8 ms·

I would be extremely hesitant to ever fly on a 737 MAX again because, even when MCAS is fixed, software is being used to fix a fundamental physics problem. I'd

by wycy 7y ago

I would be extremely hesitant to ever fly on a 737 MAX again because, even when MCAS is fixed, software is being used to fix a fundamental physics problem. I'd fly on other Boeing planes without worry, though.

ulfw 7y ago
The fix for the 787s Lithium battery problems wasn't a whole lot better. Remember those exploding left and right and the 787 fleet grounded? The fix wasn't to reengineer the large amount of electrical systems, lack of bleed air or use of different batteries. The fix was to put them in a stronger container with a hole in it so they can vent outside when they inevitably blow up again. That has worked well. So far. Kind of - https://aeronauticsonline.com/united-787-battery-failure-proves-boeings-fix-partially-successful/ https://aeronauticsonline.com/united-787-battery-failure-pro...
- village-idiot 7y ago
  That’s horrifying. I’ve also heard that the 787 was a boondoggle.
  - cstross 7y ago
    The 787 is weird (and possibly unsafe) for at least two significant reasons. Firstly, Boeing totally re-invented their approach to assembling planes. Previously they built most of the aireframe components and assembled them in their own plants. But the 787 was specced out during an ongoing Boeing/Airbus anti-trust dispute over government cross-subsidies that turned nasty (escalated to USA/EU level, mediated via the WTO, with sanctions threatened). For strategic reasons Boeing decided to outsource subassembly production to third parties and retain only overall control and final assembly (the goal was to have 51% of the work go through the EU, so that the EU would shoot themselves in the head if they applied sanctions against Boeing aircraft). (Similarly, Airbus did much the same: you can buy A320s—the 737 series' Airbus rival—built entirely in China, for example.) Anyway, this resulted in huge cost overruns, delays as small suppliers grappled with trying to supply components of reliable quality and consistency in Boeing-scale quantities, and so on. On the other hand, it gave Boeing a shiny new 21st century supply chain which they're using on new projects, so the $30Bn wasn't entirely wasted on just one bird. Secondly, Boeing went full-tilt for composites in place of aluminum as the main structural material. Now, Airbus had been building composite airframes for decades at this point, but they got there incrementally, and not without fatal accidents. See for example the crash of American Airlines flight 587: https://en.wikipedia.org/wiki/American_Airlines_Flight_587 https://en.wikipedia.org/wiki/American_Airlines_Flight_587 It turns out that switching to all-composites from aluminum has some serious gotchas, including entirely different wear/fatigue/delamination issues. Boeing has done surprisingly well up to this point with the 787 (although the early Ethiopian Airlines hull loss ground-side due to a runaway battery fire should be a warning—it was a shiny new plane and the battery fire burned through the top of the hull, turning it into a $200M write-off; an aluminum bird could probably have been patched and repaired). But we have no idea whether Boeing managed to avoid baked-in long term weaknesses in the airframe, of the kind that only show up 10-30 years into an aircraft's life. Such weaknesses can show up suddenly and kill an entire type within a matter of months (see for example the fate of the Vickers Valiant, a British strategic bomber of the 1950s that succumbed to cracked wing spars and was hastily scrapped). Anyway: this is why I'm very dubious about flying on 787s, at least for another few years. Your mileage may vary, obviously ...
    - foldr 7y ago
      >American Airlines flight 587 The accident investigation found that the vertical stabilizer was stressed beyond its certified load limits by the pilot's rudder movements. I can see why people were inclined to blame composites at the time of the crash. But 18 years have passed now, and there was never another incident where an A300 had a structural failure of the vertical stabilizer. There's a good comment here: https://forums.jetphotos.com/showthread.php?50480-Airbus-Composite-Unsafe&p=551764&viewfull=1#post551764 https://forums.jetphotos.com/showthread.php?50480-Airbus-Com...
      - rbanffy 7y ago
        > vertical stabilizer was stressed beyond its certified load limits by the pilot's rudder movements. That's something you don't expect to be possible on an Airbus.
        gsnedders 7y ago
        Why not? The Airbus A300 has fully mechanical linkage, and none of the fly-by-wire systems introduced later.
        rbanffy 7y ago
        Precisely because Airbus was an early adopter of fly-by-wire systems and envelope protections.
    - sgc 7y ago
      I find your first point much more relevant than your second. Boeing had been using composites extensively in military aircraft since at least their work on the B-2, and had been using composites in smaller areas from well before then. That was all was before they purchased Northrop Gumman, which brought considerably more expertise in house.
    - huslage 7y ago
      The 787 is not weird. It is an evolution of practices and learning from across the industry, academia and governmental organizations (NASA, ESA, etc) that culminated in a new product. The 100% composite structure has been completely flawless for the most part, with the largest issue being how to recycle the plane when it's done. Boeing has long outsourced the production of many components of all of its planes to various vendors, the big difference with the 787 was that they did this on a global scale. The use of LiIon batteries was a logical next step as well. Manufacturing issues in the first sets of batteries required them to re-engineer the safety system around them, and the vendors that created the batteries now have stricter standards to adhere to. None of these issues currently compromise the safety of the airframes. It's easy to pile-on after incidents occur, but these are machines made by people. People make mistakes all of the time. You wouldn't not use a computer because it had bugs. The likelihood of you falling out of the sky in a modern airliner is still vanishingly small and is getting smaller every day.
- antongribok 7y ago
  That's not exactly true as per your link. They did make changes to the battery, as well as outside the battery.
- retSava 7y ago
  Similar thing there - the model was delayed and thus likely high pressure and incentives internally to get on with it. According to the article, a series of fires didn't stop Boeing from allowing the plane to keep flying or to be sold, but FAA had to step in and ground it. Then, I can imagine, the cost of [FAA grounding] > [properly fixing it] means it got fixed. At least till the cost comparison tilted the other way.
- raverbashing 7y ago
  I'm with Boeing in this fix. The problem is not with the "the large amount of electrical systems, lack of bleed air". This is how things evolved. The main issue IIRC was manufacturing defects in some batteries that caused internal short circuits. > The fix was to put them in a stronger container with a hole in it so they can vent outside And this is an acceptable fix (beyond better QA/manufacturing practices of the battery). If the batteries fail the fault should be contained. The article you linked explains the changes Boeing implemented. Yes, batteries failed. The battery failure was contained correctly. Besides improving the reliability of the battery (which was addressed with some changes) that's what Boeing should have done (and did). They're not going back to NiCa or Lead batteries
  - gsnedders 7y ago
    Also, unless you can guarantee the failure rate of the battery to be low enough, those incidents made it clear the battery needed to be better contained—even if you also decrease the failure rate.
foldr 7y ago
This is not the case. The 737 MAX has different handling characteristics to a regular 737, but there is nothing inherently unsafe about those handling characteristics. The purpose of MCAS was just to prevent the need for pilots to recertify by masking the difference.
- danharaj 7y ago
  Without MCAS a MAX has flight characteristics that would not pass FAA certification.
  - foldr 7y ago
    I don't believe that's true. What's your source?
    - tzs 7y ago
      There are specific regulations on how the stick force must change in response to various flight conditions. Without MCAS the stick force curve of the 737-MAX does not satisfy those regulations. Do an HN search on "MCAS stick force curve" (without the quotes)[1] and you can find some discussion of this with cites to and quotes from specific sections of the regulations. [1] https://hn.algolia.com/?query=MCAS%20stick%20force%20curve&sort=byDate&prefix&page=0&dateRange=all&type=comment https://hn.algolia.com/?query=MCAS%20stick%20force%20curve&s...
      - foldr 7y ago
        There is no source in those comments for the claim that the 737-MAX would not satisfy these regulations without MCAS. Note that the actual regulations are a tad more complex than the incomplete sentence quoted: https://books.google.co.uk/books?id=5tAhOC4KC8MC&pg=PA200&lpg=PA200&dq=%22%22The+stick+force+curve+must+have+a+stable+slope%22%22&source=bl&ots=_B6qqMDW-K&sig=ACfU3U1jvCJhRgh2GLNa_3uPSPUBdWUvWA&hl=en&sa=X&ved=2ahUKEwijvpCNqa_iAhWIUt8KHT_1AagQ6AEwAnoECAoQAQ#v=onepage&q=%22%22The%20stick%20force%20curve%20must%20have%20a%20stable%20slope%22%22&f=false https://books.google.co.uk/books?id=5tAhOC4KC8MC&pg=PA200&lp...
sealthedeal 7y ago
100% agree. Anytime you are using software to hide a larger problem, that is a huge red flag.

by wycy 7y ago

ulfw 7y ago

The fix for the 787s Lithium battery problems wasn't a whole lot better. Remember those exploding left and right and the 787 fleet grounded? The fix wasn't to reengineer the large amount of electrical systems, lack of bleed air or use of different batteries. The fix was to put them in a stronger container with a hole in it so they can vent outside when they inevitably blow up again. That has worked well. So far. Kind of - https://aeronauticsonline.com/united-787-battery-failure-proves-boeings-fix-partially-successful/ https://aeronauticsonline.com/united-787-battery-failure-pro...

village-idiot 7y ago
That’s horrifying. I’ve also heard that the 787 was a boondoggle.
- cstross 7y ago
  The 787 is weird (and possibly unsafe) for at least two significant reasons. Firstly, Boeing totally re-invented their approach to assembling planes. Previously they built most of the aireframe components and assembled them in their own plants. But the 787 was specced out during an ongoing Boeing/Airbus anti-trust dispute over government cross-subsidies that turned nasty (escalated to USA/EU level, mediated via the WTO, with sanctions threatened). For strategic reasons Boeing decided to outsource subassembly production to third parties and retain only overall control and final assembly (the goal was to have 51% of the work go through the EU, so that the EU would shoot themselves in the head if they applied sanctions against Boeing aircraft). (Similarly, Airbus did much the same: you can buy A320s—the 737 series' Airbus rival—built entirely in China, for example.) Anyway, this resulted in huge cost overruns, delays as small suppliers grappled with trying to supply components of reliable quality and consistency in Boeing-scale quantities, and so on. On the other hand, it gave Boeing a shiny new 21st century supply chain which they're using on new projects, so the $30Bn wasn't entirely wasted on just one bird. Secondly, Boeing went full-tilt for composites in place of aluminum as the main structural material. Now, Airbus had been building composite airframes for decades at this point, but they got there incrementally, and not without fatal accidents. See for example the crash of American Airlines flight 587: https://en.wikipedia.org/wiki/American_Airlines_Flight_587 https://en.wikipedia.org/wiki/American_Airlines_Flight_587 It turns out that switching to all-composites from aluminum has some serious gotchas, including entirely different wear/fatigue/delamination issues. Boeing has done surprisingly well up to this point with the 787 (although the early Ethiopian Airlines hull loss ground-side due to a runaway battery fire should be a warning—it was a shiny new plane and the battery fire burned through the top of the hull, turning it into a $200M write-off; an aluminum bird could probably have been patched and repaired). But we have no idea whether Boeing managed to avoid baked-in long term weaknesses in the airframe, of the kind that only show up 10-30 years into an aircraft's life. Such weaknesses can show up suddenly and kill an entire type within a matter of months (see for example the fate of the Vickers Valiant, a British strategic bomber of the 1950s that succumbed to cracked wing spars and was hastily scrapped). Anyway: this is why I'm very dubious about flying on 787s, at least for another few years. Your mileage may vary, obviously ...
  - foldr 7y ago
    >American Airlines flight 587 The accident investigation found that the vertical stabilizer was stressed beyond its certified load limits by the pilot's rudder movements. I can see why people were inclined to blame composites at the time of the crash. But 18 years have passed now, and there was never another incident where an A300 had a structural failure of the vertical stabilizer. There's a good comment here: https://forums.jetphotos.com/showthread.php?50480-Airbus-Composite-Unsafe&p=551764&viewfull=1#post551764 https://forums.jetphotos.com/showthread.php?50480-Airbus-Com...
    - rbanffy 7y ago
      > vertical stabilizer was stressed beyond its certified load limits by the pilot's rudder movements. That's something you don't expect to be possible on an Airbus.
      - gsnedders 7y ago
        Why not? The Airbus A300 has fully mechanical linkage, and none of the fly-by-wire systems introduced later.
        rbanffy 7y ago
        Precisely because Airbus was an early adopter of fly-by-wire systems and envelope protections.
  - sgc 7y ago
    I find your first point much more relevant than your second. Boeing had been using composites extensively in military aircraft since at least their work on the B-2, and had been using composites in smaller areas from well before then. That was all was before they purchased Northrop Gumman, which brought considerably more expertise in house.
  - huslage 7y ago
    The 787 is not weird. It is an evolution of practices and learning from across the industry, academia and governmental organizations (NASA, ESA, etc) that culminated in a new product. The 100% composite structure has been completely flawless for the most part, with the largest issue being how to recycle the plane when it's done. Boeing has long outsourced the production of many components of all of its planes to various vendors, the big difference with the 787 was that they did this on a global scale. The use of LiIon batteries was a logical next step as well. Manufacturing issues in the first sets of batteries required them to re-engineer the safety system around them, and the vendors that created the batteries now have stricter standards to adhere to. None of these issues currently compromise the safety of the airframes. It's easy to pile-on after incidents occur, but these are machines made by people. People make mistakes all of the time. You wouldn't not use a computer because it had bugs. The likelihood of you falling out of the sky in a modern airliner is still vanishingly small and is getting smaller every day.
antongribok 7y ago
That's not exactly true as per your link. They did make changes to the battery, as well as outside the battery.
retSava 7y ago
Similar thing there - the model was delayed and thus likely high pressure and incentives internally to get on with it. According to the article, a series of fires didn't stop Boeing from allowing the plane to keep flying or to be sold, but FAA had to step in and ground it. Then, I can imagine, the cost of [FAA grounding] > [properly fixing it] means it got fixed. At least till the cost comparison tilted the other way.
raverbashing 7y ago
I'm with Boeing in this fix. The problem is not with the "the large amount of electrical systems, lack of bleed air". This is how things evolved. The main issue IIRC was manufacturing defects in some batteries that caused internal short circuits. > The fix was to put them in a stronger container with a hole in it so they can vent outside And this is an acceptable fix (beyond better QA/manufacturing practices of the battery). If the batteries fail the fault should be contained. The article you linked explains the changes Boeing implemented. Yes, batteries failed. The battery failure was contained correctly. Besides improving the reliability of the battery (which was addressed with some changes) that's what Boeing should have done (and did). They're not going back to NiCa or Lead batteries
- gsnedders 7y ago
  Also, unless you can guarantee the failure rate of the battery to be low enough, those incidents made it clear the battery needed to be better contained—even if you also decrease the failure rate.

foldr 7y ago

This is not the case. The 737 MAX has different handling characteristics to a regular 737, but there is nothing inherently unsafe about those handling characteristics. The purpose of MCAS was just to prevent the need for pilots to recertify by masking the difference.

danharaj 7y ago
Without MCAS a MAX has flight characteristics that would not pass FAA certification.
- foldr 7y ago
  I don't believe that's true. What's your source?
  - tzs 7y ago
    There are specific regulations on how the stick force must change in response to various flight conditions. Without MCAS the stick force curve of the 737-MAX does not satisfy those regulations. Do an HN search on "MCAS stick force curve" (without the quotes)[1] and you can find some discussion of this with cites to and quotes from specific sections of the regulations. [1] https://hn.algolia.com/?query=MCAS%20stick%20force%20curve&sort=byDate&prefix&page=0&dateRange=all&type=comment https://hn.algolia.com/?query=MCAS%20stick%20force%20curve&s...
    - foldr 7y ago
      There is no source in those comments for the claim that the 737-MAX would not satisfy these regulations without MCAS. Note that the actual regulations are a tad more complex than the incomplete sentence quoted: https://books.google.co.uk/books?id=5tAhOC4KC8MC&pg=PA200&lpg=PA200&dq=%22%22The+stick+force+curve+must+have+a+stable+slope%22%22&source=bl&ots=_B6qqMDW-K&sig=ACfU3U1jvCJhRgh2GLNa_3uPSPUBdWUvWA&hl=en&sa=X&ved=2ahUKEwijvpCNqa_iAhWIUt8KHT_1AagQ6AEwAnoECAoQAQ#v=onepage&q=%22%22The%20stick%20force%20curve%20must%20have%20a%20stable%20slope%22%22&f=false https://books.google.co.uk/books?id=5tAhOC4KC8MC&pg=PA200&lp...

sealthedeal 7y ago

100% agree. Anytime you are using software to hide a larger problem, that is a huge red flag.