Transport Canada Official Says 737 MAX MCAS System 'Has To Go' (aerotime.aero) 130
Freshly Exhumed shares a report from AeroTime: In a growing line of whistleblowers and skeptics voicing their concerns before the expected re-certification of the Boeing 737 MAX, another rogue agent has emerged. In an email sent to regulators in the U.S., Europe and Brazil, a Transport Canada safety official called for the entire removal of the MCAS system from the 737 MAX. The official believes that the U.S. plane maker should remove the software, largely blamed for the two deadly 737 MAX 8 crashes, before the aircraft is cleared to fly again.
"The only way I see moving forward at this point is that the MCAS has to go," Jim Marko, manager of Aircraft Integration and Safety Assessment at Canada's aviation regulator -- Transport Canada -- wrote in the email, according to The New York Times, which first reported the news. In the email, sent to the U.S. Federal Aviation Administration (FAA), the European Union Aviation Safety Agency (EASA) and Brazil's National Civil Aviation Agency (ANAC) on November 19, 2019, Marko expressed his "uneasiness" about Boeing's attempts to fix the MCAS software. "Judging from the number and degree of open issues that we have, I am feeling that final decisions on acceptance will not be technically based," he was quoted as saying by Canada's National Post. "This leaves me with a level of uneasiness that I cannot sit idly by and watch it pass by..." Marko continues to say that, according to him, the only feasible option at this point is to remove the MCAS software altogether, with all the compliance issues that such move would entail, if regulators and the public were to regain confidence in the sign-off on the 737 MAX.
"The only way I see moving forward at this point is that the MCAS has to go," Jim Marko, manager of Aircraft Integration and Safety Assessment at Canada's aviation regulator -- Transport Canada -- wrote in the email, according to The New York Times, which first reported the news. In the email, sent to the U.S. Federal Aviation Administration (FAA), the European Union Aviation Safety Agency (EASA) and Brazil's National Civil Aviation Agency (ANAC) on November 19, 2019, Marko expressed his "uneasiness" about Boeing's attempts to fix the MCAS software. "Judging from the number and degree of open issues that we have, I am feeling that final decisions on acceptance will not be technically based," he was quoted as saying by Canada's National Post. "This leaves me with a level of uneasiness that I cannot sit idly by and watch it pass by..." Marko continues to say that, according to him, the only feasible option at this point is to remove the MCAS software altogether, with all the compliance issues that such move would entail, if regulators and the public were to regain confidence in the sign-off on the 737 MAX.
The problem of no MCAS (Score:5, Informative)
The system was built because the aircraft was built with larger engines than the airframe was designed for. Rather than invest the time and effort of building a new airframe from the ground up, one suited to the larger engines, Boeing cut corners all over the place in a desperate effort to compensate for the instability problems that the new engines brought with them.
However, that leaves the fact that without MCAS, the 737 MAX is inherently unstable and unsafe and therefore unsaleable and unflyable. Of course, even _with_ MCAS......
Re:The problem of no MCAS (Score:4, Insightful)
However, that leaves the fact that without MCAS, the 737 MAX is inherently unstable and unsafe and therefore unsaleable and unflyable. .
No, it’s not. It just flys differently from a 737 classic or NG, requiring different training. MCAS wasn’t about safety, it was about $money$. It was about making the MAX fly “like” the older models, so that pilots didn’t need a new type rating to fly the MAX - a fatal mistake as it turned out. And to save millions they’ve cost themselves billions. Classic management mistake. What the Canadian official is saying by “with all the compliance issues that such move would entail” is that by removing MCAS the MAX would need its own type rating. To fly it would require pilots be retrained for it, including how to handle the issue the bigger, higher and more forward engines bring. Not a bad thing.
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Actually, the "fatal mistake" in the first place wasn't having MCAS, it was in "hiding it" from differences training and implementing it poorly including no comparison of AOA sensors. This was magnified by the decision to utilize MCAS in a low speed situation and make it much more aggressive (including adjusting up to 2.5 degrees each time it activated rather than only up to 0.6 degrees) and error prone (eliminating the requirement for high G forces to activate so if the 'active' AOA sensor was giving bad d
Re:The problem of no MCAS (Score:5, Insightful)
Let's face it, the problem with MCAS was everything. Hiding it was definitely wrong. Using only one AoA sensor was extremely wrong. Making it overpower the pilot was wrong. Making the warning light optional was wrong. Making it hard to disable was wrong. And making a plane that needed it instead of designing a new airframe was wrong. There was literally no aspect of MCAS which was not wrong.
Re:The problem of no MCAS (Score:5, Insightful)
The 737 MAX didn't need MCAS to be safe and it didn't/doesn't need a "new airframe" to be safe.
The 737 MAX is perfectly safe and certifiable without MCAS. The problem MCAS addressed was that without it the 737 MAX didn't "handle" enough like the rest of the 737 family so a 737 Type rating would (probably) not have been sufficient for a pilot to fly it.
The "no MCAS" behavior of the 737 MAX exists in other planes without problems. If MCAS has been properly implemented and/or training had been done correctly, it wouldn't have presented a problem either.
Re:The problem of no MCAS (Score:4, Interesting)
Only kinda sorta. It would not be certifiable as a new aircraft, only as a grandfathered one. IIRC any modern aircraft fuselage has to withstand a 15g impact, 737 is certified for the older 10g standard.
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Only kinda sorta. It would not be certifiable as a new aircraft, only as a grandfathered one. IIRC any modern aircraft fuselage has to withstand a 15g impact, 737 is certified for the older 10g standard.
Also the fact that the position of the engines can cause the Angle of Attack to increase without pilot input would be a hindrance to certification. That's why there was a stall prevention component to MCAS. This probably wouldn't be a show stopper, but something pilots would need to be trained on.
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Only kinda sorta. It would not be certifiable as a new aircraft, only as a grandfathered one. IIRC any modern aircraft fuselage has to withstand a 15g impact, 737 is certified for the older 10g standard.
Also the fact that the position of the engines can cause the Angle of Attack to increase without pilot input would be a hindrance to certification. That's why there was a stall prevention component to MCAS. This probably wouldn't be a show stopper, but something pilots would need to be trained on.
Finally, someone who gets it! Some people parrot "unstable airframe" without understanding why, but a lot deny the truth without understanding.
Boeing wanted a quick fix to compete with Airbus. So they popped on bigger engines than regular ground clearance could handle. So they raised them a lot, providing the core problem.
So we now have an airframe that likes to stall, and not with a linear onset.
It is nothing that anyone would design into a new airplane.
Anyhow, I prefer my passenger planes to ha
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> The 737 MAX is perfectly safe and certifiable without MCAS.
> The "no MCAS" behavior of the 737 MAX exists in other planes without problems.
No, it's not. As I said in another comment: it's repeated very frequently, but that doesn't make it true. Many airliners have that behavior. Pilots know it and can deal with it, as you say.
The real reason for the existence of MCAS is something else. For certification of airlines it is a hard requirement that increasing the angle of attack requires increasing forc
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I think that would have introduced sufficient airframe changes to make them recertify the thing, which they were trying to avoid.
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The 737 MAX didn't need MCAS to be safe and it didn't/doesn't need a "new airframe" to be safe.
The 737 MAX is perfectly safe and certifiable without MCAS. The problem MCAS addressed was that without it the 737 MAX didn't "handle" enough like the rest of the 737 family so a 737 Type rating would (probably) not have been sufficient for a pilot to fly it.
The "no MCAS" behavior of the 737 MAX exists in other planes without problems. If MCAS has been properly implemented and/or training had been done correctly, it wouldn't have presented a problem either.
Explain how the 737 Max is perfectly safe and certifiable as it sits.
I'll give you a starting point - tell us about how the engine size and placement affect high rate of attack situations at low speeds.
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100% on all great points, and I'll add: allowing MCAS to make gross, rather than fine adjustments, was absolutely wrong.
I wonder if commercial pilots are generally trained on what to do if a plane starts flying itself in severely incorrect ways. Normally you'd shut off the autopilot. MCAS was hidden. Must have been sheer terror in the cockpit.
Re:The problem of no MCAS (Score:5, Interesting)
100% on all great points, and I'll add: allowing MCAS to make gross, rather than fine adjustments, was absolutely wrong.
I wonder if commercial pilots are generally trained on what to do if a plane starts flying itself in severely incorrect ways. Normally you'd shut off the autopilot. MCAS was hidden. Must have been sheer terror in the cockpit.
Pilots will just go manual and then they have a somewhat higher stress level, but they have time to figure out what is wrong. MCAS prevented that and that killed them, literally, just as loosing a major part of the control surfaces would have. The whole thing ignored fundamental principles of the design of flight control devices. This whole thing was at the very least criminally negligent homicide on mass-scale.
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Going to manual would have saved the two crashed aircraft. MCAS doesn't prevent shutting off the automatic systems. There is a cut out breaker in the center console. The problem was there was no training to recognize the MCAS behavior and the pilots didn't know why the plane was continuing to trim down. They didn't know to kill the automatic trim control.
I believe the second crash they never touched the throttles either and by the time the plane crashed, it was exceeding the maximum design speed of the plan
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I've read that they had figured out how to shut off the MCAS and managed to save the aircraft and get it flying stably again, but then they turned it back on. This time they were too low to recover and the MCAS flew them into the ground.
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From what I've read, they didn't know MCAS existed. They thought they were turning off automatic trim, which they did, and MCAS was therefore rendered unable to kill.
But that did not turn off, nor reset, MCAS, nor did they have any instrumentation or any kind of info that would have told them that MCAS went haywire.
I don't know if MCAS is the only thing doing automatic trim, or if there are other inputs, like anti-stall. Certainly autopilot is an input, but they would have disabled that at the first sign
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They thought they were turning off automatic trim
Ah, that makes sense now, I was wondering why they would have turned the damn thing back on. Since the switch doesn't actually reset the MCAS, just disconnect it, when they turned it back on it would have immediately forced the elevator back to the max setting again. Since this time they were only a few thousand feet off the deck it killed them.
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Fact is, you couldn't disable just MCAS. There wasn't an MCAS-off switch. It was indirectly: You had to switch off the electric motors for the trim wheels meaning all trim from then on was manual. The trouble is, the state of the plane being what it is (crashing) meant it requires an abnormal amount of physical manpower to turn the trim wheels, much more than normal. Turns out a heavy pilot would have to thrust in all his weight to turn the
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My reading also. The MCAS is basically a lethal trap in this situation. Of course, bad MCAS design, sensor failure, far too large trim (2.5%) by MCAS and missing information and training for the pilots all combined to kill them, but realistically nothing of these factors was the pilot's fault. That mans the design killed them and that must not happen.
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This whole thing was at the very least criminally negligent homicide on mass-scale.
So a typical decision from E-suite management that have no actual background in the industry they think they're competent to run. Short-term stock value will win out over long-term stability every time in those situations, and the public be damned. This crew just didn't manage to jump ship quick enough to cash out before the bill came due.
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Lets hope that this crew of greedy scum will see some harsh personal consequences. I do not have high hopes for that, but the screw-up was so massive that there is a chance.
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The executives probably should make sure not to book any travel to Indonesia or Ethiopia for a few years. I can't see the US gov't doing anything about it, since they let the likes of Kissinger wander around at will.
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But maybe an MCAS-like system would have saved Air France flight 447 from stalling and falling into the sea. I don't think it is inherently a terrible idea or anything. Sometimes the pilots really are wrong. Of course it wasn't really an anti-stall safety feature. That was not its purpose.
MCAS was so poorly implemented in so many ways though that I don't see how anyone could trust anything Boeing does anymore. Only a completely incompetent retard would have thought the MCAS system was fine the way it was. I
Re:The problem of no MCAS (Score:5, Insightful)
Well, depends what you mean by "MCAS-like." Flight 447's problems started when they started getting unreliable readings from the pitot tubes. That's kind of like the unreliable readings from the AOA sensors that cause MCAS to plunge into the ground.
If you mean sort of like MCAS is supposed to work, absolutely. Airbus planes have lots of computer interventions that prevent the pilots from exceeding the allowed flight envelope. These were turned off on flight 447, probably because of the malfunctioning instruments.
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Well I just meant that Flight 447 showed that the basic idea of the bitey dog to fight against the pilot (yes like Airbus) is not quite as bad an idea as it sounds at first: that an anti-stall system isn't inherently a bad thing. MCAS was just implemented terribly. Flight 447 showed that there is an upside even to having a system like that that cannot be really turned off. What if flight 447 had had an anti-stall system that the pilots could not turn off and that the plane did not automatically disengage wh
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No, it probably would have killed them. The automatics on flight 447 did what they were designed to do: when their inputs didn't make sense they disengaged and told the pilots it was up to them. The pilots couldn't save the situation either, but they did have the chance to do so.
Either today or sometime in the future you could probably make an automated flight system that's better than a pilot, even in exceptional circumstances. You could intelligently compare potentially faulty ai
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Let's face it, the problem with MCAS was everything.
Pretty much. There is apparently no major decision here that was not botched. That only happens when you have no real domain experts involved in decisions, design and implementation. And that only happens when you have sacked or otherwise silenced the real experts you had. Probably we will find a "shoot-the-messenger" culture was at work as well.
It is hard to imagine Boeing can recover from this. The experts they are missing do not grow on trees. While anybody with some skill in software security and reliab
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Where do you people keep getting the new airframe bit from? There is nothing fundamentally wrong with the 737 airframe with the new engines or otherwise. MCAS wasn't there to make the unsafe safe. It was there to avoid needed a type certification. The way it works with aircraft is that pilots have to be certified to fly a given airframe. This involves both book learning, simulator time and flight time with an instructor before they can take it solo. For a jet liner this is an expensive undertaking. Previous
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the "fatal mistake" in the first place wasn't having MCAS, it was in "hiding it"
Don't forget that the software itself is pure crap. I mean, resetting itself every couple of minutes to drive the controls further out of balance, who coded that? And what should be done to them?
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the "fatal mistake" in the first place wasn't having MCAS, it was in "hiding it"
Don't forget that the software itself is pure crap. I mean, resetting itself every couple of minutes to drive the controls further out of balance, who coded that? And what should be done to them?
Obviously, there was no actual evaluation of the behavior of this system in border conditions and the impact on the whole flight process (including pilots). Making sure this is done is management responsibility.
Re:The problem of no MCAS (Score:4, Interesting)
Hopefully that was a decision made and reviewed by a design team rather the person coding it. Hopefully we learn more eventually about how this mess happened. Seems something is quite wrong with the design/review/skill/implementation/test process here -- esp. on the second change for the "low speed" case which eliminated checking input from the G force sensor which (apparently) would have caught a seriously flawed AOA reading.
Then there was the confusion about if the "AOA Disagree" indicator was/was not enabled based on which options the plane was configured with...
Sounds likely there was a very serious management and cultural problem in this part of Boeing to me.
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The indicator is an expensive option that Boeing told the airlines was unnecessary. Understandable I guess, since they didn't tell them that the MCAS even existed, why would you buy a failure indicator for a system that you don't think you have?
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If development is highly compartmentalized and coders don't have the "big picture" and aren't given the time to understand how what they are doing fits in, I could see it. I'd hate to work in such an environment, but they exist. Esp. with the second change which is what made MCAS so aggressive (and so wrong when it was wrong).
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Especially when corporate management with no real-world experience insists on laying off experienced personnel because they're too expensive and rely on low-bid contractors (very much the situation at Boeing). Boeing is going to be another victim of the 'MBA Disease'.
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Actually, the "fatal mistake" in the first place wasn't having MCAS, it was in "hiding it" from differences training and implementing it poorly including no comparison of AOA sensors. This was magnified by the decision to utilize MCAS in a low speed situation and make it much more aggressive (including adjusting up to 2.5 degrees each time it activated rather than only up to 0.6 degrees) and error prone (eliminating the requirement for high G forces to activate so if the 'active' AOA sensor was giving bad data, there was no second input, the G force, required to activate MCAS).
On a stable airframe, MCAS would not be needed. There is a time and place for unstable airframes, such as high performance fighter jets or designs that simply won't stay in the air without constant computer corrections - also military.
But an unstable airframe should never be used on a passenger jet. They should want to stay in the air, not freak out when the engine nacelle suddenly provides lift at the worst possible time.
Re:The problem of no MCAS (Score:5, Interesting)
People have it in their head that its Boeing saying "we want to save costs, therefore we choose the cheaper approach" and make it all about profits.
It's not (entirely) about that. It's much more complicated than that.
To make a single aisle aircraft which didn't require MCAS but still brought the benefits of the larger engine (efficiency et al), Boeing would have needed to raise the undercarriage, which means a new wing and a new centre wing box, which means a new fuselage, which means .....
Basically, Boeing would have needed a clean sheet design, because the modifications they needed to make wouldn't have been covered under the grandfathering rules under the existing 737 manufacturers type certificate.
A clean sheet would have taken Boeing 10+ years to develop, and $20Billion in funding.
But such an aircraft wouldn't have been heads and shoulders above the Airbus A320NEO in terms of reduced operating costs, it would indeed have been a marginal reduction - so Boeing would have ceded the narrow body market to Airbus for an entire decade only to offer a product which was marginally better in terms of efficiencies and cost savings for the airlines, and that product would have been more expensive as well. Basically, that would have been the end of Boeings involvement in the large narrow-body aisle for the foreseeable future.
MCAS has worked for a decade on the Boeing 767 just fine, so going with it was a no-brainer for Boeings management - and if they had got the execution right, we wouldn't be having this conversation right now, the MAX would be in service and racking up the orders and deliveries. Because MCAS works when implemented correctly. Boeing failed to implement it correctly on the MAX.
So yes, considerations about costs were certainly involved, but not in the way that people like to post about - it wasn't about saving a few dollars (or a few hundred million dollars) here and there, it was about saving $15Billion and Boeings involvement in the narrow-body market.
Tangentially, MCAS also offered a way for Boeing to keep the same type certificate, which they were under pressure to do from their largest customers (Southwest et al), and it was certainly a benefit, but it wasn't the sole factor (or even main factor) in the decision making progress.
And if anyone thinks Im defending Boeing here - go check my posting history on previous MAX stories. I'm not a Boeing fan - but at the same time, theres no point in vilifying them for something which isn't the whole truth.
Just how hard to fly without MCAS? (Score:3, Informative)
So the nose pulls up a bit at full power. Might need an hour in a simulator to really get used to that. Is that really such a big deal?
I suspect that this is all about safety bureaucracy compromising safety. The new "type" requires a new pilot "certification" which is a huge bureaucratic exercise and so Boeing put in dubious fudges which then go wrong.
Was the air frame so inherently unstable that it was unflyable without MCAS? That would have been a worry. Some modern fighters are like that, but not an
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So the nose pulls up a bit at full power. Might need an hour in a simulator to really get used to that. Is that really such a big deal?...
I have flown many small aircraft. They all behave a bit differently. But it does not take long to move from one to the next.
Thank you. I've flown only a bit, but did very well, partly because I understand the mechanics, physics, aerodynamics, etc. I've commented many times that some extra thrust-induced rotation should be no big deal. Correct me if I'm wrong, but one of the top jobs while flying is maintaining level flight, (or intentional climb or descent angle), so the human would be compensating anyway. Just like driving a car- your main job is keep it between the lines (well, some people do). Road camber, ridges, alignm
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You forgot "depended on a single sensor which was prone to failure".
I consistently see pilots forget to mention this, and it baffles me that they don't understand how stupid the person designing this system was.
I also don't understand why the engineer who designed this isn't in jail.
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It’s many people’s opinion that without MCAS or a full fly by wire system, the MAX couldn’t be certified under FAA regulations as it’s considered too unstable in flight.
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I'm not a full pilot, but I don't think the MAX is unstable. It just handles a bit differently, and without MCAS, pilots need to be retrained.
Imagine driving a Miata versus a full-sized pickup truck.
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The issue is it’s unpredictability in its instability, not the fact that it’s unstable or handles differently but the fact that it can throw you very seriously with no notice in phases of flight where moments are critical.
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Citation? Do you fly them?
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So the nose pulls up a bit at full power. Might need an hour in a simulator to really get used to that. Is that really such a big deal?
Have you spent an hour in a simulator? I have. By the end of it I was pretty good at landing and taking off in a plane.
Would you let me fly you around the world?
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If you are already type certified on a 737, then yes an hour or perhaps two in a simulator to get used to the 737MAX without an MCAS is all that would be needed, and yes I would be more than happy for such a pilot to fly me around the world.
That is what the MCAS saved in terms of training. I would note that if Boeing had just scrapped the MCAS back in March the plane would very likely be flying now and you could have trained all the pilots for the new type certification for *less* money than sticking with
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Was the air frame so inherently unstable that it was unflyable without MCAS?
No. The entire problem is that it would have been unlike existing Boeing 737's. That would mean a separate certification for the pilots which is expensive and maintaining separate pools of pilots for the 737 Max and previous models which is also expensive.
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Stabilizer? You horizontal stabilizer, aka the elevator? i.e. the thing the stick controls?
It would be extremely worrying if the engines could out power the elevator. Would make it unflyable. Maybe at slow speed full power can over them.
Citations?
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Well, and airbus has no force on the yolk.
If it pitches up then the pilot will feel that in their inner ear, apart from eyes and instruments.
If it stalls without pitching up that would be frightening, but weird.
Do you have any citation or actual experience?
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To make a single aisle aircraft which didn't require MCAS but still brought the benefits of the larger engine (efficiency et al), Boeing would have needed to raise the undercarriage, which means a new wing and a new centre wing box, which means a new fuselage, which means .....
Sorry but this is false, you're only describing one of the possible alternatives. Boeing did not need to re-design the frame. This was about pilot type certification and cost alone. Bolting the bigger engine on the plane changed the handling. This put Boeing in a situation where their customers would have to recertify pilots, an expense which is normally created by buying a different type / model of aircraft. This leads automatically to one thing: customers going to tender.
The reason Boeing and Airbus use t
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The airframe of the A320 is 20 years younger, so not ancient, just old. And it was developed as a bleeding edge aircraft, unlike the 737 that was supposed to be a quick and dirty short range version of the previous Boeing jets.
And yes, Boeing desperately needs a new single aisle airframe. 737 is 1950s technology under the hood with the consequenly complicated and frequent maintenance unlike the Airbus that automatically detects potential and actual faults and can give the mechanics a printout of them.
Re:The problem of no MCAS (Score:4, Informative)
> MCAS has worked for a decade on the Boeing 767 just fine, so going with it was a no-brainer for Boeings management
That's not ture. A comparable, but different system was used on the Boeing KC-46 Tanker based off the 767, but not carrying commercial passengers like the 767. It also had dual sensors and full pilot override so that the system will disengage with stick input from the pilot.
> I'm not a Boeing fan - but at the same time, theres no point in vilifying them for something which isn't the whole truth.
With regards to the above point, I can't help but think that you're not presenting the matter truthfully either.
On your points with timescales, Boeing started the Yellowstone project (to replace legacy technologies and airframes) by the early 2000s, and was already well into planning for a 737 replacement (in the form of the Y1) by the end of that decade. The Y1 was publicly announced in 2010, but was scrapped a year after because the 737 MAX design winning out.
Boeing had ample time to plan for a A320 competitor but didn't take any action until the A320neo was publicly announced in 2010. Really, it was their own business decisions set them down this path. They should have anticipated that the newer more fuel-efficient but larger engines would need a substantial redesign of the 737 and went down that path in the mid 2000s, but instead they spent their money buying back Boeing stock and transforming their company to more resemble McDonnell Douglas (and its problematic culture) after their 1997 merger.
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Went to view the Apollo 11 exhibit at the Air and Space Museum at Boeing Field in Seattle a few weeks ago. They have 737 MAXs parked on every available piece of tarmac and even an employee parking lot. My friend in Everett says that Paine Field is much the same, and that they've started parking them in Eastern Washington as well. This thing has become the Ford Pinto of airliners and may bring the company down.
Re:The Boeing way (Score:2)
For years now Boeing and Airbus have had a different approach regarding safety.
Airbus has allways gone towards automation: fly by wire, anti stall guards, far reaching auto pilot functions.
Boeing has allways put the pilot in control...until MCAS. For me it seems ironic that Boeing is now caught in the biggest 'Computer says NO" type of accident.
My guess is that under pressure of timing and avoiding the type certfication they introduced the MCAS but didn't have the experience to pull it off reliably on such
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The "different approach" stuff was simply an excuse. Airbus has caught Boeing with their pants down in 1984, because Boeing has released two new aircraft designs just a couple of years before. Every new aircraft design Boeing has developed after the A320 release (777, 787) had fly by wire with envelope protection as well, simply because it is a good idea and does make flights safer.
That unpleasant experience - being out-innovated by Airbus - was the reason why the 787 had so many new technologies crammed in
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They didn't have the experience to pull it off because management has laid off all the experienced people in order to bring in low-bid contractors. This sort of 'penny wise/pound foolish' behavior focusing on short-term stock prices rather than long-term company stability has taken over most of the large manufacturers in the US.
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However, that leaves the fact that without MCAS, the 737 MAX is inherently unstable and unsafe and therefore unsaleable and unflyable. .
No, it’s not. It just flys differently from a 737 classic or NG, requiring different training. MCAS wasn’t about safety, it was about $money$. It was about making the MAX fly “like” the older models, so that pilots didn’t need a new type rating to fly the MAX - a fatal mistake as it turned out. And to save millions they’ve cost themselves billions. Classic management mistake.
Which part are you denying? It isn't unflyable. But it's sure as hell unstable.
You're right they wanted the plane to act like the classics. But in doing so, they had to compensate for that sudden lift from the nacelles at the worst possible time - and a tendency to stall. So we had a software driven plan plane that treated everyone to a multi dromp rollercoaster ride before it killed them.
There is just no way that a passenger jet airframe should ever be on a unstable airframe.
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It just flys differently from a 737 classic or NG, requiring different training.
And avoiding that training might be why Boeing engineered a single point of failure system. Had they put in a dual channel MCAS (monitoring both AOA sensors), there would be an 'AOA disagree' condition that pilots would have to deal with. And that means training, which Boeing was trying to avoid. However slight that training might have been.
In the final analysis, Boeing should have considered offering free training for the 737MAX differences. It would have cost them less than the current fiasco will. But I
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Is that really true? It seems like the behavior is predictable, and not that serious. Throttle up, nose goes up. What do we do when the nose goes up? Compensating can't be any harder than drifting.
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That's not really the problem. Any aircraft with the engines mounted under low-slung wings (so virtually all airliners) will pitch up when you add power. The issue MCAS was supposed to address is apparently that if you're in or near a stall in the MAX it can be extra difficult to bring the nose down. While in an NG you can probably recover just by pushing the stick forward, in the MAX you might not be able to. So software was added to help out, and make it feel like an NG. MCAS was only supposed to activate
Myth (Score:2)
Yeah, right. MCAS as important always-active stabiliser sounds like a red herring to me. Like the pilot/autopilot can't do a little trimming without some obscure safety-only software?!
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Agreed, and exactly what I've said. FAA would have required additional flight training, and Boeing feared it would hurt sales, so they bamboozled FAA with magic MCAS. It's stunning that nobody really checked it out. Maybe it's time for crowdsourcing.
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If it's that bad, then the whole design needs to be scrapped considering that the supposed solution to the problem that lead to two crashes was to disable MCAS. Which, according to you leaves the plane dangerously unstable, If so, then basically the plane is a deathtrap with or without MCAS.
I'm not saying it isn't that bad, BTW. While I doubt it actually makes the plane unflyable, apparently without MCAS, the plane does not meet FAA standards due to it's tendency to nose up and subsequently stall.
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If you ask a commercial pilot they will tell you that the Max would fly just fine without MCAS. It would just fly a bit differently than the other 737s. This is probably why the Transport Canada guy said what he did. It isn't really needed.
Personally I think if they fix the system it isn't a terrible thing to have for a bit of extra anti-stall protection even if that wasn't its original purpose. Air France flight 447 stalled and fell into the sea because the pilots acted like idiots. So I don't think anti-
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Boeing used to have an entire office park in Bellevue full of programmers, guys with 20+ years of experience in the aircraft industry. That's now empty and most of the programming is being subcontracted to whoever the lowest bidder is, some of it in India and China.
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It just means more training for the pilots so they're aware that the plane fly's different then then the old 737.
Re:The problem of no MCAS (Score:5, Informative)
Aerospace flight test engineer here, with almost 30 years' experience including 737-based aircraft. No, 737 MAX is NOT inherently unstable. Rather, it is slightly LESS stable than the FAA's minimum standards, but still stable. The amount of force that must be applied to the pitch control to maintain steady level flight is slightly reduced in certain situations, but it definitely still has positive stability, just not as much positive as before.
Note that stability is not a 1 or 0 binary choice. It's very analog. An airplane (or any system) can be very strongly stable, or weakly stable, or neutrally stable, or slightly unstable, or strongly unstable. Imagine a golf ball sitting in a bowl. A wok is weakly stable; the ball can move around a lot but will still tend to return to the middle. A shot glass is very strongly stable; the ball will always stay in the middle. The MAX design is still well in the stable regime, just less far towards strongly stable than is required by FAA minimum requirements for certification for an transport-class airplane. Imagine that golf ball in a small soup bowl (737) versus a bigger soup bowl (737 MAX).
Also note that instability is the norm for modern fighter jets. Computers keep them pointed in the right direction by constantly tweaking the control output to make the airplane *act* stable in most circumstances. But stability is the enemy of rapid maneuverability, and maneuverability is the key to winning fights. Hence, we intentionally design unstable aircraft that carefully avoid that instability when it's not needed.
Re:The problem of no MCAS (Score:4, Insightful)
The MAX design is still well in the stable regime, just less far towards strongly stable than is required by FAA minimum requirements for certification for an transport-class airplane.
Thanks for sharing on topic that has already been beaten to death hundreds of times here on Slashdot. :)
I'm curious about your comment though. So if the 737 MAX without MCAS doesn't meet the FAA minimum requirements for certification for an transport-class airplane (however small that might be), then doesn't that mean that all the airlines that have bought these planes cannot use use them?
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The whole thing comes (probably) from an irrational believe in Software as "magic" that can fix anything. The execution clearly shows that no actual software safety and reliability experts were involved in the implementation (otherwise there would _never_ have been a single sensor driving this thing), but it seems no such experts were involved _anywhere_ in the decision process either. On some level, it looks like Boeing does not know how to design aircraft anymore and is only staying in business by tricks
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It doesn't take an expert to see that depending on a single sensor that is prone to failure is fucking stupid.
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It isn't really prone to failure more than any other sensor, but yes it is still idiotic.
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IMO the AoA sensors actually are more inherently prone to failure than many (not all) other types of sensors. There is a reason there is generally more than two of them.
The other reason that they can read drastically different depending where they are mounted.
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Indeed.
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There are still "experts" in the E-suites at Boeing, just their expertise is in stock price manipulation. Welcome to the new face of American industry.
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Probably exactly right. Your comment would deserve a "+1, tragic" moderation. Love the Carlin quote!
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The system was built because the aircraft was built with larger engines than the airframe was designed for. Rather than invest the time and effort of building a new airframe from the ground up, one suited to the larger engines.
To add to that point the nacelle of the engines protrudes so far above the wings that the top of the nacelle provides lift in high angle of attack situations. The sudden intrusion of the nacelle becomes a real problem in making the aircraft have a tendency to stall.
It's an unstable airframe for this reason.
The 737 was built low to the ground to allow access to smaller airports that might only have wheel-up ramps. A lot of modifications have been done over the years to provide bigger engines, which is
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Re: The problem of no MCAS (Score:2)
unstable and unsafe and therefore unsaleable
They will get rid of the MCAS one crash at a time.
the world according to bickernomics (Score:2)
This is what socialism sounds like on the ground. Everyone runs around pointing over the fence, glibly spending other people's money, because that's so much easier to spend than your own.
———
Certifying a whole new airframe is hugely carbon intensive (hint: that's why it's so darn expensive).
If you can find a way to avoid his cost, subject to other per
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1) Training and certification. While the FAA (and other organizations) could be talked into not requiring new training and certifications with a small iteration of the same frame, a different line of airplanes would definitely require new training and certification.
2) Boeing stopped making the 757 in 2004. Boeing was actively looking to retire this model not keep making it.
3) Many airlines do not want to have another airplane model if they can help it. Especially the budget airlines like Southwest.
Re:The problem of no MCAS (Score:5, Interesting)
757 is quite old. I thought making a small 737-size version of 777 or 787 would be better. To compete with Airbus, what Boeing should do is standardize the cockpit over all of its planes to ease pilot retraining for flying all of its planes and go all fly by wire like Airbus. 777 and 787 are fly by wire like Airbus has been fly by wire since 1984. When fly by wire is done right, it is safe, reliable, prevents pilot error, time tested, reduces pilot training costs, etc.The problem with MCAS was its band aid approach and the fact that it violated the good design principles used on fly by wire systems that have been used reliably for decades.
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A shame they didn't fork the improvements of the 757 into a smaller variant at the time, though I can unders
simple fix (Score:5, Funny)
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If it's Boeing, we ain't going...
*sharp inhale*
Ooh that's .. perfect.
Boeing is culpable, anyway you look at it. (Score:5, Interesting)
One thing we hear is that MCAS as just about making Max fly like the older 737 planes, thus the difference with the MAX was just that it handled differently, not that it could stall mid air and crash. However, MCAS it is said was installed to tip the noise of the plane down if a dangerous condition was detected that could lead to a stall. Since MCAS was needed to rectify it, that means the flaw did not exist in older airplanes. So what is it? Either MCAS tips the nose down because of a near stall condition or it does not. It sounds like it does try to compensate for a flaw, doesnt it?
Also, how often did this near stall condition occur? Does it occur very often so that MCAS activation would say activate at every 100 flights, or is it a one in a million fluke sort of an event?
Regardless of above questions, Boeings reckless behaviour comes from not disclosing MCAS to the pilots, and the change that removed the ability of the pilot to kill all computer trim control, while leaving electric trim intact which would allow the pilot to correct the trim, otherwise without electric trim it can be impossible for them to do so. This is a massive scandal.
Also the use of one computer and one sensor is a huge no-no, and this has been contrary to common design for decades, A320 had redundant computers and sensors in 1984. also putting a limit on far the nose down can go is a major flaw and also a flaw is not looking at the altitude in the computer to ensure that the tip down wont run the plane into the ground. A stalled plane crashing would be less deadly than a plane ramming in at 400 mph.
Boeing corporate structure needs to be changed, 737 Max must fly, but there has to be changes, not business as usual. Say, 40% engineers, 20% floor workers, and 20% marketing and finance, 10% military, something like that. All aspects need to be represented.
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A board of directors of Say, 40% engineers, 20% floor workers, and 20% marketing and finance, 10% military, something like that. All aspects need to be represented.CEO should not be paid stock options any more, instead needs to focus on quality.
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You are joking. By the time any Engineer has slithered the way to a board job they have lost any engineering ability they might once have had.
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It sounds like it does try to compensate for a flaw, doesnt it?
Not to me. MCAS was not intended to be an anti-stall feature. It was just intended to make the aircraft nose up less in some circumstances so that it felt more like a 737. According to real pilots the tendency to nose up a bit more under thrust is not really dangerous. It is just different.
As for the rest yes MCAS was so badly designed that I have zero confidence in Boeing's ability to build safe aircraft. It really is amazing. An intelligent 10 year old could design a better system than what they came up w
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However, MCAS it is said was installed to tip the noise of the plane down if a dangerous condition was detected that could lead to a stall.
I think you're simplifying this. The "dangerous" condition was the handling problem. Think of anti-stall as the Automatic Emergency Braking features on a modern car. Shit shit shit slam on the brake. MCAS on the other hand is like the following distance control of cruise control. It doesn't trigger the emergency braking, what it does do is make minor corrections.
In that regard the "dangerous" conditions is that the plane pitches the nose up due to pilot throttle without pilot input on the yoke. Fundamental
Obligatory (Score:2)
There once was a Boeing called Max
Whose certs were incredibly lax.
When a kludge on a whim
Fed in way too much trim
'Twas death for hundreds of pax.
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That's it in a nutshell. Well done !