I'm not entirely discounting the rudder inputs hypothesis. However, the design flaw in the original software has been corrected. Rudder forces now decrease with increasing airspeed, as they should. That's why I posted earlier today to the effect that it probably would take something like a tornado to rip the fin off.xxxxxxxxxxxxxxxxxxxxAs for Kevin's definition of maneuver speed that you are agreeing with, I'm not saying that his statement is wrong, I'm saying that my statement is also correct. They are the same issue. Here's why ...At maneuvering speed (I'm an American), full deflection of the elevators will produce thus-and-such angle of attack. An infinitesimal increase in that angle of attack will cause the wings to stall, by design, just as Kevin said. Now ...The issue with vertical gusts is that they can create angles of attack much larger than can be created by control inputs. But in those cases too the wings will stall, again by design. The critical angle of attack is the same in both cases.It doesn't matter how the critical angle of attack is achieved. Once it is exceeded the wings will stall. Below it the wings will not stall and the airframe normally (repeat normally) will not disintegrate because the design limit G-load will not have been exceeded, much less the ultimate G-load, which is when the airframe breaks rather than simply bending irreversibly. So I stand by my assertion that if the aircraft had been at maneuvering speed it probably would taken something extreme, like a horizontal tornado, to rip the wings off.xxxxxxxxxxxxxxxxxxxxSo really the question is now, Was the aircraft at maneuvering speed?At this point we can't know. As I said earlier, the fact of discrepant airspeed readings does not prove what happened. I still "smell" bomb. But I can see why Air France and Brazil might rule them out immediately -- perhaps playing ostrich because the alternative would be bad for business.xxxxxxxxxxxxxxxxxxxxP.S. I hope nobody is going to take exception to my "infinitesimal increase in angle of attack" phrase above. I was conducting a thought experiment.

If your book does not publish a turbulence speed, then by all means, use maneuver speed in turbulence. I understand your reasoning that a stall is a stall and that is why Va is a safe bet. However, the turbulence penetrations speeds (Vb) that do get published tend to be different than Va. For example, for the EMB-145, Va is 200 while Vb is 250/.63. For the 747-200, Va is 330-348 while Vb is 290/.82. If you look through FAR Part 25.335, you also see that Va and Vb are determined differently.I'm not sure why you're still smelling bomb unless you're an adamant conspirist or cynic, because if there was a problem with their pitot tubes, that could very well have led to aircraft breakup. The Airbus is a fly by wire aircraft and depends on accurate information from its air data computers for control. If the pitots were indeed clogged, then the resulting too-low airspeed indication could have caused controllability problems for both the AP and pilots from the use of incorrect, low airspeed control gains, or even a stick pusher activation while the aircraft was actually at high speed. No bomb or even turbulence would be necessary for major pieces of the aircraft to break off in those situations.

KevinAu,I'll have to follow your suggestion and look into why Vb is allowed in a design sense to be higher than Va. For me that is counterintuitive. In fact it sounds downright dangerous since it may very well have been the cause of this accident -- a G-overload that would have been avoided at a lower airspeed. Perhaps Vb is intended as a penetration speed for mild to moderate turbulence. No pilot in his right mind would knowingly fly into or even close to a thunderhead, but do you agree that if he had to, Va would be the safe airspeed? (By the way, I know a former airline pilot who would never allow himself to be routed closer than 20 miles to a thunderhead.)As for bomb inclination (repeat inclination), I'm not a conspiracy theorist, I'm a realist. I believe that more turbine airliners have been brought down by bombs than by turbulence, and there was a case in which the attempt was foiled. (The shoe bomb case.)Icing is a different matter, it's being a fairly common cause of crashes of commuter airliners. However, I've never heard of this happening in a turbine transport. If this is a first for a large jet, suspected to be the pitots, so be it.xxxxxxxxxxxxxxxxxxxxSo my leaning toward bomb is more by a matter of tentative elimination than anything else. I'm not saying that weather can't have done it. In fact, the snapped-off vertical stabilizer is very suggestive given the Queens crash.

Regarding Va and Vb, check out post number 13 at this link "http://www.airlinepilotforums.com/technical/31482-rough-air-penetration-airspped-vra-2.html" for the FAA's requirements, as well as a few of the following posts.One of the replies discusses how Va may have as much to do with control surface damage as with wing or fuselage damage. So again, I wasn't wrong about the meaning of Vb, a term I was not familiar with. It appears to me that Va is exactly wrong for severe turbulence.But thanks for the terminology education.

KevinAu,I'll have to follow your suggestion and look into why Vb is allowed in a design sense to be higher than Va. For me that is counterintuitive. In fact it sounds downright dangerous since it may very well have been the cause of this accident -- a G-overload that would have been avoided at a lower airspeed. Perhaps Vb is intended as a penetration speed for mild to moderate turbulence. No pilot in his right mind would knowingly fly into or even close to a thunderhead, but do you agree that if he had to, Va would be the safe airspeed? (By the way, I know a former airline pilot who would never allow himself to be routed closer than 20 miles to a thunderhead.)As for bomb inclination (repeat inclination), I'm not a conspiracy theorist, I'm a realist. I believe that more turbine airliners have been brought down by bombs than by turbulence, and there was a case in which the attempt was foiled. (The shoe bomb case.)Icing is a different matter, it's being a fairly common cause of crashes of commuter airliners. However, I've never heard of this happening in a turbine transport. If this is a first for a large jet, suspected to be the pitots, so be it.xxxxxxxxxxxxxxxxxxxxSo my leaning toward bomb is more by a matter of tentative elimination than anything else. I'm not saying that weather can't have done it. In fact, the snapped-off vertical stabilizer is very suggestive given the Queens crash.

There's a great many number of ways a blocked pitot tube can kill you. Evidently, the Airbus pitot tubes have been susceptible to clogging in moisture and have had a running requirement to be replaced.If the pitot tube was clogged and the pressure leaked out, the airspeed would have drifted down towards zero. In that case, if the computers began using low airspeed gains, it could have caused wild oscillations since the commanded control surface movements would have been several times larger than what would be necessary at their actual speed. If the indicated airspeed dropped into the stall area, then the Airbus would have fired the stick pusher, pushing the nose violently down and then the autothrottles would have firewalled the engines. Bad if that they were actually still at cruise speed.If the pitot tube was clogged and the last pressure was trapped, then everything would be fine until they initiated an altitude change. At which point their airspeed indicator would have begun acting as an altimeter. As they descended, the indicated airspeed would go lower and lower. If they were descending in flight level change mode, where power was idled and speed was held with pitch, then they would have pitched down further and further into a deeper and deeper dive as they tried to hold an ever decreasing airspeed. Until they broke apart. If they descended using a vertical speed mode, in which a rate of descent is held, while power adjusted to hold speed, then the autothrottles would have started increasing power in the descent as the airspeed indication wound down with decreasing altitude. Until they broke apart. If they started a climb with trapped pressure, then airspeed will have started increasing with increasing altitude. In that case, they would have ended up in a situation where the aircraft was continually increase pitch attitude or decrease power in the ascent to try to hold down an ever increasing airspeed. Until they stalled. And broke apart.None of these scenarios required bombs or turbulence. But who knows. Just understand that a blocked pitot destroying an aircraft is not as far fetched as you think.

Just understand that a blocked pitot destroying an aircraft is not as far fetched as you think.

I never said it was far-fetched, only that it seems less likely to me than other possible causes. Clearly anything that would put the aircraft into a significant dive could cause loss of the airframe owing to shock waves on the control surfaces as the aircraft exceeded Vne or whatever it's called.Let me try to quantify my current feelings ...1 - 40% bomb leading to immediate airframe destruction beginning in a crusing attitude.2 - 30% pitot icing leading to aircraft upset leading to overspeed leading to airframe destruction3 - 30% vertical stabilizer snap-off leading to aircraft upset leading to overspeed leading to airframe destructionIn cases 1 and 3 the differential airspeed readings could be caused by the attitude of the descending wreckage.In case 2 the differential airspeed readings are the cause of the accident, not an effect, though they might continue for the same reasons as 1 and 2 as the wreckage descended through warmer air.So I'm not fanatical about any position as you seem to assume that I must be. In contrast you seem 90+ % committed to scenario 2. I'm not saying you're wrong, only that other possibilities seem strong to me absent hard information about a ) the nature of the damage to the airframe, and b ) the nature of the injuries to the passengers.EDIT: My attitude is colored by my having read so many aircraft accident reports. In the USA the NTSB takes nothing for granted though the investigators will first look into what they think is the likely cause, in order to get possible emergency information to the FAA. But after that, and in parallel with that, everything is looked at, including routinely ordering up autopsies of the flight deck occupants even when it seems obvious that the results would not be relevant.

There's a great many number of ways a blocked pitot tube can kill you. Evidently, the Airbus pitot tubes have been susceptible to clogging in moisture and have had a running requirement to be replaced.If the pitot tube was clogged and the pressure leaked out, the airspeed would have drifted down towards zero. In that case, if the computers began using low airspeed gains, it could have caused wild oscillations since the commanded control surface movements would have been several times larger than what would be necessary at their actual speed. If the indicated airspeed dropped into the stall area, then the Airbus would have fired the stick pusher, pushing the nose violently down and then the autothrottles would have firewalled the engines. Bad if that they were actually still at cruise speed.If the pitot tube was clogged and the last pressure was trapped, then everything would be fine until they initiated an altitude change. At which point their airspeed indicator would have begun acting as an altimeter. As they descended, the indicated airspeed would go lower and lower. If they were descending in flight level change mode, where power was idled and speed was held with pitch, then they would have pitched down further and further into a deeper and deeper dive as they tried to hold an ever decreasing airspeed. Until they broke apart. If they descended using a vertical speed mode, in which a rate of descent is held, while power adjusted to hold speed, then the autothrottles would have started increasing power in the descent as the airspeed indication wound down with decreasing altitude. Until they broke apart. If they started a climb with trapped pressure, then airspeed will have started increasing with increasing altitude. In that case, they would have ended up in a situation where the aircraft was continually increase pitch attitude or decrease power in the ascent to try to hold down an ever increasing airspeed. Until they stalled. And broke apart.None of these scenarios required bombs or turbulence. But who knows. Just understand that a blocked pitot destroying an aircraft is not as far fetched as you think.

Exactly what I was thinking...

Something just came to me!

• Airbus recommends that airlines replace pitot tubes on the Airbus A320 and A330/40 because of a problem of water and ice building up in them.
• People say there is a possibility that there were supercooled droplets in the clouds
• The pitot tube could have iced over causing the airspeed indicator to fail or go erraticEDIT:
• Significant moisture or precipiation causes too much water to build up in the pitot tube.

1. This causes the computer to think the aircraft is stalling.
2. Computer engages lo-speed protection and could do a very step unrecoverable dive
3. ACARS says the Airbus logic was disabled.
4. Pilots try to take over and recover the plane.
5. Aircraft airspeed gets too high and the structure fails, or it is too late for them to recover.
6. This reminds me of Korean Air 7373. Although it is a lot different than this, the dive was so steep, that it was unrecoverable. Although the altitude was a great deal lower than the Air France flight.

• Because of the prediction of super cooling the airplane may have had to much ice to recover as well.
• I just don't think it is a bomb. If you look at all the pictures, there are no ashes, parts of been recovered in large pieces, there are no scorch marks, even peoples TICKETS, have been recovered, ACARS was still able to send a message, if the nose feel off, it wouldn't be able to communicate as the MCDU is in the cockpit. The bomb thing every post is getting old though. Almost ever other post, I hear lockerbee and bomb... :(

I believe the statement "If it ain't Boeing, I ain't goin!" now :(I hope the carbon the 787 is stronger than this...BTW: zzmike, if there was a partial bomb, I think they plane wouldn't have gotten lost and they would have contacted somebody. Again everything that they have found has no ashes on it or scorch marks, etc. A bomb seems very unlikely, and the bomb threat last week towards AirFrance has been dismissed as phony.

As for bomb inclination (repeat inclination), I'm not a conspiracy theorist, I'm a realist. I believe that more turbine airliners have been brought down by bombs than by turbulence, and there was a case in which the attempt was foiled. (The shoe bomb case.)

Most airliner incidents happened because of pilot error or a flaw in the plane design. Only a very small percentage have been caused by a bomb. This is common knowledge of avaition!Approximately 80 percent of all aviation accidents occur shortly before, after, or during takeoff or landing, and are often described as resulting from 'human error'; mid-flight disasters are rare but not entirely unheard of. Among other things, the latter have been caused by bombs, as in the 1988 Lockerbie incident, mid-air collisions such as in the 2002

I believe the statement "If it ain't Boeing, I ain't goin!" now :(I hope the carbon the 787 is stronger than this...

I go further than that. If it isn't a major USA or UK carrier, I won't ride with them regardless of aircraft type.Regarding my three leading scenarios,1 - 40% bomb leading to immediate airframe destruction beginning in a crusing attitude.2 - 30% pitot icing leading to aircraft upset leading to overspeed leading to airframe destruction3 - 30% vertical stabilizer snap-off leading to aircraft upset leading to overspeed leading to airframe destruction.It would be prudent to alert the airlines regarding susceptibility to pitot icing because this is the only scenario that the airlines can reasonably respond to. In other words, that pitot icing MIGHT plausibly be a cause is sufficient to elevate the priority of replacing the pitot tubes with the new design -- but it doesn't follow that pitot icing must be the cause simply because the airlines are being alerted.

I just noticed the photos of the vertical stabilizer. Very interesting because this is the second time an Airbus vertical stabilizer has failed at its fuselage attachment lugs, which is what the photos suggest. If true this would bring the aircraft down just as it did in Queens in 2001.

first of all, we don't know that yet, seccond the A330's FBW rudder mechanism works in a totally different fassion then the non-FBW A300-600's

I go further than that. If it isn't a major USA or UK carrier, I won't ride with them regardless of aircraft type.

any good reasson for this?

Maybe Airubs should use the composites in the GE90s fan blades, man are they tough!

AA587's rudder came off when passing 187% of it's design load (150% is required), and thats after it had been weakened by the severe yawing of the first (pilot induced) rudder reversals.I have a hard time believing that's not "tough enough"....

first of all, we don't know that yet, seccond the A330's FBW rudder mechanism works in a totally different fassion then the non-FBW A300-600'sany good reasson for this?AA587's rudder came off when passing 187% of it's design load (150% is required), and thats after it had been weakened by the severe yawing of the first (pilot induced) rudder reversals.I have a hard time believing that's not "tough enough"....

I don't care how the rudder mechanism works. The fin appears to have snapped off, which is not speculation, we have the photos. Its failing at the attachment lugs implies strong side loads and tends to reinforce the weather-caused scenario.USA/UK for enforcement of maintenance regulations. Major carriers for pilot training standards. Put the two together and you get my constraint.I didn't say the vertical stabilizer wasn't tough enough, I said that it clearly failed at the fuselage attachment lugs.

Hello,

I go further than that. If it isn't a major USA or UK carrier, I won't ride with them regardless of aircraft type.

Metthink you have better chance (statistics apply) to use a Australian carrier .. Qantas for name it :)Jordanian Airlines or El Al is not bad either .....Regards.Gus.

I don't care how the rudder mechanism works. The fin appears to have snapped off, which is not speculation, we have the photos. Its failing at the attachment lugs implies strong side loads and tends to reinforce the weather-caused scenario.

alright, my bad then, thought you was implying there's a flaw in Airbus's tailfin/rudder assembly design.btw, it seems to have snapped off above the Atachment bolts.

USA/UK for enforcement of maintenance regulations. Major carriers for pilot training standards. Put the two together and you get my constraint.

so according to you the other major European, Asian etc airlines don't fit that discription?I think a lot of people will take offence with that statement (including me)

I didn't say the vertical stabilizer wasn't tough enough, I said that it clearly failed at the fuselage attachment lugs.

that one was directed at gman :(

Although it is interesting ammo for speculation, at this point I don't think we can really determine much from the tailfin being busted off. It could have happened on impact with the water, collision with other wreckage during a fall to earth, or been knocked off by an impact from another part which separated for some reason.That said, although the tailfin of Airbus aircraft have been called into question a few times because of various incidents, most people will be aware that a JAL 747 had its tailfin almost completely blown off when its rear pressure bulkhead gave way after a repair to the bulkhead failed, following a tailstrike incident seven years beforehand. Both the loss of the tailfin and damage to the hydraulic lines resulted in a crash, but in that instance there was nothing wrong with the tailfin or the hydraulics themselves, so in a similar fashion, we may be seeing the effect rather than the cause when we see that busted tailfin from AF447 floating alone in the sea.As far as I am aware there was no such bulkhead damage to AF447, but we do know that the aircraft was involved in a collision with another airliner a while back, and although damage was considered slight, it may not have been as slight as it appeared given that the aircraft has now suffered some kind of misfortune.Al

USA/UK for enforcement of maintenance regulations. Major carriers for pilot training standards. Put the two together and you get my constraint.so according to you the other major European, Asian etc airlines don't fit that discription?I think a lot of people will take offence with that statement (including me)

Me Too!!! The Uk Civil Aviation Authority has the strictest regulations in the world!!! Period!!!!Vololiberista

some new photo's have just been posted on a.net, of the recovery of the vertical stabilizer:©http://www.fab.mil.brit doesn't look like a clean break at all, from this angle.

It certainly looks like a stress failure at altitudeVololiberista