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Comment by Alupis | Hacker News Reader

1) The problems with the 737-MAX are fixable and will be fixed (either in a new airplane name by branding, or with time as people trust the new MAX variant again)

2) We can't discount all the revenues generated by defense spending, both by the US and abroad. That's a non-trivial amount of Boeing's income.

3) The US Gov't may not allow Boeing to fail for National Security reasons. Both as a major Defense Contractor, and as the sole producer of domestic airliners. (that is, if Boeing is even in a position to fail)

I think the 737-MAX issues are bad, but not bad enough to destroy the company. The 737 airframe has been the workhorse for decades, and I don't see that changing soon. Major airlines operating the 737 variants will just continue to use the perfectly good 737-700,800 and 900 variants until something new and fixed comes out.

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I can't believe Boeing has been able to get away with the 737-MAX. It is a unique plane with unique flight characteristics running a complex software simulation so that it "feels" like an existing plane. It's an abomination designed to sell a new plane without having to retrain pilots.

I think the fact that this has been allowed to happen is evidence of your third point. I'm not sure if the MAX plane or MAX brand is salvageable but I don't think Boeing as a company will be allowed to fail.

>It is a unique plane with unique flight characteristics running a complex software simulation so that it "feels" like an existing plane. It's an abomination designed to sell a new plane without having to retrain pilots.

Well...not to excuse the poor decisions that lead to the problems with the MAX, but this arguably isn't one of them. Military jets have been unflyable without computer assistance for decades, and it was only a matter of time before such tech made it into commercial aerospace. Though the advantages of maneuverability conferred to fighters from dynamic instability aren't useful in passenger flight, I'd argue that computerized flight controllers are sufficiently mature and battle tested that building a commercial jet which is dependent upon computer control isn't really an oversight, provided the systems are well designed and redundant.

Remember, the issue here wasn't with the flight characteristics per se, it was penny pinching administrators who removed redundancy from a critical system to save (and attempt to mark up) a couple hundred dollars per plane.

>Remember, the issue here wasn't with the flight characteristics per se,

Well, it was and it wasn't. In order to meet the stated demands of their customers (large airlines who didn't want to retrain pilots on a new type), they had to stick to the same 737 type certificate. The engines on the MAX change the centre of gravity such that the handling characteristics were too different. The regulators would not have allowed the MAX to share the type certificate with the 737NG as it was, so MCAS was born.

I'm convinced that the MAX 8 itself could have been certified as a distinct type (without MCAS, using some other system that wasn't half-baked) and we would not be having this conversation because those two crashes would not have happened.

At least as I see it, the flight characteristics led to MCAS because of penny pinchers.

The 737-Max could not pass 25.173 certification standard. This was the result of larger engines needing to be mounted farther forward due to the constraint of the 737 landing gear.

It was a desire to keep a common type rating that led to the need for MCAS to pass 25.173 because of the landing gear causing an insufficiently (though still positively) longitudinally stable aircraft, not a desire to keep the handling characteristics "similar" to the other 737s, but to keep them legal at all.

1 - https://www.law.cornell.edu/cfr/text/14/25.173

>The 737-Max could not pass 25.173 certification standard. This was the result of larger engines needing to be mounted farther forward due to the constraint of the 737 landing gear.

What I'm suggesting is that if they were to just call it say, the 797 (or whatever), then they could make the handling characteristics different from the 737 and solve the pitching moment problem in a different way that would have been safer.

Yes. They could put the larger engines under a different wing with taller landing gear and call it a 757. ;)

No need. The plane is perfectly flyable without MCAS. It just handles differently to other 737s in parts of the flight envelope.

There is a legal need (to pass 25.173 requirements). The Max doesn't have MCAS because it feels different from another 737; it has MCAS because it feels different from the legal requirement to certify any civilian transport aircraft.

> has MCAS because it feels different from the legal requirement to certify any civilian transport aircraft

Source for that claim?

I’ve read extensively on the topic and have internal Boeing sources and everything I’ve seen says MCAS was needed to maintain the type rating, not that without MCAS the plane wasn’t airworthy.

25.173.a requires the aircraft to meet this section at speeds as low as the minimum speed for steady unstalled flight.

25.173.c requires the stick force curve to have a stable and minimum slope of 1 lbf/6 knots.

At high angles of attack (low speeds), the stick force reduces slightly as compared to lower angles of attack (higher speeds). This requires a negative slope at a point on the stick force curve, violating both the minimum slope and the stable slope requirement of 25.173. (indirect source: https://www.wsj.com/articles/how-boeings-737-max-failed-1155... ). They couch it as "pushes the nose up" (though the image cited is dual sourced to Boeing and a WSJ graphics author, so I'll wager that "pushes the nose up" is WSJ content rather than Boeing content).

I've never seen the claim regarding 25.173 properly sourced.

Don't know if any of these will satisfy or not, in advance of a final NTSB/FAA/Boeing finalization/post-mortem (I doubt all the internal docs are ever going to come out, of course):

http://newsinflight.com/2019/03/29/what-causes-boeing-737max...

https://abnormaldistribution.org/index.php/2019/04/30/ieee-s...

https://www.quora.com/Does-the-fact-that-the-pilots-of-the-7...

https://seekingalpha.com/article/4286602-boeing-737-max-misc...

They could have if they'd been willing to accept a new type rating, but airlines aren't keen on retraining their 737 pilots unless they have to. Boeing's retention of the same rating was a selling point to airlines otherwise if they're having to train people anyways maybe Airbus would be worth a look?

>Military jets have been unflyable without computer assistance for decades

I think you'll find those have ejector seats fitted. I'm not sure that kind of dynamic instability will ever be worth the it for passenger jets. It's not as if they are getting into dog fights much.

Airbus controls have functioned this way since the 80s. A given stick deflection will produce the exact same amount of rotation no matter the aircraft weight or speed.

Well...not to excuse the poor decisions that lead to the problems with the MAX, but this arguably isn't one of them.

The situation of Boeing is that they've boxed themselves into a corner from an engineering and regulatory viewpoint. The plane could be made flyable with enough modifications - of course. But those modifications are supposed to meet regulatory constraints AND the FAA is facing heat for letting them get away with what they got away with.

But with enough pressure, sure, the FAA may approve WTF Boeing does to make the plane work. But then, there's a big spotlight on this stuff and there are a lot of people saying right they'll never fly an 737 MAX ever again. Sometimes bad publicity can distracted or waited out but I don't see this as possible now - the story too photogenic, Boeing can't wait years. Just as much, the world's regulatory agencies aren't necessarily deferring to the FAA any more after this.

So this looks really bad for Boeing.

> Military jets have been unflyable without computer assistance for decades

Yes, but the maneuverability demands on military jets are what caused that to be a requirement. Passenger aircraft are not generally supposed to be unstable on any axis, and don't pull a couple of Gs in any direction for dogfights (as if dogfights are still a thing).

Military jets come with a different risk tolerance from civilian airliners. I think there's a defensible position that says this kind of pitch-up behaviour is an unnecessary risk on a civilian plane, however reliable you make the computer system that compensates for it.

>> Remember, the issue here wasn't with the flight characteristics per se, it was penny pinching administrators who removed redundancy from a critical system to save (and attempt to mark up) a couple hundred dollars per plane.

This sounds good (blame it on cheapo mgmt) but really is not true. For one, the system never had redundant sensors, so they couldn't have been "removed". Secondly, the systems were designed by engineers -- with the mandate of no retraining necessary, true -- but I don't see where anybody stood up and said this is a failed/doomed system (except outsiders, after the fact). Third, "hundreds of dollars" is a total joke. The point of compatibility with previous 737s was a major selling point, worth billions of dollars in orders from airlines who liked the 737, instead of requiring them to choose between an entirely new Boeing design vs a semi-familiar (for many airlines) Airbus. It also had side effects of getting to market faster and reducing recertification and training expenses, likely totalling billions in additional savings.

Sources: https://www.theverge.com/2019/5/2/18518176/boeing-737-max-cr... https://www.seattletimes.com/business/boeing-aerospace/a-lac...

There's nothing wrong with fly-by-wire per se but it has specific engineering requirements -- including requirements for the skills of the engineers who design it -- that absolutely must be obeyed. Boeing's leadership treated it as "a little bit of software" as though it was merely an Excel macro. Safety critical software is just not in the same category as a mobile app but Boeing execs ignored the distinction.

Military jets aren't really comparable. The pilots have signed up for a job with an elevated risk of death, and they are often asked to do far riskier things like "go dogfight this MIG near the North Korean border" or whatever. The "acceptable" level of fatalities in military aviation exists, whereas in passenger flights it's basically treated as zero.

> Military jets have been unflyable without computer assistance for decades, and it was only a matter of time before such tech made it into commercial aerospace.

Er...no? The difference is that for the military jets there is an advantage, a requirement, that is helped by the plane being unstable and thus needing assistance (manoeuvrability).

For commercial airliners, there is no such requirement or advantage in normal circumstances (that is, unless you are trying to salvage an old airframe and press it into a role it is unsuited for because you are to cheap to develop the appropriate new airframe). You want a regular plane to be stable.

I was listing to the news this morning on KPR (NPR in Kansas). 70% of the 787-MAX is built in Kansas, and the news story was about the state stepping in to pay Boeing workers salaries. I've never heard of such an arraignment between industry and government. Of course with all the news about the halt of production, I have not heard the word "layoff".

> The US Gov't may not allow Boeing to fail

I agree entirely. They'll either bail them out, or just pass laws that prevent Boeing from being Sued.

The government might pass laws, but it will only fly inside the States if other countries disagree. In this one, Boeing is limited.

At one point in time the US State Department and presidential admin would've been able to negotiate, coax, or strong-arm other countries to certify things they were reluctant to. With a gutted state dept and an admin full of incompetence, this wouldn't happen nowadays...

Both China and the EU have said that they will independently recertificatify the plains.

They could force them to spin off the defense contractor part and only bail that part out, perhaps.

"1) The problems with the 737-MAX are fixable and will be fixed (either in a new airplane name by branding, or with time as people trust the new MAX variant again)"

The public doesn't trust these planes. It doesn't matter how fixable they are.

Secondly, its not a software problem, the plane is structurally deficient. A problem they tried to solve with software. These planes cannot fly without a computer adjusting them to keep the balance, something that is not true of any other major aircraft. The problem can be solved with software, but its more like a bandaid.

EDIT:

Heres a quick explanation of the plane:

The 737 engines used too much fuel so to make a more attractive plane for poorer countries, Boeing decided to install more efficient engines with bigger fans, creating the 737 MAX.

Boeing used a 737 airframe for economic reasons (it was way cheaper, didn't require pilot retraining), but needed more ground clearance for bigger engines. The 737 design cant be practically modified to have taller main landing gear. The solution was to mount to engines higher on the plane. This made the plane more unstable, so they slapped the software solution on. This "fixed" the problem, but then the plane was more complex to fly, which led to the crashes. But Boeing didn't want a plane that required retraining, so they hid the complexity of the software solutions, which led to crashes because the pilots didn't know what was going on.

>Secondly, its not a software problem, the plane is structurally deficient.

Aerospace engineer here. This is incorrect. The MAX exhibits different pitch behavior at high angles of attack than the 737NG, which would normally require a different type certificate. MCAS was their attempt to change the handling characteristics of the MAX aircraft so that it was sufficiently similar to previous iterations of the 737.

This is not the same as being "structurally deficient". The fatalities arose from a combination of ethic failures at Boeing, financial pressures from large customers, bad safety design of the MCAS system, and inadequate pilot training.

Plenty of aircraft flying today exhibit nose-up pitch tendencies at high angles of attack. This is not an intractable problem; it's just not a problem that Boeing could solve while keeping to the 737NG type.

I'm sure the pitch up tendency is worse on the MAX, but I don't believe MCAS was added to enable the re-use of the same type certificate. The handling problems were worse than anticipated as is evidenced by the low-speed activation of MCAS.

My guess is that the 737 MAX on its own wouldn't meet the handling requirements. It's been a while since the Ducommun scandal, but more recently Boeing was caught knowingly installing unsafe parts (NG/MAX slat tracks that didn't meet spec) and forging repair documentation for Air Canada. Pardon me if I take any claims that Boeing is spewing with a lump of salt.

inadequate pilot training.

It's hard to train for something that the manufacturer won't disclose or implement in the sims. It's even harder when the remedy (moving the trim wheels) is physically impossible.

>the re-use of the same type certificate.

That was the demand from the airlines; that there be no training delta. For that you need to remain within the same type, or at least close enough that they're equivalent.

>My guess is that the 737 MAX on its own wouldn't meet the handling requirements.

Correct.

>It's hard to train for something that the manufacturer won't disclose or implement in the sims. It's even harder when the remedy (moving the trim wheels) is physically impossible.

Yes. The training the pilots received on the differences between the MAX and the NG (i.e. no training) was inadequate to prepare them to fly the aircraft safely.

That was the demand from the airlines; that there be no training delta. For that you need to remain within the same type, or at least close enough that they're equivalent.

Those are two separate issues. There are currently four generations of 737 on the TC[1] and sim time is required between the different generations. Look at the 777 vs 777X, there are radical changes and yet the 777X is (for now) grandfathered on the 777 TC. A change requiring a new TC (or STC) is an order of magnitude more dramatic.

The training mandate drove the poor design of MCAS but wasn't the reason MCAS was implemented. Even with training the MAX would never have met FAA regs without something like MCAS.

The list price of the MAX is around $100 million, and Southwest wanted $1 million per aircraft if training were reqiured. If it were simply a matter of more appropriate training Boeing would've already taken the 1% haircut and moved on. American talked a good game about not wanting the MAX at all if training were required, but let's face it they'd probably rather take the training hit than wait in line for an A320 production slot. Instead Boeing shuttered the production line because the problem is simply not that easy to solve.

If it were simply a matter of stick force gradient Boeing could've likely just modified the elevator feel computer. Instead Boeing went the route of moving the whole damn stabilizer, a particularly odd choice because the stabilizer moves very slowly -- slower than a reasonable person would want to prevent an impending stall.

1: http://rgl.faa.gov/Regulatory_and_Guidance_Library/rgMakeMod...

All these arguments are about engineering.

It's no longer an engineering problem.

Now it's a trust problem.

Boeing, the FAA, and the airlines have demonstrated that they can't be trusted to make the right decision when passenger safety conflicts with quarterly earnings per share.

They'll roll the dice and hope they can fix the problem, as cheaply as possible, before the next catastrophe.

So it doesn't matter if they find an engineering fix.

The public will never trust that it's really fixed, and re-branding this dud won't fool anybody.

The sooner Boeing figures this out, the less money they'll lose.

This is why Boeing never should have been allowed to self certify. Decisions about Matters of safety should have been given to people who didn’t have to weigh it against earnings per share.

Thanks for the clarification; I don't work for the airlines so I wasn't aware of the sim time requirements.

Here's the detailed list of differences training requirements:

http://fsims.faa.gov/wdocs/fsb/b737_rev_15.pdf

> The handling problems were worse than anticipated as is evidenced by the low-speed activation of MCAS

Where the heck did you get that from? The MCAS failures were caused by a failure of the AOA sensors, not any kind of handling characteristics.

Where the heck did you get that from? The MCAS failures were caused by a failure of the AOA sensors, not any kind of handling characteristics.

MCAS was originally intended to handle high speed, high altitude situations. Flight testing found that there were handling problems at lower speeds and altitudes that MCAS could "fix". So MCAS was given roughly twice the authority it was originally designed with and it was then programmed to activate in lower speed situations as well. The FAA, of course, was kept in the dark.

If you're curious go through the Seattle Times articles.

>> The handling problems were worse than anticipated as is evidenced by the low-speed activation of MCAS.

I'd say the handling is bad enough to require something like MCAS in order to be safe. If not, they would have just disabled it and ate the cost of training pilots for the new variant. Instead they think it's better (cheaper) to try to fix MCAS while letting planes pile up that will likely require extra training on the new fix anyway.

In other words I agree. It probably doesnt fly well without help, as opposed to just flying differently.

I tend to agree with assessment. Now, the original article to which these comments apply would have strength if it had shown where the putive losses are hidden. Still there appears to broad parallels between ethical lapses and claims that Boeing cares more about financial engineering than customer safety at the top.

"This is not the same as being "structurally deficient". The fatalities arose from a combination of ethic failures at Boeing, financial pressures from large customers, bad safety design of the MCAS system, and inadequate pilot training."

Boeing used a 737 airframe for economic reasons (it wwas way cheaper, didnt require pilot retraining), but needed more ground clearance for bigger engines. The 737 design cant be practically modified to have taller main landing gear. The solution was to mount to engines higher on the plane. This made the plane more unstable, so they slapped the software solution on. This "fixed" the problem, but then the plane was more complex to fly, which led to the crashes. But Boeing didn't want a plane that required retraining, so they hid the complexity of the software solutions, which led to crashes because the pilots didn't know what was going on.

Sure you can say the plane was structurally fine, but this is semantics, they created a plane that was unstable because it was cheaper.

>Sure you can say the plane was structurally fine, but this is semantics, they created a plane that was unstable because it was cheaper.

In the aerospace industry, semantics matter. "Structurally deficient" implies that the aircraft structure itself (i.e. the spars, ribs, load-bearing skin, etc.) is unsafe. This is not accurate, and neither is it accurate to say the MAX is "unstable". These are terms of art with precise engineering meanings.

Precision in language matters, and to dismiss it as "semantics" pre-empts any meaningful discussion of the issue at hand. It's like saying float vs char is "semantics". Those differences matter.

Yes it is accurate. The plane crashed twice. They put engines on top of the plane that weren't made for the body.

It did crash twice, but not because it is structurally unsound. And not because it is unstable.

edit: Also, when you say the engines were put "on top of the plane" it makes me question if you've ever actually seen a MAX 8.

You should stop posting about issues that you are completely clueless about. I'd point out where you're wrong, but in short: everything.

Well, the plane did crash twice. Everything else seems wrong though.

It really annoys me when people just dismiss a point with the phrase "this is semantics". Semantics is meaning! You're ignoring the meaning of what you responded to. If you don't think the point was valid, you should give a reason.

Yeah. If anything the phrase should be more like "syntactics". Semantics is anything but semantics.

When someone says “it’s just semantics”, they mean that the argument is only over the definition of words, not over that actual meaning.

That may be what they think they mean, but I can't recall an instance where that was accurate, including here.

Apart from that, I don't have to like people saying "it's just semantics" if they mean the exact opposite.

No I'm not, the plane is flawed. Boeing created a flawed plane to cut costs. Then they slapped software on it and called it fixed. Sure because it can fly you could call it "structurally sound", but its not. The plane is a pile of trash

I'm not saying you're wrong, just that it's irritating that you aren't supporting your opinion. You just state your opinion and follow it with something dismissive. Twice now.

Interpreting your comments in the most charitable way, you must have reasons for your opinions that convince you, so it would contribute more to the discussion if you explained why.

Nobody rejects "semantics".

Oh so sweet this history revisionism.

“ The 737 engines used too much fuel so to make a more attractive plane for poorer countries ...“

It was AMERICAN Airlines and Southwest (of yes the USA) who pushed Boeing into creating the Max, not “poorer countries” (unless you count the US among those)

Yes this is more accurate—Southwest in particular is a huge 737 customer, and they wanted to be add longer legs with minimal changes (same ground crew, berthing and piloting). The versatility of crew is a key part of their business model.

> These planes cannot fly without a computer adjusting them to keep the balance, something that is not true of any other major aircraft.

I think you mean any other major civilian aircraft. No recent major combat aircraft can fly at all without significant computational assistance.

This does not excuse the 737-Max shitshow in the slightest...if anything it makes it worse.

Airbus is definitely a civilian manufacturer and all their aircraft are strictly fly-by-wire. But as far as I know they are at least dynamically stable, unlike many combat aircraft and the 737 Max.

Update after reading na85's comment: The 737 Max is dynamically stable.

Also apparently a few Airbus models are not FbW.

> Also apparently a few Airbus models are not FbW

Only the legacy ones before the A320, namely the A300 and A310. Not really relevant nowadays.

> any other major civilian aircraft

Aside from Airbus? Isn't basically every Airbus in the sky at this point flown by a computer with the pilots making requests for what they'd like it to do? This has long been a fundamental ideological difference between Boeing and Airbus, with Boeing just now starting to get into the same game Airbus has been doing for a while.

I think only the A300 and the A310 are not fly-by-wire.

Don't forget Boeing's own 777 and 787, both are fly-by-wire also.

Stretching my knowledge about those planes a bit, so it'll probably show, but I think the distinction I'm going for is not how the controls are activated (hydraulic vs electrical), but what role computers play in day-to-day flying. Boeing has long held that pilots are in charge, and as a result Boeing planes are pretty manual without a great deal of automation. Airbus has a differing philosophy, where the computer is fundamentally in control of the plane, and the pilots manipulating the controls are asking the computer to do something for them -- it decides if that request is valid for the flight mode and then acts to make it happen. One of the most well-known relatively recent failures of the Airbus system was the Air France flight, and IIRC a main cause was the computer switching to a mostly manual flight mode (due to a sensor failure) and the resulting change in how the flight controls work confused the copilot to the point that he stalled the plane.

In any case, that's what I was trying to get at. The game Boeing is playing with MCAS is a step in the direction that Airbus has a lot more experience with.

> One of the most well-known relatively recent failures of the Airbus system was the Air France flight, and IIRC a main cause was the computer switching to a mostly manual flight mode (due to a sensor failure) and the resulting change in how the flight controls work confused the copilot to the point that he stalled the plane.

That's a rather misleading take, given by people pushing a certain agenda. The first officer in question was hauling the stick back as far as it would go. This resulted in the plane stalling. That's not a matter of confusing flight modes or computer behaviour - pretty much any aeroplane will stall if you pull the stick back all the way (and what else would you expect to happen?)

> That's not a matter of confusing flight modes or computer behaviour - pretty much any aeroplane will stall if you pull the stick back all the way (and what else would you expect to happen?)

As far as I know, on the normal flight mode (normal law) the computer behavior of an Airbus is that it will not stall if you pull the stick back all the way - it will go as far as it can before stalling, and no more. But that depends on the sensors which had failed, so the computer had to switch to a mode which didn't have that protection.

I think the confusion came from the fact that the captain didn’t get haptic feedback from the joystick that the first officer was pulling it in the opposite direction, plus a lack of communication between the two, or was that a different crash?

> These planes cannot fly without a computer adjusting them to keep the balance, something that is not true of any other major aircraft. The problem can be solved with software, but its more like a bandaid.

Why is it wrong to rely on software?

I'm not sure I understand the issues you're talking about but many military aicraft are deliberately built to be dynamically unstable and need constant software control to fly.

>I'm not sure I understand the issues you're talking about but many military aicraft are deliberately built to be dynamically unstable and need constant software control to fly.

Some specific fighter variants are built this way, yes. But the risk tolerance for a single-seat fighter aircraft that has to fly combat sorties is very different than for a civilian airliner with hundreds of people onboard.

> many military aicraft are deliberately built to be dynamically unstable and need constant software control to fly.

Yes. It's also well understood that combat pilots accept the possibility of death when they sign up for military service. That's not the risk tolerance that is accepted for passenger travel.

Read my update, this was a criminal action taken to cut costs

Because people died and will continue to die unless the airframe/engine configuration , which they knew was faulty, is changed to not be garbage.

It is crazy to accept a flawed design when people's lives are at stake. A plane isnt a movie or a song. You cant just fix stuff in post. Do it right the first time.

> These planes cannot fly without a computer adjusting them to keep the balance...

First I have heard of this issue, though I haven't been following it closely. Citation, please?

https://theaircurrent.com/aviation-safety/what-is-the-boeing...

http://www.boeing.com/commercial/737max/737-max-software-upd...

https://www.youtube.com/watch?v=H2tuKiiznsY

Look up MCAS.

Yeah, I know about MCAS, and nothing I have found suggests the airplane is inherently unstable.

In fact, a cursory search shows the opposite.

https://news.ycombinator.com/item?id=19556707

If you haven't been following closely, then do a modicum of your own research first before you ask for citations.

The MCAS is exactly the cause of the issues and was the software that caused the crashes because it behaved unexpectedly to the pilots. The whole reason why Boeing leaned on software was because their sales pitch was that this new plane was essentially the same as a 737 so it didn't need any extra training. But this was false. They needed this MCAS because the mechanics of flying the plane were vastly different, I think because of the location of the engines, etc. That's the whole issue, where Boeing lied to the FAA and sold the 737MAX as a drop-in replacement for the 737 when it really wasn't. So if you don't even know this then you need to start from scratch and do your own research.

> the mechanics of flying the plane were vastly different

I suggest you need to continue doing your own research on when MCAS comes into play and why. Especially if you're going to condescend to others.

Everything you wrote it true, but doesn't support the statement:

> These planes cannot fly without a computer adjusting them to keep the balance.

I haven't seen anything suggesting that. If MCAS was completely ripped out of the computers, these planes still can be flown, right? The pilots would need to be trained on the differing characteristics, but it isn't inherently unstable like some military jets are.

The planes would still physically fly without MCAS. (They are not unstable.)

The planes could not legally fly without MCAS, because they fail a required stick force linearity certification requirement. (FAR 25.173)

I dont have time to find all the sources for this. But basically Boeing tried to make a flawed plane because it was cheaper and they could fly more people around on less fuel. The plane was also designed for runways in third world countries. Then they hired 8$ an hour software engineers to patch up the issues that they knew about (which ended up taking down the plane anyways).

Not all the sources. Just one, reasonably well documented source.

From what I understand, MCAS functions to emulate the similar flight experience of prior 737 aircraft to minimize pilot retraining..l

I think that there are two issues. MCAS was needed because the airplane wouldn't meet FAA rules without it. Fixes for things like that are not necessarily bad. Problem comes from two issues. Not wanting to require retraining meant they tried to bury the MCAS's existence to the point of not having a way to disable it and only it. And second the flight envelope problems were worse than originally expected. So they gave MCAS more control authority.

They ended up with a problem where bad inputs to the MCAS system could only be countered by disabling the electric trim motors. Once you did that the only way to fix the trim was via a manual wheel which didn't have enough mechanical advantage when the elevators were loaded. That itself was a festering problem carried forward from the original design.

>We can't discount all the revenues generated by defense spending, both by the US and abroad. That's a non-trivial amount of Boeing's income.

It's 30 percent of Boeing's income. Definitely not enough to prop them up.

The US Government needing you is always enough to prop you up.

It's enough to keep the company alive, but even the most hawkish US politicians aren't going to throw enough federal cash at Boeing to keep them running in anything resembling their current scale and capabilities if they go under.

Trump just spent $28 billion bailing out farmers for losses that he initiated: https://www.bloomberg.com/news/articles/2019-12-04/trump-s-2... That's more than the $25 billion bailout of GM and Chrysler by President Bush that so many Republicans railed against. Plus, the farming bailout won't be repaid, while the automaker bailout was repaid in full.

Times have changed.

Iunno, even in the financial crisis, the feds didn't even feel it was necessary to wipe out equity shareholders when they went to bailout.

The feds could always rewrite regs to help Boeing, like limiting the grandfathering that allows airlines to fly aircraft that don't meet current safety regulations.

The Fed's didn't wipeout equity shareholders during the financial crisis because big investors were leveraged. The whole point of the bailout was to prevent losses on leveraged assets from rippling through the financial system and collapsing the whole thing.

More leverage should equal more risk. You shouldn't be saved just because you took too much risk. That's how it's supposed to work!

Sure, unless the entire system is at risk of crumbling, then one may not want to cut off their nose to spite their face.

It wasn't just that everybody was leveraged, but the structure of that leverage, the short time periods of rolling over the debts and loans that would result in an extremely rapid negative feedback loop, various accounting rules insensitive to what was necessary for the system to unleverage, etc.

My understanding was that Boeing were originally planning to do a clean redesign of the 737 (similar to the 787), but due to customers going with the A320neo, they rushed out the 737 MAX instead. So that last point about 737-700/800/900 may not be valid.

> but not bad enough to destroy the company.

Not very much, including the impending launch disaster tomorrow, would destroy Boeing. The us can't let it fail, it's too big.

> including the impending launch disaster tomorrow

I think you mean tonight, and why do you think it will be a disaster?

https://www.nextspaceflight.com/launches/details/170

Because I can see the future? ;)

Foresight is 20/20. See my comment that is a child of (https://news.ycombinator.com/item?id=21703179)

It was obvious that this was going to happen. NASA was giving a pass to Boeing on a lot of things,there was lots of organizational pressure to not screw it up, and it failed its previous test due to careless error.

Sadly the put order I placed did not execute because I don't know how to effectively trade in illiquid markets yet.

You'd have done well on that one. That's why I asked how you knew, it was a pretty bold prediction and to see it come true like that is quite a thing. Pity you didn't answer sooner!

Haha it's not the first time I've made s spectacular long prediction. I correctly predicted Sarah Palin being the us vice presidential candidate a full six months before it happened.

That was so totally, terribly bad for McCain that I thought he would never ever go for it. You really should put some money on these, looks like you're going to be well off. OTOH of course then you'll score a long string of 0's....

I don't really know how to find these information markets. Sometimes the predictions I make aren't really tradeable, like that time I told my coworker that the house he bought would be beneath a volcano in 15 years (that one came true last year). I also correctly predicted a few startup-relevant things like that theranos was nonsense (prediction circa 2011) and that sriraj raval was kind of a snake.

I've also made some duds like predicting that catalunya would successfully secede.

>either in a new airplane name by branding

That's some magical thinking right there. Very few people are going to get on one of these planes as long as the bad design is papered over with a software fix.

I think you overestimate how many people know what type of aircraft they're flying, or will care a year from now.

Additionally, I would be happy to put my family or my own backside into a Max8 flown by a Southwest, American, or United crew.

My objection to flying on an American or United Max8 is the American or United part, not the Max8.

Can they fix the damage to their perception? No one I personally know will ever step on a 737-MAX plane.

They already renamed it

to anyone else wondering: they are now calling it 737-8200 apparently [1]

[1] https://www.bbc.com/news/business-48995509

> Major airlines operating the 737 variants will just continue to use the perfectly good 737-700,800 and 900 variants until something new and fixed comes out.

I think airlines love the situation. The balance between supply and demand for new aircraft has taken a hit. That means any glut in capacity has been erased and pricing power has gone up a lot.

Airlines had an excuse to cancel flights and put you on a different schedule, all while claiming force majeure.

While the 737 variants are fine, they have a shorter range than the MAX. The MAX can do some interesting transatlantic routes (UK,FR,ES,PT) and east coast US/Canada that are dicey in a non-MAX.

This makes no sense. Airlines hate canceling flights: they already maximize the hell out of their fleet utilization, so there's very little space capacity in the system and the knock-on effects of having to find new seats for 100+ pax per cancelled flight are massive. Pricing power has indeed gone up, but not in the airlines' favor: for example, Airbus can now charge what it wants for the A320 (the only viable 737 competitor) and wages for qualified A320 pilots are skyrocketing.

Yes, the situation is even better for $Manufacturer where $Manufacturer != Boeing.

But airlines aren't suddenly cancelling flights. They're looking at their schedule and consolidating whatever they can. And charging more for the remaining seats.

And the value of the aircraft they already own just went up.

I've also seen some airlines downgauge turbojets to Q400s, which is slower but saves a ton on fuel.

Routes that needed to run X times per day to be competitive (because people want flexibility in departure and return times) can now be consolidated into X minus Y flights with the same number of passengers.

It's 2019, airlines have automated processes to rebook when a flight is cancelled.

And upstart airlines trying to build their fleets couldn't.

Still not buying it. The value of the Maxes they own sitting on the tarmac has plummeted and all the capital they consumed now has a big fat zero ROI (negative, really, because they still need maintenance and interest payments). If airline X has to reduce flights because they can't fly them, and airline Y doesn't, those flexibility-demanding, well-paying business pax will migrate to Y, and it's Y who will reap the most gains from the sudden reduction in competition.

And automated rebooking is a fantasy. Sure, the airline will try to default you onto some other connection, but I've always ended up talking to a human afterwards and picking out a better alternative.

> 1) The problems with the 737-MAX are fixable and will be fixed (either in a new airplane name by branding, or with time as people trust the new MAX variant again)

What's your confidence level that, in let's say 6 months, 737-MAX flies again in the US and the EU?

(Feel free to answer with another time frame that makes more sense for you).

> We can't discount all the revenues generated by defense spending, both by the US and abroad. That's a non-trivial amount of Boeing's income.

Boeing still needs to pay an extremely hefty WTO penalty for that because it's considered state subsidizing. Bad idea to consider it a plus, in terms of accounting.

2) We can't discount all the revenues generated by defense spending, both by the US and abroad. That's a non-trivial amount of Boeing's income.

Sure you can. McDonnell Douglas was a failed commercial airplane manufacturer propped up by their military sales. Look where that got them.

It got them bought by Boeing, whom the US federal government could rely on to take over production and support for McDonnell Douglas aircraft (several hundred of which are still in service today and will be for years to come.)

But who could take over for Boeing? Lockheed Martin is the only plausible answer, but is that what anybody wants? Together Lockheed and Boeing would be something like 4x as large as the second largest contractor for the federal government, so that's not great. And would Lockheed Martin even want that? Right now Lockheed Martin provides support for 50-some C-5's, but with the addition of Boeing they'd have to take on support for hundreds military aircraft derived from Boeing's commercial models. Particularly, all of the Air Force's hundreds of tankers for aerial refueling are made by Boeing (or McDonnnell Douglas), derived from commercial airliners with hundreds more on order. Would Lockheed get back into the commercial airliner business (which they left in the 80s)? If not, then what would the economics of Lockheed manufacturing and supporting hundreds of airliner-derived military jets look like?

The problems with the 737-MAX are inherent in the airframe design. It is unstable and it needs software to correct the instability. The 737-MAX is the only version of the 737 series with this issue. It is not the same "airframe" as all of the other 737 aircraft.

> It is unstable and it needs software to correct the instability.

Can you be more specific about the nature of the instability? Is it lateral, longitudinal or directional stability that is at issue?

The issue at hand is longitudinal stability, specifically a positive but insufficient amount of it at high angles of attack.

People who run around parroting that the Max8 is "unstable" are telling you more about their level of knowledge of aerodynamics than facts about the Max8 airplane.

the technical problems? of course. the cultural problems that caused the problem in the first place?

Do you have a citation on #1? If it's not the case, then there could be massive financial impact to Boeing...

What kind of citation would you need? It's a software and sensor reporting problem in the rushed-to-market new MCAS system - both fixable obviously.

That doesn't seem like it's asking enough whys to me. Why was the MCAS system necessary? Why didn't the sensor fall back to its backups?

There are underlying hardware concerns, from the wings to the sensors themselves, that may require retrofits. MCAS can be patched, but I'm not convinced that a patched MCAS can fully address the hardware concerns.

> Why didn't the sensor fall back to its backups?

MCAS was added to the autopilot/flight computer system, which was brought forward from previous 737 designs, where there are two flight computers, each with an independent set of sensors; in case of disagreement, between the flight computers, autopilot would disengage and return control to the pilot. And in general, the types of things a pilot would do in response to commanded nose down would disable the autopilot until manually engaged again.

Unfortunately, MCAS acts autonomously, was not disclosed to pilots, and was not able to be disabled without also disabling electric trim control. Because it was built on top of the existing flight computer, which is safe enough, the behavior doesn't appear to have been separately considered.

From what I've read of the proposed fixes in news stories, it doesn't really address the root issue in my mind that the pilots should be able to turn off MCAS; although it does seem likely that it would activate erroneously less often, and that the plane will remain more controllable in the event that it does activate erroneously, it still seems like the situation would be dangerous in case it arises; which would seem possible if both Angle of Attack sensors failed in the same way at the same time. A third AoA sensor might help detect broken sensors, and make it less likely that all three would return the same wrong value simultaneously, but a switch to turn off MCAS would follow the Boeing philosophy of giving pilots control and letting them handle rare events.

Part of the MAX complexity was keeping MAX handling sufficiently similar to legacy 737s that you wouldn’t need new Certs for pilots.

Boeing will have a lot more freedom if it can do away with that.

But I don’t know if they can do that without bringing up the MAX to modern standards. The 737 is an old design.

But I largely disagree with grandfathering new planes because they’re built to an old design.

We don’t allow it for cars, why would we for aircraft?

My understanding is that the second sensor was listed as optional and not required. Therefore airlines decided to not select the option to save costs.

This is not the airlines fault. The second sensor should not have been optional if failure of the first sensor might lead to catastrophic failure.

Why didn't the sensor fall back to its backups? Because, unfathomably, it was designed to only listen to one sensor. Why? Absolutely no good reason that anyone can see. Can that be fixed? Absolutely, change the code to listen to both sensors. It's not a whole lot more complicated than that.

And if one of two sensors fails, which these exposed sensors do often, how do you know which one it is?

Intuition says you need three.

If one of two sensors fails, and the computer sees that, it knows not to fight the pilot, which was the problem, wasn't it?

That's fine, but seems self defeating. Now the pilot needs training to fly without MCAS, so why have it at all?

Your question applies to all systems that can fail, so the implication must be wrong.

You either make sure it doesn't fail, or you can continue flight without it. Either way, it has to be fail safe.

There is a backup to extend the landing gear if the primary hydraulic system fails, the plane can fly with one engine out, we make sure that even if an engine explodes it does not damage the air-plane, etc.

On the latter point, you can continue flying without autopilot or landing-assenting electronics and pilots are trained to do so.

MCAS has failed on all counts, it has been very unreliable and fail-deadly.

The system should have a number of alternatives. The first would be to consult the gyro system.

Change the code to listen to both sensors? And which one should it use as truth when they disagree?

It‘s a hardware problem because the plane is instable. The MCAS was the fix but didn‘t work. We will See...

In what manner is the plane unstable?

>It's a software and sensor reporting problem in the rushed-to-market new MCAS system - both fixable obviously.

Its a lot more than that...planes crashed and people died.

It doesn't matter if you fix the underlying problems, there will be a giant loss of confidence in the company and the product. That is all rightfully so, the company put profits in front of safety, and there is no reason to believe that will be fixed.

It might shock you, but this is far from the first time an airliner crashed due to fixable problems.

Time heals all wounds, so to speak. Boeing suffered a pretty bad PR problem, which then drove cancelled orders and more. It will take time to earn that trust back with the 737-MAX, however there's still plenty of 767, 787, some 747, and a few 757's still flying without any problems.

>It might shock you, but this is far from the first time an airliner crashed due to fixable problems.

It may shock you that pilot error is the leading cause of airline crashes.

Nevertheless, to your point these crashes occurred due to "fixable problems" sure...and anytime a plane crashes due to "fisable problems" legally it goes without saying there was negligence. But what seems to be ignored here is there was more than negligence...based on the documents already made publicly available the company knowingly shipped the planes with the issue.

>Time heals all wounds, so to speak.

Well I'm sure that was what the managers thought when they minimized the engineers concerns about these aircraft...then again you don't see very many Zeppelins flying around nowadays.

Is the 737-MAX fixable? Boeing is stopping production of them, so they know that it's not going to be for a while, if ever.

The 737-MAX's problem is that they changed the center of gravity of the plane so that it's not stable without an active system to correct that (MCAS). A failure in that system has already crashed 2 planes and killed hundreds. I don't think you can throw an active system on an inherently unstable airframe and call it a fix. Airplanes need to be as fail-safe as possible.

They are suspending production of them to avoid various issues:

1. Cash flow issues, since they have hundreds sitting around they haven't been paid for yet. 2. Storage issues, since they have hundreds sitting around. 3. To make it clear to the FAA that there's a limit to how long re-certification can take without larger economic impacts.

I would fully expect that with Boeing and the Airlines' pressure on the FAA, and the FAA's current schedule, the aircraft should be re-certified in January. It could slip again, with another issue or a government shutdown, but those are not that likely.

> 3. To make it clear to the FAA that there's a limit to how long re-certification can take without larger economic impacts.

Good to know they've got their priorities straight. Would hate to see the U.S. economy lose any jobs building unsafe aircraft.

How many people does hurting the US economy kill? What about raising ticket prices, making more people drive instead of fly?

There is a trade-off to be made here, and it's not just between money and lives - it's also between the certainty of a small number of deaths and the chance of a large number of the same.

One of the issues with the system was that pilots didn't know about the system. It is possible to add an override and train pilots accordingly. The question is what kind of requirements the relevant authorities put on it and when they are willing to sign the papers. After two fatal crashes this isn't a rubber stamp but solvable.

> It is possible to add an override and train pilots accordingly.

This was always possible. The reason Boeing didn't do it in the first place is because it would have required full retraining of all pilots.. the promise of the 737-MAX, at least from an airline perspective, is that you can take all your existing 737 pilots and put them through a much shorter cross-training program and immediately have highly qualified staff operating these planes in your fleet.

Without this, the 737-MAX will have to be operated as any other entirely new aircraft. Boeing's mistake here really is manifold.

> Without this, the 737-MAX will have to be operated as any other entirely new aircraft.

Whatever they do - scrap it an build a new model (be it derived from 737 pre-MAX or something else) or "fixing" 737-MAX there will be lots of eyes on it and request for training. I don't think the argument is relevant. They are too deep in the sh*t.

While this is true (the MCAS being at fault), it was compounded by incorrect and/or absent reporting of what the MCAS system was doing. One of the indicators was tied to an optional set of features on accident (spaghetti code?), which caused budget airlines that didn't purchase the optional features to not show pilots when there was a problem with MCAS.

That coupled with lack of training of how to react to exactly that scenario, and we have the events that transpired.

All of which is fixable one way or another.

If it’s fixable, why isn’t it fixed? Why are they stopping production? It’s been a year.

Once the second crash happened there was extra oversight and other issues that were signed off on during the design phase were once again put in question. Its no longer just MCAS being modified but what happens when the two flight computers disagree.

So to answer your question there are now multiple issues at play and they are effectively redesigning the flight computer system as a whole. This is not a quick fix.

Because rushing a fix into production and then having another airline crash would be far more severe than the current situation.

So it makes sense to step back, and fix things the right way before you reintroduce the system back into the market.

You can fix the issues that have been found in the MCAS, sure. You can do more training, rewrite the code, introduce more tests/checks, etc...

But what you cannot do is change the fact that the MCAS is necessary. The plane is always and forever going to be off-balanced and require an active system to account for that. Active systems will fail. Maybe they can fix it such that the failure rate is negligible, but I doubt it.

All Airbus airliners (the only other serious airline manufacturer in the world) are fully fly-by-wire and require computers and sensors to even get off the ground, let alone maintain level flight.

Unstable flight profiles are not foreign in aircraft, and requiring computer systems to maintain stable flight is nothing new.

The problem is entirely how this specific system was implemented... and that can be fixed.

The fact that Airbus are fly by wire doesn't mean they are "unstable".

They might be, but fly by wire does not imply that.

For the record, I don't believe Airbus plans are unstable in the way the MAX is, whose instability, from what I understand, came about because they were trying to fit larger engines on the original 737 frame (to prevent pilot retraining), and so had to move the wings higher.

In some avionics podcast A380 pilots described that that huge beast is a quite good glider. This makes sense since you want to reduce fuel usage and just enjoy smooth sailing.

Something like an F-16 however is less stable and requires constant adjustment of flaps etc. there dynamic properties of air to air dogfight are more important.

I'm not saying unstable planes cannot be built, just that I don't trust a company that's already had 2 planes go down to get it right.

A quick google search seemed to imply most unstable airframes were military or experimental, not commercial. Unstable airframes are not appropriate for commercial airliners unless you can point to a good reason. "We don't want to train pilots" is a bad reason. The FAA should have pushed back very hard on this point.

Personally I think the flaws in the 737-MAX design process were so deep that it would be safest to just scrap the plane. It's not that the issues cannot be fixed, but rather that we'd be better off starting over from scratch knowing that good design principles will be followed the whole time.

It is not "unstable" in that sense.

At high thrust, slow speed, high aoa it is a little too close to neutrally statically stable.

C f. to airliners that can break up from dynamic yaw instability if the yaw dampers fail in some flight regimes.

Thanks for explaining! I suppose I've been using "unstable" a bit too liberally in this thread.

Airbus planes don't fall out of the sky when air speed sensor fails.

Air France Flight 447 crashed with all souls on board lost when the air speed sensors on the Airbus A330 failed.

https://en.wikipedia.org/wiki/Air_France_Flight_447

Have you read about accident you linked?

"It highlighted the role of the co-pilot in stalling the aircraft while the flight computer was under alternate law at high altitude. This "simple but persistent" human error was given as the most direct cause of this accident"

I don't know why you are being downvoted, because you are right. While software and sensors to account for unstable airframes is not uncommon in aviation, before the 737 MAX, there has never been a civilian passenger plane with such a dynamically unstable frame requiring real-time correction via software and sensor data. In civilian aircraft, unstable frames like what we saw in the 737 MAX were not a thing. And honestly, I don't want them to become a thing either.

I also acknowledge that the specific terms I use in this comment might not be 100% down to the letter terms used in the aviation industry (such as unstable frame). The point being made here is corners were cut, Boeing is 100% to blame for the situation they find themselves in with the 737 MAX.

In avionics, fighter jets are unstable requiring computers and algorithms to keep them flying. This is in part to the speed of which they travel, the [Dassault Rafale](https://en.m.wikipedia.org/wiki/Dassault_Rafale) has multiple levels of redundancy to correct negative flight conditions (it has three computers I believe).

Even with the fixes, the plane is still going to be unstable. However, fortunately, unstable planes like passenger jets which move slower can still be manually flown (unlike fighter jets moving at Mach 1). But, I am definitely not going to fly on a 737 MAX if I can avoid it, not until it has proven itself in service for 10 years. I wouldn't say fixing an engineering problem with the software and additional sensors inspires confidence.

Dynamically unstable airframes should not be a thing in passenger jets. The only reason the 737 MAX is unstable is that they put bigger engines on a 737 and moved them up because of how low the 737 sits on the ground, thus disrupting the centre of gravity and requiring pitch correction when at full thrust.

The Airbus A320 has no such issues with its design. It can safely glide during total engine loss for quite a long distance. Could the 737 MAX claim the same thing?

At full thrust the nose would point too far upward with the new design, potentially causing a stall. MCAS automatically pushed the nose down if the nose was detected to be pointing too far up. Pilots received a two-hour training course on an iPad before being allowed to fly on the 737 MAX, they didn't even highlight the new MCAS system. The training material didn't even mention the new MCAS software...

The worrying thing about this entire situation is the MCAS system relied on a single AOA (Angle of Attack) sensor and overreacted and took control of the plane. Given planes are known for their levels of redundancy, a single sensor and some overzealous software coupled with other mistakes resulted in hundreds of lives lost. Pilots were not even notified in the cockpit that the MCAS software had taken over control of the plane. How insane is that?

This all happened because Boeing pretended the 737 MAX was basically the same as the 737. The cause of the problems was not because of poor software, it was because Boeing tried to cut costs and put in a bandaid solution for the unstable frame they created. The software did its job, it's the lack of redundancy and ability to manually override the system that was the problem. They're just doubling down on it because there is no alternative to the engineering problem they created.

MCAS = May Crash Any Second

Inherently unstable? Where are the CG and CP actually located on the aircraft?

of course it's fixable - be realistic.

It's the more a problem of increasing lift from the forward-mounted engines, not CG. Active control systems are just fine. The airframe is not inherently unstable.

armchair aerospace engineers are the worst.

Right.

What people are missing is that if Boeing is 'too big to fail' for the US Government, then burying the risk, soaking up the resulting windfall, and pressing the accelerator as they turn towards the brick wall was the right thing for them to do.

I'm uncertain about your point where everything is fixable- don't forget, it needs to be fixable without significant pilot training, or else it'll remove airline's reason to stick with boeing.

However, that doesn't matter! Boeing can fail as hard as it wants, and the executives will keep their money, and the US Government will still need to save the company.

The only losers will be pension funds, employees, and citizens- people without any say in the matter.

The government can pay for the pilot retraining - which Boeing should have done in the first place.

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