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AF 447 Thread No. 12

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AF 447 Thread No. 12

Old 17th May 2019, 21:29
  #1641 (permalink)  
 
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@alexd10, there is no value accrued to encouraging a bloviating fool to post on Tech Log, but there may be some value in discouraging the same.

You get what you incentivize, condone, and encourage. Psychology 101.

(and yes, on the technical side, you are correct. Brevity in this case was being used to respond to low quality garbage.)
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Old 1st Jun 2019, 08:57
  #1642 (permalink)  
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https://www.planetepluscanada.com/em...-vol-rio-paris
Watched it last night.
Absolutely thrilling.
Most poignant moment: the faces of investigators listening to the DCVR.
Surreal...surreal!
They were shocked and just were stunned into silence...faces were contorted with angst forever etched in disbelief.
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Old 17th Jul 2019, 11:58
  #1643 (permalink)  
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AF charged, Airbus no case to answer.
https://www.huffingtonpost.fr/entry/...ef=fr-homepage
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Old 18th Jul 2019, 00:53
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Originally Posted by Winnerhofer View Post
https://www.planetepluscanada.com/em...-vol-rio-paris
Watched it last night.
Absolutely thrilling.
Most poignant moment: the faces of investigators listening to the DCVR.
Surreal...surreal!
They were shocked and just were stunned into silence...faces were contorted with angst forever etched in disbelief.
The video is not available anymore. Any other place we can watch this documentary?
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Old 18th Jul 2019, 06:18
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Originally Posted by Winnerhofer View Post
AF charged, Airbus no case to answer.
https://www.huffingtonpost.fr/entry/...ef=fr-homepage

Not sure. The news report the recommendations of the prosecutor but the investigating judges have the final word and can decide anything they want: all parties charged, all parties released or any mix (subject to a possible later appeal).

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Old 21st Jul 2019, 11:12
  #1646 (permalink)  
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Originally Posted by saviboy View Post
The video is not available anymore. Any other place we can watch this documentary?
Only clips for now:
https://www.youtube.com/playlist?lis...g5ww4ls1Zxgrj5
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Old 21st Jul 2019, 13:57
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Originally Posted by Winnerhofer View Post
Thanks. seems very interesting. Hopefully, they make the whole thing available soon
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Old 11th Nov 2019, 22:13
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Old 10th Feb 2020, 15:47
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Old 22nd Jun 2020, 10:46
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https://www.airbus-win.com/wp-conten...all_vl_mix.mp4

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Old 21st Aug 2020, 14:02
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Old 1st Sep 2020, 10:18
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https://globoplay.globo.com/v/7627502/
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Old 16th Apr 2022, 22:12
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Old 17th Apr 2022, 09:43
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I don't understand how airbus allowed the PHR to trim itself up to full up.
There is no situation (apart from something very remote) in which this would be safe or even reasonable.
Every light GA pilot knows that you don't trim an aircraft below 1.3Vs...

This single feature caused at least to accidents and hundreds of deaths.
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Old 17th Apr 2022, 10:46
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I forgot to mention that I watched the entire video above. This guy seems to come from nowhere but his analysis is one of the most accurate that can be found on this type of video. Only the official sources would be more precise, some of which are not available to the general public.
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Old 17th Apr 2022, 11:43
  #1656 (permalink)  
 
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Originally Posted by CVividasku View Post
I don't understand how airbus allowed the PHR to trim itself up to full up. ...
This single feature caused at least to accidents and hundreds of deaths.
I disagree. The aircraft trimmed full nose up in response to the co-pilot's continuous back stick demand for more nose up.

One of the holes in the cheese could have been closed with
so that the other pilot may have recognised the gross handling error of constantly pulling back.
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Old 17th Apr 2022, 11:56
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@ CVividasku; irrelevant. The "pilots" of AF447 caused the aircraft to crash - obviously not deliberately - RIP.

Hold full back-stick, or yoke in any aircraft, and it will stall. Keep holding full pitch-up during the stall and descent, and you will crash. The standard stall recovery is to immediately pitch down - this should be instinctive to experienced airline pilots.

Yes, the Airbus side-sticks are not easily visible to the other pilot, especially in dark conditions. I would add simple software to bring up the square ground control check display on both PFDs if a side-stick was held at or near a limit in flight for more than, say, a few seconds, so the other pilot would be alerted to what the first pilot was doing with their side-stick.
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Old 18th Apr 2022, 13:35
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Originally Posted by Goldenrivett View Post
I disagree. The aircraft trimmed full nose up in response to the co-pilot's continuous back stick demand for more nose up.

One of the holes in the cheese could have been closed with active side sticks so that the other pilot may have recognised the gross handling error of constantly pulling back.
Active sidestick is not something new, Airbus could have coupled both side sticks easily, however it added some weight so I assume that was the main reason why they did not do it.

Yes, holding full back stick without a good reason and with no protection is stupid, but accompanying/encouraging/amplifying a stupid movement is stupid too, isn't it ?
Actually, there are two other important examples that show the error in Airbus design :
- The MCAS accidents (from Boeing) showed that uncommanded/uncommandable/hidden/insufficiently visible trim runaway is dangerous, but Airbus too is capable of surprising trim runaways.
(Actually, since Airbus hides in fact the entire THS from the pilot, if the pilot is made aware of a THS movement it is necessarily a surprise)
- The XL airways crash at perpignan showed the sheer danger of a fully upwards THS. Even with full down stick, they could not impose the correct trajectory on the aircraft.
Instead, the aircraft imposed them with a deadly climb up to more than 50 nose up pitch.

The THS, or more generally pitch trim, should only relieve the efforts on the stick. A correctly designed aircraft should (that's only my opinion as a pilot) always be controllable with a trim completely ran away in the wrong direction. And if that's not possible by the law of physics (as seems to be the case of the airbus) there should be serious measures to prevent this type of accidents :
- The THS cannot move to an area where the airplane won't be controllable in an automatic/hidden fashion, or
- The THS should revert automatically to a desirable position when the pilot applies large stick inputs that cannot be satisfied by the elevators only.

To me, this sounds like common sense.
Hold full back-stick, or yoke in any aircraft, and it will stall. Keep holding full pitch-up during the stall and descent, and you will crash. The standard stall recovery is to immediately pitch down - this should be instinctive to experienced airline pilots.
In the case of the XL airways crash, they applied full pitch down and would have been able to recover the aircraft in this dire situation, if only airbus had not trimmed itself automatically fully up.

Try to answer this question positively : is there any good reason to allow the THS to go fully upwards or fully downwards, in a way that will make the aircraft uncontrollable ?
Is there any good reason to allow the THS to go automatically and unknowingly outside of a safe zone that could be computed from the current CofG ?
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Old 18th Apr 2022, 18:04
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When you pull or push the stick it is to change the attitude which you have to see on the PFD. 447 guy just pulled never looked at the pitch. They didn't see anything nor hear the stall warning. AT FL350 pulling 16 pitch is irrational. The pilots didn't know unreliable speed procedure and stall recovery procedure either. That may have triggered the fear factor causing loss of cognitive awareness. That's why all their actions appear irrational. Connected stick may have some virtue but if pilot doesn't know if pull is correct or push then it's not going to help.
Anyway ultimately the automation has come to rescue again. Now there's fourth source that is called Digital Back Up Speed it's calculated speed from load factor, CG etc. without any anemometric data that compares normal ADR speeds. Whatever is outside threshold is rejected through ECAM actions. If all are wrong then digital speed is displayed which you fly. In A350 it's automatically done. So no more 447.
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Old 19th Apr 2022, 05:22
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Originally Posted by CVividasku View Post
......
- The XL airways crash at perpignan showed the sheer danger of a fully upwards THS. Even with full down stick, they could not impose the correct trajectory on the aircraft.
Instead, the aircraft imposed them with a deadly climb up to more than 50 nose up pitch.
.........
In the case of the XL airways crash, they applied full pitch down and would have been able to recover the aircraft in this dire situation, if only airbus had not trimmed itself automatically fully up.
You should read the Accident Report for this Perpignan flight, which by the way was not a commercial flight. You will then see that it is much more complex than what you summarised to try supporting your views.

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