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> Apparently the 737 Max pitched up a bit too much for comfort on power application as well as at already-high angles of attack. It violated that most ancient o

by coin 5y ago

> Apparently the 737 Max pitched up a bit too much for comfort on power application as well as at already-high angles of attack. It violated that most ancient of aviation canons and probably violated the certification criteria of the U.S. Federal Aviation Administration. But instead of going back to the drawing board and getting the airframe hardware right (more on that below), Boeing relied on something called the “Maneuvering Characteristics Augmentation System," or MCAS. Nope, this is 100% false. The purpose of MCAS is to give the MAX the same aircraft handling characteristics so that it retains the original 737's type rating. Thus 737 type rated pilots can fly the MAX under their 737 type rating. A big part of selling the MAX is type rating commonality with the airlines existing 737-train pilots. Juan Browne, a real 777 airline pilot, mentions this in one of his excellent YouTube videos (https://www.youtube.com/user/blancolirio https://www.youtube.com/user/blancolirio). > I have been a pilot for 30 years I suspect this person is a private pilot with no actual airline aviation experience. Edit: This is the same guy that boosted his aviation credentials by citing that he's flown a 757 simulator (https://www.eetimes.com/software-wont-fix-boeings-faulty-airframe/ https://www.eetimes.com/software-wont-fix-boeings-faulty-air...). So yes, he's a GA pilot that has flow in some aircraft simulators. > Among Boeing’s critics is Gregory Travis, a veteran software engineer and experienced, instrument-rated pilot who has flown aircraft simulators as large as the Boeing 757.

TedShiller 5y ago
- deleted 5y ago
  [deleted]
- WalterBright 5y ago
  I'm not a pilot either, but I worked for 3 years on the 757 stabilizer trim system and detail design, so know a lot about it. My lead engineer was a pilot and would take me flying and let me fly for a few seconds. A good chunk of the engineers at Boeing are also pilots. My dad and brother are pilots. Many of my friends are pilots. FWIW. But you don't have to take my internet credentials seriously, and you shouldn't. So here's some documents which you should, if you want to be informed about this: Boeing Emergency Airworthiness Directive "Initially, higher control forces may be needed to overcome any stabilizer nose down trim already applied. Electric stabilizer trim can be used to neutralize control column pitch forces before moving the STAB TRIM CUTOUT switches to CUTOUT. Manual stabilizer trim can be used before and after the STAB TRIM CUTOUT switches are moved to CUTOUT." https://theaircurrent.com/wp-content/uploads/2018/11/B737-MAX-AD-1107.pdf https://theaircurrent.com/wp-content/uploads/2018/11/B737-MA... 2018 - 035 - PK-LQP Final Report http://knkt.dephub.go.id/knkt/ntsc_aviation/baru/2018%20-%20035%20-%20PK-LQP%20Final%20Report.pdf http://knkt.dephub.go.id/knkt/ntsc_aviation/baru/2018%20-%20... Aviation Week 19-Sep-2019: "The [LA] pilots countered with main electric trim nose-up inputs. At least 25 automatic stabilizer nose-down, pilot-directed stabilizer nose-up exchanges took place and then several nose-down inputs were not countered." "The MCAS activated twice, and the [EA] crew countered with electric trim." https://www.bloomberg.com/news/articles/2020-03-09/why-did-boeing-s-warning-on-737-max-fail-to-stop-second-crash https://www.bloomberg.com/news/articles/2020-03-09/why-did-b...
  - sofixa 5y ago
    > A good chunk of the engineers at Boeing are also pilots I don't know how you square that with the MCAS disaster. Everything relating to it ( design, piss poor implementation that somehow passes tests and certification, hiding it from the FAA, airlines and pilots) at best indicates that the people involved have maybe seen an airplane, once, from afar. IIRC the Ethiopian pilots followed the Boeing airworthiness directive to the letter and the plane still crashed. Boeing accepted responsibility for the crashes. Sadly there won't be any criminal prosecution and it's highly unlikely there will be significant changes at Boeing and the culture that led to 300+ dead will probably lead to other issues ( like the poor quality on the 787s manufactured in South Carolina). How many people have to die for serious changes to be made? I hope that future Boeing models will require full certification from the EASA and other aviation authorities, the FAA has zero legitimacy.
    - WalterBright 5y ago
      > I don't know how you square that with the MCAS disaster. There was nothing wrong with the MCAS concept. There was a lot wrong with its implementation, and I cannot explain why that happened. I've never seen any credible story of how it came about. > the Ethiopian pilots followed the Boeing airworthiness directive to the letter No, they did not. The EAD says: 1. restore normal trim with the electric trim switches 2. turn off the stab trim system The EA pilots: 1. turned off the stab trim system with the nose disastrously trimmed down > Sadly there won't be any criminal prosecution Be careful with criminal prosecutions. I understand the desire for revenge, but criminal liability will cause everyone involved to be silent about issues, cover them up, be uncooperative, and not fix them. (Because to fix them means to admit criminal liability.) To make systems safe requires a "no fault" culture. > How many people have to die for serious changes to be made? That implies that airplanes have never had crashes before due to errors all around. There have been lots of them, and with each one, designs, processes, and training get better.
      - froh 5y ago
        > "no fault" "No blame" No fault is what we want to achieve. Also we need to maintain liability of the managers deciding to not do certain measures, for cost reasons. It's perfectly fine to invent MCAS, to maintain 737 "look and feel" to the pilot. It's not okay to not introduce it properly. It's not okay to only think about MCAS failure modes, symptoms and remedies after the fact. It's not okay to make the business decision (!) To not thoroughly train for potential failure. There has to be liability at the decision making level.
ronenlh 5y ago
> The purpose of MCAS is to give the MAX the same aircraft handling characteristics so that it retains the original 737's type rating. The article mentions that prominently in a few paragraphs, this is the first one: “That's because the major selling point of the 737 Max is that it is just a 737, and any pilot who has flown other 737s can fly a 737 Max without expensive training, without recertification, without another type of rating.”

by coin 5y ago

TedShiller 5y ago

deleted 5y ago
[deleted]
WalterBright 5y ago
I'm not a pilot either, but I worked for 3 years on the 757 stabilizer trim system and detail design, so know a lot about it. My lead engineer was a pilot and would take me flying and let me fly for a few seconds. A good chunk of the engineers at Boeing are also pilots. My dad and brother are pilots. Many of my friends are pilots. FWIW. But you don't have to take my internet credentials seriously, and you shouldn't. So here's some documents which you should, if you want to be informed about this: Boeing Emergency Airworthiness Directive "Initially, higher control forces may be needed to overcome any stabilizer nose down trim already applied. Electric stabilizer trim can be used to neutralize control column pitch forces before moving the STAB TRIM CUTOUT switches to CUTOUT. Manual stabilizer trim can be used before and after the STAB TRIM CUTOUT switches are moved to CUTOUT." https://theaircurrent.com/wp-content/uploads/2018/11/B737-MAX-AD-1107.pdf https://theaircurrent.com/wp-content/uploads/2018/11/B737-MA... 2018 - 035 - PK-LQP Final Report http://knkt.dephub.go.id/knkt/ntsc_aviation/baru/2018%20-%20035%20-%20PK-LQP%20Final%20Report.pdf http://knkt.dephub.go.id/knkt/ntsc_aviation/baru/2018%20-%20... Aviation Week 19-Sep-2019: "The [LA] pilots countered with main electric trim nose-up inputs. At least 25 automatic stabilizer nose-down, pilot-directed stabilizer nose-up exchanges took place and then several nose-down inputs were not countered." "The MCAS activated twice, and the [EA] crew countered with electric trim." https://www.bloomberg.com/news/articles/2020-03-09/why-did-boeing-s-warning-on-737-max-fail-to-stop-second-crash https://www.bloomberg.com/news/articles/2020-03-09/why-did-b...
- sofixa 5y ago
  > A good chunk of the engineers at Boeing are also pilots I don't know how you square that with the MCAS disaster. Everything relating to it ( design, piss poor implementation that somehow passes tests and certification, hiding it from the FAA, airlines and pilots) at best indicates that the people involved have maybe seen an airplane, once, from afar. IIRC the Ethiopian pilots followed the Boeing airworthiness directive to the letter and the plane still crashed. Boeing accepted responsibility for the crashes. Sadly there won't be any criminal prosecution and it's highly unlikely there will be significant changes at Boeing and the culture that led to 300+ dead will probably lead to other issues ( like the poor quality on the 787s manufactured in South Carolina). How many people have to die for serious changes to be made? I hope that future Boeing models will require full certification from the EASA and other aviation authorities, the FAA has zero legitimacy.
  - WalterBright 5y ago
    > I don't know how you square that with the MCAS disaster. There was nothing wrong with the MCAS concept. There was a lot wrong with its implementation, and I cannot explain why that happened. I've never seen any credible story of how it came about. > the Ethiopian pilots followed the Boeing airworthiness directive to the letter No, they did not. The EAD says: 1. restore normal trim with the electric trim switches 2. turn off the stab trim system The EA pilots: 1. turned off the stab trim system with the nose disastrously trimmed down > Sadly there won't be any criminal prosecution Be careful with criminal prosecutions. I understand the desire for revenge, but criminal liability will cause everyone involved to be silent about issues, cover them up, be uncooperative, and not fix them. (Because to fix them means to admit criminal liability.) To make systems safe requires a "no fault" culture. > How many people have to die for serious changes to be made? That implies that airplanes have never had crashes before due to errors all around. There have been lots of them, and with each one, designs, processes, and training get better.
    - froh 5y ago
      > "no fault" "No blame" No fault is what we want to achieve. Also we need to maintain liability of the managers deciding to not do certain measures, for cost reasons. It's perfectly fine to invent MCAS, to maintain 737 "look and feel" to the pilot. It's not okay to not introduce it properly. It's not okay to only think about MCAS failure modes, symptoms and remedies after the fact. It's not okay to make the business decision (!) To not thoroughly train for potential failure. There has to be liability at the decision making level.

ronenlh 5y ago

> The purpose of MCAS is to give the MAX the same aircraft handling characteristics so that it retains the original 737's type rating. The article mentions that prominently in a few paragraphs, this is the first one: “That's because the major selling point of the 737 Max is that it is just a 737, and any pilot who has flown other 737s can fly a 737 Max without expensive training, without recertification, without another type of rating.”