This is incorrect. Given their TAS, VS and Pitch their AoA was around 60º, way beyond a mere stall into "deep stall" territory. The flight path alone was like 45º (TAS = VS), and increases to 60º as you add 15º nose-up pitch (all ballpark numbers as I'm not bothering to check the accident report). You need to check your fundamentals because you should know angle of attack is the only reason a healthy airfoil will stall. Cheers, - jahman.

Of course angle of attack is the only reason an airfoil will stall. I've no idea what you read out of my post to make that statement. I'm sure your math is good, but I'd like you to reconcile that with what we know about what happened that night. As far as I know, they descended in a wings level fashion, with roll attitude perfectly under control. On a swept wing aircraft, the wingtips stall first, thereby making positive roll control difficult. When a swept wing aircraft stalls, it will roll steeply off on a wing. That does not appear to have happened here. And if there was still enough airflow to allow roll control at the outboard sections of the wing, then how could any other part of the wing be further stalled? And also, it was an Airbus. Even at the reduced control law level they were at, probably Alternate Law, there may still be stall protection in there. And my bet is the control laws just kept the plane from fully stalling and departing controlled flight throughout the descent.

However, there were still fly by wire laws in effect during the descent and they appear to have kept the plane at the edge of flyability during the descent.

My understanding is that the horizontal stabilizer was full nose up during the whole descent and this made difficult or impossible to recover from stall. Is this correct? Was the horizontal stabilizer autonomously moved in that position by the airbus flight control laws? Were the pilots aware of the position of the stabilizer during the event?

My understanding is that the horizontal stabilizer was full nose up during the whole descent and this made difficult or impossible to recover from stall. Is this correct? Was the horizontal stabilizer autonomously moved in that position by the airbus flight control laws? Were the pilots aware of the position of the stabilizer during the event?

I've no idea where the stabilizer was positioned. The only point I'm trying to get across is, there are benefits to allowing an aircraft to do natural things, such as stall fully and momentarily depart controlled flight. Because the departure is a natural response to control abuse, it has the benefit of ignoring the abusive control input and allow the aircraft to naturally seek a flyable condition. By building in all these protections into a plane's fly-by-wire controls, it may have in this situation, prevented the airplane from fully stalling, departing controlled flight, and then self seeking a flyable condition.

And if there was still enough airflow to allow roll control at the outboard sections of the wing, then how could any other part of the wing be further stalled?

Because this is not a Cessna we are talking about, on the A330, roll control is provided by the outboard ailerons and the inboard spoilers. Therefore the ailerons could be inneffective and there could still be roll control authority. Al

Because this is not a Cessna we are talking about, on the A330, roll control is provided by the outboard ailerons and the inboard spoilers. Therefore the ailerons could be inneffective and there could still be roll control authority. Al

Yes, you could be right about that. But a downward deflected aileron on one of the wings during a stalled condition should still cause a nasty wing drop. I'm sure I am being way too radical to say it wasn't stalled, but you should think about how it went into the water with her pitch and roll under perfect control. That is telling you something.

Yes, an aileron drop could cause an asymmetric stall for sure, but as far as we know it did not, however, with even a small amount of pitch up, you have to consider that going down at 15,000 FPM - regardless of forward motion - has got to mean a very high angle of attack on the wings, probably way past the normal unstalled airflow angle. That may even have put the elevator in a badly disturbed airflow zone, making pitch authority impossible, especially if the tailplane had iced up. Al

I know we keep quoting 15000fpm here. We've also been quoting 4 minutes of hell as well. To descend at 15000fpm for 4 minutes they would have to had begun at FL600. I thought they fell from FL370.

Yes they did drop from 37,000 as far as I am aware, but I should imagine they would have increased to that rate of descent rather than held it all the way down (or maybe the other way around as the air got thicker), which again suggests that the thing was probably getting into more trouble as things progressed, not helped by some guy holding the stick back and awaiting an aerodynamic miracle to occur. Whatever the case, four minutes is a long time, even half that time is, and should have been long enough to figure out an appropriate response assuming the systems were intact enough to allow some kind of manual reversion, flight mode intervention or whatever. Anything other than just bending the stick back and waiting for impact. Look at the Airbus that went into the Hudson, that crew had a lot less than four minutes to play with, and they had no engine thrust at all; a different situation of course, but a calm and skilled response to what was undoubtedly an equally challenging one. Al

Microsoft Fright! Cheers, - jahman.

LOL

No matter what, I think there are issues here that this crash is going to raise: 1. How much envelope protection is too much? Could this have been averted if the plane had less envelope protection in the FBW? If the plane is supposed to be unstallable by virtue of the fly by wire, then did the fbw's intervention keep the pilot's continuous stick back input from attaining a full stall that would have broken the nose downward and allowed a recovery? Or if the plane was stallable and did truly stall, then why was there no stick pusher activation that would have broken the nose downward and allowed a recovery? 2. Pilots who are trained from day one to fly airliners and then start flying them with only a few hundred hours of experience. Is that really a good idea to have pilots flying hundreds of people around who's only experience has been a training environment geared towards flying an airplane precisely by numbers in a crew environment? Without experience gained from flying combat, flight instructing, or cargo into dynamic environments, making decisions on their own, and handling problems over the course of years and a few thousand hours, can they really handle anything other than normal flight?

Without experience gained from flying combat, flight instructing, or cargo into dynamic environments, making decisions on their own, and handling problems over the course of years and a few thousand hours, can they really handle anything other than normal flight?

It's long been my opinion that this very matter is a big problem, and one that is now coming back to bite us in the &@($* on a depressingly regular basis. For example, I voiced strong protestations to the CAA in the UK some years ago when they changed the PPL curriculum to no longer include teaching spin recovery, but instead teaching ''spin avoidance'', as I said at the time, that's all very fine, but not having been taught how to actually get out of a spin, rather than being taught to avoid them is not going to help anyone if they do get into a spin as they watch the ground come up and think about how else they could have avoided it instead of getting on the rudder and then jamming the stick forward PDQ. Personally, I thought that decision was madness but unfortunately such protests about it fell on deaf ears, and the same kind of thinking permeates the ''push that button and watch it fly'' mentality of a lot of modern airliner operations, where basic stick and rudder skills and common sense airmanship are hugely neglected and often considered of little importance compared to knowing the FMC and the MCP. Airline pilot's wages are very poor these days, and if you pay peanuts... Of course whether this may relate to the situation on AF447, or have been the cause, I don't know, but it sure doesn't help matters, that I do know. Al

Of course angle of attack is the only reason an airfoil will stall. I've no idea what you read out of my post to make that statement. I'm sure your math is good, but I'd like you to reconcile that with what we know about what happened that night. As far as I know, they descended in a wings level fashion, with roll attitude perfectly under control. On a swept wing aircraft, the wingtips stall first, thereby making positive roll control difficult. When a swept wing aircraft stalls, it will roll steeply off on a wing. That does not appear to have happened here. And if there was still enough airflow to allow roll control at the outboard sections of the wing, then how could any other part of the wing be further stalled? And also, it was an Airbus. Even at the reduced control law level they were at, probably Alternate Law, there may still be stall protection in there. And my bet is the control laws just kept the plane from fully stalling and departing controlled flight throughout the descent.

To answer your question, what made me wonder whether you understood how a wing stalls is that I did show the AoA was around 60º, but you still doubt AF447 was stalled. What gives? You do know sub-sonic swept wing airfoils stall at between 14º to 18º AoA (22º with slats extended), but 60º? The aircraft is more than stalled, it is falling out of the sky! Here are the calculations (from a previous post):

At the end of the report the investigators state: "The last recorded values were a vertical speed of -10,912 ft/min, a ground speed of 107 kt, pitch attitude of 16.2 degrees nose-up". That VS is -10,912 fpm * 60 min/hr * 1 / (6,080 ft/nm) = -107 kn, so at that point the AF447 vertical track was arctan (107 kn / 107 kn) = 45º for an angle of attack = 45º + 16º = 61º

Even though the calculated AoA is at the end of the flight, it does remain fairly constantly at an inordinately high AoA (fairly constant descent rate according to the straight blue altitude line and fairly constant GS gold line, with pitch at 10º nose-up for the most part but registering excursions to +20º and -5º), so high in fact the ADC/FMC (not familiar with Airbus equipment terminology) no longer computes AoA properly. From the FDR (p. 106): An interesting calculation would be to figure what FL was the point of no return to initiate successful recovery. The FDR does show a fairly constant roll oscillation all the way down from 20º - 40º right to 15º to 20º left wing down due to the roll instability you mention, with lots of aileron, spoiler and rudder activity at the roll oscillation frequency as the FBW fights to control the now unstable aircraft. Cheers, - jahman.

Ok, that's proof enough of a stall. I hadn't heard of the roll oscillations. I began to doubt the stall because I would have expected them to experience a violent roll upset if they were stalled. But it looks like the FBW worked violently enough to keep the plane from rolling off. If the FBW hadn't prevented a roll upset, they would probably have broken out of the stall. So if the plane was stalled, was there a stick pusher activation?

Just checked the CNN source to (again) make sure I had the correct transcript: Recall the thread's title: "The crew's last 2 minutes that AF and the govt don't want you to hear". It would seem then the exchange you mention is prior to the last 2 minutes- jahman.

I attach an extract from BEA's transcript in its Interim Report No 3 - Appendix 1 - FDR / CVR Summary TableAs I said previously, the recording ends at 2h 14 min 28,4 and the last message is timed at 2h 14 min 26.

It's long been my opinion that this very matter is a big problem, and one that is now coming back to bite us in the &@($* on a depressingly regular basis. For example, I voiced strong protestations to the CAA in the UK some years ago when they changed the PPL curriculum to no longer include teaching spin recovery, but instead teaching ''spin avoidance'', as I said at the time, that's all very fine, but not having been taught how to actually get out of a spin, rather than being taught to avoid them is not going to help anyone if they do get into a spin as they watch the ground come up and think about how else they could have avoided it instead of getting on the rudder and then jamming the stick forward PDQ. Personally, I thought that decision was madness but unfortunately such protests about it fell on deaf ears, and the same kind of thinking permeates the ''push that button and watch it fly'' mentality of a lot of modern airliner operations, where basic stick and rudder skills and common sense airmanship are hugely neglected and often considered of little importance compared to knowing the FMC and the MCP. Airline pilot's wages are very poor these days, and if you pay peanuts... Of course whether this may relate to the situation on AF447, or have been the cause, I don't know, but it sure doesn't help matters, that I do know. Al

I agree here! I remember my spin training (as I should!!) in order to pass having to recover within 10deg of original heading. and of course, stall training too. Having to recover within 50ft! This accident is very sad in that 3 passengers could have done better than those 3 pilots.1. They elected to fly directly into a major storm.2. When IAS became untrustworthy they did not fly attitude and thrust.3. They ignored the stall warning and did not initiate a proper stall recovery4. Thereafter they held the a/c in a deep stall all the way down in spite of the massive rate of descent All of these are elements of basic training. Passengers expect their pilots to be professional. But, sadly in this case they did no better than children.vololiberista