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Ethiopian airliner down in Africa

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Ethiopian airliner down in Africa

Old 17th Mar 2019, 03:33
  #1701 (permalink)  
 
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Pictures from the BEA Twitter feed.

The CVR:





And the FDR:


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Old 17th Mar 2019, 03:49
  #1702 (permalink)  
 
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Originally Posted by compressor stall View Post

I would not point the bullet that low. I’d say bigger picture. “Folks we are not going to build a new type because there are commercial advantages in sticking with our 1967 design, like not updating to modern safety requirements through grandfather rights and no pesky pilot conversion costs. Put bigger engines on it, increase the TOW and seats. We’re in this to make money. Make it work. Do your best.”

That cost saving is looking very expensive right now. The backstory will be in MBA textbooks in the future.
I agree with your view, actually. I was only talking about the practical implementation. Clearly, this could not have happened in isolation. That "interns" are permitted/required to put together something so unsuitable for the purpose (and that such a requirement exists in the first place) is a systemic issue.
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Old 17th Mar 2019, 04:20
  #1703 (permalink)  
 
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I assume Boeing is already under an internal "document preservation" -- do not delete -- order. Discovery is coming. This is going to get ugly, Trying to dodge a preservation order, or even presumption, is going to make it worse.
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Old 17th Mar 2019, 04:48
  #1704 (permalink)  
 
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The question is how do you define the trigger(s) for applying the runaway stabiliser trim drill? STS, MCAS and the AP will (and do) adjust the trim without pilot input, so what exactly are you looking for? Also, this is not on a low workload flight deck level at 20,000’, this is shortly after takeoff in a critical flight phase where all margins are much smaller and spare cognitive bandwidth is much reduced. It needs to be simple logic, not a large branching flowchart.

I guess what I’m trying to say is that suppose the trim starts moving after takeoff: is that a runaway or is it normal operation? I can’t see a quick and easy way to figure it out ...
Very easy to figure it out. This happens by itself when it dawns on you that the one thing you are fighting with the aircraft over is the pitch trim. There may be a few annunciations here and there that you haven't seen before (and a stickshaker that started whilst still on the runway), but everything else about the aircraft seems to be working normally.

Again:

The nose attitude keeps wanting to go low. You keep applying trim to make it go up. You make a trim up input, but the aircraft then trims nose down. You are spending a lot of time and effort on trying to trim for nose-up, but something keeps trimming nose-down. Pretty easy to figure out.

Last edited by FGD135; 17th Mar 2019 at 07:31.
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Old 17th Mar 2019, 05:03
  #1705 (permalink)  
 
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Ham-fisted

What a ham-fisted fix MCAS is. Others here have referred to it as a "kludge", which would have to be a similarly appropriate description.

As designed, the MCAS can (and will) produce nose-down pitching moments far, far stronger than the small nose-up moments it was designed to counter.

As designed and certified!

Can anybody seriously describe such a fix as anything other than ham-fisted?
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Old 17th Mar 2019, 05:22
  #1706 (permalink)  
 
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Can anybody seriously describe such a fix as anything other than ham-fisted?
FUBAR ^3 for starters

BA will no doubt blame the janitor or low level manager.

The section of commercial involved ( design-aero- software- certification ) by whatever name must be held accountable - whomever pushed-signed- approved needs be fired up to and including the commercial president and probably the Boeing CEO.

bring in those who argued against it- get some northrup- Lockheed types in and have them fix it.
Anything less will doom the 737 series yet to be built

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Old 17th Mar 2019, 05:50
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Al Jazeera have an interesting documentary on the 787, something about broken dreams. It's on YouTube. Worth a watch if you have a hour to burn.
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Old 17th Mar 2019, 06:13
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Simply stated, Boeing rushed the ac into production to counter the NEO series. The extended landing gear to counter the long standing issue withe engine size, larger diameter engines that weigh far more, yet no new wing design.
Put them further forward and higher on the wing to fit, and when instability issues show up, a software patch. Forget to mention this in the FCOM or training.

It appears to get the ac to actually fly, you have to turn off the AP....

Broken dreams or broken promises?
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Old 17th Mar 2019, 07:58
  #1709 (permalink)  
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[QUOTE=CONSO;10421152]FUBAR ^3 for starters. BA will no doubt blame the janitor or low level manager./QUOTE]

Still have to work on reinforcing the flight crew response. The cues appear to have been lost in the noise, and even with being forewarned by the JT accident, the crew of ET has had a bad day.. The HF side of this will hopefully filter into a responsive training of crew. The question is what interrupted the crew getting to the stab cutout step.
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Old 17th Mar 2019, 08:07
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Extra crew training is just keeping a link in the chain.

A modern civil airliner should be designed not to rely on the flight crew having to adopt non standard (unique?) piloting techniques to counter a faulty bandaid put there to mask inherent aerodynamic flaws.
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Old 17th Mar 2019, 08:16
  #1711 (permalink)  
 
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Originally Posted by S speed View Post
Al Jazeera have an interesting documentary on the 787, something about broken dreams. It's on YouTube. Worth a watch if you have a hour to burn.
Hour to burn, I see what you did there
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Old 17th Mar 2019, 08:35
  #1712 (permalink)  
 
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Originally Posted by yarpos View Post
Hour to burn, I see what you did there
Haha, but seriously... Go search Al Jazeera 787 broken dreams. I'm not senior enough to post links yet, otherwise I would have done so.
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Old 17th Mar 2019, 08:40
  #1713 (permalink)  

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A modern civil airliner should be designed not to rely on the flight crew having to adopt non standard (unique?) piloting techniques to counter a faulty bandaid put there to mask inherent aerodynamic flaws.
They could always increase the height of the main undercarriage and bring the engines down to where common sense says they should be like the A210. It would have been better if they had developed a B757 light rather pursue the religion of 737 commonality with the 200 series.

Let's hope the regulators inject some common sense into the Boeing brain.
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Old 17th Mar 2019, 08:46
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Originally Posted by sky9 View Post
It would have been better if they had developed a B757 light rather pursue the religion of 737 commonality with the 200 series.
.
I’d say there’s more than one Boeing Exec thinking that right now.
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Old 17th Mar 2019, 08:54
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Originally Posted by FGD135 View Post
You are spending a lot of time and effort on trying to trim for nose-up, but something keeps trimming nose-down. Pretty easy to figure out.
The Ethiopian crew didn’t figure that out on a blue sky CAVOK day. The Lion air crew didn’t figure that out even with a dedicated maintenance engineer on the flight deck looking for the problem. What about in real bad weather when you need all your skill. I don’t want to have an aircraft acting on me then. If it takes a test pilot, o.k. then the Max is test pilots only...
That the other airlines got away with it might well be more luck than skill.
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Old 17th Mar 2019, 09:13
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Originally Posted by Cows getting bigger View Post


Indeed, poorly implemented risk assessments at design level. As for the firproof box and exhaust solution, one needs to ask the FAA whty they basically accepted that an airborne fire scenario was suddenly acceptable. (There’s a REALLY long thread somewhere about that).
The 787 at Heathrow the fault was in a poorly manufactured Emergency Locator Beacon from a supplier. The two halves of the box were screwed together by the manufacturer trapping one or more wires which were shorting out and eventually while parked at LHR got hot enough to cause the Emergency Locator Beacon to catch fire fire.
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Old 17th Mar 2019, 09:21
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Originally Posted by HdwJunkieSLF View Post
I assume Boeing is already under an internal "document preservation" -- do not delete -- order. Discovery is coming. This is going to get ugly, Trying to dodge a preservation order, or even presumption, is going to make it worse.
Or shredder working in the small hours...
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Old 17th Mar 2019, 09:38
  #1718 (permalink)  
 
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Originally Posted by EDLB View Post
The Lion air crew didn’t figure that out even with a dedicated maintenance engineer on the flight deck looking for the problem.
The Lion Air crew didn't figure that out, period.

AFAIK, there is no evidence that the engineeer on board was on the flight deck, or even that their presence on the flight at all was for troubleshooting purposes, rather than just a scheduled flying spanner.

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Old 17th Mar 2019, 09:42
  #1719 (permalink)  
 
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Originally Posted by sky9 View Post
They could always increase the height of the main undercarriage and bring the engines down to where common sense says they should be like the A210.
I'm not sure that alone would fix it. And on top that would further lower the thrust line away from cg, i.e. increase thrust related pitch up moment.
The aerodynamic problem surely mostly stems from bigger nacelles plus installed more forward.
OK, lowering might allow you to move them back a little. but I'm not sure they are not so much in front also for cg reasons, in which case you couldn't move them back so easily.
What would have really helped are bigger tail feathers. And additionally that would have allowed you to move cg back. Which in combination with a longer gear would have allowed you to move the nacelles a bit back.
That would probably have been the correct solution. And with such an approach you could have taken the 737 into the new age. But that would have taken longer and cost more (in short term).


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Old 17th Mar 2019, 10:00
  #1720 (permalink)  
 
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Originally Posted by compressor stall View Post
Extra crew training is just keeping a link in the chain.

A modern civil airliner should be designed not to rely on the flight crew having to adopt non standard (unique?) piloting techniques to counter a faulty bandaid put there to mask inherent aerodynamic flaws.
Well that is just the point. Uncommanded/runaway trim has had the same procedure since the first 737 - switch the stab trim switches off and those have also been in the same place. So this was a totally standard response to a potential error.

I have some sympathy with Reamer's responses here. The expectation is that a professional pilot will be trimming and sensing trim as second nature as a 'muscle memory' regardless of other things happening, Rather like you expect a car driver to carry on steering, It is further expected that if the trim starts annoyingly trimming against the pilot that the pilot will rapidly identify this and follow the decades old standard procedure and switch stab trim off and not wait until the nose down trim was requiring significant force. After the Lion Air crash this decades old standard procedure was put out in a directive to all Max operators. So now who of them could claim that this was an unexpected procedure? Well all those that don't bother to keep up with the directives - I would have thought that there would be some kind of sign off procedure in each airline requiring all Max pilots to sign as having read the directives which just refreshed the existing standard procedure ensuring/reminding crews that uncommanded nose down trim should be stopped by using the standard runaway trim procedure. Apparently not.


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