I thought "traditionally" the pitch trim wheel went "ping, ping, ping" like a bicycle bell?
Easily distinguished from just about everything else.

Machinbird;

First three sentences: Yes. On the other hand, I was mainly interested in the motion of the airplane, and did not work out the "seat of the pants feel". The lift coefficient and hence alpha is based on the acceleration normal to the flight path.My data do not go beyond alphamax, so anything beyond that should be taken with the appropriate grains of salt.

That's a depressing read. At least they got around to radio ATC for clearance to fall out of the sky :ooh:

(from Report: West Caribbean MD82 at Machiquez on)

Hi

to fill some emptiness (no job presently) I started to build a model into x-plane, a simuator game that claim to calculate air forces mostly correct.
I did a blended wing, during flight tests i got severe problems to recover high altitude stalls. I figured out a reliable procedure for x-plane to recover from such a stall.

First let my say all what is reported here about that behavior looks reasonable to me. The 7000ft/min compares perfect to the trim setting. (What is not fully correct the trimsetting is corret for the speed 60-80 IAS, but the vvi is looking good for the flight maneuver.)
The stall speed is independent from altitude regarding IAS as long no oblique shock or vortex occurs.

My problem was after the stall the ACFT reached a stable position with 20-30 degrees AoA what i not could not terminate. After many crashes I decided to fly the stall what mean not try to recover early by pressing the yoke forward. I pulled gently until the rear stop was reached, power idle, engine secured by igniter, while gamble to keep wings leveled, checked the horizontal trim settings (I found best was take off trimm working). When reached that carefully move the yoke forward to reach more than 30 degrees downwards but not more than 60 degrees. While dive let the speed increase, just a little below maneuver speed bring pitch to the horizon. Reset power.

This is not the procedure for reacting for a stall warning alarm, what still is just add power. It is for my little blended wing in x-plane. I never lost more than 10000 feet but thats better than an impact.

What the pilot might have felt
 

If they stalled it at a load factor of less than one g, that would result in a stall at a considerably lower speed. The Airbus Safety newsletter mentioned that buffetting would occurr as the aircraft approached stall.

But in this case, if the aircraft stalled at less than a G, the speed would be lower and there may not have been any or much buffetting. If that is the case, the PF may not have felt enough of a stall or break to make him think he had actually stalled it. Stall horns go off when you approach stall, not after you stall.

What very well could have happened is that as the stall warning started and the PF applied TOGA. The aircraft didn't buffet, shake or break into a conventional stall, it stopped flying and started falling at a lower speed.

Absent the break or buffett, when the stall horn stopped the PF likely thought that he flew out of the approach to stall and was flying again. All speculation, of course, but if that is what happened it would offer an explanation of what the PF thought and would explain a lot better his actions.

engine-eer,
 

Engine-eer,
Sounds like a very plausible scenario to me, i.e. non-recognition of the full stall at the start (after intial nose-down following recognized impending stall) for reasons stated. But what is so baffling is that the PF (and others) would persist in such a belief in the face of a rapid and continuing descent for 30K ft with the stick full aft and substantial nose-up attitude (even if credibility in IAS never returned). [Assumes all relevant data provided by BEA, skeptical icon ...]. Of course a continuing stall alarm would have helped greatly one assumes but really, at some point reality should have dawned, leading to forward stick +/- power, i.e. at least an attempt at recovery.

Sorry to bring the discussion back to this issue but for me it's the most troubling one in a way. Let's hope the CVR will reveal much more about state-of-mind of some or all involved.

<returns to piston gallery>

Trim wheel motion
 

Christian, for things Boeing, I believe you are correct.

A while ago on earlier threads, PJ2 briefed that the A330/340 trim wheel moved silently.

Don't know why they made that decision at Airbus, but I think they need to revisit it.

As far as I remember, same thing on Concorde (Sud-BAC, then Airbus).
I'll have to check, or ask friends to check.
If even to an ancient as myself that was "obvious", one does wonder why it was changed.

The A300-600 has a whooler if there is more than a few seconds trim operation but it is cancelled when the autopilot is engaged.

Hi,

I think pprune can thank the BEA to have generate as much traffic on their forums by making public only a few fragments of the CVR
It is as if BEA would cause an outbreak of rumors ... not the best effect on the public.
When we know that their goal was to silence the rumors appeared in several newspapers .. it seems quite successful. :8
In short .. BEA com in all its splendor
One may wonder how to make public the entire CVR (less passages not related to technic matters) would prevent the ongoing and the result of the investigation to proceed calmly and with the confidence of the public.

The public calms down and moves onto the next disaster du jour when a a paper or talking head explains a theory to them with authority (one voice).

Since PPRune never speaks with one voice the media only use PPRune to incite questions.

So let's just carry on with our multiple theories based on what scraps of fact are fed to us :}

jcjeant

Red section...what are you suggesting?
The transcript of the CVR needs to be complete. Otherwise how do we know AF447 maintained a sterile flight deck? The Buffalo incident is a good example of non-sterile environment to the point of distraction in my humble opinion. Lest those lessons never be learnt.
Transparency is the only way forwards. Otherwise who do you suggest should erase parts of the transcript, AF, BEA, French Judiciary...?

"Transparency is the only way forwards."

I agree. Nothing good will ever come from secrecy, whether it be from a group, organisation, authority or society.

A certain European country learnt it's lesson last century. Their equivalent of parliament now has a glass dome for a roof.

Trouble is, any advertising/PR guy will tell you that first impressions last a long time - and, in many peoples' minds, for ever......

Some quite respectable newspapers, for example, appear to have got the impression that the pilot caused the initial 'steep climb.' Even the BEA thing doesn't actually say that - indeed, in very 'spare' wording, it rather confirms the opposite, that the pilot countered the climb with 'nosedown control inputs' and restored the aeroplane to a situation of reasonable airspeed and a reasonable AoA:-

So we're really no further forward as to what caused the stall in the first place?

But BAE's repeated mentions of 'noseup inputs' later on appear to have put over an impression that the pilot caused the whole thing?

My own position is that the BAE would have been 'within its rights' not to publish the CVR this early in the investigation. Alternatively it could have published the whole of it. But just publishing a few isolated quotes is, in my view, plain wrong.

And its also clear that, from the rest of the text, with its descriptions of control movements, power settings etc., they've already analysed quite a lot of the FDR information too. Again, I'd have preferred 'all or nothing.'

If you look at the paragraph preceding your selective quote (timestamp 11s earlier), you will find:
I concur that we don't know enough about the nature of that input to conclude with certaincy it caused the climb, but there's nothing in that note saying it didn't. So far the chain of events NU input by PF -> climb -> ND input -> reduced climb is the least complicated (and thus probably a likely) way to connect the few dots we have.

Sounds to me that you're making exactly the same assumption in reverse.

The investigation is without a doubt proceeding calmly. I am sure 99.99% of the public don't care/are not interested/have confidence. This thread is mostly pointless speculation with most of it being complete nonsense written by people who no little about flying jet transport aircraft e.g.Sterile flight deck? What?

I read this thread for amusement and for the occasional gem like post #1208.

Zorin 75:

What's depressing is how easy the recovery could have been by trading altitude for speed. That requires putting to nose well down in such circumstances followed by a judicious application of power.

aterpster: what I found most striking in the MD82 event was that the nose trim kept going up ... similar to what AF447 has.

Nose drop to lower AoA. Speed up. Watch RoD decrease.

I've been watching the comments on round versus strip gauges and personally agree: the strips don't give me the same "feel" as round gauges. Thanks to mimpe for a bit of an explanation on that. :ok:

Quote:
That's a depressing read. At least they got around to radio ATC for clearance to fall out of the sky

The lack of a distress call (or actually any call) from AF447 has never been resolved. Wonder if this was a conscious decision ?