speedbirdconcorde

@RatherBeFlying

Yes, great ideas. The one thing about a display is that its not static..meaning, when things start to really go awry, designers should use the display to focus the pilots attention - perhaps remove extraneous detail - as opposed to overloading the crew in situations when you dont want them to be overloaded with information.

When your dropping at -10k fpm its quite easy to calculate when you will instantly go to 0 fpm if the conditions remain unchanged ! If a crew is unaware ( I am assuming ) that they are falling at such a rate, then there is a weakness with the interface. In conditions that fall outside of expected behaviour, clarity of information to the crew is paramount.

Even after two years, the posts here show a diverse range of opinion. I am sure the pilots wanted to get home as much as anyone else on the flight, but they, and everyone else on board had their final flight. The technology is there. The man/machine interface still needs to be addressed.

bearfoil

speedbirdconcorde..... same question?

RatherBeFlying

One would like to think a crew would begin to get concerned when they had lost as little as a 1000' below cleared level -- Attitude Instrument Flying and all that...

Agreed the instrument scan seems to have gone out the window.

Since no mention of altitude was made until 9000' the simplest explanation is that altitude was not in anybody's scan. Otherwise it would most likely have been mentioned by one of the crew much earlier.

speedbirdconcorde

Bear...we shall probably never know. One can assume this or that but its really irrelevant if the pilots are not alive to confirm. The only thing I believe we really know at the moment is that confusion reigned in the cockpit.

People lost their lives, so all we have left is the data...from that, we have to ensure that the probable cause of this accident should not result in the same ending ever again...

cheers

GarageYears

The purpose of the Stall Warning is to warn of an approaching stall condition and in this accident it is clear that the fact the aircraft WAS STALLED wasn't identified, at least explicitly.

It has been noted that at one point the Stall Warning was sounding continuously for some 54 seconds, with apparently no attention - not one of the crew ever uttered the word "stall", at least in any of the released CVR content. It remains to be seen in the future whether the full CVR transcript will indicate otherwise (assuming it makes the light of day at some point downstream).

However my question (or perhaps statement) is why is there no "YOU ARE STALLED - DO SOMETHING ABOUT IT!" warning? Something that cannot be ignored.

Certainly, overspeed, for example, is upsetting and may lead to bits of the airplane falling off, so being concerned about that is reasonable, but in the order of things being stalled certainly trumps an overspeed condition.

Unless I am having a seriously bad day, all the necessary conditions for the computing system of the aircraft to be aware that things were seriously pear-shaped were still available - and I think it takes just two:

- AoA seriously negative
- Altitude (or vertical speed) winding off the scale

Can there ever be a legitimate combination of such an AoA and vertical speed that is NOT a stalled aircraft? If not then how about flashing a warning on the center glass reading: "AIRCRAFT STALLED! AIRCRAFT STALLED! REDUCE AoA!"?

There are far better qualified folk on this board to define better conditions (factoring more parameters I'd bet) for such a warning, but what is wrong with doing this?

Given the horizontal speed can be suspect whether or not this need be factored into such a critical warning I will leave as an exercise for the reader, but it seems to me this incident and the Buffalo crash seem to warrant a stage 2 warning beyond approach to stall, that instantly and unequivocally let's the crew know what is happening and has the key resolution (AoA reduction) as the key tag-line?

Make the cockpit displays FLASH the message in RED TEXT on a white background every 5 seconds, whatever, but make it clear and unambiguous.

airtren

As a reminder, these posts were aligned with the BEA analysis, and likely the recommendation that has been delayed now. Would you put BEA experts in any of those 3 categories?

Let me tackle it one by one:

1. "Understand the Airbus FBW concept"

What does the Stall Warning have to do with FBW?

It is an Emergency Error Message to the pilot, about the state of the plane, that can be fatal. The "media" for transmitting commands from the pilot to the controls can be anything as long as it does the job of carrying the commands. It can be wire (FBW), WI-FI (wireless), optical fiber, cable, compressed gas/air, hydraulic, etc....

Furthermore, regarding its importance, and place within the system, the Message can be generalized. It is not different than ANY Emergency Error Message about a possible fatal situation or condition, relative to the functioning of a box, coming from the box to the operator of that box, with the purpose to trigger an action of the operator of removing the condition, or cause of the situation.

2. "Have never flown an Airbus".

Doesn't Air France action/opinion on the Stall Warning also represent Airbus pilots position and interpretation?

A pilot trained to fly Airbus is also trained to follow certain procedures to bypass the a/c weaknesses.

Good training is a MUST, no doubt. But good training, and peer pressure in the pilot community coming with the good training, while has positive effect, it also, creates a paradoxical situation, in that it is a brain-washing mechanism, that contributes to hiding or minimizing weaknesses, or problems with the a/c.

3. "axe to grind with Airbus."

This is one of the most detrimental criteria, and has become typical.

It makes it very easy to arbitrarily label, categorize and dismiss. It makes it easy to muddy/fog the path to the truth.

PEI_3721

GarageYears, et al,
As much as new designs might enhance the salience of a warning, if the crew’s mental model has rejected the warning as being false, inappropriate, or unwarranted in the situation as perceived, then enhancement is of little point.
Remember ‘shut up gringo’ ?
Some other aircraft have, and for good reason, a stick shaker and stick pusher.
Now an electronic version of that sounds very simple, particularly if it repositions trim. However, remember that a ‘rush’ makes for poor law – similarly quick system changes and redesign might have pitfalls elsewhere.
Thus, let the designers think through their system; they probably evaluated such an option in the initial design - certification case to show why it is not required.
Finally all parties must ensure that any change fixes the problem, but do we actually know what the problem is, except perhaps human limitations in perception and understanding.

henra

Hmm, I somehow understand your frustration about this unfortunate systems behaviour, but by all means the Stall warnings were not bogus when they sounded. Even at that time the A/C was still deeply in a stall. Remember this was at Alpha > 30°.
If you want to call something bogus it is the fact that they stopped above a certain AoA.

In this whole event I do not see a single bogus stall warning.
Even not the first ones. Looking at the FDR traces it is clear that at 1,6g the Stall AoA would surely be momentarily exceeded. That should happen somewhere above 1,4g at that speed / altitude.

Still I'm sure the logic for the stall warning will be an item which will be reviewed by Airbus and rightfully so.

airtren

We’re both facing possibly the same problem with the charts – alignment, and resolution - which BEA experts and those having the source or better resolutions of the charts don’t.

Your chart that I can see on my screen reading your post, shows that the SW graph is misaligned with the PF stick action graph, being too much to the left, and thus the SW spikes are to much to the left relative to the PF stick graph.

As mentioned, there are 8 SWs in the ‘a/c recoverable window”, which from left to right, are in 2 groups of 4. There is a remaining 2 SWs to the right, between 6000ft and 0ft altitude. These 2 make it total of 10.

While I can give up on the first 2 SWs (the first pair at the left) of the first group of 4 SWs – which I didn’t dismiss initially, because of the PF stick unsatisfactory graph resolution. but I agree, it does not show unambiguously enough longer duration stick movement at this time.

I will stick with the 2 which were left of the first group of 4 (at the left), as there is PF clear corresponding stick motion – less NU first, followed by ND.

The second group of 4 SWs (at the right), is clearly in the ND/NU heavy stick action region. Don’t dismiss a ND action because there is no perfect vertical match – as the SW does not follow the ND action instantaneously.

After more thinking, it is clear to me that the last 2 SWs (out of 10) that show on the graph to the very right, between 6000 ft and 0 ft, which I didn’t include in my previous post, are to be considered as well in this discussion.

They in fact, fall in the same category with the others, as the ability to recover or not recover does not change the character and source of the problem.

It is wrong to say that the failure of the SW to relay the correct information to the pilots does not matter because it was too late for them to recover anyway.

It does not matter if the SW gave the wrong indication once, or 10 times.

It is sufficient to do it once, as it can happen again, and again, in similar situations, if a fix is not developed. The recovery or not recovery from stall is not removing the possible similar behavior on other planes in similar situations.
It is bogus not because it was a Stall Warning out of silence during a Stall.


It is bogus, because it was a Stall Warning giving the wrong indication relative to the PF actions, and relative to the state of the “a/c” relative to Stall.

The message from the PF/NPF/CDB perspective was signaling a transition from NON STALL to STALL, when in fact the transition was from STALL to NON STALL.

You are missing the point, if you think, that the exact internal cause, or the mechanism of triggering the message matters. It does not matter, relative to the needs of the pilots, and state of the “a/c”.

In the same time, you’re making my point – if the internal mechanism was creating the condition in which the STALL Warning went silent, that mechanism need be fixed, in that it need to be depending on more parameters, such that there is a parallelism, that removes the risk that the NCD of one parameter results in NO MESSAGE.

Which one would correspond to WSJ, and which NI? Media makes money from disseminating information, and scandals make money….But there is a gauge that each of us has, and in this case it is not the trash, that you could throw a Blanket Dismissal at.

This crash has been under investigation for more than 2 years now, and many following it had the ability to have a good enough understanding without being influenced by one press article, or another.

What’s the today’s press and TV news in France? More of course... as there is more reaction by the parties involved....

It’s a STALL recovery, in quite drastic height, attitude, and speed conditions first.

One major difference had to do with the pilots basic training, that shaped their flying instinct, and reflex.

is an additional aspect of the Stall Warning, which you may understand or may not, in terms of system error message, relative to system state.

It’s ONE ERROR for three different possible states of the system:

• State 1. transition from NON-STALL to STALL
• State 2. steady STALL
• State 3. transition from STALL to NON-STALL

As long as there is no clear separation between 3 distinct messages, the operator need to understand certain parameters and apply the algorithm to differentiate. In a stressful life and death situation, that's too much.

It is a lot easier to let the computers do the differentiation and showing the right message.

Understanding how THS work is important, very important. But the “information about the THS wheel position change” is not about how it works. It’s about saving the time needed to watch it and memorize its positions to check it. When time is crucial for life or death decisions and actions, any time interval and ant sensory and brain computer and memory cycles that can be spared, are an addition to what can be used to save the situation. So what if other planes don’t have it. Is the validation of other planes needed for Airbus?
There is one very simple, but also major reason to have it: Operating it in relative secrecy, when the results cannot be easily perceived by the entire team in the cockpit contributes to the type of AF 447 accident.

As we speak about this, I still have an unanswered question relative to the Airbus 330 stick functioning:

Is the control surface deflection proportional with the duration of a stick action in a certain position – if it is longer action in a certain position, is the deflection different than shorter action in that position?
....
As all of the above are part of the "a/c to pilot information interface", the current technology level makes a screen large enough to see from all seats, with a clear 3D image animation of the plane with its AoA and roll position space, and position of control surfaces long over due.

wozzo

Press release on 3rd August 2011

It's an interesting read, full text:

xcitation

Clearly not every circumstance can be trained, programmed and simulated.
Once we accept that fact then we see a need for augmenting the resources on the flight deck in an emergency situation.
One solution would be an irridium satellite phone uplink with AF operations center supplying flight data and errors. It should also connect a voice channel. It would automatically connect when system errors reach a critical threshold level or manually activated.
It is easy to envisage a pilot receiving a call "This is AF operations: AF447 your a/c has 3 failed pitots and UAS. You are approaching stall, recommend immediate pitch down, side stick forward over...".
Satellite phone costs are cheap and air time would only be used in an emergency. There is presumably already an AF technical operations center which could be set up with the required telemetry systems.
We already see ECAM telemetry. This needs to be taken to the next logical level.

hetfield

Are they kidding....

mm43

STALL WARNING
That statement can not be misconstrued. The crew never acknowledged the Stall Warning. The exception could be that they reacted to it inappropriately once stalled.

airtren

If one comes from a Nordic or Germanic country, it used to be quite a difference. Not that much anymore, at least with the latter....

A French intellectual may say that:

French have a somewhat different education, in that arts, prose and poetry have a more important role than in other educational systems

French have a Balzac, a Hugo, a Proust, to name a few, which are revered more by the regular people than in other cultures significant writers would be....

French are more artistically and romantically oriented relative to their practical orientation. That shows, that even the simplest technical writing can become a little piece of art prose, with turns and meanders, rather than a very practical, straight forward, concise, easy to read piece of information.

That's what a French intellectual may say...

asc12

GPWS works like this, I'd say. "Sink Rate! Sink Rate!" and then "Pull up! Pull up!"

You could have Betty give an explicit suggestion (like "Pull up!") for a developed stall: "Nose down!" or something. Of course I agree that pilots should be able to recognize the development of a stall, but it's been shown that pilots can fly perfectly good airplanes in to the ground without recognizing they're about to do so-- which case presumably led to the development of GPWS to begin with.

I like this idea, although (humor follows) the confusion of messages close to the ground would be interesting: "Sink rate"... "Impending stall"... "Stall! Nose down!"... "Pull up!"

Tjosan

And the last fifty feet, too late too late.

Lonewolf_50

"stall warning"
I decipher this as "Get off of our freakin' back, folks! We're tryin' to do a quality investigation here!"

I empathize.

airtren

The (...)c'est pas possible - "that's not possible" - of the Captain at 2:12:44

mm43

Yes, he said that in the middle of a 5 sec SW burst. I estimate he had probably already heard at least 15 secs of SW from arriving on the FD, and in any case, was he actually referring to the SW or the V/S??

grity

is it possible that the rollinputs are induced from a "karman vortex-street" behind the fuselage of this widebody with his angular incident flow in case of higher AoAs ?


P.S.
what can be a reason for UAS until the ice dedectors has no ise detected........