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Ethiopian airliner down in Africa

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Ethiopian airliner down in Africa

Old 21st Apr 2019, 19:17
  #4201 (permalink)  
 
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[QUOTE=Chronus;10452687Automation is therefore the way forward and that involves a cost for knowledge and learning from many mistakes. It was so in the past, where the process involved the misfortunes of many, so it will be in the future. This particular incident shows that until such time when machines are free from mistake, human fallibility shall remain. For reason that their fallibility is replicated in any machine they design and manufacture. Perhaps AI will resolve this weakness and we shall have machines designed by machines. Then we shall have fulfilled our pursuit for excellence. Don`t you remember when you were first instructed in Instrument Flying, I do. I was told trust your instruments.[/QUOTE]

Do we also need to learn again how tires are manufactured? Millions of cars are driving perfectly safe but still cheap chinese wheels crack because they are manufactured cheap and without x-ray check.
Hundreds of millions of cars have ESP, a system which could easily block single tires on the highway without a chance to react before hitting a tree. Still I have not heard of a single accident. Cost pressure on such systems (ESP, engine ECU, gearbox ECU...) is by orders of magnitude higher than in aviation. You're not counting fractions of cents in aviation. On the other hand lines of code are not considered cost-relevant within automotive, a programmer more or less does not really matter. It should be the same in aviation.

Almost every function within a car is single-point-fault tolerant if a defect would stop the car. Single point fault tolerance is not restricted to safety, but also extended to 'limp-home' to the garage and any other function which would be more than annoying in case of an error. So why the heck didn't they just compare 2 (already existing) sensors? Every system engineer would (if allowed to). Emission standards require such a 2oo2 to avoid abnormal emission (..of a single car in case of random HW defects).
In addition, EVERY sensor is usually range-checked. Why would you activate a 'stall-avoidance feel' if the AoA is at its mechanical limit which would mean the aircraft is flying backwards or is in free-fall?
Designing such a system in a safe way is nothing new, it is state of the art for >20 years. SW is controlling your car's engine and acceleration, brake (ESP), airbag, gearbox, there are fly-by-wire systems, trains, signals and so on. If you want to see state of the art safety:
This robot could break their necks or dump them into the ground with a fraction of it's available force. Instead it' perfectly safe.

But the process is costly and takes time. And it requires qualified engineers and a safety culture and a certain independence & priority between commercial interest and safety requirements.

To me it looks like Boeing was putting the priority on sales, not on safety.

Open any ISO/IEC on safety, you will probably find a list of sensor plausibilisation methods and how safe they are considered to be. The simple ones (range check, considered 60%) would have saved 1 aircraft, the better ones (2oo2, linearity... (90%/99%)) both.
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Old 21st Apr 2019, 19:42
  #4202 (permalink)  
 
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Originally Posted by DaveReidUK View Post
To clarify, there are no MCAS-related events in NASA's SRS system.
Seen that the existence of MCAS was unknown even to the SW Airline pilots until the Lion Air crash, how would pilots report an MCAS related event?
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Old 21st Apr 2019, 20:00
  #4203 (permalink)  
 
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Easy--trim the airplane. After a few series of "arguments" with the MCAS, turn off the trim via the Runaway Stabilizer checklist.
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Old 21st Apr 2019, 20:58
  #4204 (permalink)  
 
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Originally Posted by etudiant View Post
Seen that the existence of MCAS was unknown even to the SW Airline pilots until the Lion Air crash, how would pilots report an MCAS related event?
I think we can safely assume that such an event would be reported, even if not identified as such.

There were none.
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Old 21st Apr 2019, 21:38
  #4205 (permalink)  
 
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Originally Posted by DaveReidUK View Post
I think we can safely assume that such an event would be reported, even if not identified as such.
There were none.
Maybe all the 'first world' planes have the options 'plausibilization' and 'AoA display' ordered, so a single AoA failure is just worth a small note in the log?

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Old 21st Apr 2019, 23:47
  #4206 (permalink)  
 
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Originally Posted by Loose rivets View Post
And the Million $ per aircraft promised payment, though I think that might be AA specific.


I'm still reeling from the shock of watching the subcontracting issues on the parallel thread. I was totally unaware of this. The gist I got was that the problem is so serious that no one seems able to face addressing it.

Current crews and engineers will no doubt be au fait with the issue. Just what is going on?

Rather drawn out, but so bewildering it took my mind off MCAS.

Boeing 737 Max Software Fixes Due to Lion Air Crash Delayed
Link not working.

It seems the $1M deal was with at least the company with the largest single order of 280 aircraft - Southwest Airlines.

That seems a very high number to compensate for simulator training being a requirement - $1M is a lot of simulator hours.

https://www.forbes.com/sites/peterco.../#1dc5a8462e18
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Old 21st Apr 2019, 23:54
  #4207 (permalink)  
 
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Originally Posted by Bend alot View Post
That seems a very high number to compensate for simulator training being a requirement - $1M is a lot of simulator hours.
Well, first you need to buy the simulators, and they are not cheap. And I do mean simulators, as in plural, because if you're Southwest, you cannot quickly cycle your pilots through a single sim.
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Old 22nd Apr 2019, 00:22
  #4208 (permalink)  
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When we moved up the ladder to more modern iterations in the old days, we did a 'Differences' course, which was about a working week in the classroom. I recall having to do performance etc., again as well. Flying was all on the real aircraft, the BAC 1-11. Yes, we stalled to the push. All in the Swinging Sixties.


"Link not working" Try direct to the Tube below.

I just don't know what to make of this, though I assume pre-MAX era.

Is it history that's faded? because it seems to be a bigger problem than the MAX. A head honcho in the FAA who admits that Boeing wrote his assessment and he signed it. Banging major fuselage parts into place that should be accurate to 1/3000" over entire production runs but turn out to be hand made.

Sully's statement. 'Unprecedented in aviation history.'
$27 billion down today. Though hey, a slight rallying.
This lurking in the background:

Last edited by Loose rivets; 22nd Apr 2019 at 00:39.
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Old 22nd Apr 2019, 00:50
  #4209 (permalink)  
 
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Originally Posted by 737 Driver View Post
Well, first you need to buy the simulators, and they are not cheap. And I do mean simulators, as in plural, because if you're Southwest, you cannot quickly cycle your pilots through a single sim.
If you need to buy new simulators to train for the MAX fleet, then the aircraft is different to other 737's.

So Boeing and FAA claims, of they are basically the same and do not require simulator training gets hard to swallow.

Now I can live with larger TV screens and more powerful engines as a reasonable change not requiring simulation, just look at the Toyota Hilux range - different engines and gauges but they drive similar.
But changes like that made on the MAX, to the spoilers and introduction of MCAS (flight controls) should have appropriate training. My personal opinion is a short read and sign on a iPad is not good enough.

Here is a link to the changes.

Boeing 737 MAX - Differences
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Old 22nd Apr 2019, 01:34
  #4210 (permalink)  
 
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NG / New differences
Flight Control Systems
Only the F/Os column cutout switch module is affected because it is the only module that interfaces with the FCC..

Help... think I must've missed something earlier.on that rin-down of changes.. Anyone else wondering where that jumped out of...

Last edited by HarryMann; 22nd Apr 2019 at 01:52.
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Old 22nd Apr 2019, 05:44
  #4211 (permalink)  
 
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FAA has an express statutory power to reinspect, re-examine, suspend, or revoke any certificate, including a type certificate, where "safety ... and the public interest require that action”. Read about Special Certification Reviews and examples such as MD-11 at https://scholar.smu.edu/cgi/viewcont...3&context=jalc.

Hopefully FAA led Joint Authorities Technical Review of MCAS will amount to a multi-national SCR. See https://www.faa.gov/news/updates/?newsId=93206.

Bad news for Boeing is that MAX grounding is not likely to be lifted before JATR reports in 90 days.
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Old 22nd Apr 2019, 06:14
  #4212 (permalink)  
 
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Originally Posted by ozaub View Post

Bad news for Boeing is that MAX grounding is not likely to be lifted before JATR reports in 90 days.
I do not think the family and friends of the 346 fatalities consider it bad news at all.
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Old 22nd Apr 2019, 06:25
  #4213 (permalink)  
 
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Re: Joint Authorities Technical Review. This is a very unusual move by the FAA.
Political positioning, need for world consensus to protect FAAs standing?
Or a much needed safety initiative to look at issues arising?

The team will evaluate aspects of the 737 MAX automated flight control system, including its design and pilots’ interaction with the system, to determine its compliance with all applicable regulations and to identify future enhancements that might be needed.’

Is this just an ‘evaluation’. Or if aspects are not compliant with regulations (whose regulations), will change be mandated or only treated as ‘enhancements’, or aspects which should be incorporated in future (non-grandfather rights) regulations?

Previous regulatory overview Ethiopian airliner down in Africa

and technical / training areas requiring review Boeing 737 Max Software Fixes Due to Lion Air Crash Delayed

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Old 22nd Apr 2019, 10:47
  #4214 (permalink)  
 
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Originally Posted by safetypee View Post
Re: Joint Authorities Technical Review.
The team will evaluate aspects of the 737 MAX automated flight control system, including its design and pilots’ interaction with the system, to determine its compliance with all applicable regulations and to identify future enhancements that might be needed.’
Boeing had better have every single expert to hand with every schematic and line of code ready to be looked at. If the inspecting Engineers ask for clarification on X,Y and Z it could take Boeing another month to go get the information and come back. This could be a simple exercise or could be months depending on what depth it goes to..And the final answer may not be positive. I was worried when I heard since MCAS was fingered that a cross FCC bus was added to handle it better. That's major tinkering with major components. Not the sort of thing to be done in a few months as an add-on!

Hopefully none of the regulators will take any notice of the commercial imperatives to getting the MAX back in the air. Trump's White House might browbeat the FAA but none of the foreign regulators..

G
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Old 22nd Apr 2019, 16:30
  #4215 (permalink)  
 
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Originally Posted by groundbum View Post
I was worried when I heard since MCAS was fingered that a cross FCC bus was added to handle it better. That's major tinkering with major components.
Pretty sure cross FCC bus is already there, not absolutely sure AOA is on it, but if not, adding it would be a lot different to creating entirely new bus.

MCAS could have been done with two AOA sources in the first place, it wasn't (allegedly - see whistleblower quotes further up thread) because that would require an MCAS-fail warning light and sim-training. This now appears to be being done in a half-arsed way by using AOA-disagree as a de-facto MCAS-fail warning, which means operators who don't currently have AOA-disagree option will presumably need to implement extra training (or get blamed for future MCAS prangs) but the US operators with the no-sim-training penalty clauses will not because they already have the AOA disagree option. Funny that...
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Old 22nd Apr 2019, 16:42
  #4216 (permalink)  
 
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Originally Posted by infrequentflyer789 View Post
Pretty sure cross FCC bus is already there, not absolutely sure AOA is on it, but if not, adding it would be a lot different to creating entirely new bus.

MCAS could have been done with two AOA sources in the first place, it wasn't (allegedly - see whistleblower quotes further up thread) because that would require an MCAS-fail warning light and sim-training. This now appears to be being done in a half-arsed way by using AOA-disagree as a de-facto MCAS-fail warning, which means operators who don't currently have AOA-disagree option will presumably need to implement extra training (or get blamed for future MCAS prangs) but the US operators with the no-sim-training penalty clauses will not because they already have the AOA disagree option. Funny that...
I thought I'd read that AoA-Disagree was going to be added by default as part of the fix(?).
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Old 22nd Apr 2019, 16:43
  #4217 (permalink)  
 
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Originally Posted by groundbum View Post
I was worried when I heard since MCAS was fingered that a cross FCC bus was added to handle it better. That's major tinkering with major components. Not the sort of thing to be done in a few months as an add-on!

G
They say that it is a software only fix which raises the uncomfortable question of why it was not implemented to read both sensors in the first place. I am still not onboard with the idea that any engineer would make such a decision simply to hide the feature from the regulatory process but it makes one wonder. If so then manslaughter charges are appropriate and I am not kidding, that would be like designing a commercial kitchen without fire suppression because you did not want to involve the fire department in the permit. (And then blaming the cook for starting a fire!)
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Old 22nd Apr 2019, 17:29
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Originally Posted by Water pilot View Post
They say that it is a software only fix which raises the uncomfortable question of why it was not implemented to read both sensors in the first place. I am still not onboard with the idea that any engineer would make such a decision simply to hide the feature from the regulatory process but it makes one wonder. If so then manslaughter charges are appropriate and I am not kidding,
Safety culture and a certain independence within the organisation between the responsible safety managers and commercial decisions, is, at least within automotive & machine, part of the ISO26262/IEC61508 and therefore state of the art.
They may have a few things to explain...

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Old 22nd Apr 2019, 19:11
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Originally Posted by Bend alot View Post
If you need to buy new simulators to train for the MAX fleet, then the aircraft is different to other 737's.

So Boeing and FAA claims, of they are basically the same and do not require simulator training gets hard to swallow.

Now I can live with larger TV screens and more powerful engines as a reasonable change not requiring simulation, just look at the Toyota Hilux range - different engines and gauges but they drive similar.
But changes like that made on the MAX, to the spoilers and introduction of MCAS (flight controls) should have appropriate training. My personal opinion is a short read and sign on a iPad is not good enough.

Here is a link to the changes.

Boeing 737 MAX - Differences
So what simulator exercises would you incorporate to reflect the differences in the MAX, specifically the MCAS? How about an uncommanded nose down trimming? That is already incorporated in a conventional stab trim runaway, a basic requirement of getting a type rating on any B737. Or how about an unreliable airspeed including stick shaker? An unreliable airspeed exercise is also part of a type rating on any B737. In other words, there is nothing so uniquely different with the MAX that justifies a new simulator let alone MAX (MCAS) specific training. And even if you were to provide this (redundant) training, there is no guarantee that the crews would do the drill anyways as we have tragically witnessed with these accidents.

Not having the exact simulator for training has loads and loads of precedents - I can guarantee that the simulator configurations at a non-airline specific training facility (Flight Safety, CAE, Boeing, Airbus) would be different than what one would find on the aircraft of a particular airline. And even airline specific training facilities often don't have simulators that match their fleet as the fleet may have many configurations. As an example, where I work we have B767-300's with GE and Pratt engines, those engines start and behave completely differently (GE uses N1 as the reference power, Pratt uses EPR). Or an A340 simulator that is used for both the -300 and -500 which have entirely different fuel systems, different engines (CFM vs Rolls Royce), B787 simulators where the -800 and -900 are different (the -900 has more flaps settings for example).

The point is is that is both impractical and unrealistic to have "perfect" simulators; instead one has relied upon professional and experienced pilots to deal with differences between the simulator and the aircraft and also deal with different aircraft within a fleet.
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Old 22nd Apr 2019, 20:34
  #4220 (permalink)  
 
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Originally Posted by L39 Guy View Post
So what simulator exercises would you incorporate to reflect the differences in the MAX, specifically the MCAS? How about an uncommanded nose down trimming? That is already incorporated in a conventional stab trim runaway, a basic requirement of getting a type rating on any B737. Or how about an unreliable airspeed including stick shaker? An unreliable airspeed exercise is also part of a type rating on any B737. In other words, there is nothing so uniquely different with the MAX that justifies a new simulator let alone MAX (MCAS) specific training. And even if you were to provide this (redundant) training, there is no guarantee that the crews would do the drill anyways as we have tragically witnessed with these accidents.

Not having the exact simulator for training has loads and loads of precedents - I can guarantee that the simulator configurations at a non-airline specific training facility (Flight Safety, CAE, Boeing, Airbus) would be different than what one would find on the aircraft of a particular airline. And even airline specific training facilities often don't have simulators that match their fleet as the fleet may have many configurations. As an example, where I work we have B767-300's with GE and Pratt engines, those engines start and behave completely differently (GE uses N1 as the reference power, Pratt uses EPR). Or an A340 simulator that is used for both the -300 and -500 which have entirely different fuel systems, different engines (CFM vs Rolls Royce), B787 simulators where the -800 and -900 are different (the -900 has more flaps settings for example).

The point is is that is both impractical and unrealistic to have "perfect" simulators; instead one has relied upon professional and experienced pilots to deal with differences between the simulator and the aircraft and also deal with different aircraft within a fleet.
I'm sorry but this is genuinely disengenous.

You can't argue what about this, or that.

They didn't have this, or that.

They had all of it.

What you are arguing is that because individual elements of the failure were trained independently, that there was no combination of trained failures that could be expected to overcome the flight crew.

That no matter what the automation did and no matter how many failure modes were presented concurrently, that the flight crew should be expected to compensate regardless.

This just doesn't make sense.

The problem here is precisely that the combination of so many individually trained and for that matter untrained failures was too numerous to encourage and support successful and timely diagnosis by a typical crew.

Last edited by Turbine70; 22nd Apr 2019 at 23:41.
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