Uplinker

"Perhaps my terminology was off - I am obviously referring to AF447 after the upset: dropping with stalled wings, extremely low forward IAS, and very high downwards V/S. Perhaps I meant 'fully developed stall'?"

The BEA, in its report, simply refers to a "sustained stall".

Court case I hope would bring out a couple of points. 1) I did stall training in the A330 simulator in alternate law. (Prior to the crash) the simulator buffeted & then dropped its nose as most aircraft do. Hence after the crash I thought oh it doesn’t stall conventionally.
2) I have always wondered what Bonin meant when he supposedly said. “We have no indications”

As said on this forum the final report missed out quite a bit.

Does such a position exist at AF?

It certainly doesn't happen/exist at some other airlines that do augmented crew operations.

Aren't we missing the point here? If the pilots in the seats had applied the appropriate pages of the "Unreliable Speed" QRH (roughly 2.5 degrees NU and 80% N1) instead of applying the pages which apply to "After TO", this would not have happened. So it is an AF training matter and, depending on who delivered their TR training, maybe Airbus as well.

Given the sudden emphasis in some quarters in the captain's action/inaction/whereabouts there does certainly seems to be some danger of that.

PV1

The airspeed dropped below 60kts and was treated by computer as non computed data to stop the stall warning. Can any stall be deeper than this?

mcdhu

Yes we are, technique analysis has been done to death. The point now is the use of the law following an accident and the implications for open reporting.

vilas

There is a specific definition of a deep stall.

PV1

It appears that the best "nothing" that they could have done was just to let go the controls. Everyone would most likely then have survived.

PV1

I'm not so sure about that. A deep stall is commonly accepted as a stall condition which can't be recovered from - at least not using 'conventional' techniques (i.e. command nose down). However I've never seen or heard where that is an official definition of a deep stall.

tdracer

"However I've never seen or heard where that is an official definition of a deep stall."

I'm not sure I'd know where to look for an "official definition" of even a simple stall. Nor many other generally-understood aeronautical terms, come to that.

DP Davies (Chief test pilot CAA from years ago) wrote about aerodynamics so "handling the big jets" is a must read.
The link below explains what you already know, but is included for readers of the thread who may not be familiar with fluid dynamics.

Stall (fluid dynamics) - Wikipedia

Davies
 

He discusses the super stall in handling the big jets with an unconventional pitch up characteristic approaching the stall followed by turbulent flow over the tailplane inhibiting conventional recovery.
Iirc the 737 max "fix" was because of the reduction of normal pitch down force approaching the stall.

By all means read Davies, but bear in mind that the book is now over 50 years old and pre-dates FBW (the most modern aircraft mentioned is the A300). His stall recovery advice is no longer taught. That said, his explanation of aerodynamics is excellent.

I always understood that the deep stall - so called - was asociated with T Tail Jets, like the Trident, 111, 727 etc. We certainly did training on that and unusual attitude recovery in the T Tail that I flew and I thought that unusual attitude recovery on instruments was a standard sim element. If it isn't then it should be

Still is on a recurrent basis.

I think deep stall is a thread drift. There's another stall on highly swept supersonic fighter like the Russian MiG-21, the super stall where it's not possible to power out with full power and after burner unless the AoA is reduced. It causes significant loss of altitude.There's nothing like that on Airbus 320/330. What can happen to most commercial aircraft is incipient stall or fully stalled. AF447 was not on the verge of stall but taken well beyond that and held there in fully stalled state. There were 24000 posts on AF447. You can't chew it anymore. The courts will decide if at all, whether the training syllabus of the manufacturer sufficiently covered unreliable airspeed and stall recovery and for Air France part did they train their pilots accordingly.

Indeed and the Judges do not have aviation training and aircraft manufacturing knowledge so they rely on various experts and their reports . The problem for them is that there are by now 3 reports saying slightly different things. The accident occurred 12 years ago and for the family's victims this has turned into a nightmare', which is complicated by the presence a a few lawyers on a crusade to make a name for themselves as it is well mediatized as we are talking about Airbus and air France..

From a purely technical , training and safety point of view, everything on AF447 has been learned, and corrected . This type of accident will almost certainly never happen again .. What we see now are legal issues about who has to pay money to who and how much...

Dave, here's a quotation from a 1998 Boeing document that may touch on what you're looking for:

PV1

the fact that anyone here is using the term “deep stall” just highlights the total lack of knowledge of aerodynamics and SOP on stall recovery. Shocking