem with intelligent speculation, especially since that is all we have at this point, and may ever have.

[Leightman]

The bank angle would be my guess for the vstab deformation, gravity and not load factor. The slightest amount would cause it to fail to one direction vs. the other. I wasn't aware of the other evidence. I'll have to reread the report more carefully. I appreciate the thinking you put into this, but I think you might be forcing some conclusions upon the evidence. But that's the definition of speculation and I have no problem with intelligent speculation, especially since that is all we have at this point, and may ever have.

Given that the investigators have all the information, I am assuming for the time being that the interim's current conclusion is correct regarding wings level. But bank angle IS a question of very small degrees relative to the known outcome, and the deformations I cite could easily be explained by a slight bank angle as you point out.

I do speculate and try to use corroborating evidence to support a scenario. Whatever the subsequent answers, I consider it a win win situation. If my speculation gets shot down in flames, then I gain some confidence that my best shot isn't good enough, that some of my assumptions are wrong, and that the evidence solidifies that a different perspective is more probable. If no one can definitively shoot it down, then the outcome of solidified evidence (or even probability) is also a net plus. That is my perspective on the importance of the question of how a flight data instrumentation problem could cascade to a total loss of display. This seems like a rather large and critically important loss given the importance of flight data. That is, it does suggest an unrecognized systemic architecture fault in addition to the apparent loss of airspeed information. If the AOA sensor also became inoperative, it would be an infinitely extreme event, or the result of a weather scenario the cumulative vision here has yet to articulate. To my mind, no one has yet offered any unrefutable reason why a loss of airspeed would result all the ACARS messages we have, except perhaps the last one.

[Leightman]

Backup airspeed indicator

Several people have suggested coming up with a new kind of airspeed sensor to be used as backup. There are good reasons why we still have basically the same pitot after about a centruy of useL it is simple and works most of the time. Any replacment or alternative would have be simple, and also fairly linear in its response over a very wide speed range. The ideas sugsted as alternatives have the same problems as a pitot because ice could compromise them. Suggestions also suppose a probe of some kind or a tube in the airstream, both of which would cause air pressure variances which would increase icing problems. I don't have an answer, and I don't think one is apparent or it would already have been thought of. But if anyone can come up with a device to measure airspeed that has a mostly linear output, is not sensitive to wide temperature variations, and does NOT involve a probe or tube (ie, that could be part of a flat surface), you might stand to make a lot of money.

[Evan]

Several people have suggested coming up with a new kind of airspeed sensor to be used as backup. There are good reasons why we still have basically the same pitot after about a centruy of useL it is simple and works most of the time. Any replacment or alternative would have be simple, and also fairly linear in its response over a very wide speed range. The ideas sugsted as alternatives have the same problems as a pitot because ice could compromise them. Suggestions also suppose a probe of some kind or a tube in the airstream, both of which would cause air pressure variances which would increase icing problems. I don't have an answer, and I don't think one is apparent or it would already have been thought of. But if anyone can come up with a device to measure airspeed that has a mostly linear output, is not sensitive to wide temperature variations, and does NOT involve a probe or tube (ie, that could be part of a flat surface), you might stand to make a lot of money.

The sonic anemometer idea seemed like a good one, being that it is solid state and can be heated against icing (and not susceptible to clogging). I realize no such device exists for the transonic speed range, but I don't understand the physics involved enough to know whether that is an inherent limitation or one that can be overcome by design. If possible, it would be a very simple solution.

[SYDCBRWOD]

Homework for WhiteKnuckles

Anything in itallics are your comments quoted.

But maybe this crash suggests a need to sign treaties to allow pulling useable equipment from maybe a DAY away?

Q1. Why do we need pinger locators to be only a day away and how would this save lives?

The notion of putting a sub to sea AFTER concluding the plane is lost is kinda Johnny-come-lately.

Q2. Can you explain why the French (or any other nation) should be stationing or pre-positioning submarines in various parts of the sea. Can you also explain why the french deplayed the SSN in the first place.

[MCM]

WhiteKnuckles,

Well, I'm glad you won't waste your time replying, but you'll find that NONE of my last post had anything to do with you at all. It was entirely based around swissair's comments that he doesn't believe the BEA, and that there is no evidence.

Evan,

Having a second way of working out airspeed is quite a good idea as a standby, although I don't know enough about the mechanics of a sonic anemometer to know if it is practical for aircraft mouting. I assume it still has to have some sort of part exposed to the air, which still leaves the usual problems... although as you say, a backup that uses a different system is a good idea.

That said, it is usually quite rare for pitot tubes to provide false information, however there seems something somewhat curious about this particular type that has had more than its fair share of problems.

[Evan]

Evan,

Having a second way of working out airspeed is quite a good idea as a standby, although I don't know enough about the mechanics of a sonic anemometer to know if it is practical for aircraft mouting. I assume it still has to have some sort of part exposed to the air, which still leaves the usual problems... although as you say, a backup that uses a different system is a good idea.

That said, it is usually quite rare for pitot tubes to provide false information, however there seems something somewhat curious about this particular type that has had more than its fair share of problems.

Well, I doubt any such improvement will come about. I know it's not even halftime in the investigation, but I have to point out what we've learned so far. All of the supposedly fail-safe Airbus redundancy has been sold under false pretense. All three autonomous systems meet just outside the airplane in the form of exposed air data sensors that share a common fault potential. The odds of this happening are rare, and the odds of this happening in concert with the circumstances that may have brought down AF447 are extraordinarily so. Nevertheless, until Airbus provides a truly redundant sensor feed for its vaunted electronics, it is no longer to be called redundant, because redundancy is an absolute state, There are no fractional degrees of redundancy. The only redundancy in the Airbus cockpit as it stands are the pilots themselves, and pilots have their limits as well.

I hope that, as we speak, some brilliant engineers at Airbus are sprawling schematics on the floor and doing some real headscratching. Amongst all the interrelated and interdependent logic that form the foundation for FBW, there is a hidden potential for disaster that is probably harder to identify than it is to fix.

[MCM]

I agree with you that the Airbus systems are not entirely redundant.

The Air Data problem with the Qantas aircraft gave us a wakeup to the fact that triple redundancy in Airbus terms, well, isn't. A single failure could lead to a very nasty situation. There are certain systems in some Boeings as well that are supposed to be triple redundant but in fact aren't, however they aren't as "final" as on the Airbus.

The problem with redundancy is what part of the system are you saying has a backup. As you say, individual components have backups, but the airbus system is so complex that you don't know what combination of failures will lead to what result. Another issue is how much the pilots of these aircraft trust their instrumentation, and which failure is more likely.

An airspeed failure on an Airbus aircraft seems to have far more reaching and sometimes apparently unrelated issues than on other aircraft, which l guess adds to the possibility for situation confustion.

I am sure Airbus already know the details of which probe failed when, and why it lead to that result. They will report it in the final report, which is the appropriate place to put it.

Is this the first time I've agreed with you Evan?

[TeeVee]

Or the pingers aren't working - not the first time that has occurred....

Or they are searching in the wrong area...

Or there was a thermocline that deflected the sound...

Now, your proof of this french rodent?

No proof at all. I'm just pondering. I am not qualified to answer anything in this forum unless you have some legal questions. However, it is no secret that the US and presumably some of its allies, have incredible sonar equipment aboard their subs.

THink about this: our subs are designed specifically to be able to detect at extreme distances, the subs of our "enemies." And, apparently, we have been quite good at this over the past few decades. "Hi def" hi gain sonar is not new.

FDR's and CVR's have pingers that are specifically designed TO BE HEARD. So, assuming they survived the crash (didn't I read somewhere that they have never failed???), our super sonar equipment (being towed by a french ship) and the french sub in the area for nearly one month, presumably should have been able to locate the boxes.

I understand how thermoclines can mask sounds, though not sure to what extent. Perhaps if someone here is a hydro engineer or former sub-jock we can get this cleared up.

My thoughts on the rodent are simply this: let's assume airbus and the french government are aware of certain facts that would make airbus less than popular. Do you honestly believe that they would not cover it up, or that a cover up is not possible? We all know that governments and big businesses cover stuff up. The US does it, Boeing has probably done it (no proof), Dow chemicals has done it, Dupont has done it and the list goes on and on. Is Airbus so far beyond reproach?

[TeeVee]

Hi TeeVee, can you share more of our thoughts, your take, your direction on this so far futile search? Thank you.

Hi SwissAir.

Please see my response to SYD's questions as well as this.

Not being an aviator or engineer by any far stretch of the imagination (the closest I've gotten to flying a plane was sitting in the right seat of a TropicAir cessna grand carravan in belize. the pilot threatened me with extreme bodily harm if i touched anything).

Assuming there is no cover-up, i can only surmise that the FDR's and CVR's pingers have failed. The only other explanations are that they were not designed to be heard from the depths the landed at, or the searchers are incompetent.

Honestly, I'm not leaning toward any of the above.

[SYDCBRWOD]

No proof at all. I'm just pondering. I am not qualified to answer anything in this forum unless you have some legal questions. However, it is no secret that the US and presumably some of its allies, have incredible sonar equipment aboard their subs.

THink about this: our subs are designed specifically to be able to detect at extreme distances, the subs of our "enemies." And, apparently, we have been quite good at this over the past few decades. "Hi def" hi gain sonar is not new.

FDR's and CVR's have pingers that are specifically designed TO BE HEARD. So, assuming they survived the crash (didn't I read somewhere that they have never failed???), our super sonar equipment (being towed by a french ship) and the french sub in the area for nearly one month, presumably should have been able to locate the boxes.

I understand how thermoclines can mask sounds, though not sure to what extent. Perhaps if someone here is a hydro engineer or former sub-jock we can get this cleared up.

My thoughts on the rodent are simply this: let's assume airbus and the french government are aware of certain facts that would make airbus less than popular. Do you honestly believe that they would not cover it up, or that a cover up is not possible? We all know that governments and big businesses cover stuff up. The US does it, Boeing has probably done it (no proof), Dow chemicals has done it, Dupont has done it and the list goes on and on. Is Airbus so far beyond reproach?

No, Airbus is not beyond reproach, but to paraphrase a popular expression, one piece of possible evidence (they didn't locate the pingers) does not a conspiracy make. I'm prepared to give a company the benefit of the doubt until I start to see a pattern emerging in their behaviour or solid evidence (not the absence of something) to the contrary.

I'm not sure it's true that the pingers have never failed (they aparently were not operating on the A320 that played submarine on the Hudson river last year). The quote I have seen was from Honeywell(?) who pointed out that they have never failed to find a black box IIRC, some may have been found without the benefit of the pingers.

As I pointed out in my earlier post, they certainly had the right equipment for a passive search but there are a stack of reason why the pingers may have been missed or indeed may not have been functioning.

A cover up by Airbus would require co-operation of the government (not beyond belief), and the french navy (again by itself, not beyond belief), the techs from the BEA that operated the pinger locators (and there may have been I'd guess staff there from Honeywell to assist in the black box recovery) which is looking more unbelievable, and the co-opting of all of these organisations and people. That's where it starts getting difficult to believe a secret of this magnitude could be kept. It's not like the the Dow coverup where all the employees were from the same company - much easier to manipulate and keep quiet.

[mfeldt]

My thoughts on the rodent are simply this: let's assume airbus and the french government are aware of certain facts that would make airbus less than popular. Do you honestly believe that they would not cover it up, or that a cover up is not possible? We all know that governments and big businesses cover stuff up. The US does it, Boeing has probably done it (no proof), Dow chemicals has done it, Dupont has done it and the list goes on and on. Is Airbus so far beyond reproach?

The question is what would make Airbus less popular than an aircraft falling out of the sky for no apparent reason? If there is a serious problem in the A330 (which apparently isn't the case, because they don't crash every week - in fact it was the first crash since service entry), why would they hide so that it could cause another crash - making Airbus even more unpopular... m.