Boeing keeps talking about fixing them and putting them back in the air, but I dunno. At this point, it should be agreed the fundamental design flaws are serious, and Boeing should have simply made a brand new plane, with much more modern controls and predictable maneuvering. Yes, pilots would have to be certified for these new plans, but that cost pails to the money lost from these grounded fleets.
I'd honestly like to see the 737 MAX taken out of service and Boeing simply ending this line. The old planes should be stripped for parts and as much recycled as possible. It's going to cost them a lot of money, and it should. Their mistakes lead to the deaths of two whole planeloads of passengers. Airbus, Bombardier and others will probably make a lot out of this disaster, and that's probably a good thing and will help competition in this small/narrow market.
The bugs will be addressed and they'll still fly. Airlines have no choice, there's a limited capacity in the world for airplane construction, several thousands of orders on the books for the 737 and 320 waiting to be filled. What can an airline do? They can cut back some orders but not all orders.
> I'd honestly like to see the 737 MAX taken out of service and Boeing simply ending this line.
I have an alternate history fantasy where instead of going with the MAX and then trying to kill the C-series as they did, they instead bought into the C-series. Swapping the cockpit for a Boeing cockpit design. Built the -500 stretch of the C-series, and then used the C-series to replace the 737 line in the <165 pax market. And moved ahead on the 797/NMA for which they'd have a shorter version covering the 200-270 pax market as a pure passenger mover as it's proposed.
A) Adding two more angle-of-attack sensors so a pilot can be reasonably sure of auto-adjust will work. Retrofitting those would be expensive, of course.
B) Put the two buttons back the way they were and add a "light" indicator an angle-of-attack sensor failure.
C) More pilot simulator training so pilots know what to expect in the unusual situation that the system fails.
I suspect the answer would be: "Even now we're not willing to bite the bullet and pay all the expenses we were dodging before".
Searching, it seems Southwest already did something like this (after the first crash, in fact). The problem might be that if Boeing does this on their dime then Boeing would be essentially giving every one of their "bargain" customers the features of their "luxury" customers, which I would speculate might be a vastly expensive proposition especially if it sets precedent going forward.
And it's worth pointing out that 737s already have two of these sensors, but don't use them both for MCAS (?!?!).
"22.214.171.124 Probe heating
The probes that are installed on the aircraft are heated electrically to remove water
by vaporisation when the aeroplane is on the ground and to protect them from icing
Even if the pitot tube is heated (mandatory), very often airframe icing leads to a blocked static port, rendering even more indicators useless.
0.00001 * 0.99 = 0.0000099
0.99999 * 0.01 ~= 0.01
P(failure|alarm) = P(alarm|failure)*P(failure)
= 0.99 * 0.00001
0.0000099 + 0.01
For the noise sensor scenario, is the sensor failing or is the ancillary (and single point of failure) noise sensor failing? What happens when you have a false positive like that and a false negative on another sensor?
For the correlation scenario, when you have two systems that disagree, how do you determine which one is failing? Are their precisions and tolerances sufficiently close that you’ll get a warning at a useful point in time?
This system is critical to the Max 8 remaining classified to 'fly the same' as the 50+ year old 737 air frame design so it's critical to pilots being certified to fly the plane at all. Ergo it is a critical system and needs more redundancy or the Max 8 needs to just have a new type certificate and pilots certified to fly it as well.
Boeing REALLY REALLY doesn't want to do this because it would require airlines to retrain their pilots to use it in their fleets making them less attractive to airlines. The whole fiasco is a confluence of 1) Cost of retraining pilots on a new air frame 2) need from airlines for a more efficient plane 3) the old 737 design not having any more room below the wing for a bigger engine (which is pretty much the main way we get more efficiency these days).
While true I don't think that airlines and regulators will go for it, if there's even the slightest risk of an additional accident. No matter what.
And Boeing's "communcation strategy" after the incidents doesn't really help to instill confidence in the plane.
There's also the possible hardware fix to add an additional AoA sensor and change the software to limit the total deflection allowed + add a way to disable the MCAS only while keeping the electronic trim. The plane itself isn't irredeemable by a long shot though.
The engines are mounted incorrectly, so much so that Boeing believed pilots need the assistance of MCAS on take-off now.
The bug isn't with its algorithms, rather the need for MCAS to begin with. They can't "address" it. That's why I'll be very careful not to ever book a flight on a 737 Max, probably easier to simply stick to Airbus-only airlines: Jetblue, Alaska/Virgin, etc.
This overstates the issue. The engine mounting changes the flight characteristics enough that the MAX 8 needs to be flown differently in certain corners of the flight envelope. The MCAS was added to avoid having to re-train pilots or trigger a new type certification.
The engine mounting certainly does not make the plane unsafe.
I don't think this is a very...'precise' statement. what is "safe" in the context of aviation? If you had no MCAS, then this plane has a very bad propensity to stall. I hope we can both agree that's an unsafe airplane. You can't just say "don't do that [pull up too much] and then you're fine". The aircraft "wants" to pitch up too high and stall, which predicated the MCAS system itself. So to me, yeah the engine mounting (in and of itself) makes this plane quite unsafe.
Now, with a properly functioning MCAS it may be "safe", but when the MCAS is itself another point of failure, my opinion is that the aircraft is only safe on paper, while in practice it's just got too many hacks and kludges for it to be practically safe for the millions of safe flight hours that these things are expect to deliver.
Airbus aircraft are “safe” despite the fact that dual conflicting pilot input is averaged without stick feedback (see the Airfrance flight from Brazil). If electronics being used to fly the aircraft upsets you, you’re going to be in for a real shocker on any airbus.
The parent comment and entire thread is 100% correct. There is nothing inherently unstable or unsafe about the MAX 8. It has a pitch-up characteristic that's mild compared to some other commercial jets like the 757.
The only reason MCAS was put on that plane was to allow the MAX 8 to share a type rating with the rest of the 737 family, to make it so that it handles like any other 737 despite the pitch-up characteristic.
Go ask any commercial pilot, go watch any of the commercial pilots on youtube who have commented on this, go look on stackexchange. The notion that the MAX 8 is inherently unstable, or unsound, or dangerous, is a laughable myth to anyone in the industry. I get that the news cycle is financially rewarded for fearmongering, but I really expected people who frequent HN to know better and do some cursory research into the topic rather than posting comments that perpetuate bullshit.
There are several major issues with what boeing has done, such as the alleged failure to reclassify MCAS as a critical system after flight testing. But instead of discussing these legitimate issues, public debate seems to have been directed towards a bullshit myth about the airframe being inherently unstable. This has been eye-opening and dispelled my notion that HN had above-average quality of discussion on technical topics.
So, what do you have? NO TRAINING on this airplane, a bugged software system, poor aerodynamics, poor design choice, stress on elevator, etc. The ethiopian airlines plane had such force that pilots were not able to manually turn the trim control wheel. Do you know how much force that plane had to have that the jack screw couldn't be operated manually? THAT is a severe design flaw. THAT is what is being investigated. Who is investigating Boeing? Boeing is investigating Boeing. Boeing on 5/7/19 admits it knew they had a severe problem but it can still be fixed. Who certified the fix? Boeing. But now the FAA is investigating that fix which was promised by April. Again, this is a severe design flaw with still many unknowns yet to be found.
Do you have any personal experience with or references for this claim?
Personally I won't fly on one in my lifetime.
I'll leave the analysis of why to others to figure out why I fly on other airplanes.
Incidentally I have seen pilots argue that the max is inherently unsafe on this forum which is probably why people are reiterating it.
What is your area of expertise and what is your opinion?
It's perfectly rational to look at the results, regardless of "why", and decide that the risk is just too great.
In this plane which is not "fly-by-wire" the pilots are part of the safety loop and are given a certain short amount of time to respond to an emergency.
Troubling to me is the footnote in the manual which there are times where the manual wheels for the trim require 80 lbs or 100 lbs or more of force. This amount of force would potentially preclude female pilots on these planes to handle these sorts of emergencies.
This is completely false. The 737 MAX does not have relaxed static stability in the manner of a fighter jet. It just has different handling characteristics than earlier 737s at high angles of attack -- a region of the flight envelope that the pilot should never take the plane into in the first place.
Fighter jets of the kind you're referring to require continuous and precise adjustments of the flight control surfaces merely to avoid departing from controlled flight. This is absolutely not the case for the 737 MAX.
Okay, how's: you can use thrust to pitch up a 737 beyond the authority of the elevator.
Airbus aircraft are “safe” despite the fact that dual conflicting pilot input is averaged without stick feedback (see the Airfrance flight from Brazil).
There is an aural warning (DUAL INPUT) on Airbuses with conflicting input.
The precise wording would be that it is dynamically unstable, and the ball is with Boeing now to prove it's not the case. Also after all we discovered on the last weeks, Boeing better make a good case, or they won't convince anyone.
The US aviation industry is about to change. I don't know into what, but it's not in a stable situation.
Airliners are very safe. They're not in dynamic stability like jet fighters and don't need active measures at all times to stay airborne. Having sensors and systems that coordinate to keep the aircraft flying optimally to remove pilot load and increase safety margins is a good thing and has been in use for decades.
The problem here was a badly implemented system without redundancies and without enough training so that pilots were actually aware of the flight profile and MCAS. Also aircraft do not have millions of flight hours, they wouldn't reach a million even if they flew 24 hours a day for 100 years.
- it is difficult for pilots to understand how MCAS works, and how to diagnose failures. They are not programmers or engineers. And MCAS doesn't provide any debugging information about its work anyway. And pilots don't have time to analyze it.
- it adds new points of failure
- sometimes there are situations when automatic systems shut down and pilots have to control everything manually. With MCAS, they would have more things to look after. Pilots who got used to flying with autopilot are usually not comfortable with manual flight, and systems like MCAS only make things more complicated for them. An example is a recent crash of SSJ100 in Moscow where experienced pilots failed to land a plane manually after autopilot has turned off.
So I think that plane designers should be very careful with adding more automatic controls. Especially if their purpose is only to save money at cost of making place less safer.
If I remember correctly, the behavior you promote as "fine" is forbidden by the regulators, and not accidentally.
Without the active MCAS the plane would have not been certified because the behavior of controls is then not inside of the prescribed limits.
If the plane must have natural behavior, then MCAS would not allow it to be certified because it's artificial control.
At high angle of attack, the MAX-8 is more unstable than pilots were trained to expect. And the MCAS has done an absolutely miserable job of fixing this. Worst case scenario bad: it caused the loss of two airplanes that, if the MCAS had never been added to the MAX-8, would have reached their destinations just fine.
Until the it flies predictably in every flight profile (including high AOA), it's demonstrably wrong to say "the aircraft flies fine." Maybe it will eventually "fly fine" but Boeing's got quite a bit of work to do first.
The specific design of MCAS and not adding any new procedures, was to lower the training requirements. Specifically, anyone certified on the old 737 was still certified on the max.
If they had improved the interface of MCAS and changed the procedure for runaway trim, it would have required more training. However, without MCAS or another remedy for the 'decreasing stick pressure at increasing pitch' problem, the plane would not have been allowed to fly at all.
The original one is
and was written at night, so there's some loopy phrasing in there I never corrected. Let me unpack some of it to fit the context here.
The pressure applied on the stick itself does not change. Rather, the function of how much deflection you get out of the plane per unit force applied to the stick changes.
Design regulations state an airframe for which this curve at any point goes negative cannot be certified as a civil transport airplane.
That means, there should be no point in the flight envelope where the sensitivity of the controls drastically changes. It should be a predictable increase in force required to get more deflection, all the way to stall.
With the MAX without MCAS, this rule is broken at high AoA when the engine nacelles start making lift.
MCAS is meant to compensate for this necessary breakage by inducing some mistrim.
The effect of mistrim in that case is to cause the controls to require more force to induce those last few degrees of deflection, using the AoA sensor as the primary indicator as to whether the system should activate, in order to bring the curve into compliance.
The problem, as hinted by the response to my post in that thread, is that an honest to god stick-pusher would be more akin to the system you'd want for that. Adding the AoA sensor as a single point of failure is insane, due to the consequences should that sensor start spewing garbage data in normal flight.
Most of those are realizations I came to after stumbling across a Royal Aeronautics Society interview of D.P. Davies, a British test pilot for the ARB, the aircraft certification authority for the U.K., which I believe I linked in the comment.
At the time I wrote it I was in the midst of a deep dive into the more arcane aspects of control systems. I have some literature tucked away somewhere that I was referencing, bit I'd need to dig rather deep in my browsing history to recover all the context.
An interesting historical note: MCAS is similar to a system McDonnell Douglas implemented in MD-11's (LSAS, Longitudinal Stability Augmentation System) for the same reasons as Boeing eventually implemented MCAS: to be able to claim that the new aircraft flew just like the old MD-10.
Makes one wonder if someone brushed the dust off something that really shouldn't have been emulated again after the merger.
Pilots are trained extensively not to trust what motion feels like, and to use the horizon and instruments. An adjustment in stick pressure is not a notable new threat, they just need to be trained for the plane's behavior.
It seems that what you claim is "not a new threat" is actually forbidden by the regulations, because it was recognized to be a threat.
I'm not quite sure how that is related to beginner flight lessons. (?)
Most commercial planrs fly 3000 hours a year. There are about 400 787-Max planes built - that's a million flight hours per year already (if they weren't grounded...)
Unless there is something about the magnitude of MCAS necessity that Boeing did not tell us yet.
Boeing's original stance of "stupid pilots should have followed runaway trim procedures" does not seem very consistent with actively removing a two-stage disable feature that already existed (and which, in hindsight, might have saved those lives). How desperate exactly were they to never ever let the pilots catch a glimpse off the real flight characteristics?
The engine position exacerbates a problem already plaguing the 737 since the Classic. I think you're understating the problem quite a bit here.
Anecdotal: I know of at least one family that booked a trip on a non-Boeing airline, at additional cost, to avoid risking being on a Max.
Imagine that after the Max is back in service, that there is a serious incident in the first few months - it doesn't have to be fatal, just a close call of some kind - how many more customers will avoid the Max at all costs?
By the time you've arrived at the airport and see the MAX at your gate, it's too late and you've already paid your fare.
1. to make certain I don't board one of these machines by mistake. I will not risk my life over this egregious comedy.
2. to vote with my dollars and punish Boeing and businesses that do business with Boeing, especially if they refuse to remove these planes from their fleet.
What Boeing committed here is leagues beyond the recent emissions scandals. It's criminal and the perpetrators should be afraid of the coming justice. This should honestly be as close to a company-ending event as one could imagine. We shouldn't treat this lightly, slap on the wrist, business as usual. This must never happen again.
i booked a boeing 787 dreamliner but ended up in a crummy 777 from a decade ago.
In a world that had actually severe consequences for corporate negligence, regulators would force Boeing to let airlines cancel/change all orders, and compensate them for the 737 Max models they already shipped to them, as they cannot be flown safely. Boeing's behavior does not indicate that they are interested in properly fixing this problem as opposed to getting it certified via corporatism / the FAA allowing them to perform a big part of their own checks.
No choice? It's a choice between risking passengers' lives and money. Be real about what the choice is.
Even that would've been acceptable and similar systems are already in use in other planes but it was the inadequate info, redundancy, warnings and controls to disable the system that created the problem.
It's easily fixable but still a tragedy of greed and oversight that led to the situation in the first place.
From what I have read, the new aircraft design had a habit of raising it's nose when engine power was applied, which put the plane into a situation where it might stall.
The MCAS was added to automatically detect this behaviour and stop the nose lifting.
So basically, without the MCAS, under certain scenarios the plane had a tendency to want to stall.
That does suggest the aerodynamic design of the plane is less than ideal and this could even be considered a design fault.
There are serious flaws with a safety system (MCAS) which was added to prevent the need for more training and a new type rating for pilots who are already rated to fly the 737. This needs to be fixed.
The problem is the fact the MCAS is required to fix the pitching problem.
Boeing tried to fix the design issue with a workaround solution only to then find they had created another, even bigger problem.
You can claim this because now all the FAA approvals for this planes, all tests need to be redone by somebody that we can trust. Sure they but larger engines, did they improved the supports, the bolts ,FAA "checked" this updates but can you trust them? the idea that MCAS is the only subsystem that must be fixed and checked is flawed, everything needs to be tested.
Sure the FAA definitely needs to be questioned as to how they let this through without enough redundancy and pilot awareness but the engines are not the problem and certainly not the supports and bolts. Those are things that are well-tested before it even gets to the FAA and having extreme paranoia about the industry doesn't help.
I imagine that putting a larger engine is not as easy, isn't a larger engine heavier? the forces larger? Don't you need to test the engine supports, the wings, all the related mechanical support structure.
Your theory that only MCAS is an issue is already false since it was found that without autopilot 2 humans don't have the physical force to control the plane , so probably a new requirement in the FAA should be added that with autopilot off 1 single pilot should be able to control the plane. You may say this is related to MCAS but6 it is obvious that this item was not in any checklist for things to test so even with a working MCAS but other emergency where autopilot would be turned off you would get in the same situation.
So there's not just the design workaround but there seems to also be process gaps that contributed to the situation.
My simple solution? Disable MCAS, keep the stick trim switches as on previous 737s, and require MAXs to only fly with a forward CG. 2000 kg of forward ballast might work. Even better, reduce aft weight by increasing economy seat pitch (20 rows rather than 30 or so), thereby reducing aft CG :-)
That said, I think seating pitch and spacing is definitely a conversation that needs to be had. I'm an average-sized guy, and I have a hard time with today's airline seats. I would hate to see what it's like for someone taller. There definitely needs to be more stringent regulation of airline seating to mitigate ever-vanishing personal space.
There's a difference between software stability controls and specifically emulating behavior.
MCAS is a longitudinal stability enhancement. It is not for stall prevention (although indirectly it helps) or to make the MAX handle like the NG (although it does); it was introduced to counteract the non-linear lift generated by the LEAP-1B engine nacelles at high AoA and give a steady increase in stick force as the stall is approached as required by regulation. ... This new location [of the engines] and larger size of nacelle cause the vortex flow off the nacelle body to produce lift at high AoA. As the nacelle is ahead of the [centre of gravity], this lift causes a slight pitch-up effect (ie a reducing stick force) which could lead the pilot to inadvertently pull the yoke further aft than intended bringing the aircraft closer towards the stall. This abnormal nose-up pitching is not allowable under 14CFR §25.203(a) "Stall characteristics". Several aerodynamic solutions were introduced such as revising the leading edge stall strip and modifying the leading edge vortilons but they were insufficient to pass regulation. MCAS was therefore introduced to give an automatic nose down stabilizer input during elevated AoA when flaps are up.
Airbuses operate in C* law (they are not positively stable)  and the stick is just that, a spring-loaded.... stick; it meets regulations by default.
However MCAS also makes the MAX behave like the older design which specifically led to the gap in training and controls over the system. If they just had stability control but without the emulation of behavior then there would be new training and certification, which is something they wanted to avoid but would've prevented these accidents.
Emulation is incidental. Redesigning the 737 with FBW is not something that Boeing would've considered, even for a moment.
Is the cause for that just oversight then? And further exacerbated by similar behavior leading to even less training requirements?
At least that was my understanding.
I don't think there is anything fundamentally wrong with that. But when you have active systems for that rather than passive ones you're in a different design domain. Boeing was trying to pretend they weren't.
As far as I can tell there are definitely some flaws, which seemed to have crept in as a result of the attempt to make them behave like older designs, but it seems optimistic to assume you can simply remove the flaws by sacrificing on that point.
Training and technical improvements can resolve these problems and it's ready to fly. If that's still deemed too risky then Boeing can remove the behavior modifications with training and certification as a completely new design. It was this cost that they were trying to avoid through emulation but clearly not done in a safe enough manner.
This doesn't mean the aircraft is fundamentally unsound, it's just a flying characteristic and can be managed just fine if the pilots knew about it and what the MCAS system was doing to counter it.
And here's a good overview: https://leehamnews.com/2018/11/14/boeings-automatic-trim-for...
The 787s or A320neos could start dropping out of the sky at any minute. Maybe their carbon fiber panels start disintegrating midair after some number of pressurization cycles. The 787s almost did drop out of the sky due to battery problems. Because of the complexity involved, the only hard proof of an aircraft's safety is many years of successful flying.
Other planes have had fatal flaws that took a lot more work to discover. The silver lining of the 737 MAX's MCAS problem seems to be that it is at least quite straightforward to fix, as far as aircraft bugs go.
IMHO Boeing should payout millions for each death they caused, fix the mistakes that caused them, reorient their culture towards safety first, and return the 737 MAX to service. If they work very hard and learn from this mistake there's no reason to think they can't regain the public's trust within a few years.
A brand new design actually supporting the engines used would not have aerodynamic issues that place the airframe outside the limits set forth by regulations.
The 737 is riddled through with legacy design features and needs to be put to pasture once and for all. And designing a replacement wouldn't be from scratch; there are plenty of other modern airliners to base a new one off of.
Complete bullshit. I’ve boarded/deplaned without a jetway in Beijing, SLC, JAC, and AMS in the last couple of years alone.
An embedded staircase is an option on the 737
Yes, it's true that it would be have been free from this specific MCAS issue. But what other issues would a new design have had? It's impossible to know.
It's also true that if Boeing had done a better job of implementing the MCAS design it would have been viewed as a triumph of software solving hardware problems.
Air France 447 crashed in large part because the pilot flying was incapable of handling the aircraft at cruise speeds without software assisting him. He thought the plane would stop him from doing something stupid but it didn't because the software failed in a somewhat similar way to the MCAS failures (sensor failure).
Airbus hasn't done anything to make their planes easier to fly at cruises speeds without software because software assisting pilots with complex flight characteristics is a fundamentally sound idea. The important thing is that the software actually works. Clearly the first version MCAS did not work reliably but there is no reason to believe that it couldn't work reliably.
And yet hundreds of people died in Air France 447 because the pilot stalled the aircraft when sensor failure disabled the Airbus software without the pilot realizing it.
In the case of MCAS, people died because the Boeing software didn't disable itself due to sensor failure.
Definitely not the same issue but both examples of software-sensor-related fatal crashes.
Automation creates complacency, which can be lethal when things go wrong.
The fresh design could tackle problems such as noise in a new way in order to get new customers.
The problem will be addressed, and life will continue. It is tragic, and there will be major repercussions within the manufacturer and regulator but the design will be fine.
The primary reason for the downgrade being:
Barclays’ survey of airline passengers says many people will avoid the 737 Max “for an extended period” once the aircraft is flying again.
I very likely would not. Would you? Would others?
It’s one thing to answer a question of a pollster, it’s another to take concrete action.
Why? Because I'd be so unbelievably pissed at myself if the plane nosed itself into the ground, at least for the time it took to impact.
I also vote with my money.
Simple answer? I won't be flying airlines that use the 737 Max. Stick to the NG or pick up some 320's. Between work and personal travel for our family, that's over $50k of gross revenue per year (we both travel a lot for work). Maybe nobody else cares? I'm betting there are more people like me and my wife.
Granted I might not be a typical discount shopper, I pick flights based on comfort, not price and have checked the aircraft/airframe I will be in for years.
However, I have a tough time seeing anyone I know taking a risk with flying the 737 max for a 10% discount in fares.
Typically, fuel costs to the airline can be estimated at 10-20% of the ticket price on domestic flights (5 gallons per seat per hour). 737 Max is advertised as providing up to 20% in fuel cost saving, which would bring the cost to 4 gallons per seat per hour. Which should not affect a ticket price by more than $4-6 per hour of flight.
Are you suggesting that people aware of the issue will be wiling to risk their lives for a chance to save $8-20 to their destination?
And to add to that very few 737 Max are in service right now, only 300 or so of 5000 orders have been fulfilled. These supposed savings are not yet factored into the price of most tickets, they are future reductions at best. And likely these will not even be reductions, just a way for carriers to earn more per seat.
In the case that I for some reason couldnt determine it ahead of time I would complain emphatically enough.
Such a move would be ill-advised.
Your point still stands, of course.
Airlines need their airplanes, and if boeing would recompense them for the lost planes they’d be instantly out of business.
Conversely, the carriers cannot just write off a significant part of their fleet and buy new ones, which wouldn’t show up for years anyway.
More than that - they're continuing to manufacture them. There's quite a few of them stacked up at KPAE, just sitting there waiting for their software updates, all painted in customer livery. (They're not even manufactured at PAE; they're ferried there for storage.)
They did not think - it'd ever happen. The shortcuts were taken for bringing 737 max quick to market.
I don't think so. Traditionally manufacturers and airlines never argue about a security incident of the competition. I only know of one issue were this unwritten rule was not respected.
(Not to mention that these planes have never crashed in most countries, even with an admittedly serious bug.)
In... Most countries? That's such a weird standard to hold an aircraft to. Even very serious aircraft issues before typically only resulted in crashes in a handful of countries!
Did I read that wrong or do you want 100+ of the 200ish countries in the world to have experienced a 737 MAX crash before scrapping the MAX?
Actually, I think if the planes can be fixed (and I'd be shocked if they couldn't), the two crashes before the fix will no longer be relevant for assessing safety.
As it should be. That's how important safety is. Boeing brought this on themselves by letting a second airplane crash before responding properly.
If it were fixed tomorrow at that point we could discuss how it effects risk in the future.
You are calling me out over nothing. This is uncharitable, to say the least. Why make trouble?
Talking about countries is just another way of saying that the plane was flying in many places all over the world and the risk of accident, despite these horrible accidents, was never very high. As you say, would never happen.
your parenthetical still shows some finger pointing towards “poor” countries’ pilots and ignores the number of crashes and reports for as young as this plane is and the numbers in use.
You have a strange idea about how to assess risk. It's like faults are somehow contagious.
They are. If 737 MAX was rushed to market and this is the first issue we become aware of, how many more are hidden?
If Boeing makes a habit of rushing planes to market without certification, how many more ticking time-bombs are flying around?
There’s no question that Boeing’s implementation had major issues, but there is IMO a higher burden of argument(?) to declare that a fundamental inevitability.
This could simply be a case of Boeing incompetent/reckless/...
Aviation adapts to problems and it always has. Southwest installed additional gear on their planes to help prevent this when the first plane crashed. It’s not far fetched that companies in countries with lesser regulations might skip out on training or plane enhancements that would lessen the chances of this problem.
Clearly, that didn't happen, or a second MAX wouldn't have crashed under very similar circumstances.
> Southwest installed additional gear on their planes to help prevent this when the first plane crashed.
Southwest ordered the MAX with an AoA indicator; it wasn't retrofitted.
> ... to help prevent this ...
It's questionable whether the AoA indicator would've made a difference. However, an AoA disagree alert that is standard in the previous 737 gen was "accidentally" made part of the AoA indicator extra feature set on the MAX, and the AoA disagree just _might_ have made a difference. 
> It’s not far fetched that companies in countries with lesser regulations might skip out on training or plane enhancements that would lessen the chances of this problem.
An AoA indicator is not mandatory anywhere in the world.
If you make controls more complicated, pilots will make more mistakes in critical situation.
Welcome to the internet where other people's money doesn't matter.
In term of public perception, it is a PR disaster but not unprecedented. The DC-10 went through a similar rocky start where passengers just wouldn't want to board it. But after the flaws were fixed it turned out to be quite reliable.
As evidenced by the ever-crashing 787s and A350s.
(Engines on newer models can be - and usually are - iterations of older designs. The A380's RR engines are built on the same platform as the Tristar's, introduced in 1972!)
Bad design decisions forced from chasing the bottom dollar, optional, critical safety features with the warning indicator and now these switches.
> Boeing declined to detail the specific functionality of the two switches
That's also interesting- I assume they are in CYA mode and wouldn't discuss anything that could be sensitive to the current investigations in any point. I wonder how hard the Seattle Times had to work to get manuals for the MAX.
I hope the loss of life is vindicated in the end.
I hope there are lessons learned from this but I fear our culture of quarterly profits and lack of real punishment for companies and their directors will result in nothing drastic happening.
Hopefully, their planes don't need MCAS ;)
Bit separately, I know people in DC who work in this field and they say the same thing.
I dunno, I see it as the opposite: regulation (apparently) made it impossible to just train pilots on this one new feature, instead requiring a full recertification of both the airframe and the pilots, which is incredibly expensive and unnecessary relative to what was actually required to save lives.
So one way of looking at is is: regulation caused perverse incentives that ultimately got people killed.
You’re basically saying that because shitty people don’t want to follow safety regulations we shouldn’t have them.
Having safety in mind doesn't make something unambiguously good, fit for purpose, or free of net-negative consequences. The specific content of rule determines that.
Even if your assessment is valid, you’d likely be throwing away the baby with the bath water if you’d cut regulation to avoid it.
Is that less regulation? More regulation? I don't know, and I doubt it matters if it's "less" or "more" since the goal is fewer dead people, not passing an ideological Turing test.
You are suggesting stronger regulation of some aircraft ('upgrades', as you rightly say), without weakening regulation for any other aircraft. So it's certainly 'more regulation'.
> I doubt it matters if it's "less" or "more" since the goal is fewer dead people, not passing an ideological Turing test.
It's a political question, so there's at least some question of ideology. Full-bore libertarians would doubtless find some way to oppose your suggestion.
You said regulation caused perverse incentives that ultimately got people killed. It would be more fair to say that a loophole in the regulations, caused the perverse incentive.
Remind me, when's the last time we had a major fatality incident in the US domestic passenger airline business?
And how does that compare with the prevailing state of affairs before "deregulation?"
Difficulty: answer with numbers, please, rather than insults, downvotes, or political attacks.
Weather forecasting has gotten much better in the years since deregulation. We’ve also been operating a mostly-jet fleet, which has larger inherent performance margins than the turboprops (and, worse, pistons) before them. And we have decades of experience about how pilots kill airplanes to inform operations and regulations.
It’s not clear that airfare deregulation either hurt nor helped airline safety in the US. US-flag air carrier ops are extraordinarily safe and I believe the FAA makes a positive contribution to that outcome.
Doesn't really matter much. Incidents in aviation that can happen on continent X could usually have happened on any continent.
The regulations we have in place here in the US -- to say nothing of our airlines' own policies -- would have kept that aircraft grounded until the problem was diagnosed and addressed.
It seems like that's really the crux of the problem. They made changes that they didn't feel it was necessary to tell their customers about. Just another step along the "I know you bought this product from us, but it's still our product at the end of the day" timeline that we're stuck on.
Further, I'll bet that it transpires that no one entity inside Boeing is really to blame for this mess. The engineers in charge of the AOA indicator subsystem didn't know that someone else in the company was going to drive a safety-critical component from it. And that engineering group may not have realized that the AOA data they were getting came from only one of the two sensors. My guess is that Boeing not only hid this information from their customers, they hid it from themselves.
The problem will have to be addressed at the top, but I don't agree with those who say that blaming, firing, or jailing the CEO is going to be helpful. The culture that allowed this to happen will have grown organically over time.
There is a reason why the aviation industry focuses on fixing the problem rather than the blame. A witch hunt makes everybody feel better in the short term but provides no guarantee of actual forward progress.
1. The A320neo caught Boeing completely off-guard;
2. The threat of the likes of American Airlines (already a mixed Airbus/Boeing customer and the largest airline in the world) placing a large A320neo order for regional aircraft operations scared the bejesus out of Boeing management;
3. For airlines like Southwest that are pure 737, the prospect of adding a plane that didn't share a common type rating with their existing fleet would complicate their lives and make them vulnerable to a sales pitch from Airbus; and
4. The development cycle for a completely new body was too long for many customers as it would arrive several years after the A320neo.
I don't think any of this is in dispute so the constraints for Boeing were to design a more fuel-efficient plane that shared a common type rating with the 737. To get there:
- They added newer, more fuel efficient engines. These changed the flight characteristics so they had to be moved;
- These engines moving made the plane more vulnerable to a stall situation. To counter this, they added MCAS, which would point the nose down when the AoA sensor told it the nose was too high;
- Standard configuration had 2 AoA sensors but MCAS only ever read from one;
- There was a safer configuration as an optional extra purchase;
- Telling airlines and pilots about this and providing overrides risked the common type rating.
I don't believe any of this is in dispute. It is widely believed, but not yet proven, that the primary cause of both fatal crashes was a runaway MCAS that drove the planes into the ground. It's also believed that with proper training a pilot may have been able to counter this (as happened the day before the Lion Air crash with a pilot in the jump seat).
Now what I find interesting is the response people have to all this. Some claim this is a fundamental design flaw that puts a shadow over the plane. Others believe it will be corrected and everything will be fine.
I'm firmly in the first camp: the plane CLEARLY flies differently to a 737. An automatic system, with no triple redundancy, was required to correct the flight characteristics of the plane.
I'm no expert but it seems to me the plane is fundamentally flawed at this point.
> the plane CLEARLY flies differently to a 737[...]
That's going from a length:span ratio of 0.86:1 to 1.17:1, you think those sort of airframe changes don't make for a plane that flies differently?
Maybe the whole notion of a "common type rating" is foolish, and pilots should need to re-train from scratch for the smallest of changes. Change the paint job? New type!
There's a lot of "the engines moved!" discussion around the 737 MAX which seems to be ignorant of decades of significant airframe changes not impacting type, to little apparent ill effect until now.
Consider cars: You can get most full-size sedans with either four or six cyliner engines, manual or automatic transmission, and regular or sporty suspensions. That's potentially eight different sets of handling characteristics. But they're all going to be in a fairly narrow cluster of "this still drives pretty much like a Camry." When you decide "instead of the six-cyliner engine, let's drop in a 700 horsepower turbocharged V8", it's no longer anywhere near that cluster.
The 737-100 had 62 kN of thrust, the 737 600-900 up to 120 kN, that whole line (and beyond) shares the same type rating.
I don't think this is correct. A lot is being made about the engine move with regard to aerodynamic behavior, but it doesn't seem at all outside of the bounds of what is considered standard. Pilots report that a similar 'light stick feel' at high AoA is already present in aircraft like the 757.
It's not that the aerodynamic change was worse or better, it's simply that it was a change at all. MCAS was there to satisfy the type rating. MCAS is not anti-stall.
The crucial mistake appears to be the extreme failure mode of the system; it is permitted to input high stabilizer trim angles without limit. Without any kind of restriction, the failure goes from annoying (pull up on flight stick + fiddle with stab control until you solve it) to the deadly crashes we've seen where pilots are in extremely tricky situations.
The fix could be as simple as making MCAS cutout in the case of an AoA disagree (no real hardware changes here) as well as limiting the input of extreme trim angles.
It seems you are correct :
> MCAS is a longitudinal stability enhancement. It is not for stall prevention (although indirectly it helps) or to make the MAX handle like the NG (although it does); it was introduced to counteract the non-linear lift generated by the LEAP-1B engine nacelles at high AoA and give a steady increase in stick force as the stall is approached as required by regulation.
MCAS's only observable intervention is to push the nose down to prevent stall, which means it is by definition anti-stall.
Boeing says MCAS is an acronym for "Maneuvering Characteristics Augmentation System", but a better name for MCAS is "Machine Controlled Anti Stall".
According to this article, the intended purpose was to restore the back-force needed to put the airplane in a stall, as the effect of the new engines was to make the control feel lighter at high AofA. The article also discusses the certification requirements with regard to acceptable handling characteristics.
FWIW, Boeing CEO Dennis Muilenburg is quoted in  as saying that "When you take a look at the original design of the MCAS system. I think in some cases, in the media, it has been reported or described as an anti-stall system, which it is not. It's a system that's designed to provide handling qualities for the pilot that meet pilot preferences.
"We want the airplane to behave in the air similar to the previous generation of 737s. That's the preferred pilot feel for the airplane, and MCAS is designed to provide those kinds of handling qualities at a high angle of attack."
Of course, the elephant in the room not being mentioned here is whether Boeing's primary motive for replicating the handling characteristics of earlier versions of 737s was an overriding concern with avoiding pilot training.
Boeing 737 MAX without MCAS violates that requirement (caused by the lift generated by large engine nacelles in front of the wings). MCAS is indeed designed to restore that required back-force. Back-force that is required to prevent stalls.
I suppose one could debate whether the stall prevention effect of MCAS is direct or indirect. But I don't think it's debatable that it is designed to comply with a certification requirement that's intended to help prevent stalls.
Boeing may be denying that MCAS has a stall prevention purpose only because to say so might put it in the critical systems category, requiring additional training. If so, this would apply as much to the fix as it does to the original version. To acknowledge that it has a stall prevention function might require an additional AofA sensor as well as additional training.
Having the control get 'lighter' (more sensitive to increased back-force) as one approaches the stall is definitely an undesirable characteristic, as it increases the risk of a distracted pilot stalling. While a change in the opposite direction might have been problematic (insofar as additional training is a problem), the way it actually goes is more likely to prompt the FAA to require something be done about it.
Forgive me if I'm missing something but these extra options are AoA cockpit indication and AoA discrepancy alert when two sensors disagree.
They don't alter software, MCAS would continue relying on just one sensor regardless of this indication. It's just an extra bit of information for pilot's decision making.
Sounds to me like another hack over the hack hardly adding much extra safety.
Note that the 737 already has two such sensors, but only consults one at a time for MCAS, so there'd be a software change required in addition to adding a new sensor.
But yes it's certainly not impossible sounding. It's like a minor recall where the planes get fixed on site.
If the needed telemetry is already exposed to MCAS, it could all be fixed in software.
Maybe it would be better just to use old time-tested design instead of saving small money at the cost of safety.
Now we can assume that the Max won't re-enter service until this issue is completely solved (I'm sure regulators will be extra-scrupulous here and customers will want cast iron re-assurance).
However, is anyone going over all the other safety decisions and changes made to other Boeing models over the period of the Max development?
It seems unlikely that this was an isolated incident of rushing things for commercial benefit...
Hopefully it will result in Bowing being required to make this a new plane and a lot of pilot re-certification. If it does return to the market, I wonder if they'll be forced to rebrand it. It's obviously not a 737.
So, in all probability, we don’t even know the list of fatal flaws even yet!
The flaw is using software to fix a hardware issue.