[Ford5]

Originally Posted by V.Narayan

Jeroen has explained it very lucidly. It seems to me that you are reading internet articles and taking views to be facts. Views and tastes may be preferences of some but they are not facts. The yoke has the one advantage that both pilots know at a glance what the other is doing. The side stick deprives you of the advantage {Air France AF447}. Mostly it is what you are used to. Conceptually I believe Boeings flight design philosophy is more sensible where the pilot is in command at all times i.e. the pilot and not the computer flies the plane - tragically messed up in the 737MAX. However over these 30 years since the A320 was first introduced the Airbus system of the computer flying the plane has matured to a very high degree.

Emirates has cancelled 787 Dreamliner orders in favour of A330 Neo and A350. Their existing A380 pilots or a whole host of Airbus pilots from other airlines can fit right in here, unless ofcourse the B to A training transition is funded by the Airline, which mostly they would not do owing to significant costs. Look up the Paris air show, compare Airbus to Boeing orders. Wait for December 2019 to see many 737 operators (TOT as on date, but can well go into 2020 with one more new problem discovered yesterday) cancelling their orders mostly in favour of Airbus Neos. Norwegian fired their 737 max pilots as well. Fly Dubai is in the process of evaluating A320 Neo to replace their majority 737 fleet.

The way I see the general direction, it is Airbus gaining over Boeing for the single aisle market which is the most cut throat.

Regards AF447, dazed Third pilot Bonin over rode the systems despite all the warnings and FO never noticed air speed decay all along leading to a unrecoverable stall. Both pilots drove the plane to the ocean, following which Airbus made changes involving auto thrust to avoid stall. Similar instances have happened with career Boeing pilots crashing their planes due to error in judgement.

Lack of training and wrong decision making is not a good recipe, whether A or B. Nevertheless, I never intended to let the thread go OT. May Boeing stick, oops yolk win.

[Jeroen]

Originally Posted by Ford5

Beg to differ. Emirates has cancelled 787 Dreamliner orders in favour of A330 Neo and A350. Look up the Paris air show, compare Airbus to Boeing orders. .

You are doing the same thing again. You take a few random examples and extrapolate the world from it. Actually, you don’t need to when it comes to order, backlog and forecast for Boeing and Airbus. Very detailled reports are abundant on the internet.

Eg:
https://dsm.forecastinternational.co...nd-deliveries/

This report is from April, a bit difficult what will happen with the deliveries of the Max this year of course. Prior to the second Max crash forecasted delivered aircraft for Boeing was marginally higher than Airbus. Airbus can not deliver more aircraft in the short run. So the difference we will be seeing between Boeing and Airbus deliveries this and most likely next year is the Max effect bringing down the Boeing numbers. I doubt much will change on the Airbus numbers as they can not ramp up so quickly.

Boeing had a more healthier book to bill ratio than Airbus during 2018. That is likely to change during 2019. But you can not compare anything these two giants do on just a year to year basis. Manufacturing, selling and buying these type of aircraft is a long term, strategic, affair.

Originally Boeings order intake for 2019 were likely to have been slightly higher than Airbus.

Cancelling Boeing orders for Airbus is a long term business decision. It is debatable what the exact rationale behind it is. But I am pretty sure it is not because Airbus has a side stick compared to Boeing Yoke. It is also not because of the different flight control regimes.

Make no mistake, the big carriers like to have Boeing and Airbus nicely balanced out. They would be in a very awkward position if one or the other faulted. It would become a monopoly for the remaining party and also deliveries would be a nightmare as neither one could take over the full production capacity of the other in years to come. Aviation would take a severe hit if Boeing is going to be hurt to badly over this Max affair.

Boeing’s number are commercial aircraft only. They have a fairly substantial military portfolio as well.

Jeroen

[V.Narayan]

Originally Posted by Ford5

Emirates has cancelled 787 Dreamliner orders in favour of A330 Neo and A350. Their existing A380 pilots or a whole host of Airbus pilots from other airlines can fit right in here, unless ofcourse the B to A training transition is funded by the Airline, which mostly they would not do owing to significant costs. Look up the Paris air show, compare Airbus to Boeing orders. Wait for December 2019 to see many 737 operators (TOT as on date, but can well go into 2020 with one more new problem discovered yesterday) cancelling their orders mostly in favour of Airbus Neos. Norwegian fired their 737 max pilots as well. Fly Dubai is in the process of evaluating A320 Neo to replace their majority 737 fleet.

I agree there is little point in continuing the discussion. Moreover it is off topic. You are picking up unrelated pieces of internet information and relating them to the universe. Buying aircraft from Boeing or Airbus is never decided on flight control regimes or yolk versus side stick. Nor does more or less orders in one Paris Air Show mean anything.


Unlike some of the other threads on Team BHP on the aviation threads most of us who are from the industry try and maintain a quality of these posts by bringing a deeper perspective, better explanation or more relevant data to the discussion. Let's stay with that please. Don't mean to insult or hurt you.

[itwasntme]

The 737 Max saga suddenly comes to IN shores! Please read it with a pinch of salt as there is a strong US nationalism/parochialism coupled with outrage at the $9/hour rate compared to $35 in the US.

https://www.bloomberg.com/news/artic...hour-engineers

[Sutripta]

Originally Posted by Sutripta

^^^
CNN (the link above) says microprocessor failure can cause problems. Other reports say that the FAA has determined that the processor is not powerful enough.

Any clarity anyone?

Some time has gone by from the time this made its appearance. All that had happened is that a new term, 'lag' has been added.

Apparently the processor 'lags'. (I'm using the term used in the popular press). Either of the terms 'not powerful enough' and 'lags' do not make sense in a real time system. Real time systems do not follow our conventional intuitive ideas about speed and responsiveness.
So what exactly is going on?

On another note slightly old news, but EASA has apparently laid down five areas of concern. One of them is that the autopilot does not disengage fully. We were discussing the philosophy of this very thing a few posts back!

Regards
Sutripta

[Jeroen]

Originally Posted by Sutripta

On another note slightly old news, but EASA has apparently laid down five areas of concern. One of them is that the autopilot does not disengage fully. We were discussing the philosophy of this very thing a few posts back!

New one to me. Is there a link that you could share?
Thanks Jeroen

[Sutripta]

^^^
I think it was on Bloomberg. Will try to hunt it down tonight.

Regards
Sutripta

[Sutripta]

^^^
https://www.bloomberg.com/news/artic...-can-fly-again

Boils down to whether Boeing actually (irrespective of what it calls it/ says it is) considers MCAS to be a secondary system, or something like the active flight control systems which keep designed to be inherently unstable (and thus agile) fighters in the air.
Disengaging those active controls will cause the aircraft to fall out of the sky. So have to be on/ engaged no matter what.

Regards
Sutripta

[Jeroen]

MCAS is not supposed to be doing much, in fact anything during most of the flight regime. It only assists in case of high AoA. Of course that was the theory at least. And had it not been for the problem with the AoA indicators we would have not been any wiser today.

Not sure what they mean with not being able to switch of the autopilot. More details are likely to emerge in the next days/week.

Jeroen

[V.Narayan]

Originally Posted by Sutripta

^^^
https://www.bloomberg.com/news/artic...-can-fly-again

Boils down to whether Boeing actually (irrespective of what it calls it/ says it is) considers MCAS to be a secondary system, or something like the active flight control systems which keep designed to be inherently unstable (and thus agile) fighters in the air.
Disengaging those active controls will cause the aircraft to fall out of the sky. So have to be on/ engaged no matter what.

Thank God for EASA. I have always held on this forum that EASA is the world's gold standard for aviation regulation and safety. Now they are the only really independent neutral examiner & approver of the corrections Boeing is implementing.

[Sutripta]

Originally Posted by Jeroen

Not sure what they mean with not being able to switch of the autopilot. More details are likely to emerge in the next days/week.

Guess it means that in some cases even when the pilot thought he was the sole controller, MCAS was lurking about, pulling strings.

Originally Posted by V.Narayan

Thank God for EASA. I have always held on this forum that EASA is the world's gold standard for aviation regulation and safety. Now they are the only really independent neutral examiner & approver of the corrections Boeing is implementing.

Hope some people in US don't feel slighted, and decide retaliatory action is called for.

Regards
Sutripta

[Sutripta]

Originally Posted by Jeroen

MCAS is not supposed to be doing much, in fact anything during most of the flight regime. It only assists in case of high AoA.

I have problems with 'assist'. You don't?

Of course that was the theory at least.

And what is your personal opinion now? (If possible without putting on your lawyer hat please. )

And had it not been for the problem with the AoA indicators we would have not been any wiser today.

And we come to the issue at the heart of it all - why did the importance of the MCAS, in fact the existence of the MCAS itself have to be downplayed/ kept under wraps?

Regards
Sutripta

[arijitkanrar]

Originally Posted by Sutripta

And we come to the issue at the heart of it all - why did the importance of the MCAS, in fact the existence of the MCAS itself have to be downplayed/ kept under wraps?

Because MCAS is a part of the Auto-trim system. It acts to compensate for a very specific handing characteristic of B787 MAX. It engages with the Auto-trim and disengages when the Auto-trim is disengaged. The speculation that it doesn't fully disengage is different matter altogether and will definitely be investigated by all parties concerned.

In effect its no different from the way different subsystems the Fly-by-wire systems of an Airbus aircraft operate. There are different subsystems which work together to keep an Airbus in controlled flight. During the flight the pilot doesn't need to know which subsystem is doing what to keep the aircraft in the air. If any of these subsystems don't work right, the pilot has to deal with a flight controls issue and doesn't need to know which specific subsystem failed. Similarly on the MAX if the MCAS fails, the pilot has to take action as per Auto-trim failure (or Runway Stab-trim issue to be specific). Pilots don't need to know that specifically MCAS has failed. For e.g. there won't be an item in a checklist that asks pilots to verify if MCAS has failed. The checklist will cover trim issues and how to deal with trim problems.

[A350XWB]

Originally Posted by arijitkanrar

It acts to compensate for a very specific handing characteristic of B787 MAX.

Not B787 MAX, it's B737 MAX.

Originally Posted by arijitkanrar

If any of these subsystems don't work right, the pilot has to deal with a flight controls issue and doesn't need to know which specific subsystem failed.

Wrong. In most of the error situations, the specific system where the error occurred is intimated to the pilots because the recovery action depends on this information. It helps them to go through the specific checklist and take the appropriate action. This is the same that Boeing implemented in their fix in case of AOA sensor disagreement; alert the pilots of this particular issue and avoid the kick in of MCAS in such a situation (earlier design relied on a single sensor and if it was faulty, still the MCAS kicked in thinking that there is a potential stall situation). In most cases, it's not like "I have a problem, now you take care of it". Experts, please comment.

Originally Posted by arijitkanrar

Similarly on the MAX if the MCAS fails, the pilot has to take action as per Auto-trim failure (or Runway Stab-trim issue to be specific). Pilots don't need to know that specifically MCAS has failed. For e.g. there won't be an item in a checklist that asks pilots to verify if MCAS has failed. The checklist will cover trim issues and how to deal with trim problems.

As I've told earlier, suggesting something after having multiple accidents and insights are very easy. Most of the people in the industry also agree that it's not as easy as telling to follow the Runaway stabilizer checklist. Go through this article. Quote from the article -

What about the runaway stabilizer checklist?
It was a shot in the dark, another checklist. “Runaway trim” occurs when some kind of failure causes an airplane’s horizontal stabilizer to move — or “trim” — when it shouldn’t be moving at all. Usually, this creates a constant up or downforce that the flight crew has to try to counteract for the remainder of the flight. It’s kind of like trying to drive when your wheels are out of alignment.

This was for the previous flight. The third pilot gave it a shot in the dark as mentioned in the article, that's it. On the fateful flight, they did not have a third pilot or the altitude to recover.
The MCAS implementation was also a complete goof-up as was discovered during the investigations. The actions of the MCAS was way beyond it's certification limits. Boeing's own bulletin describing the changes is a dead give away that they rushed to the roll out without sufficient testing and considering all possibilities.
Boeing's update on MCAS

The additional layers of protection include:

• Flight control system will now compare inputs from both AOA sensors. If the sensors disagree by 5.5 degrees or more with the flaps retracted, MCAS will not activate. An indicator on the flight deck display will alert the pilots.
• If MCAS is activated in non-normal conditions, it will only provide one input for each elevated AOA event. There are no known or envisioned failure conditions where MCAS will provide multiple inputs.
• MCAS can never command more stabilizer input than can be counteracted by the flight crew pulling back on the column. The pilots will continue to always have the ability to override MCAS and manually control the airplane.

Boeing Statement on AOA Disagree Alert.

[Jeroen]

Originally Posted by Sutripta

I have problems with 'assist'. You don't?

No, not particularly. Truth is many system on a modern aircraft are there to assist the pilot. Pilots are often unaware what those system are doing exactly or even when they are doing it.

Here is an example from a Boeing 747-400 manual

The control system includes an automatic speed trim function which improves the airspeed stability in certain flight phases. Typically, when the airspeed rises, the aircraft will increase pitch on its own and will climb, which in return will decrease the airspeed and thus restabilize it. Under certain conditions, however, the aircaft is not able to induce sufficient nose up momentum on its own. To compensate this problem, the speed trim function will—to a certain degree— move the stabilizer in the nose up direction when the airspeed rises. Speed trim is active when all of the following conditions are true:
+ 20 seconds have passed since liftoff.
+ Pilot is not trimming the stabilizer.
+ Autopilots are disengaged.
+ Flap lever is not set to 25 and not set to 30. + IAS is between 120 and 220 kt.
+ SRM L and hydraulic system 2 are operative; or SRM R and hydraulic system 3 are operative.

How different does that sound from MCAS really? It’s been in operations for decades “assisting” pilots during climb outs on every 747-400 out there.

There is this notion that pilots need to know every little detail that goes on, and must be able to resort to manual control at the touch of a button. Pilots are no engineers and have a functional level of understanding of some of the aircraft system.

When you disengage the auto-pilot, how much automation needs to disengage?

I don’t think anybody would like to see the hydraulic power assist on the flight controls disengage? If you disengage the autopilot, that would disengage the auto trim (but not the function described above!). But the trim function is speed specific. At higher speed less trim is required, so there is automation that controls how much trim is dialled in at the pilots (or auto-pilot) input depending on the speed. Do we leave it on, or should that be disabled too if you disengage the the auto-pilot. How much “assistance” do you take away?

Dis-engaging the auto-pilot does not disengage the auto throttle either. Two complete (set of) systems with a very complex set of interactions. And yes, I believe the auto throttle too is there to assist the pilot. If you disable the auto-throttle you still do not have full manual control over the engines either. There are still some electronic boxes involved, chief amongst them is the EEC (Electronic Engine Controls). You can disable those two, separate actions though, on the overhead panel.

Although it would be nice to think you press a button and everything would be down to manual control, in practice it does not work that and it might not even be possible or desired. What gets disengaged and what not via the auto-pilot is a carefully designed solution.

Originally Posted by Sutripta

And what is your personal opinion now? (If possible without putting on your lawyer hat please. )

Boeing got it wrong somehow. I can understand their overal initial approach to MCAS, but with what we know now, they got it wrong on multiple fronts with the actual implementation.

I still like to think that this is a case of primarily a bad design process, rather than an intentional/deliberate choice. (E.g. like the cheat devices on Diesel Engine, that was an intentional/Deliberate choice of a group of engineers and managers)

It might turn out to be wishful thinking, although we will probably never know. It appears Boeing really underestimated what the ramifications of a single sensor fault could be. It appears they never even tested such scenario’s. Neither desk simulation or real flight testing. Which is remarkable to say the least. Either, they felt it was just not worth the trouble (and they were operating within all legal constraints) or some persons took a conscious call not to go that way.

What is also interesting is to see how difficult it appears to be to recover these 737 MAX whilst nose down. Of course, these two tragic events where caused by the MCAS misbehaving, but MCAS is just some additional hardware and software on top of the existing (auto) trim systems. To put it differently, if a crew would encounter a run away stabiliser for other than MCAS problems, they might find themselves in the same situation. difficult to recover from, especially if you are low to the ground.

Originally Posted by Sutripta

And we come to the issue at the heart of it all - why did the importance of the MCAS, in fact the existence of the MCAS itself have to be downplayed/ kept under wraps?

Again, it comes down to what importance is attached to a system during the design phase. Not every system is known to pilot, not every system gets its own dedicated alarm and or check list. It almost sounds they had come up with this neat solution (quick, simple, neat) and convinced themselves it ticked all the other boxes (e.g. legal, safety and certification requirements). They just went on with it. No opposition, no real oversight.

Everybody is screaming to have AoA descrepancy alarms / MCAS alarms installed. There is no evidence that suggest, even remotely, the outcome of these two flights would have been different.

Both crews found themselves in a situation with multiple alarm warnings, stick shaker going continuously, (huge racket) and they were barreling towards the grounds. Adding another red LED into the equation is not necessarily going to get you better situational awareness and decision making. Only so much information a pilot can absorb and process.

In that respect demanding additional training, instruction and simulation is at least as relevant as another red LED.

What I have always found puzzling: We have seen quite a few fatal accidents, where pilots, for a variety of reasons, find themselves with a multitude of alarms, erroneous readings of various instruments etc. For some reason the aviation industry likes to rely on humans to make sense of it all. That’s remarkable to say the least, because humans are not that great at it. Why do we not have advanced automation assisting pilots to figure out what the heck is going on?

Jeroen