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AF447 wreckage found

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AF447 wreckage found

Old 18th Aug 2011, 13:08
  #3041 (permalink)  
RWA
 
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Quoting philip2412:-

"do you believe,every pilot inthe whole wide world,capable of flying an jet
a/c would after a/p disconnect had put the a/c in a climb of 7000ft/m ?"

Welcome, philip2412.

But as to your question, it remains by no means certain that the climb was caused by pilot inputs. Please refer to Page 111 of the BEA's third report:-

http://www.bea.aero/docspa/2009/f-cp...90601e3.en.pdf

This shows that, at the time the THS started moving and the sudden climb commenced, the PF was applying relatively small movements, up or down - largely consistent, in my less-than-expert view, with an attempt to 'fly pitch and power.' However, the THS was already well on its way to 'full up.'

Agreed, the PF later applied TO/GA and a lot of noseup - presumably in response to the stall warnings. But by that time the aeroplane was ALREADY in a steep climb that, on the available evidence, had been commanded not by the PF but by the THS.

For confirmation, it's worth mentioning that, if you look further down the table, you'll see that the increase in the angle of attack from the point the THS began moving appears EXACTLY to parallel the THS's progress towards 'full up'........ and started long before the PF applied full noseup stick.

I'm prepared to accept that the pilot(s) could, arguably, have made a better job of attempting to recover. But I'm not at all sure that 'pilot error' caused the initial steep climb. Indeed, on the (limited) available evidence, it appears to have been the THS that started it, not the PF.......

Last edited by RWA; 18th Aug 2011 at 13:28.
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Old 18th Aug 2011, 14:21
  #3042 (permalink)  
 
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I can't believe that this drivel is still going on....

Face it. The 2 co-pilots porked up in spades. The PF's agricultural flying commanded the THS - it did what he'd erroneously commanded. He then failed to understand that he'd stalled the aircraft through incompetent handling.

Poor system knowledge, lack of awareness and no idea of basic principles.

But why on earth the captain decided to go and sleep before the aircraft was clear of the known serious weather forecast for the route....

Air France arrogance and their unwillingness to face the consequences of inadequate training on a complex aeroplane seems to me to be a contributory factor.
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Old 18th Aug 2011, 14:29
  #3043 (permalink)  
 
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While the devil's often in the detail, BEagle, I'm inclined to agree with you. Seems to me that some posters would have spent considerable effort trying to blame the iceberg for the sinking of the Titanic.
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Old 18th Aug 2011, 14:38
  #3044 (permalink)  
 
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I'll try again to frame what I see is the beginning of the confusions in this place.

What was assiete at 2:10:03? We know the Pitch of this a/c at 2:10:05 was 0 degrees. Knowing this would give a rough 'trend'.

Because here's the deal: After taking controls (after 2:10:05) the Pitch actual of the a/c is ? Trending ?

A normal cruising PITCH value would be ~2.5 degree?

If we consider that this a/c was @ PITCH lower than expected and perhaps trending even lower when a/p was lost, called into question is the perhaps not too relevant "Book".

What does the "Book" have to say about this?

Throughout, I see this "Book" as simplistic in nature. It assumes straight and level, unaccelerated flight?

Some say that the pilot should have done nothing by way of maneuvering.

NOT FAIR. The airframe was assumed to be active; sit still and watch the nose drop further?

Or "SET 5 degrees PITCH and CLB THR." Sorry, also not pertained.

That is a COMMAND to maneuver, quite possibly.

Consider: A "proper" PITCH command by the PF could have involved a PITCH excursion of as much as 6 degrees, perhaps a bit more.

The a/c did not immediately climb. What shall he do? Likely wait and see what his initial stick produced? From the Traces, I think that is what he did. I will forgive this gent some anxiety, and perhaps that, brand new to the grip with a/p loss, he is NOT conversant completely with Neutral Point. Throw in a proven wing drop that the a/p quit on, OK?

Rolling, Nose Low, Cavalry Charge, Master Caution, etc.

Not an Emergency? Like DePressurization? hmmm.......... The "Book" calls the loss of the AutoFlight system an "UPSET".

In what language is "UPSET" not an emergency?
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Old 18th Aug 2011, 15:08
  #3045 (permalink)  
 
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Someone mentioned that the js may have been occupied at the time.By the PF's better half.Has this been proven one way or another(CVR)?

Here are 2 relatively inexperienced co-pilots with no clear chain of comand order left by absent skipper.What dynamic would the presence of a 3rd party,especially a spouse or relative,have on this democratic mess?People act differently when theyre being watched than when alone.What led PF to over-react to a relatively benign situation(AS loss for 50 secs) and why didnt PNF intervene if he knew,as Lyman keeps saying he did,what was going on?Was it just atrocious flying skills or is there something else here as well?
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Old 18th Aug 2011, 15:20
  #3046 (permalink)  
 
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To be clear, the Sidestick visibility issue is not involved in my saying PNF knew. I base it on what the PNF said to PF, and what I know of French culture, not necessarily cockpit culture. One never prompts, or interrupts with critique, another's efforts. For PNF to have done so shows me he was elevated to that concern. Also not elevated sufficiently to remove PF from Stick control. In the middle. That way lies confusion. No command ethic should be operated as a democracy, certainly. This does not foreclose teamwork. Who would confuse democracy anyway with teamwork?
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Old 18th Aug 2011, 15:38
  #3047 (permalink)  
 
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Nz Law (active in NORMAL & ALTERNATE)

CHARACTERISTICS IN PITCH

IN FLIGHT

When the PF performs sidestick inputs, a constant G-load maneuver is ordered,
and the aircraft responds with a G-Load/Pitch rate.
Therefore, the PF’s order is consistent with the response that is "naturally"
expected from the aircraft:
Pitch rate at low speed; Flight Path Rate or G, at high speed.


• The aircraft maintains the flight path, even in case of speed changes
• In case of configuration changes or thrust variations, the aircraft
compensates for the pitching moment effects.
• In turbulence, small deviations occur on the flight path.
However, the aircraft tends to regain a steady condition.


AIRBUS PITCH CHARACTERISTIC
Operational Recommendation:

Since the aircraft is stable and auto-trimmed, the PF needs to perform
minor corrections on the sidestick,
if the aircraft deviates from its intended flight path.
The PF should not fight the sidestick, or overcontrol it.
If the PF senses an overcontrol, the sidestick should be released.
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Old 18th Aug 2011, 16:03
  #3048 (permalink)  
 
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Originally Posted by RWA
But as to your question, it remains by no means certain that the climb was caused by pilot inputs. Please refer to Page 111 of the BEA's third report:-

http://www.bea.aero/docspa/2009/f-cp...90601e3.en.pdf

This shows that, at the time the THS started moving and the sudden climb commenced, the PF was applying relatively small movements, up or down - largely consistent, in my less-than-expert view, with an attempt to 'fly pitch and power.' However, the THS was already well on its way to 'full up.'
Huh?



The pitch up coincides pretty precisely with the NU inputs. Airbus pilots please correct me, but I'd guess inputs using 50% of the total stick travel probably are not what you would call "relatively small movements"? The THS is still more or less stationary at this point.
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Old 18th Aug 2011, 16:23
  #3049 (permalink)  
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ventus45;
Originally Posted by ventus45 in post #3028
Then there is the advanced version of the above, the revered "pitch and power". As some have noted, (PJ2 in particular) works OK on climb out, but has wharts on at anywhere near ceiling, aerodynamic, or propulsive.

My point is, all of these "simplistic SOP's" can "lead you up the garden path" and are thus counter productive, and dangerous.

Thinking that maintaining a positive pitch attitude (pick a number, 2, 2.5, 3, 5, degrees - whatever) should be part of a procedure to recover from a stall is idiotic. Thinking that the use of power is a primary or even a seconday way to recover from a stall is idiotic.
I think you're confusing the published response to the UAS with a previously-published stall recovery procedure. Please read my post carefully. I'm not discussing the stall or stall recovery. I am discussing the UAS Memory drill in force at the time of the accident, and also discussing the crew's response to the loss of airspeed information.

It is the UAS procedure to which I refer when I state that maintaining level flight with pitch-and-power settings existing just prior to the event will keep the aircraft in stable, level flight, (obviously the crew has to fly the airplane to do this...), until the pitots and the affected ADRs sorted themselves out.

The crew had all information necessary to maintain level flight, (altitude, VSI, N1, etc), to do this but instead instantly pitched the aircraft up and essentially maintained that pitch up until the aircraft ran out of energy and stalled. That would have been the time to reduce power to idle and pitch the nose down.

Whether recovery from the stall, which had become firmly established with the NU SS inputs after the apogee, was possible or not remains an open question for aeronauticists but the prevailing opinion is, notwithstanding the potential to aerodynamically stall the horizontal stabilizer due to a full-down elevator and without rolling the THS -13 position forward even just a little, that if such recovery had begun around FL350 on the way down, that it was possible. I have read and heard that it is a testimony to the design of the aircraft that the elevator retained some effectiveness right up to impact. Some will disagree with the possibility of recovery or offer other scenarios, lower or higher, but the point is essentially moot after the apogee given the sidestick inputs.

FYI, Boeing and Airbus have already discussed responses to the stall with a view to indicated changes. Airbus presented the changed procedures at the 17th Performance and Operations Conference in Dubai and the pdf can be found here.
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Old 18th Aug 2011, 16:40
  #3050 (permalink)  
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BOAC;
PJ2 - whatever you think of the "5 deg nose-up" it would not have killed all. The a/c would have flown reasonably happily while the UAS drill was actioned. Any stall warning that might have been thus induced could have been actioned as normal.
Respectfully, I disagree.

First, it is clear that maintaining a pitch attitude of exactly 5deg can be problematic and I think that's what happened here - the PF did not have the experience at high altitude flight to achieve precise control and over-pitched in the same way as the PIOs were introduced in roll - (the reductions in roll show that he learned quite quickly about the sensitivity of roll direct).

Second, the moment one begins the climb one reduces predictability and stability at precisely the moment when both are required to retain some situational awareness and assured energy level of the aircraft. Level flight is most certainly more predictable and any pitch attitude required by rote when the circumstances do not warrant it means something is wrong either with the drill itself or the way it is being interpreted and actioned. In my view, both phenomenon are occurring here in various quarters.

By pitching up to "more or less 5deg", with thrust in CLB and A/THR likely disconnected either by the aircraft or as per the UAS drill and in "THR LK" many unknowns are introduced the most critical one being the energy level (speed) of the aircraft while transitioning from level flight to the climb resulting from the increase in pitch with the possibility of a decreasing speed due to a slightly higher than 5deg pitch.

The airplane was stable before, so why momentarily destabilize it by climbing which is what 5deg NU is certainly going to do? Maintaining level flight prevents the introduction of these unknowns and permits a calm cockpit while reaching for the QRH.

In fact, by the time the QRH page is found and the numbers read out, the UAS event would have been over and normal indications would have returned on this flight. As someone said, this should have been a log-book entry.

Last edited by PJ2; 27th Aug 2011 at 05:41.
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Old 18th Aug 2011, 16:49
  #3051 (permalink)  
 
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Originally Posted by PJ2
FYI, Boeing and Airbus have already discussed responses to the stall with a view to indicated changes. Airbus presented the changed procedures at the 17th Performance and Operations Conference in Dubai and the pdf can be found here.
Thanks, PJ2!
Sadly, it's just a pdf of a PowerPoint slideshow.... one can still hope for the full text of the presentation at the conference.

That pdf almost reads as if the authors had been reading PPRuNe
But, then: pilots, and designers, and engineers, and investigators, even if they don't post here, are not as stupid as some posters here try to make them out to be.
That they arrived at the same or closely similar conclusions as the more reasonable posters here, is barely astonishing.
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Old 18th Aug 2011, 16:56
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Oversimplification?

Is it possible that AF447 was just the result of a clueless crew (I'm sure that were good guys, but their training was clearly inadequate; hence, a training issue) and 13 degrees nose-up THS (a design issue)?
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Old 18th Aug 2011, 17:11
  #3053 (permalink)  
 
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RWA:
[Chart] shows that, at the time the THS started moving and the sudden climb commenced, the PF was applying relatively small movements, up or down - largely consistent, in my less-than-expert view, with an attempt to 'fly pitch and power.' However, the THS was already well on its way to 'full up.'
Where are you getting this fantasy from?

More importantly why?

According to the report and the controls 'chart' the THS does not move appreciably until some 45 seconds into the event, at which point the aircraft was at the apogee of the climb. The first 10 seconds of the event consist entirely of varying degrees of NU command. There's you climb... nothing to do with the THS.
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Old 18th Aug 2011, 17:35
  #3054 (permalink)  
 
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Safety C:
Therefore my point was merely that if as a group of professionals you are hell bent on the return of stick feedback, you need to find a different argument because going on about perceived automatics issues with AF447 or Habsheim or anywhere else won't help your cause.
Safety,
Remember
(Pay attention to aircraft behavior at time 00:22)
I do know these guys personally and I have talked with both of them about the reason why they were bouncing wings...
This is (another case of ) two pilots "flying the bird at the same time"! No feed-back (and no Dual Input Warning, at that time). This wasn't an accident cause the Captain decided to Go-Around in due time.
But the situation persists. And if this wasn't an issue, Airbus would have never accepted to include the Dual Input Warning only some years ago, which is a huge step for such a proud organization...
What I can't understand is your incapacity to accept that there is margin for improvement...
If there wasn't margin for improvement, we would still be in the Stone Age...
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Old 18th Aug 2011, 17:46
  #3055 (permalink)  
 
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RE:: Lyman #3036

It all depends. Yes, as you say, pitch attitude in level flight and still air would have been about 2.5 degrees nose-up. At AP disconnect, pitch was zero and slowly increasing at about 0.6 deg/s. Also the power had been pulled back from 100%N1 in still air cruise to about 85%N1. A little while ago I explained that these conditions are consistent with the airplane maintaining speed and altitude in an updraft of about 1000 fpm. 'Doing nothing' would have maintained these conditions until a change in the environment. Let's suppose the airplane left the updraft and entered an area of still air. Leaving pitch and power unchanged, it would then descend at 1000 fpm at constant speed. To restore level flight, the pilot would have to pitch up to 2.5 degrees nose-up, and increase power to 100%N1. If entering a down-draft, a little more of both. I think that the transition from updraft to still air or downdraft would explain the 'delay' in the airplane starting to climb.

Last edited by HazelNuts39; 18th Aug 2011 at 19:25. Reason: clarify
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Old 18th Aug 2011, 22:45
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Originally Posted by ChristiaanJ
Thanks, PJ2!
Sadly, it's just a pdf of a PowerPoint slideshow.... one can still hope for the full text of the presentation at the conference.
There's a bit more here: 20101536_SafetyFirst-11-Toconsult
and here: Stop Stalling | Flight Safety Foundation
still looks a bit like a report about a report though

The first few slides in that are in some ways the most worrying - explaining AOA and stall about how I would explain it to my kids (based on my knowledge from long ago when part of my career was in building stuff that flys), and a whole slide on how nose-down reduces AOA. I'd expect to be yawned or jeered off stage presenting that to actual pilots. I really really hope the transcript that went with those first slides was along the lines of "you all know that, and that, and that" but I fear it may not be.

I've looked at stall accident reports before, fascinated (I thought) at how panic and confusion could override the best of training... but I am starting to believe that this industry really has managed to train a generation of pilots who don't acutally know the basics of what keeps a plane in the air, and think(from their training) that they can accelerate and climb out of a stall.

If so, it's probably taken decades to come to light, and will probably take as long to fix. I find it more than slightly scary. Am I the only one ?
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Old 18th Aug 2011, 23:16
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I am still trying to acclimate to Airbus' use of cartoons in the FCOM.
You know, the silly drawings about overspeed that show sweat coming off the a/c's eyebrows, the wing tips glowing red, and shedding parts?

maybe it's just me. In spin training, I got out of the a/c grinning, and the CFI scolded me for not taking things seriously. They stopped spin Training what, thirty years ago?
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Old 19th Aug 2011, 00:05
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There's a question I really love to ask my F/Os that prefer to climb in V/S instead of pitch hold mode (I'm not on Airbus anymore, if you wonder): when will the aeroplane stop climbing with pitch 5°, climb power set and what will happen then.

Anyone willing to take a guess?
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Old 19th Aug 2011, 00:17
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Low Earth orbit?
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Old 19th Aug 2011, 00:25
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Originally Posted by Lyman
I am still trying to acclimate to Airbus' use of cartoons in the FCOM.
You know, the silly drawings about overspeed that show sweat coming off the a/c's eyebrows, the wing tips glowing red, and shedding parts?
Yeah, you aren't the only one.

Seems to be a trend - have you seen kids' school textbooks lately ?

Each page seems to have any text broken far beyond submission by irrelevant pictures, breakout boxes, sidebars, bubbles, and all in a cacaphony of fonts and sizes that would make any sane graphics designer weep. And that's the maths books. It's no wonder the kids are all hyperactive - a few pages attempted readng of it and my old brain was getting fried.

maybe it's just me. In spin training, I got out of the a/c grinning, and the CFI scolded me for not taking things seriously. They stopped spin Training what, thirty years ago?
Thought you were a committee these days [ http://www.pprune.org/tech-log/456874-af-447-thread-no-5-a-92.html#post6632144 ] ? You all went spin training at once ?
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