Comment by cletus | Hacker News Reader

Comment by cletus | Hacker News Reader

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Ok, so disclaimer: not a pilot. At all. But a comment someone made here in relation to the A380 being retired sprang to mind.

The question came up of why not drop from 4 engines to 2 (on the A380)? Someone answered that as soon as you change the engines you have to redesign the wing. As soon as you do that you have to redesign the fuselage. At that point you may as well just design a brand new plane.

So, my understanding of the 737 Max design is essentially that Boeing recycled the aging 737 design by putting more powerful engines on it. To make this work, they had to move the engines (and maybe the wings) forward? Is that right?

So the MCAS system seems, at least to me, designed to compensate for an engine, wing and frame configuration that was never designed for.

Add to that that Boeing _seems_ to have cut corners here and given what I think is called a common rating to the 737 Max (with existing 737 models) and not really educating pilots on what MCAS is, why its necessary, when it might kick in and how to override that if the plane is behaving incorrectly.

So, complete non-pilot and non-aeronautical engineer that I am, that seems... bad.

What's more, Boeing's reaction to the two crashes seems woefully tone deaf. Two crashes of new aircraft within 6 months of each other in perfect weather... caution would seem to dictate to ground them. I mean they grounded early 787s when they found an issue causing batteries to catch fire. What's different now and then? That issue I don't believe led to any total loss of the aircraft and those board, not even once let alone twice.

Add to that that the AOA sensor (from what I've read) doesn't have any redundancy and it just seems like a bad time is inevitable.

Could Boeing really have cut corners in this way? If so, that seems woefully shortsighted.

We're not going to solve this problem in a HN forum. Planes have a ton of hours put on them before a passenger ever steps onboard. This is a heavily regulated industry; and a lot of trust is placed in Boeing and the FAA to only build and certify safe planes. People make mistakes and that is why so many people are involved using best practices in the development of complex systems such as these.

The FAA burned all the trust and goodwill it gathered in the last 20-30 years -- depending who you ask -- within an extremely short time frame: on March 12 between 7am and 10am Pacific or so. It was pretty impressive. It was crystal clear the EASA is offering a face saving opportuntity to them by using the member states to do airspace bans but not suspending the planes of their respective airlines. Then, a few hours after that, when the FAA decided to continue the wave the "I am with stupid" flag they did the unthinkable and declared the 737 MAX not airworthy contradicting the FAA. This has never happened before. At this point the trust in FAA is gone and it is seen as a political and corporate puppet.

It was reported a day or two ago that Trump had a phone call with the CEO of Boeing, with the result being continued operation. Then, Trump makes the announcement today about the grounding, seemingly to try to take some credit for it.

It’s insane. There must be some despondent folks at the FAA right now. Years of trust squandered.

Is it possible the US have grounded them because Canada banned them in their airspace?

If the FAA didn't cave in immediately from the EASA issuing "do not operate the airplane" then it certainly wouldn't from Transport Canada. These two do not quite carry the same weight, you know? 150M passengers enplaned and deplaned in Canada in 2017 as per https://www150.statcan.gc.ca/t1/tbl1/en/tv.action?pid=231002... and https://ec.europa.eu/eurostat/statistics-explained/index.php... says this number was 1043 million in the EU. According to https://www.bts.gov/newsroom/2017-traffic-data-us-airlines-a... even the USA is below that nunber with 965M.

Thank you for a detailed answer.

> There must be some despondent folks at the FAA right now. Years of trust squandered.

Can you imagine the real workers, now some idiot Trump named to be deputy director and currently is the acting FAA director wiped out so much of their work... oh dear.

Even if they had been 100% sure the plane is sound, just to keep the larger status quo they should've acted in accordance with the EASA.

The Space Shuttle had a tonne of hours put on it before we learned of the O-ring problem catastrophically.

Everyone was trying their hardest and did their best, everything was built to spec but there were organisational and communication problems. The message that the dreaded O-rings weren't good for a cold weather launch was not heard or understood. No malice was involved but, when you have a schedule and deadlines with lots of large organisation hubris these things happen.

In only the broadest strokes is the current Boeing situation analogous to the sad fate of the Space Shuttle, however, just because a lot of testing has gone on and just because there is a lot of regulation does not mean that the layman appreciation of the situation is wrong. The layman understanding can be big picture rather than bogged down by intricacy of details.

These calls always seem easy in the aftermath, when you have the benefit of hindsight. In both of these cases, billions of dollars are on the line, but the truth is, there is always some risk. There is, as we've all heard, a greater risk of us dying in our car than any type of air catastrophe. Yet we still drive. How many flights have these planes taken? I can almost guarantee that Boeing did not build this sensor; the sensor has a spec sheet, its operational capability was verified in a laboratory and the FAA approved it. If the problem was not recoverable, they would have grounded the planes after the first accident; it appeared to be a training issue. Anyway, we can only make decisions with the information we have; it was the satellite data that suggested there was a link. It was then that the direction was clear and the call was made; this system is too dangerous as it is.

Making decisions based on fear is a fools errand. It is how you spend trillions of dollars waging wars combating terrorism when the risk of a terror related death is the US is lower than getting struck by lightening.

But the choice here is not "fly or drive", the choice here is "fly 737 MAX or fly another plane". I expect very few fliers have the budget and time to change flights, and those who can, will.

No they knew of O-ring burns before the catastrophe. They measured it, and determined that it was a tolerable amount, because it was less then 10% penetration. Problem was the root cause of the burns was not adequately determined. When you don't know the o-rings are twisting due to internal stress and that those stresses have a dependence on temperature, you miss that catastrophic O-ring failure is a risk at near freezing temperatures.

The second space shuttle crash was the same problem again. Falling chunks of ice and foam. Since nothing major had happened previously, it was assumed everything would be fine.

These failure and problems were the warning signs that something was wrong. There was no design spec for acceptable o-ring burn through or a leading edge heat shield damage threshold spec.

I bet we will find that Boeing and the FAA talked themselves into believing that

> The Vertical Pitch Indicator is reading on some MAX 8's 10-20 degrees higher than what the aircraft actually is pitched at.

Seems like not everything was built to spec

I'm really getting tired of hearing "Boeing cut corners" every time this comes up. Boeing is more a customer-driven company than most other industries. They would want to design a new plane, they in-fact were proposing a redesign of the 737 using composites and new aerodynamics, but their customers, who drive everything they do, wanted more of the same immensely popular 737, but more efficient. So they had to take the 737 and make the changes to it to get the desired efficiency. The airlines also wanted minimized difference training for the MAX for pilots already flying the NG, so Boeing worked to minimize large changes. Somewhere in this pile of things they decided, and the FAA approved, MCAS being omitted from the training. That has since been largely rectified by the airlines.

I also have noticed that everyone seems to want to pile on Boeing, as if all these other factors don't exist and Boeing is the one employing, training and supervising the pilots and maintenance people.

While this is supposed to be a site for hackers, I would somewhat expect that an engineering problem, which this largely is, would be dealt with like an engineering problem. But the commentary on this issue seems to largely be driven by emotional responses. Noone is considering the potential and now actual impact of grounding aircraft. Grounding aircraft may actually cost more lives than letting them fly, because of the higher mortality rate for other modes of transportation.

In the case of the Ethiopian crash we know very little about what actually happened, what we do know not only looks similar to the Lion Air crash, but also looks similar to the last Ethiopian crash, which did not involve a 737 MAX aircraft at all.

Many people also criticize Boeing's reaction without realizing that there is a lot of money riding on exactly what they say and do. No they will not ground a while aircraft type just because two crashed, especially when there is no official data to go on for the second crash. They will be very reluctant to admit fault, since every time they admit something is wrong customers demand money and people sue.

The way it happened with the FAA making the call its less on Boeing to compensate airlines for the inactivity of their aircraft. Which is not what Boeing wants, but is less shitty.

I couldn't agree more. I don't know if any of the commenters have built systems where lives or livelihoods are on the line; involving decisions where billions of dollars and many lives are at stake; nobody sets out to build unsafe systems or cut corners. The development process for aircraft is built with redundencies and multiple levels of validation; everything is tested and certified by internal and external experts. Software engineers fly on these planes monitoring their own software while in flight. I wonder how many people have trusted their own life with their code?

My bosses DID set out to build unsafe systems, to save money, and ordered me not to fix unsafe software for that reason; even after explicit warnings. Which crashed that nonprofit. It's common. There are many motivations including agent-principle problems, narcissism, and more. "Nobody sets out to make an excessively safe product that won't turn a profit" would be more accurate.

> by putting more powerful engines on it

I think the focus was on the engines being more efficient, not more powerful. See for example the wiki page [1]

"In summer of 2011, the objective was to match the A320neo 15% fuel burn advantage, but the initial reduction was 10–12%; it was later enhanced to 14.5%: the fan was widened from 61 inches to 69.4 inches by raising the nose gear and placing the engine higher and forward, the split winglet added 1–1.5%, a relofted tail cone 1% more and electronically controlling the bleed air system improves efficiency."

[1]https://en.wikipedia.org/wiki/Boeing_737_MAX#Design

Completely agree with your analysis, and not a pilot or aeronautics-related engineer either.

So if we're both right, responsibilities should be cleared. IMO the person/team that didn't prepare for sensor redundancy should be even criminally liable, and the authorities that were calling for not grounding the plane yet, should be dismissed, for complete disrespect to cautionary safety.

>NTSB final accident reports, with findings as to probable cause and recommendations intended to prevent future accidents, are statutorily prohibited from coming into evidence at trial; however, NTSB factual reports are generally admissible at trial. NTSB investigations typically last for a year or longer.

Just a quick Google there. Do note that the intent behind most NTSB reports being inadmissible in a trial is to secure cooperation from all parties in order to get an accurate representation of the problem that caused the disaster in the first place.

That's not to say lawsuits or criminal charges won't happen, but those proceedings will not be able to use NTSB investigatory results to make their case. They will have to independently prove their case through other means.

NTSB is not in the blame and punish game, and any civil case against Boeing will have a he'll of a time. Never mind that a criminal case will still be required to be levied against an individual at the company, and would have to prove criminal intent.

There will not likely be a terribly satisfying legal remedy to this. Taking VW and the financial industry as a starting point for successful pushback against industry, I'm not expecting a terribly satisfying legal conclusion on this one. There will probably be a review of corporate culture, maybe some extra scrutiny for Boeing for a while, some token legislation, and maybe a charity fund for victims.

Least that's what my magic 8 ball expects.

The idea that we should parade the heads of the people responsible for this around on a pike is a very emotional reaction. Of course, these will be the people who will be less likely to make any mistakes with this sort of system again, since hundreds of millions have been burned and lives lost. They will be the ones who are skeptical of datasheets, who will request more thorough testing, will spend extra time making sure they don't make the same mistake again.

Of course, we could just ground every plane when another plane of that type crashes, and be "100% certain" of no repeats.

> The idea that we should parade the heads of the people responsible for this around on a pike is a very emotional reaction.

No, it is what you normally find in laws. Doctors who perform poorly at their job are liable. Engineers who disregard basic safety measures established for decades (such as sensor redundancy) should be too (or the managers that approved the cost cut to not include redundancy).

It is common to "recycle" an existing airframe by upgrading it in various ways. In fact the customer pressure on Boeing to create the 737 Max (referenced in a sibling comment) was in part driven by the success of Airbus doing the same thing to create the A320neo. The 737 Max is the 9th or 10th variant that Boeing has created of the 737. The FAA has a process for certifying these variants.

The concept of a variant of an existing plane model should not be the focus of concern IMO.

It's a new plane. They kept the shape of the very popular 737, to the extent they could, purely for marketing purposes, even though this meant creating the first dynamically unstable ("wants to crash") civilian airliner in history, to keep that shape. (Modern fighter jets are supposed to be dynamically unstable, post Genghis John, for better maneuverability.)

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