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The many human errors that brought down the Boeing 737 Max
- ashleyn 7y agoDo we get a new one to learn in engineering school, next to the Challenger disaster, the Therac-25, and the Hyatt Regency bridge?
- Apes 7y agoThe thing is, in each if these lessons, it's not the engineers who have anything to learn, but the people making business decisions. Every one of these stories has an engineer saying, "I think this is a bad idea," only to be overridden by someone making business decisions. There is more value from these lessons being be taught in MBAs, and I don't think they are. No amount of engineering safety can overcome unsafe business leadership.
- mannykannot 7y agoAt least in the space shuttle cases, the people overriding the concerns were themselves engineers. The idea that managers, not engineers, cause failures is simplistic. Take, for example, the Thiokol engineer who told Roger Boisjoly's wife that if the Challenger inquiry led to Thiokol's shutdown, he would leave his kids on Boisjoly's doorstep - was that sound engineering reasoning?
- salawat 7y agoApparently those weren't enough. You also forgot Galloping Girdie. The Tacoma Narrows bridge. That and the rudder reversal problems Boeing had back in the 90's.
- leetbulb 7y agoI'd like to share AvE's video[0] here of a tear down of an AoA sensor. It's really quite interesting. More info on the AoA sensor's role in the Wiki entry[1]. [0] https://www.youtube.com/watch?v=NhZ0D-JRtz0 https://www.youtube.com/watch?v=NhZ0D-JRtz0 [1] https://en.wikipedia.org/wiki/Boeing_737_MAX#Maneuvering_Characteristics_Augmentation_System_(MCAS) https://en.wikipedia.org/wiki/Boeing_737_MAX#Maneuvering_Cha... TLDR/TLDW: AoA sensor measures "angle of attack." AoA sensors are physically over-engineered, but the electrical components may be questionable. If an AoA sensor fails, it may cause a stall. The 737 Max is equipped with two sensors, however, effectively utilized only one at a time because it cost extra for the "AOA-disagree" feature.
- raverbashing 7y agoIf I'm not mistaken, the Ethiopian case had a 'Anti-Ice warning' from the AOA sensor, why did MCAS consider the data of a sensor that potentially had an issue is anybody's guess. > effectively utilized only one at a time because it cost extra for the "AOA-disagree" feature. Yeah, props to Boeing who put a basic security feature as an "extra cost" option. But hey, who needs to know their AoA sensors are failing, especially when the plane is commanded by that, right?
- deleted 7y ago[deleted]
- tzs 7y agoHas anyone tried building aircraft AoA sensors other than vane type sensors? For example, when I was designing a home weather station for myself, I wondered if the anemometer and wind vane could be replaced with ultrasonic sensors and emitters. If you take four ultrasonic emitter/ultrasonic sensor pairs and arrange them in a square, and measure the time of flight of four pulses, one from each corner emitter to the diagonally opposite sensor, you can determine the component of the wind vector along that diagonal. Combine the components from the diagonals, and you get the wind vector. A bit of research turned up that this was not an original idea, and it does work. There are commercial anemometers and wind vanes (are they still called wind vanes when they don't have a vane?) for terrestrial use that work this way. There have also been many home made ones, such as this one [1]. Offhand, I don't see why such a thing would not work for an airplane. [1] http://embedded-lab.com/blog/making-an-ultrasonic-anemometer/ http://embedded-lab.com/blog/making-an-ultrasonic-anemometer...
- ncmncm 7y agoIt works at low wind speeds and in the absence of turbulence. Would it work the same at 400 knots? Its possible failure modes, too, seem a lot more complicated than for a physical vane.
- macoovacany 7y agoOff the top of my head, there are at least two more potential ways of measuring AoA: 1. Similar to your ultrasonic lattice, but using a cone of hot wire anemometers, so that each wire is set at an offset angle to the 'zero' direction. As the AoA changes relative to the cone, the resistance on the different hot wires changes (some wires become more perpendicular to the freestream, thus cooler; others will align closer to the freestream with less opportunity to cool). By measuring the resistance differences with a bridge, it's possible to derive, angle of attack, sideslip and airspeed. 2. An elliptical body with various pressure ports around the circumference, plus a pitot port. The angle of the flow can be measured by the difference in pressure between the circumference ports (and dividing by the pitot pressure).
- mannykannot 7y agoThe conclusion, "nobody did anything wrong, in a strictly technical sense" is too generous to Boeing and the FAA, given that MCAS did not have the redundancy that its classification as 'hazardous' required. It would probably take either an inquiry like those into the space shuttle accidents, or a whistleblower, to know whether anyone was raising concerns. I can believe it is possible that everyone was convinced by the "in the worst case, it is no worse than ordinary trim runaway" argument (which does not excuse the failure to meet the redundancy requirement), but then the Ethiopian Airlines crash, and its crew's inability to manually re-trim, might raise the question of whether trim runaway on any 737 model is more of a risk than had been supposed (to be fair, trim runaway has not caused 737 crashes in the past, AFAIK.)
- CaptainZapp 7y agoI think that it was criminally negligent by Boeing to not pull the plane after the Lion Air crash. They were the only ones, who really knew the inside details and they were the only ones to know how to (possibly) fix it before a lot more people had to day. Instead of being completely fortright and transparent they published an apparently completely worthless checklist. And all in the name of greed and corporate profit. That they still smear the pilots and throw them under the bus despite all the facts that came to light leaves me speechless.
- 3327 7y agoNot surprising boeing a multi billion dollar corp hires an influential PR, to push out these types of articles.
- sundvor 7y agoReally? My takeaway from the article was to never, ever get into a 737 MAX plane, regardless of what hack they manage get approved. And that their quality control has gone completely secondary to profits. I don't see why Boeing would pay to have this published.
- ncmncm 7y agoThe technical details seem correct. (I have seen 0.8 degrees elsewhere as the original amount of correction MCAS could apply per activation, not the 0.6 here. Doesn't matter much.) The conclusion is most charitably described as fanciful. There are strict rules about an automated system being able to apply more "authority" than the pilot can counter, which every engineer and manager involved knew well. There are strict rules about a single sensor failure that can make the plane unflyable, which all knew well. This is not a case of simple negligence to check documentation. This is a case of deliberate coverup of known risk factors to dodge rules specifically intended for airframe changes of this kind. It was the process of dodging these rules which kept the MCAS design from being reviewed competently.
- terryschiavo22 7y agoIt's a well-written article that's reasonably fun to read, if anyone has five minutes to spare.
- not-really-no 7y agoHey dude, fuck your user name.
- 0xcafecafe 7y ago"Although the FAA is responsible for the safety of any airplane manufactured in the United States, it delegates much of the certification to the manufacturers themselves. It has to in order to get anything certified at all, says Jon Ostrower, editor-in-chief of The Air Current and a former aviation reporter for The Wall Street Journal. Boeing already has the people and the expertise, it pays better, and it isn’t susceptible to government shutdowns. The FAA, meanwhile, says it would need 10,000 more employees and an additional $1.8 billion of taxpayer money each year to bring certification entirely in-house." I wonder if therein lies the solution. Allocation of some of the budget there instead of military perhaps? Not to mention the policy paralysis leading up to stupid government shutdowns putting people at risk.
- Apes 7y agoWhy from the military specifically? There are other budget items where we spend more.
- swarnie_ 7y agoI just looked up the 2018 federal budget for examples: Department of Defense : $574 billion Department of Veteran Affairs :$78.9 billion Department of Education : $68.2 billion Department of Health and Human Services :$65.1 billion Environmental Protection Agency: $5.7 billion Does this not seem off to you?
- erentz 7y agoI think the punishment to Boeing should be that HQ has to move back to the industrial park in Everett from Chicago. And the C-suite executives must work from offices inside the main assembly building for 20 years. Force them to reconnect with the products they make every day.
- Anarch157a 7y agoThey should force Boeing to have actual engineers on the top management, including the entire board of directors and everyone with a "chief something executive" title. Business majors and MBAs with no engineering backgrounds have no place in the top management of an aircraft manufacturer.
- crocal 7y agoBoeing’s leadership does not seem to lack engineering qualifications (reading their bio on the company website). What is the basis for your statement?
- kijin 7y agoEven better, fly them in to Everett every week using a plane that rolled out of the factory the previous week. Eating your own dog food, etc.
- thinkcontext 7y agoWhat's the Vegas line on when the plane will be flying again? Boeing says their software update is almost ready. However, I find it difficult to believe that it should fly until after investigations of the 2 crashes are complete and the results from them are used to re-examine the design. That would take a significant amount of time. Then there's the political dimension. Let's say there are Congressional hearings ongoing that are ripping apart the FAA to figure out if they delegated too much and why they missed stuff. Who would want to fly on a plane undergoing that kind of scrutiny? There's also the possibility that the FAA would unground the plane but other countries do not. Usually, much of the rest of the world just trusts the FAA, this is likely to not be the case here. Even if it was ungrounded in the US, who would want to fly on a plane if its not approved to fly in Europe?
- tigershark 7y agoRegardless of the approvals for sure I won’t fly on it. Life is too precious to waste it on a flying death machine.
- newsoul2019 7y agoHow about riding in a car? Statistically much more risky.
- tigershark 7y agoI don’t think so. 2 total losses over 350 aircrafts in 5 month. In a year, rounding per defect, you have 1% of possibility to lose a 737 max. I don’t know the exact numbers but I seriously doubt that 1% of all the people that drive on a car are dead every year.
- ackfoo 7y agoEverything you need to know about the Boeing 737 Max situation is contained in this article by Peter Garrison: https://www.flyingmag.com/inside-saving-air-france-447 https://www.flyingmag.com/inside-saving-air-france-447 Garrison is too cute by far to wade directly into the controversy--he knows that he will be crucified by all of you if he does. But he is a truly great writer who has forgotten more about aviation than almost anyone else alive will ever know. Garrison is very, very good at obliquely expressing the thing that you all won't even consider without stopping by Home Depot for a tiki torch and a pitchfork. The problem with the 737 Max, put quite simply, is us. Our attention spans have been whittled away by Twitter and Netflix, but they weren't that great to start with. We have learned to love our post-facts world; whatever feels "right" must be true, the technical details be damned. Real expertise, gained through years of experience and learning, is devalued. Throw a tall man in a good-looking uniform in the cockpit, give us decently low ticket prices, and everything will be alright. The problem was envisioned before the advent of technical automation in aviation: humans are bad at monitoring machines. It has only gotten worse as machines have gotten better at flying planes: manual flying skills have degraded, in some cases to the point of non-existence. No technical fix from Boeing can ever solve this problem. In order to solve it, we have to accept that something in a technical system will always break, and humans must be competent to take over when it does. Boeing could build their entire plane out of AOA sensors, and still an automated trim system could run away. There is simply no alternative, at this point, to having a human competent in manual flying skills ready to take over. In order to solve it, we have to admit that we have been conned by a widespread conspiracy to exploit deflationary forces to keep us happy and sort-of-productive while enriching the exploiters and increasing the disparity of wealth. They make things cheaper while wages stagnate, and we cheer. Right up until a 98-hour "pilot" drills 300 of us into the ground at 25Gs because he has absolutely no idea how to manually fly a plane. Hard things are hard. They require time and experience to master. Facts are real and objective. The Internet has enabled every ignorant asshole with an opinion and zero actual information to shout as loud as everyone else, and it has forced journalists to churn out sensational crap that panders to the ego of the crowd. Our system is bad. We are bad. The warnings are everywhere and we're ignoring them to watch Game of Thrones and drive our stupid cars to our pointless jobs that only make things worse. Saint Exupery's long dead. He's not going to leap into action and save us, we have to do it ourselves.
- PunchTornado 7y agothe ceo should step down. it's ridiculous.