All modern a/c are built to withstand a gust factor of 66 fps at best. That's only 45mph or 39 kts. In the tropics if you fly anywhere near a storm you will encounter gusts of at least that and more. In a thunderstorm cell an a/c can suddenly experience gusts of 100mph vertically in either direction.

And the structral tolerance for negative g is often much more limited.

......There was also an automated report regarding depressurisation. none of these automated messages wold have been sent if there had been a bomb!....

Bombs aboard aircraft don't mean instant fireball. More often than not they are very small explosions that trigger a series of events leading to the breakup or crash of an aircraft. It is quite possible that a bomb could have brought the Airbus down and quite possible automated comms could have taken place for a period of time afterwards. I don't buy into members posting a bomb theory as the only probable cause of the crash, but one cannot rule it out either based on the data available at this time.-John

A fascinating thread.@Belga1:Before we get ahead of ourselves wrt the disintegration of any carbon-fibre parts, I just wish to point out the following fact: The photos you have posted show an almost complete tail fin, not broken along the green line - as one of the photos suggests.The photo is not taken from directly above. You can clearly see the EU circle of stars logo, and appreciate the angle of perspective. Looking at the fin floating on the water, you can also make out the tapered leading section at the base of the fin (top left of photo). Thus, the fin actually looks fairly complete.Cheers,DanEdited to add:In fact, looking again at the EU logo, and assuming the tail fin is floating flat on the surface, I would say that from the photographer's perspective the tailfin is located about 25 degrees below the horizon in his field of view. Hence the shape of the tailfin appears quite distorted, erroniously suggesting the break along the green dotted line.

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 erratic

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... :(

Hello,

In fact, looking again at the EU logo, and assuming the tail fin is floating flat on the surface, I would say that from the photographer's perspective the tailfin is located about 25 degrees below the horizon in his field of view. Hence the shape of the tailfin appears quite distorted, erroniously suggesting the break along the green dotted line.

Thank's for your input ...Indeed .. perspectives .. shadows .. etc can distord image of the reality in a photo ...We will know if it's part or entire tailfine for sure in some hours ..Regards.Gus.

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.As I suggested in an earlier post, a storm-bred tornado is a possibility. The photos suggest this as a real possibility since encountering a reasonably vertical tornado would place tremendous stress on the vertical stabilizer.(Yes, it could have snapped off during the airframe disintegration. But yes, its snapping off might have been the cause of the disintegration since it would have made the aircraft uncontrollable, leading inevitably to overspeed and then aircraft breakup.)As for aircraft being designed to withstand vertical gusts only up to 38 mph or whatever number was cited, this isn't how they're designed. There is a design safe G-loading limit. The maneuvering speed of the aircraft is set by the design engineers so that any vertical gust that would stress the wings beyond their nominal load limit will cause the wings to stall instead of failing. This means that in principle (in principle) a vertical gust could have any speed and the airframe will not be damaged. (In principle. Obviously an extremely fast vertical gust of 200 mph such as might result from a severe horizontal tornado would throw all the design calculations out the window.)

All modern a/c are built to withstand a gust factor of 66 fps at best. That's only 45mph or 39 kts. In the tropics if you fly anywhere near a storm you will encounter gusts of at least that and more. In a thunderstorm cell an a/c can suddenly experience gusts of 100mph vertically in either direction. "In general" pilots do not go anywhere near them but some do and even fewer come out. If then the a/c as reported did experience a cabin depressurisation the pilots would have had no option but to initiate an emergency descent this reduces the gust factor loading down to 25fps which is only 17mph or 15kts. Therefore to have to do an emergency dive in a storm you can see leaves very little margin for error. Build in the weight factor as well (the heavier the a/c the closer are the boundaries of safety) What I'm trying to say in essence is that it appears that things started to go wrong whilst encountering heavy turbulence leaving very very little room for manouevre. also carbon fibre does not have a good track record. It is either 100% safe or 0% In other words you can't bend it!!Vololiberista

If you look at the above "initiate an emergency descent this reduces the gust factor loading down to 25fps which is only 17mph or 15kts." and plot where VNE and MNE cross which is closs to FL240 one can see that in a steep descent if your airspeed is 15kts+ too high you WILL start to break up!!

Hello,Location drawing antennas .. etc ... (that's a small PDF .. you can open it online easy)http://www.smartcockpit.com/pdf/plane/airb...30/systems/0001Regards.Gus.

As for aircraft being designed to withstand vertical gusts only up to 38 mph or whatever number was cited, this isn't how they're designed. There is a design safe G-loading limit. The maneuvering speed of the aircraft is set by the design engineers so that any vertical gust that would stress the wings beyond their nominal load limit will cause the wings to stall instead of failing. This means that in principle (in principle) a vertical gust could have any speed and the airframe will not be damaged. (In principle. Obviously an extremely fast vertical gust of 200 mph such as might result from a severe horizontal tornado would throw all the design calculations out the window.)

Maneuver speed has nothing to do with vertical gusts and turbulence. All maneuver speed means is that it is the maximum speed at which you can make a full control movement. A full pull back on the stick above maneuver speed will cause the aircraft to exceed its G-limit. A full pull back on the stick below maneuver speed and the plane will stall before reaching its maximum G-limit. That is why it is called maneuver speed. It is the exact speed at which you can extract the most maneuvering performance from the aircraft since you can pull its maximum allowed G's. Don't confuse maneuver speed with turbulence penetration speed. In the GA world, most aircraft manuals do not specify a turbulence speed, so manuever speed is used by GA pilots as the next best thing. But keep in mind that you really don't know what your turbulence penetration speed is and the Va you're using could be nowhere near that.

Maneuver speed has nothing to do with vertical gusts and turbulence.

I'm not wrong ..."http://www.mountainflying.com/Pages/mountain-flying/turb_va.html"

Hello,Location drawing antennas .. etc ... (that's a small PDF .. you can open it online easy)http://www.smartcockpit.com/pdf/plane/airb...30/systems/0001Regards.Gus.

Yes, the antennas location diagram shows the satcom antenna to be well forward. It also shows the electrical equipment to be about where I said it usually is.So the file you linked to supports your case how?

"Maneuver speed has nothing to do with vertical gusts and turbulence. All maneuver speed means is that it is the maximum speed at which you can make a full control movement."I agree with Kevin on this.It looks like this aircraft went into some extremely strong cells (3 possibly strong cells) and may have exceeded its structural limits. A factor may have been the airspeed malfunction causing an inappropriate airspeed which further degraded the situation. It is also possible, like the New York crash in wake turbulence that the pilot countered with rapid rudder inputs, that a similar situation happened here. Again, most crashes like this have multiple causes-but I'd expect turbulence from going into cells to be the 1st.http://features.csmonitor.com/globalnews/2...ulence-or-hail/

"Maneuver speed has nothing to do with vertical gusts and turbulence. All maneuver speed means is that it is the maximum speed at which you can make a full control movement."I agree with Kevin on this.It looks like this aircraft went into some extremely strong cells (3 possibly strong cells) and may have exceeded its structural limits. A factor may have been the airspeed malfunction causing an inappropriate airspeed which further degraded the situation. It is also possible, like the New York crash in wake turbulence that the pilot countered with rapid rudder inputs, that a similar situation happened here. Again, most crashes like this have multiple causes-but I'd expect turbulence from going into cells to be the 1st.http://features.csmonitor.com/globalnews/2...ulence-or-hail/

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.

Hello,

So the file you linked to supports your case how?

Satcom antenna is far from the nose part .. (Fly deck)If you compare (your base comparison) with the Lokerbie B747 part .. there it's really the nose part...Of course if you argue the nose part of this plane is the aera between the radar dome extremity and the leading edge of the wings .. Edited: And the Satcom antenna must have a good orientation fo be able to transmit to the sat ....But as more and more things come out of this tragedy .. more and more a explosion due to a bomb vanish out of my speculations ...Regards.Gus.

... Satcom antenna is far from the nose ...

In the Lockerbie crash the separated nose section included a significant portion of the First Class section of the cabin. The same might have been true in this accident as well, taking the satcom antenna with it.

Folks,I'm not insisting that I know what happened ...Yes, there's a good chance that the accident was caused by weather.Yes, there's a good chance that it was a bombing. (This would not have been the first airliner deliberately bombed out of the sky over the ocean. There have also been foiled attempts at this.)So let's all agree once again that we're all speculating. That said, it's an interesting discussion.