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AF 447 Thread No. 12

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AF 447 Thread No. 12

Old 3rd May 2017, 17:42
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Originally Posted by vilas
So, leave the stick alone till you figure out what changes in pitch you want. Startle or otherwise they effected huge change in pitch but never checked the result.
Completely agree!

However, as the pitot probes iced up the indicated altitude dropped by about 200 feet. The report suggests this is what led to the initial nose up command and someone who is unfamiliar with high altitude flight has potential to overcontrol in this situation (also: armrest in correct position? Seat all the way forward? All these things influence sidestick input - for me, half a turn on the angle adjust can be the difference between smooth flying and not).
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Old 7th May 2017, 23:33
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Near the TOC the Thrust was reduced for few seconds. The Pitch lowered a just few degrees (as it must). Then TOGA was restored for the remainder of the flight.

All without any comment on the CVR. (Apparently)
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Old 9th May 2017, 00:40
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Hi Linktrained,

The thrust issues are bizarre, indeed.

At one time, Bonin: "...But we have the engines, what is happening...?"

Also in re TOGA: Again, I think Bonin (PF) "...We are in TOGA, Eh...?"

Right along with no comments on STALL, what in the world can a pilot be thinking if he fears Overspeed, but stays in either Max Climb, or TOGA?

So I still think important bits are missing from the record....

jmo
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Old 9th May 2017, 03:04
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"stall !"

Then TOGA was restored...
All without any comment on the CVR. (Apparently)
Right along with no comments on STALL
IMO they acknowledged the stall condition. As per CVR transcript, after 3-4 stall warnings and noise of vibration in cockpit the throttle levers were advanced to TOGA. That's enough, no comments necessary.
However the best reconstitution out there is "Pieces a conviction AF447". It looks like the actors listened to real CVR: "apparently" in this reconstitution the word "Stall" was mentioned. Listen carefully at 4:01 at the moment the throttle levers are advanced in the video:
https://youtu.be/e_VuBMoZoo4?t=241
In CVR transcript we have the translation: (!) at 2 h 10 min 54,9
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Old 13th May 2017, 18:05
  #1425 (permalink)  
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FINALLY DCVR REVEALED IN FULL!!!!
NRJ12 prépare un comedy game inédit pour cet été
From 2:58"- 4:05"
New upcoming documentary for 01 June reveals all!
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Old 29th May 2017, 20:09
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I don't think there is anything new in this newest documentary...
They said they based their re enacment on a transcription of the CVR.
Not anything that we didn't have.
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Old 30th May 2017, 00:04
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SURELY If someone accidentally KNOCKS THE THRUST Levers ... Someone ought to say

" SORRY ! ..SHALL I PUT THEM BACK AGAIN ?"

( They were over the Atlantic... The Captain may have noticed something... He DID reappear on the Flight deck shortly after TOGA had been restored.)
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Old 31st May 2017, 08:27
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Just sign-up and watch doc:
Vof Af 447 : que s'est-il vraiment passé ? : Documentaire - 6play
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Old 31st May 2017, 09:55
  #1429 (permalink)  
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Just finished watching it.
Nothing new.
Nothing special.
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Old 31st May 2017, 17:24
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Not unexpected sir....

Any material deviation from the established dogma would be A) Denounced in high dudgeon by the adherents, or B) Launched with excruciating fanfare by the families' attorneys.

Nothing to see here, move along?
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Old 4th Jun 2017, 07:14
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Originally Posted by F-16GUY
...
But hey, if everybody is happy when the dead pilots are blamed, then lets not learn anything from this and move on to the next event that will look more or less like this one.
This is probably the way you see it! Then who is to blame if both pilots did everything wrong with their controls? That is the pure truth and we must face it, not try to deviate it! The only 2 reasons why Airbus could be blamed for being a contributor to this is because:

1. The stall alpha protection was not doing it's job or have not been implemented at all on A-330s. The stall alpha protection should control the horizontal stab, more than just the elevators, by not allowing "X" AoA to be passed, yet by looking at the DFDR the horizontal stab was moving freely towards increasing the pilot commanded elevator input until it reached -13 local angle, having the alpha reached more than 50 at some point during the fall.

2. The idiotic philosophy of having a left mounted side stick for captain and right mounted side stick for co-pilot, having both invisible from one pilot to the other was and still is "a remarkable achievement" for this disaster! Even with that option (which is kind of intriguing) to set "priority left", "priority right" or "dual input", the only pilot (on the left seat) who was sometimes pushing forward still couldn't command the horizontal stab towards a more positive value. Even on 787s, Boeing knows why they want both pilots to think and do things in the same way, not allowing conflicting data or inputs.

But anyway..., even with these kind of challenging Airbus planes problems, the pilot should've listened carefully to the strong "STALL" alarms (both aural and sound) and know what a stall actually is. I'm very convinced they both misinterpreted the definition of stall and thought that it's related to airspeed only, as many dummies behind the stick do. They were only juggling the throttles all the time, but not ONCE ever thought of listening to that stall alarm more thoroughly and get the idea of pushing full forward for a little while and see what happens, not once they have thought about it (except for the captain) until too late.

Here's the DFDR video:

https://www.youtube.com/watch?v=BR5kFOHVnUU&t=73s

* Stall = flow separation *

Flow separation has nothing ever to do with the relative speed between a fluid and a contacted solid material or with the indicated IAS or TAS. The only thing it can be triggered from is by having a relative angle between the flow and the surface exceeding "X" value above which the fluid cannot follow the surface, even if this angle may vary with speed.

It's always been and will always be the alpha that you command to get into or out of stall. For some reason though, depending on how the pilots learned or interpreted this, the term of stall is more generally or almost always seen as a lack of airspeed, which is totally totally wrong. Even if the plane can no longer sustain 1G below a given combination of airspeed and alpha, the plane is perfectly controllable even with reduced response rates, but no matter the airspeed (can be Mach 1), the plane's wings will always get flow separation (aka stall) above "X" angle of attack and the controls (especially lateral control) get almost non-responsive, which ANY PILOT must learn about in flight school before encountering it alone for the first time.

In the end, it proved that the pilots were more incapable of staying away from trouble or recovering from it than the plane itself. Nobody said "let's not learn anything from this", but the crude truth regarding the pilots should not be altered.
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Old 4th Jun 2017, 07:35
  #1432 (permalink)  
 
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The stall alpha protection was not doing it's job or have not been implemented at all on A-330s.
The aircraft was in Alternate 2. There is simply no protection as per design in Alternate 2. Anyway even Alt1 cannot prevent stall if pilot holds full back stick.
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Old 4th Jun 2017, 13:09
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A critical weakness following an event is that we continue to seek blame - the human, opposed to considering what could (should) be learnt. Additionally, the focus remains on the crew at the time of the event opposed to considering influencing factors such as training and regulation; and then there is automation, which of course is specified by the human.

Consider why the regulator required more training for unreliable airspeed (UAS), a procedure already trained for, opposed to avoiding the real threat - ice crystals. Compare this with safety activity for engine roll-back in a similar timescale. Warn crews to avoid cb's by a greater margin, use the wxr, do what is done every day, but do it better.

How was the training conducted, did the outcome match the intent. Where UAS procedures involve immediate actions, were these overemphasised opposed to the follow up actions more applicable to the cruise conditions of this and previous events.
Was the training simulation realistic, with multiple effects, systems and control degradation, or was only airspeed considered. Also, was the malfunction pre-announced, thus little benefit for training surprise and startle reported in other events.

If immediate actions require manoeuvring are Captains expected to take control, thus other crew members have no opportunity to experience degraded control systems. (if indeed that was simulated).
Did the requirement for additional training actually contribute to this event ?

And simple lessons learn't. Shared decision making for avoiding weather - is it better to ask what avoidance should be taken, forcing other crew members to actively consider the options; opposed to "is 15 left OK?" which is easily agreed with, but without any learning value for cruise pilots or future Captains.

Many automation lessons have been learnt. The pitots were being changed before the event, this negates many subsequent system issues. Revised assumptions about human ability to manage flight without ASI resulted in BUSS, not a requirement, but chosen after the fact.

So maybe we are learning that the human is not as good as assumed, but the human is still very capable. We should not expect a human to solve an automation malfunction, particularly where the function was automated because the potential situation was one which human might not be able to resolve (catch 22) - dual pitot error and ADC comparison in a triple mix system.

Have we still to learn that we should not build complex systems which rely on human intervention in case of failure, and then blame the human for failing to resolve the issue.
Blame or error in this sense is the gap between the expectancy of human performance before the event and that after the event, the difference and root problem, is in our initial assumption, which of course may be unforeseeable at that time.
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Old 4th Jun 2017, 13:46
  #1434 (permalink)  
 
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This is basic high altitude flying -

We cruise at 2.5. -3 degrees NU since jets airliners have been flying.

Approaching TOC our pitch attitude is perhaps 1 - 1.5 degrees NU higher(800-1200 FPM climb). So 3 - 4.5 degrees NU would be expected.

Putting an airplane in a position contrary to basic flying rules, and then blaming the airplane, isn't the right path either. Ten, 15, or 20 degrees NU at altitude is crazy. And the total time of total air data failure was under 25 seconds, and both were fully recovered in approx 45 seconds(?).

This is basic attitude flying. Flying isn't a game. Chasing a FD for 2,000 hrs isn't flying, it's playing a video game. Lord help us is the video game doesn't work correctly.

Last edited by misd-agin; 4th Jun 2017 at 13:50. Reason: Typos. Added "Ten...
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Old 4th Jun 2017, 13:55
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Originally Posted by MaverickSu35S
2. The idiotic philosophy of having a left mounted side stick for captain and right mounted side stick for co-pilot, having both invisible from one pilot to the other was and still is "a remarkable achievement" for this disaster! Even with that option (which is kind of intriguing) to set "priority left", "priority right" or "dual input", the only pilot (on the left seat) who was sometimes pushing forward still couldn't command the horizontal stab towards a more positive value. Even on 787s, Boeing knows why they want both pilots to think and do things in the same way, not allowing conflicting data or inputs.
You all really really (really) need to stop with that nonsense.
Have you ever stepped foot in an airbus cockpit ?

If you had seated at a pilot's seat, you would have immediately seen that.. you CAN see the other pilot's sidestick from your seat !
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Old 4th Jun 2017, 15:42
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re 'contrary to basic flying rules, perhaps this overlooks the influence of surprise and reversion to 'most recently' refreshed training.
If First Officers experiences' were limited to observing the Captain handling UAS procedure, and that was the most recent but irrelevantly trained immediate action, then we should not be surprised when startled pilots attempt to copy that procedure. Otherwise we need to revisit our assumptions about human performance.

Compare this with Colgan. Recently training for irrelevant tail stall, 'stall' warning given, surprise, procedures for tail stall executed simultaneously by both crew.
Lessons learnt; identify and revisit assumptions, consider what is taught and the context of instruction.
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Old 4th Jun 2017, 17:02
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Originally Posted by KayPam
You all really really (really) need to stop with that nonsense.
Have you ever stepped foot in an airbus cockpit ?

If you had seated at a pilot's seat, you would have immediately seen that.. you CAN see the other pilot's sidestick from your seat !
Seeing is one thing, understanding what is input is another. No Airbus pilot stares at another's sidestick to ascertain input. PM, initially, commented about VS, or altitude, not "stop pulling, we climb...!" Besides, the sidestick is not articulated as a wheel, but nudged, released, and 'stirred'......

Each stick moves independently, they are not connected, and trying to suss manual movements of the opposite stick is not appropriate?

A climb can be sustained, and is, by the aircraft with the stick mostly in neutral, hence "nudge"? The stick commands an attitude. Once selected, the "climb" is self sustaining, and must be countered with forward stick. The climb reached a rate of 7000fpm at one point, 1.75 G?

Is this about right, KayPam?

As to Colgan, the "surprise", the STALL warning, occurred because the Stall bug speed was set to anti ice ON, and had not been selected correctly; Captain had a great deal of excess room to maneuver, the Stall warn was bogus. It sounded at fully twenty knots high. Sad.
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Old 4th Jun 2017, 17:10
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FO's stick was full back for most of the event.

A confusion factor might have create into the event when the stall warning stopped due to excessive AOA. Forward stick was applied which reduced the AOA into the normal (expected) envelope which re triggered the stall warning.

Perhaps aerobatic experience with zero G, and an unloaded wing and very low, or no airspeed, might have helped in analyzing the situation and made someone realize zero G was their friend.
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Old 4th Jun 2017, 17:51
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We need to ponder why, given seventy two "STALL STALL" alerts, none of the pilots thought to address AoA? No one has come close to explaining this fact... Also, why would any trained pilot not associate STALL with the dire need for airspeed, which can only be acquired by Nose Down? If they reacted to the re acquisition of lower AoA (and the Stall Warn) by pulling back, simply to silence the Alarm, why did they ignore it the rest of the four minutes? Associating Nose Down with STALL is counter indicated.
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Old 4th Jun 2017, 23:06
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Originally Posted by Concours77
We need to ponder why, given seventy two "STALL STALL" alerts, none of the pilots thought to address AoA? No one has come close to explaining this fact... Also, why would any trained pilot not associate STALL with the dire need for airspeed, which can only be acquired by Nose Down? If they reacted to the re acquisition of lower AoA (and the Stall Warn) by pulling back, simply to silence the Alarm, why did they ignore it the rest of the four minutes? Associating Nose Down with STALL is counter indicated.

I am NOT AB Rated, so,

A look at # 1119 shows what CAN happen with an experienced Captain - on a Sim. before it was frozen.

A THS reading at this point might have been interesting , too. ( Who ever looks, normally ?)

Perhaps a repeated STALL warning becomes just another noise, even before the 72 repeats. A changing voice with vocal pitch rising, might draw attention, as well !

Last edited by Linktrained; 4th Jun 2017 at 23:16. Reason: bits
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