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AF 447 Thread No. 11

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AF 447 Thread No. 11

Old 15th Jun 2013, 20:44
  #41 (permalink)  
 
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BOAC

Airbus pilots who (correctly, as I understand it) believe that if all is working properly in Normal Law it cannot happen
I am confused by this comment. Do you mean that this belief is correct? That it cannot be stalled in Normal Law. Or that they they correctly understand the material they are given but this is incorrect.

Can you clarify whether you are saying they are right or that they are misguided in this belief.

Thanks
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Old 15th Jun 2013, 20:54
  #42 (permalink)  
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"Do you mean that this belief is correct?" - as I understand it, yes, it is correct, but I am not Airbus qualified. Sorry - I thought it was clear.
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Old 15th Jun 2013, 21:06
  #43 (permalink)  
 
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So, they are right to just pull back in Normal Law then! That's a long way from believing your aircraft magically can't stall which is what you seem to be claiming.
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Old 15th Jun 2013, 21:21
  #44 (permalink)  
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Not in my opinion. What I posted was "and full back stick can be the way out of trouble".

But now I'm confused! Can you clarify? Are you saying you can stall an Airbus in normal law? You would never catch me just pulling back on the stick and trusting in the machine, Airbus or not, despite what any TRE might tell me.

......and by the way, I am not claiming "your aircraft magically can't stall" - I would not be that foolish. Merely stating what I understand from many comments on many fora and excited, breathless words from AB pilots over the years.
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Old 15th Jun 2013, 21:35
  #45 (permalink)  
 
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An airbus can stall in normal law, although the only normal law, no failure incident that I am aware of is a severe windshear that momentarily outpaced the EFCS. The crew pulled back in sheer terror and this action along with the EFCS saved the day. The EFCS quickly unstalled the wing then maintained max alpha to rapidly recover the A/C from a 4000 fpm descent below 1000 aal.

As this example shows in a huge number of cases simply trusting the system IS the right thing to do. For example, Airbus FBWs can carry out terrain avoidance maneuvres that are simply impossible on other types. An outfit I am 'familiar with' had just such an incident, full back stick on receipt of the hard 'pull up' just saved them (rad alt at the peak around 40ft). They trusted the system in this instance as they are rightly trained to do and it saved them. Had they pulled to some other less restrictive parameter or not just got on with it (as you suggest) it is highly likely the A/C would have been lost.

In very many circumstances crews are quite right to trust the EFCS to help them out and I believe a number of A/C and pilots) are still flying today because the system helped them. There is a training issue around educating crews when to trust it and when not to and what to do if it isn't doing what it should. But that is entirely different from the claim that 'children of the magenta' as so many ignorant (in the literal sense) posters have it, only know how to fly a computer.

Last edited by busTRE; 15th Jun 2013 at 21:36.
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Old 16th Jun 2013, 07:19
  #46 (permalink)  
 
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There is training, and then there is experience. In a perfect world the experience does the training and tries to pass it along.

Unfortunately for a long time Airbus didn't train from experience, but TO the lowest common demoninator.

FBW is great. But it doesn't make up for a lack of experience and training in the extreme.

On a Bus, or any other aircraft with a FPV (bird, velocity vector, etc), drop a perpendicular from the pitch bars to the FPV. That is your AOA. If you are less than stalling AOA, you are not stalled. \

Airbus doesn't teach or train this. They should. If they had, AF 447 would have had a lower probability to happen.

This isn't Boeing vs AB. Boeing doesn't teach this either. Fighter guys with HUDS know this as gospel.
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Old 16th Jun 2013, 07:37
  #47 (permalink)  
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Originally Posted by busTRE
An airbus can stall in normal law
- since you seem to be on a different topic and seeing things I have not posted, I think I will bow out of this discussion with you. I actually asked "Are you saying you can stall an Airbus in normal law?" which is a different issue, and I did post "I am not claiming your aircraft magically can't stall". I do not recognise your supposed quote "not just got on with it (as you suggest)" by the way.

Anyway - moving on - for 3holelover (post #34) - there you have it. The answer from someone who says he/she is an AB multi-type TRE. I think we can distill the opinion there that it is taught that (as I understood) it is impossible for a pilot to stall an Airbus in normal law, but obviously as with any flying machine, dynamic un-commanded events can take a serviceable AB into a stalled situation from which it will self-recover given sufficient margins. The question of how you disabuse the 'absorbent' pilot of this instinct when all is not well has not been answered and indeed may well be pivotal. If this belief persists the fault lies fully with the training system, as I have said for many years.
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Old 16th Jun 2013, 09:57
  #48 (permalink)  
 
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Just clarify as it seems some are finding this difficult.

AB pilots are quite rightly trained that the EFCS can be trusted in NORMAL LAW, to protect the A/C from stall. In the overwhelming majority of cases, (e.g. EGPWS), using the edge of the protection such as pulling full back without hesitation is precisely the right thing to do. In the TRTO that I work for we are at considerable pains to make sure crews understand that this is not effective in degraded scenarios.

BOAC

Your statement

You would never catch me just pulling back on the stick and trusting in the machine,
strongly suggests that you wouldn't be 'just getting on with it' as a correctly trained crew would in most GPWS scenarios, for example. I didn't use your exact quote to avoid the rather cumbersome multi-quoted post look. If you would never just pull back then your FO would be quite entitled (indeed duty bound) to take-over for you and pull back while you did whatever you were doing instead of 'just pulling back'.
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Old 16th Jun 2013, 10:17
  #49 (permalink)  
 
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Another example why aviation morons will never be on the endangered species list:

For example, Airbus FBWs can carry out terrain avoidance maneuvres that are simply impossible on other types
.... just as Airbus can't stall in normal law and your grandmother can fly any Airbus.

Continue that BS and you are not only not helping Airbus's renommée, but actively encouraging stunningly stupid manoeuvres like this accident displayed.
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Old 16th Jun 2013, 10:19
  #50 (permalink)  
 
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4 years after the event and (as an engineer) I am still annoyed by this.

1. AoA meter: yes would have been useful but any pilot capable of discerning its usefulness would be unlikely to be in this situation in the first place. Crucial to recovery and avoidance of secondary stall, but you need to get to the correct mental picture first. In a situation where the world seems to have gone mad, its output would have been condemned with all other indications.

2. Unusual Attitude Mode: well that turns out to be f' all use. How unusual do you have to get. How about an unusual dynamics mode (ie descending at 10000ft/min, nose in the air, engines at full thrust when 2 mins ago was crusing at 35).

3. Inhibition of stall warning. Well Ok, see where the designers where going...

4. Affirm mode by changing some colours on the FD ? In a crisis I am supposed to notice and swing my mind around to that ?

5. Let the THS go way beyond normal limits and not scream about it ?

6. Have a SOP which says blank FD when the software could automatically do it ?

Trouble is that in design you design around nominal conditions and then think about isolated excursions/perturbations. Need to crowbar the logic in some situations.

How about a 'Ghastly Silence' mode (combine it with Unusual Attitude) in which all noises and flashing messages are inhibited except for the crucial ones (OK a button push and you can have all you secondary and tertiary warnings and warblings back), such as what protections have been inhibited, pitch, descent rate, air speed, trim and any other thing you guys think are the first things that should be addressed.................
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Old 16th Jun 2013, 10:25
  #51 (permalink)  
 
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Gretchenfrage

Being able to fly a precise max-alpha DOES allow one to fly a terrain escape maneuvre that would be unachievable on a conventional aircraft. So where exactly is the BS. Perhaps you should restrict your insulting comments to areas you have knowledge of. Of which this is not one.
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Old 16th Jun 2013, 10:34
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Originally Posted by BOAC
The question of how you disabuse the 'absorbent' pilot of this instinct when all is not well has not been answered and indeed may well be pivotal. If this belief persists the fault lies fully with the training system, as I have said for many years.
Perhaps the answer is that you cannot have it both ways. In that case you have to make a choice between one philosophy and the other.
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Old 16th Jun 2013, 10:46
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It's easy enough to reset software. Not so easy to reset human beings. To get focus back, first thing is to deny as many opportunities to focus on the wrong thing as possible.
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Old 16th Jun 2013, 11:06
  #54 (permalink)  
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Originally Posted by HN39
In that case you have to make a choice between one philosophy and the other.
- is that not EXACTLY the problem I think lies here?

The pilots need effectively to understand 2/3 'philosophies' - slightly different 'rules of flying' in each law, and to be able to 'switch' seamlessly from one to the other, probably when the is hitting the fan. An easy task for a 'HAL' with loads'a lines of code, but for we mere mortals....................
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Old 16th Jun 2013, 11:49
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Originally Posted by BOAC
The pilots need effectively to understand 2/3 'philosophies' - slightly different 'rules of flying' in each law, and to be able to 'switch' seamlessly from one to the other,
That's not what I meant. The choice I referred to has to consider the probabilities. How often happen incidents like the two described in post #46, and how often does an Airbus get into alternate law?

Perhaps we need to remind ourselves that in AF447 the airplane did not stall due to 'full back stick'. That took place half-a-minute after the airplane was stalled.
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Old 16th Jun 2013, 12:00
  #56 (permalink)  
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I understand your point, but would also point out re "how often does an Airbus get into alternate law" - that on some occasions that it has, trouble has resulted.

Incidentally, I did not directly link 'full back stick' with 447 in my posts, but since you have raised it, and perhaps to complete a circle, why was the stick subsequently held back, do you think?
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Old 16th Jun 2013, 12:19
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Originally Posted by BOAC
why was the stick subsequently held back, do you think?
That's really anybody's guess, and I've given mine earlier. He had been*keeping the nose up at around 15 degrees, and applied full back stick when the nose dropped below that target.
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Old 16th Jun 2013, 12:36
  #58 (permalink)  
 
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bus TRE

1. An Airbus can crash, stall, CFIT etc. like any other aircraft.
2. An Airbus is not worse than any other design, but it is not better just because of its design either.

I don't want to enter the statistics debate again, but another FBW design has a better safety record. This is not to say that this one is better, but it simply anihilates the eternal myth that certain thing never happen or are much less prone to happen on Airbus.

In the mentioned case it might be true that flying precise max-alpha is the best way out of terrain trouble, but this can be done just as well without Airbus FBW. I have flown the AB, the T7 and the MD11. All of them FBW and they are equally good in flying out of terrain. Even the older stick-shaker mounted aircraft can fly out of trouble close to stick shaker and with average skills the pilot can get asymptotically close to what the Airbus admittedly does very nicely.
Your call that this is only achievable on Airbus is quite preposterous.

It is this myth of some invulnerability of Airbus that cultivates pilots who fly escape manoeuvres with full stick back in any situation.

Sure enough they have heard and were once briefly trained that in such and such law this and this does not work, however if you do such and such the system reverts to this and this, you simply have to switch that and that and consider this and this, then you will know that such and such manoeuvre does not work, however the this and this can still be applied.
You super TREs, Dozys and not to forget the Clandestinos, you astronauts might well know that at any given moment and at least one of you even knows how to do that in real time. But if you are completely honest, you might admit that when the s#!t hits the fan in real life (as opposed to the desk), for some awfully long moments your brain goes into shedding mode.
It is in those moments when the dumbed down assumption that Airbus will take care of everything takes over and the followers just pull and wait. QED.

That is what I call BS, that is what any common sensed pilot and TRE should fight. A start would be to stop with such dumb assertions that Airbus does this and that better than others. It is a fine machine, but that's it.

Another BS is the call for more protections, more automation, more gimmicks to check, recheck, countercheck and overrule anything a pilot does in the cockpit.
Anything can and will fail eventually, Murphys law is a present as Alternate or Direct law. Even such add-on gimmicks can fail. What if all screens go blank? It has happened! In what law are you then????

What we need is a simple independent back-up to all the electronics like i.e. a pneumatically (wind) driven gyroscopic horizon and a unprocessed access to the flight controls.
And then we need pilots who still are capable to fly an aircraft with that!!!!!

That should help in the first moments, not any pretension that the aircraft will do it for you.

Last edited by Gretchenfrage; 16th Jun 2013 at 12:38.
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Old 16th Jun 2013, 14:37
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Hi BOAC,
why was the stick subsequently held back, do you think?
I think he was mistakenly performing this following procedure.

"Airborne, initial climb or landing
THR LEVERS AT TOGA SET OR CONFIRM
AP (if engaged) KEEP
SRS ORDERS FOLLOW
If necessary, the flight crew may pull the sidestick fully back.
Note:
Autopilot disengages if the angle of attack value goes above α prot.
If the FD bars are not displayed, move toward an initial pitch attitude of 17.5 °. Then, if necessary, to prevent a loss in altitude, increase the pitch attitude."

I guess he thought that since he was definitely airborne that it was necessary to pull fully back.

We dinosaurs were taught to "respect the stick shaker" during these manoeuvres. Airbus doesn't fit one - just another audio warning on top of constant "C chord" altitude deviation warning.
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Old 16th Jun 2013, 15:39
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Posted one year ago:
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