RetiredF4

Now watch it, this may backfire.
The crew of AF447 after the loss of control wanted to arrest the descent and climb back to their assigned flight level, therefore they pulled on the stick. The aircraft continued to descent, therefore they pulled more.........

From a pilots view it is most important to evaluate the output in relation to the input. As mentioned before, thats the control strategy of automatic systems as well. Take the input value or the output value away from the logic, and your automatics will go banana.

You need to take both into account, the input and the resulting output.

BOAC

Spot on, franzl - that was logic gone mad. How doe sit go? "To go up, pull back on the stick. To Go down, pull harder".

Aviation has always been about "is the result what I wanted". Output, as you say, matched to input.

DW - why, in order to link the controls to the surfaces electronically, was the control column removed - so we can pull out a tray and eat our food?

DozyWannabe

So here we need to dig deeper. The aircraft is descending and pulling back does not help. At some point you'd hope that the problem-solving mindset would say : "We're pulling back and still descending - why is this? We need to try a new approach".

At which point the most common reason for descending while pulling up would have to be "we're stalled". Sadly they never got that far. One of the big questions is *why* they never got that far.

jcjeant

Hi,

DW
You will have the answer in two days
If no answer .. you will ask the same question the next time ... .........

HazelNuts39

The side stick reached the aft stop at FL363.

DozyWannabe

I think that in fact we'll have a plethora of possible answers, all of which must be addressed - there simply isn't enough information to determine the HF aspects for certain.

Among other things...

In all seriousness, I've gone into this so many times now that to repeat myself would only be hogging posting space. Here are a few links to more recent posts on the subject:

http://www.pprune.org/tech-log/48235...ml#post7184647

http://www.pprune.org/tech-log/48235...ml#post7172036

http://www.pprune.org/tech-log/48235...ml#post7168364

http://www.pprune.org/tech-log/46625...ml#post6779587

And, possibly to mind mind most importantly, the role of Capt. Gordon Corps:

http://www.pprune.org/tech-log/45465...ml#post6538934

CONF iture

One more time : The fact that a "timely and effective communication with your colleague in the opposite seat" is necessary, makes the point that something is missing.

By their presence, the yokes make such verbal communication unnecessary.
Unambiguous direct and free information to all in the flight deck : Priceless !

Linktrained

Some months ago somebody asked whether there were any training aircraft fitted with S/S.

I read that the specification for training aircraft states, IIRC, that dual controls were required for what I think, was professional instruction. It specifically stated that swing-over controls were not acceptable
At least on a DH86b it meant saying " You have control... " was done without any doubts by either pilot !

bubbers44

CONF iture, yes, the yoke requires no communications of what the other pilot is doing. Us Boeing pilots know when to take over and not talk. Just say I have it.

I don't see this crash happening in a Boeing because of the fact at FL350 you can not let another pilot pull a yoke into his lap with out knowing you will go into a deep stall. Those guys did let it happen. Their inexperience shown by the most experienced guy in the left seat calling the captain instead of taking control. He let the young pilot pull into a full stall and didn't stop it because his experience was slightly more than the PF. They should have not been flying together. The captain would have prevented this tragedy but he was required to trust his co pilots to let him have his required rest. Cruise pilots are not real pilots or they wouldn't be called cruise pilots.

Clandestino

CM2 2936 TT, 807 on 330/340
CM1 6547 TT, 4479 on 330/340
Capt 10988 TT, 1747 on 330/340

When is the pilot experienced enough to be safe?
Why do the certifying authorities allow pilots consider pilots with 200 hrs to be safe riding a RHS in airliner and consider 1500 hrs enough for command - provided pilots are properly trained and checked out?
What do you see that no competent aviation authority can't?
Is there any study showing less experienced pilots to be more incident/accident prone or that high-timers are immune to certain types of mistakes?

What does? Capability to fly aeroplane manually? Would perchance ability to comprehend what is going on from the cues on the instrument panel be more useful to AF447 crew?

Yes. In normal and alternate laws, stick free, FBW Airbi are flightpath stable so they'll try to keep the flightpath no matter whether the disturbance comes from turbulence or from power coupling. Also they move elevators to satisfy G command, if you slam the thrust levers and get classic pitch-power coupling while pulling on the stick, elevators will deflect less to produce commanded G.

Sounds complicated but feels very natural. You set the nose where you want it to be without thinking about normal acceleration and roll rates.

Now there is a very, very good example why flight safety should never, ever be left to commercial enterprises. Some good and valid ideas are mixed with radical departures from what is currently accepted to be true - which wouldn't be bad in itself if it were supported by some verifiable research, instead of I-say-so's and unnecessarily complicated graphs.

If Dedale SAS France has it its way - yes. Hopefully not. IMHO improvement is needed, complete rebuild, not yet.

Monsieur Paries cites 16 events without specifying when they happened, what were the circumstances and whether they pertain to A330/340 at all. So much for the "role of the aircraft"

BEA interim2 lists 36 occurrences of unreliable airspeed on 330/40, 13 of which were available for detailed analysis. It also makes clear there were five cases of descend following the stall warning - in controlled manner, obviously.

So are we to believe BEA in this dilemma because it is official investigating body?

Nope, not just because of that. BEA has provided pretty comprehensive reference about the occurences. Aeroplanes are listed by s/n, which can be used in conjunction with DoF to find out which were the flights affected, making its claims very verifiable. Monsieurs Paries references have, for the time being, been zilch.

You are right, because this Boeing MD-80 was stalled at FL330 and didn't lose a thing, but is 20 FLs such a big difference? Is the type relevant at all? This Tu-154 was lost near FL400, this CRJ 200 was lost as the crew tried to cling at FL410 while being blissfully unaware what "backside of the power curve" means. At Stony Point B727 was lost that never got above FL248.

Monitoring who or what; Dynasty 006 was a Boeing, too.

If you read interim2, you would have known there were 36 recorded cases of Airbuses 330/340 suffering from UAS and going into alternate laws, with crews handling the situation without any damage to airframe or injury to passengers, so your question would be completely superfluous.

Wrong!

People who keep maligning FBW & FADEC when discussing the Habsheim disaster with blatant disregard to facts, don't have anything to do with Michael Asseline's defense and definitively have no his support. Capt Asseline has accepted the BEA findings. He was no stupid yet he has flown aeroplane full of passengers, at an airshow overhead the grass airfield where he has never flown the display before, without checking for obstacles, executing flyby low and slow. In retrospect it was very stupid thing to do. Analysis of the process that led him to belief it is acceptable to perform such a seemingly idiotic thing and warning every pilot about it was supposed to be the main safety lesson of the accident. Diverting the focus from it by blaming the computers, either through ignorance or agenda, is irresponsible at the very least.

Heavier than air, fixed wing aircraft specifically dislike being flown with low energy, colloquially known as: low and slow. It hurts them a lot.

At 2:10:22 CM1 called out "Alternate law, protections (law/low/lo). Anyway, what's the use of alpha prot in cruise? Other crews lost it too and lived to tell the story.

Yes, but alpha prot gives you maximum possible climb performance, there's absolutely no reason to use it when terrain is not a factor. Pilots should be constantly able to tell whether they are flying high or low.

What is so remarkable about AF447 but is mostly glossed over, is that loss of control looked extremely benign on the inside. There were no extreme attitudes, no rapid attitude changes, no high or low G, no spin, nothing. Just unwinding altimeters. How would centrifuge training help pilot feel what AF447 crew felt is way beyond my comprehension, unless we are talking about stopped one.

Actually, with connected controls, who made which input is always matter of conjecture. Of course capt was designated PF, so chances he made the final pull are extremely high. On FBW Airbus, there is no mistaking who did what with the stick.

Here: quick refresher on Birgenair, by the time it departed the envelope, autopilot and autothrottle were off.

Correct. Panic pull has been with us since there were first aeroplanes, it has nothing to do with type, sidesticks did not eliminate it or made it worse, also triggering condition can differ but result is exactly as you have described.

It cannot be cured by flying more raw data manual approaches. To prevent it it is essential to have a pilot that doesn't panic when startled. Is it achievable through training? Damned if I know.

F-16D
Because 60 years ago it was legal to train pilots on aeroplanes with single throw-over yoke, such as early Bonanzas had. Took a while to realize it wasn't the smartest thing to do.

DozyWannabe

Read more closely sir. I wasn't referring to those who in modern times malign FBW and FADEC as a result of Habsheim. I was referring simply and purely to the idea (contemporary to the late 1980s) advanced by Asseline's defence team that the BEA were obliged to defend Airbus due to the involvement of the French state apparatus. A position which is easily disproved by the facts on the ground.

That some of the posters on here have not let this go and continue in the hope of humiliating Airbus in the manner that Asseline (and later, Norbert Jacquet) were brought down is not merely a matter of conjecture - it is a matter of fact.

bubbers44

Clandestino, I wouold like to meet you some day and see what planet you come from. No Boeing pilot would pull a yoke into his lap like the PF did with the side stick. Good luck with your long story but I don't think you will have any followers.

DozyWannabe

Bubbers, it has already been proven beyond a shadow of a doubt that at least two of them did.

There is no such thing as "no XXXX pilot would or wouldn't YYYY", only that which various pilots, regardless of type, have done.

It's time to step outside our comfort zone and realise that there's something significantly wrong here.

Turbine D

For those who might be wondering about the 36 A-340/330 UAS incidents, here is the listing and details Clandestino refers to...

Lyman

So what about the possibility that the PF simply did not process/comprehend that when the A/P went into Alternate Law, that Alpha Protect was no longer active -- and that he would need to use the side stick more like a Boeing yoke than an Airbus joystick? Thus, it wasn't that he was dumb, just that he had a brain freeze in not fully comprehending that his protections were gone (despite this warning being given on the ECAM)....from SRMman

Yep. Absolutely. The first we know the crew recognized Alternate Law is at 2:10:22, seventeen seconds after loss of autopilot! full stop.

Nothing is provided us to counter this conclusion in evidence. A lot of harrumphing, posturing, etc., but no evidence. It is the salient take away from the initial (post startle) CVR data. We cannot be sure the displays were operating, nor can we conclude either pilot sussed the fact until the PNF callout.

By this time, the upset was under way. Clandestino remarks about the benign nature of the upset in his recent rather lengthy post...

The upset began the moment autopilot dropped out, arguably, and for many reasons, not all damning, many exculpatory.....

There is no going back in some chains, many cannot be unwound once begun.

Whether you believe it or don't, the case can be made that PF's stick work was based on him assuming Normal Law. It makes more sense than an endless onslaught of "No pilot in his right mind ....." ad absurdum....

To be clear, know that a loss of autopilot can occur without degrade.....frequently. Loss of autopilot is not some trained in "oh, naturally, we degrade then..."

mm43

Clandestino; That's really not what I was getting at. Put another way, if your butt sensors are only used to the usual about 1g, and you rarely pay any attention to the small inflight 'g' changes, then it seems rather obvious to me that neither of the crew noted the lack of 'g' change when applying NU/ND commands. This can only happen when you are on the ground, or as they were - stalled, and the aircraft response coming from just bigger or smaller 'barn door' effects.

The other clue was possibly the 'soft' rolling; certainly something you wouldn't expect with normal airspeed and AoA.

I know its easy to sit back and claim they were just a "clueless" crew and the chances of a similar result happening again is probably something approaching infinitesimal odds, but the "why" surrounding this event has to be addressed and corrected. So if that means crews need to experience the full range of acceptable 'g' forces in normal flight and those that could be expected in recovering from LOC, then so be it.

DozyWannabe

Let's be clear - what accidents like Flash Air have proven is that the physical response from the human body is more often than not wrong. Getting too deep into it is going too far. It doesn't matter what control law the machine was in - the input sequence was inappropriate.

No-one's saying the crew was "clueless", but let's be honest. If you're at full thrust, full back-stick and the aircraft is still falling - what else can it be other than stall?

mm43

Dozy;

Well, you just said it.

jcjeant

Hi,

Machinbird
Interesting to know that Jean Pariès is a ex DGA ex BEA
The loop is closed .. lol
Jean Paries - Lucina

RetiredF4

.....a failure in the barostatic system causing not only erroneous speed indications, but also a downwinding altimeter at a never before seen rate (."...that can´t be.....") and a pegged VS?

Not saying that it was like that, just spinning your question a bit