[Jeroen]

Originally Posted by GoBlue

One of the thoughts that occurred to me when I started looking at this (I am not a pilot or an aerospace engineer -- I have sometimes worked with distributed control software for databases) was why there had never been a parallel problem with far-more-heavily automated Airbus planes. As I started to look into this I became rather alarmed at the direction of the 737-MAX control systems. I believe that some of the problems are actually even worse than described in the article so I am adding my thoughts here as well. The closest you have is Air France 447 but that was caused by pilots overwhelmed by warnings and failing to follow protocol rather than failing systems themselves. Airbus has never had a malfunctioning anti-stall system actively bring down an airplane. So why not? Why is this a specific problem with the MAX fleet and not the A320's, A330's etc?
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As a thought here is a very interesting link to a somewhat different approach/view on this matter:

https://airfactsjournal.com/2019/03/...-trust-pilots/

Just quoting a small part:

Though the pitch system in the MAX is somewhat new, the pilot actions after a failure are exactly the same as would be for a runaway trim in any 737 built since the 1960s. As pilots we really don’t need to know why the trim is running away, but we must know, and practice, how to disable it.

The problem for Boeing, and maybe eventually all airplane designers, is that FBW avoids these issues. FBW removes the pilot as a critical part of the system and relies on multiple computers to handle failures.

Boeing is now faced with the difficult task of explaining to the media why pilots must know how to intervene after a system failure. And also to explain that airplanes have been built and certified this way for many decades. Pilots have been the last line of defense when things go wrong.

AF447 is no different in the sense that it found itself outside its certification envelop. The pitot tubes iced up, the crew responded poorly. And again, the crew could have prevented the whole disaster in the first place if they had chosen to divert slightly due to this active weather front.

Although the whole world is now breathing down Boeing’s neck about this topic, I believe not enough attention is given to the involvement of the pilots in these two very unfortunate accidents.

No matter how much automation you throw at it, at some point a situation will occur where it stops working, throws some completely unexpected wobble. This is where pilots need to step in and take over. (until such moment we get full autonomous flights with no pilots, but you won’t see me on those!)

So in that sense I do not agree with the above author completely. FBW does not remove the pilot as a critical part of the system. He/she gets a different role to play. But again, even the most heavily automated system will break down according to Murphy’s law. And we all know Murphy has been proven correct, time after time.

I was mentioning this earlier in this thread. A public outcry has pushed Boeing into the spotlight of the defended, but the question that is simply not answered and is becoming politically incorrect to even suggest: Should the pilots have been able to handle this situation, or to put it plainly, did they mess up?

To add: Lion air messed up big time, by shoddy maintenance and allowing an essentially un-airworthy aircraft to take to the sky. We could ask the same question there; why did those pilots not manage to recover the plane? Their colleagues who flew this plane the previous day encountered the same problems and landed, with some extra help, but still. Some guy knew how to deal with the problem, apparently the other involved pilots did not.

Safety in general and certainly in aviation, comes through multiple layers of design, processes, checks, double checks, oversights etc. Boeing and the FAA have certainly something to explain/rectify. But we should not forget that other safeguards have/should been build into the system as well. E.g. properly trained and experienced pilots, properly executed maintenance routines.

I find the public Boeing/FAA bashing unbalanced as it addresses only one part of the safety chain. As with nearly all aviation accidents it takes multiple contributing factors. The same is very likely true in these two tragic accidents. Unfortunately, due to public Boeing/FAA witch hunt we need to be doubtful if the final reports will be presenting a as balanced view as they should. If they don’t aviation safety has really been compromised for the years to come.

Jeroen

[Sutripta]

Originally Posted by Jeroen

https://airfactsjournal.com/2019/03/...-trust-pilots/

Once again the comments are interesting. But going through them made me check the date of the article vs. the Ethiopian crash date. Anything more recent from the same author or same publication as more details emerged from the Ethiopian crash?

Regards
Sutripta

[Jeroen]

Originally Posted by Sutripta

Once again the comments are interesting. But going through them made me check the date of the article vs. the Ethiopian crash date. Anything more recent from the same author or same publication as more details emerged from the Ethiopian crash?

Nothing I have come across recently. Any particular details you are thinking of that might give him pause for further thought?

[Hayek]

Have to disagree with the idea that this was substantially pilot error. The fact is that airlines like ET and Lion fly plenty of NG 737s, with the same “mediocre” pilots and maintenance practices that folks talk about in some of these threads. Crashes are exceptionally rare despite these practices, because planes are generally designed to be safe. This plane seems to go into a dynamically unstable mode very easily - in nose up condition which is why the MCAS was needed in first place, and in nose down position triggered by the MCAS and faulty angle of attack data. In short, it is a fundamentally dangerous plane, which requires far better pilots than exist in a world of fast expanding low cost carriers.

I am not surprised Boeing is taking so long to get this sorted - let’s be clear that the MCAS would have been made so aggressive for a reason - because the designers concluded that the risk of a stall was very high. Tamping it down is not going to be so easy - what happens if one sensor is showing too low an angle of attack, MCAS gets disabled due to the mismatch and the plane goes into a stall? That is a simple layman’s question - I am sure regulators will ask such questions and a lot more. I would still assume a non zero chance of a full recall being needed - or separate type certification being needed to fly the Max - which would kill the economics of the program.

[AkMar]

I fully second Hayek's views. Easy to blame pilot error for the crashes, but not all pilots will be super skillful! Systems have to be designed in such a way that pilots with below exceptional skills should be able to handle them, and MCAS surely doesn't seem to be meeting this requirement.

[A350XWB]

Originally Posted by Jeroen

AF447 is no different in the sense that it found itself outside its certification envelop. The pitot tubes iced up, the crew responded poorly. And again, the crew could have prevented the whole disaster in the first place if they had chosen to divert slightly due to this active weather front.

Can we really compare the AF447 to the 737MAX accidents? In case of AF447, when the airspeed data became unreliable, the aircraft switched to the alternate law and informed the pilots during the autopilot cut out. There were aural and visual warnings. There were also a barrage of STALL warnings which the crew ignored, for some reason. The aircraft was perfectly hand flyable in that case. The automated protection was not available due to the switch to alternate law, otherwise the aircraft would not have allowed itself to stall at all.
In case of 737MAX, the aircraft was actively pushing the nose down and in defense of the Lion Air crew, they did not even know what was causing it. Boeing thought that this knowledge is not needed for the pilots.

Originally Posted by Jeroen

Although the whole world is now breathing down Boeing’s neck about this topic, I believe not enough attention is given to the involvement of the pilots in these two very unfortunate accidents.

Yes, there might be other contributing factors to these accidents. But do you believe that a large corporation like Boeing would accept that they screwed up big time, so easily, if there was not something really bad behind the curtains? And, if the MCAS system is so well designed that only some training material would help in resolving the issue, why is Boeing taking so long to include a fix and has to re-certify the whole thing? From the investigations, it has already come to light that the system was incorrectly categorized as hazardous instead of catastrophic (in case of failure), the system pushes the nose way more than the actual design suggests it would, there is no redundancy to the data source etc.

Originally Posted by Jeroen

Their colleagues who flew this plane the previous day encountered the same problems and landed, with some extra help, but still. Some guy knew how to deal with the problem, apparently the other involved pilots did not.

How sure are we, that the problem encountered the previous day was exactly the same as Lion Air Flight 610? What if the pilots that day were facing a far more worse condition? We don't know yet, right?

[Jeroen]

Originally Posted by Hayek

Have to disagree with the idea that this was substantially pilot error. The fact is that airlines like ET and Lion fly plenty of NG 737s, with the same “mediocre” pilots and maintenance practices that folks talk about in some of these threads.

Originally Posted by AkMar

I fully second Hayek's views. Easy to blame pilot error for the crashes, but not all pilots will be super skillful! Systems have to be designed in such a way that pilots with below exceptional skills should be able to handle them, and MCAS surely doesn't seem to be meeting this requirement.

Originally Posted by A350XWB

Can we really compare the AF447 to the 737MAX accidents? In case of 737MAX, the aircraft was actively pushing the nose down and in defense of the Lion Air crew, they did not even know what was causing it. Boeing thought that this knowledge is not needed for the pilots.


How sure are we, that the problem encountered the previous day was exactly the same as Lion Air Flight 610? What if the pilots that day were facing a far more worse condition? We don't know yet, right?

Some additional thoughts/comments. I never said it was a case of pilot error, only that it needs to be investigated much more and it is not given enough attention. The public at large has condemned Boeing, but there could well be much more.

The amount of piloting skill required to handle emergencies is part of the design/verification process of any plane. In general pilots do not need exceptional skills at all. But we have seen plenty of cases where pilots skills were simply not up to the basic level they should have been.

Everybody keeps hampering about the pilots not knowing about MCAS. But there is a procedure how to handle a runaway trim situation. The problem with MCAS manifest itself to the pilot as a runaway trim.

The author of the article I referred to, mentioned this as well. Knowing how to diagnose and deal with a runaway trim situation is a basic pilot skill.

The first Lion crew manage to diagnose the problem and subsequently brought the situation under control as per the standard procedure.

We do not know why the two other crews did not manage to do so.

The reason it is taking Boeing so long and the reason they are responding as they are, is more likely to be due to public pressure and other parties/authorities, being extremely cautious, rather than based on fact. That is part of my concern. All attention is drawn to one (very import) element, but the side effect is that everything else gets overshadowed. Which simply is not good enough from an aviation safety point of view.



Jeroen

[vharihar]

Originally Posted by Jeroen

I find the public Boeing/FAA bashing unbalanced as it addresses only one part of the safety chain. As with nearly all aviation accidents it takes multiple contributing factors. The same is very likely true in these two tragic accidents.
Jeroen

And I find it strange to see the extent to which you seem to be going to defend Boeing!

In my assessment, any NNC maneuver that is exceptionally challenging for a human to accomplish especially when under duress, cannot be considered an acceptable NNC with no fault to the manufacturer (despite the fact that some pilot on a prior flight may have successfully ran thru the NNC)

[Jeroen]

Originally Posted by vharihar

And I find it strange to see the extent to which you seem to be going to defend Boeing!

In my assessment, any NNC maneuver that is exceptionally challenging for a human to accomplish especially when under duress, cannot be considered an acceptable NNC with no fault to the manufacturer (despite the fact that some pilot on a prior flight may have successfully ran thru the NNC)

I am not defending Boeing at all. Clearly there are things that went wrong on their end. Also the way the certification was handled between the FAA and Boeing needs some major rethinking.

I'm saying aviation accident investigation needs to address each and every part on the total chain. I am looking for a much broader and deeper approach.

Being able to work very consistently and methodically under duress is something that is part of the job requirement for pilots. We do not know exactly what happened in the cockpit yet, certainly no formal conclusions have been reached by those investigating. Part of the investigation needs to be whether the pilots performed as expected. Again, the ability of figuring out what to do in an emergency situation is not considered an exceptional skill level perse. We also know that the latest crew attempted to run the NNC but actually did not complete it, or rather reversed it. The question still remains, given under the circumstances, did they perform as expected.

Because if they did it does lead to other questions; Did they simply run out of time, was the NNC (as we have been lead to believe) simply not adequate enough. Or is there something else that needs to be considered?

Again, coming back to the poor maintenance routines of Lion. The first crash could have been prevented by them. That does not absolve Boeing for their part in this drama, obviously.

Boeing can update MCAS or completely scrap the 737 and come up with a new plane. If the maintenance procedures are not adhered too, if the pilots lack sufficient skill, you will have accidents again.

So from that point of view I believe focusing all attention on Boeing and not spending as much time, dedication, public media attention on these other factors is simply not helping aviation safety at large.

The notion that the 737 Max will be safe after the MCAS update is simply not correct. A plane, any plane, is never safe in isolation. It needs maintenance, correct procedures, pilots, ATC and a thousand other things to fly safely. Focusing on one isolated, albeit hugely important, part is not enough.

Jeroen

[desertfox]

9600 Hrs of testing has gone into the 737 MAX now. With the new software and MCAS interference parameters altered. Total cut out of MCAS and Stablizer trim switches also enabled.

FAA will clear it soon. But the continental guys EASA might need more convincing. All indicators point out to the fact that the Ethiopian Air crew had re enabled the stab trim switches. Human error.

Why did these problems not occur with Southwest airlines or Air Canada, United, AA ?

The world has changed today. Airports everywhere have conveyors and freight handling equipment. In a departure from producing ground loading aircraft it was high time Boeing should have gone for a taller landing gear. And bogey wheels for the MAX 9 and planned MAX X ( 10 ).

The 737 MAX 8 & 9 delivered already and produced and stored might fly again in about 3 weeks and it will be a huge relief to thousands of souls.

[Jeroen]

Originally Posted by desertfox

All indicators point out to the fact that the Ethiopian Air crew had re enabled the stab trim switches. Human error.
.

Correct, but in just about all mainstream media, it was reported that the crew did follow (NNC) procedure and therefor it must be something wrong the aircraft, e.g. Boeing. But the did not follow the NNC, they reverted it almost immediately.

We do know that several aspects do need improving/rethinking on the Boeing front. That is beyond doubt, but again there is more to these two accidents than just Boeing.

But there are several unanswered question about the behavior of the crew on both accidents.

[Zappo]

Originally Posted by Jeroen

But there are several unanswered question about the behavior of the crew on both accidents.

I barely understand much of flying. However, the intrigue of this whole storyline has kept me hooked to it. I do agree with you to a large extent about the general tendency of people to go overboard in certain matters like these and the recipient being hounded so bad that many other relevant issues at times get overshadowed. That's a very regular phenomenon everywhere. In this case Boeing is at a receiving end of it and for a very good reason I would say.

However, as you alluded to it, were the pilots absolutely blemish free? We probably are not very sure about it yet. May be they were not. They were probably mediocre pilots... you know, the average "Meets Expectation" rated guys, just like in any other organization as well. Nonetheless they were certified pilots with 1000s of flying hours under their belt. Also, I am pretty sure every pilot in the commercial domain is not a Chesley Sullenberger. How many air disasters of this proportion have we seen in the past decade? Very few I guess. And here we have a new airplane that sees its first fatal incident within a year of launch followed by yet another one within 5 months. Both show the same set of reasons, more or less, responsible for the crash.

If you start with the Lion Air incident, as you pointed out, on the previous day to the accident, they encountered something similar with this plane. May be it was not so severe at that time. We don't know. But what we know is that the actual pilots on that day were also flummoxed. It was a happenstance that there was a spare pilot flying in the cabin who figured out a way to recover from the incident. The second day, two new set of pilots failed and went down with this plane. So 5 pilots involved in two days... only 1 could do something in similar situations. The next incident happens in 5 months. By now the world knows what happened. Theories are floating around how to recover from such a scenario. Boeing has also added its bit. Apparently the Max 8 pilots have been made to undergo some simulation for dealing with such situations in future. All good. And yet, a plane in air again goes into a nosedive and BAM! So better informed pilots now and yet the same result. Score is now only 1 out of 7 pilots passes.

If you look at this situation the first thing that strikes you is that irrespective of all their mediocrity they have not been bringing down planes every few months. So is the plane a real big contributor here? Does it need nothing less than superlative pilots? And if so, is it fair to ask the regular commercial pilots to fly this plane without some additional certifications?

I think it needs some thoughts here.

[Jeroen]

Originally Posted by Zappo

However, as you alluded to it, were the pilots absolutely blemish free? We probably are not very sure about it yet. May be they were not. They were probably mediocre pilots... you know, the average "Meets Expectation" rated guys, just like in any other organization as well. Nonetheless they were certified pilots with 1000s of flying hours under their belt.

If you look at this situation the first thing that strikes you is that irrespective of all their mediocrity they have not been bringing down planes every few months. So is the plane a real big contributor here? Does it need nothing less than superlative pilots? .

I would really caution against using the term mediocre. We should be very careful in passing judgement, especially on a situation where so many questions are left unanswered.

In order to become a pilot every individual needs to pass the same bar so to speak. And that bar is pretty high. Either you pass or you don’t in essence.

So the standard is pretty high. What we do see is that aviation has become incredible safe. So the number of potential incidents that can lead to disasters as these have come down year after year as well.

What we can also see is that, irrespective of the total number of incidents and accidents coming down, pilot error in just about every type of aviation is still, by far, the largest (contributing) factor.

And we have also seen the number of incidents/accidents during manual flying has gone up. For whatever reasons, those few accidents we see very often are related or partly related to pilots not having sufficient manual flying skills. That shows up in particular during high stress situations and emergencies. So it always warrants very close examinations if pilots behaved as what could have been expected and if not, why not?

As to my earlier post. Aviation safety is a pretty complex and layered thing. Different elements in the chain can prevent accidents due to error by others. (eg. maintenance) or maybe these pilots could have prevented an accident due to design fault by Boeing too. We don’t know yet.

Pilots have screwed up before, and the day got saved by ATC, or vice versa. We have seen planes before with design issues. Pilots and maintenance saved the day in many incidents. etc. etc.

This doesn’t absolve anybody from their own individual responsibility. But the aviation safety system requires to scrutinise every aspect of these accidents. Everybody needs to be held accountable and pull their full weight so to speak. A well conducted aviation accident investigation will look at each and every aspect. With a public condemnation of Boeing this can potentially backfire on the final report.

Aviation authorities in charge of accident investigations need to be completely impartial. I am not saying they are not. But say for instance they find these pilots really fell short of what can be expected under the circumstances. Who is going to believe them. The public has already decided that it is all down to Boeing designing a crappy plane. Everything less than that outcome will be seen as whitewashing, protecting corporate interest etc. Such a shame, as aviation safety is only served by having an unbiassed approach to all factors.

Jeroen

[Sutripta]

Originally Posted by Jeroen

Nothing I have come across recently. Any particular details you are thinking of that might give him pause for further thought?

Including the Air France incident muddies the waters.
Lion Air and Ethiopian - list the similarities and differences, and rewrite the article if necessary.

Lots and lots and lots of questions. And as I have said before, this is not the place to ask them, or expect answers. (After all, we barely answer automotive technical questions with competence!)

But I would like to put my views on the "by wire" thing, because I think two issues are getting mixed up. In line with this forum, I'll use an automotive example - throttle by wire.

Suppose we have a system in which the accelerator has no mechanical connection to the butterfly, but instead operates a pot. The signal from the pot is used to open the butterfly a certain amount. So Throttle by Driver, mechanism 'by wire'.
Now take the same signal from the pot, but also take other signals, and process these to determine how much to open the throttle. So Throttle by Computer, mechanism still 'by wire'. The drivers desire has changed from a command to just a suggestion.
The important thing is who is in charge, and where necessary, how does authority (control) pass from one to the other. This is an age old question, and everyone has his own opinion, and a spare!

Aside - nothing to do with computers - Long time back (pre internet) VW broke away from the norm when it came to front wheel offset. All manufacturers (except VW) designed it so that the vehicle was inherently stable, esp in case of say a tyre blowout. But this assumed that the driver was neutral, a dummy. VW's philosophy was that the driver would react instinctively in case of a blowout, and his instinctive action would make the car unstable. Their system, while inherently less stable, was more stable if expected instinctive driver action was factored in.

But the best of all worlds would be if one could train the drivers to alter their instinctive reaction.

Where one has the option, the human should be trained, trained, and trained once more so that his instinctive muscle memory is in sync with design philosophy and implementation of the rest of the system. Can't do it with drivers, but certainly can be done with pilots, I feel.

I am not defending Boeing at all.

Well, the feel that one gets is that the older 'nonlaymen' on this forum did think that Boeing + FAA could walk on water.
One I think is having very serious doubts about it, and is a very sad because of it.
Not so the other.
In the interest of fairness, and getting to know all sides, Boeing + FAA does need supporters and believers in its corner.

Originally Posted by desertfox

FAA will clear it soon.

As I said before, it will be very interesting to see how the FAA will respond.
I feel pressure will be brought to bear on the other regulators and stakeholders (the international panel of nine) to clear the 737Max, and the FAA sweetly goes along with the consensus.

Regards
Sutripta

[Jeroen]

Originally Posted by Sutripta

Including the Air France incident muddies the waters.
Lion Air and Ethiopian - list the similarities and differences, and rewrite the article if necessary.

There are potential similarities: Systems break down, pilots can’t recover. Both cases had equipment failing, putting the plane in a situation that nobody had anticipated, manual flying under emergency conditions. From a piloting skill, RCM very similar aspects come into play.

Once we understand in more detail why the Lion Air and Ethopian crews could not recover, we might find it is very similar to the AF situation.

Originally Posted by Sutripta

Where one has the option, the human should be trained, trained, and trained once more so that his instinctive muscle memory is in sync with design philosophy and implementation of the rest of the system. Can't do it with drivers, but certainly can be done with pilots, I feel.

Agree. Instrument flying is the most basic of this sort of muscle memory training. Pilots are taught to trust their instruments and not their senses.

Even so, plenty of incidents and accidents where even experienced pilots fall back to instinctive behaviour. (E.g. Stall conditions at low altitude, in nearly all cases you need to get the nose down and build airspeed. Pilots have been known to pull up on the stick, even though they did have sufficient altitude left.

You could argue if the few hours Simulation time every 6 month or so, is sufficient to build and maintain the correct muscle memory.

Originally Posted by Sutripta

Not so the other.

I was more surprised about how much of the certification was left to Boeing, then theis design shortfall. Design have been wrong before. Certification is not a 100% guarantee that design shortfalls get caught either. But again it is a layer of safety.

Originally Posted by Sutripta

As I said before, it will be very interesting to see how the FAA will respond.
I feel pressure will be brought to bear on the other regulators and stakeholders (the international panel of nine) to clear the 737Max, and the FAA sweetly goes along with the consensus.

I am not so sure about that. That is what I have been trying to say all along. This whole process is now in the public eye. So the FAA will ensure that it is seen as pulling all the stops on this one. In the end the 737Max will fly again, I am in no doubts about that.

I am interested to see the full/final investigation reports of both accidents. My concern is that this whole Boeing problem is drawing away attention from other, extremely relevant factors in these accidents. Why bother looking into the maintenance / piloting skills if we know Boeing made a design error, and the FAA effectively approved it, as they effectively handed over certification to the same said Boeing? Big thing, but not the only thing that needs due attention

Jeroen