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Anon Boeing engineer reveals why the 737 door blew off

215 points by jslezak 3y ago

tony2016 3y ago
American airline companies should just buy Airbus planes until Boeing gets its act together.
jslezak 3y ago
What a mess
dboreham 3y ago
Ah, so the mystery is solved: the doors were never bolted. Inspections done in Renton caught this in 99% of cases but nobody thought to follow the defect to source and get it fixed there. Classic case of "you can't inspect-in quality".
- deleted 3y ago
  [deleted]
- avalys 3y ago
  That’s not what is stated in the linked posts.
  - monocasa 3y ago
    > With that out of the way… why did the left hand (LH) mid-exit door plug blow off of the 737-9 registered as N704AL? Simple- as has been covered in a number of articles and videos across aviation channels, there are 4 bolts that prevent the mid-exit door plug from sliding up off of the door stop fittings that take the actual pressurization loads in flight, and these 4 bolts were not installed when Boeing delivered the airplane, our own records reflect this.
    - avalys 3y ago
      Did you read the whole thing? Boeing removed the bolts to fix another issue around the door and neglected to reinstall them.
      - mardifoufs 3y ago
        Sure, that's not unbelievable. Tampering with the records is the weird part. I can't think of any reason why spirit or Boeing would be willing to do that when they can just... fix the repair if they knew about it? And if they didn't, then why tamper with the process management systems?
      - dboreham 3y ago
        Spirit removed them, not Boeing.
      - monocasa 3y ago
        I read 'they were never bolted' as 'upon delivery of the aircraft, the bolts holding in the plug were not installed' in order to differentiate from the case of 'the bolts loosened during use of the aircraft after delivery to customer'. But I can see how we could read to different statements from the parent.
    - jacquesm 3y ago
      Pretty wild because such a delivery would normally include at least one flight.
    - k1t 3y ago
      Although TFA doesn't explicitly say the bolts were there to begin with, the bigger issue is that repairs were required on this door, the repair team lied about what they did, which bypassed a QA check that would have likely caught the missing bolts. Given the awful (criminal?) behavior of the repair team, it seems reasonable to assume the bolts were initially present and they just forgot to put them back - rather than that they were missing from the start.
  - dboreham 3y ago
    It says two things: > has in the past 365 calendar days recorded 392 nonconforming findings on 737 mid fuselage door installations which prompted my comment. then it says that the door in question was re-worked by Spirit employees. It implies that the bolts were removed and not re-fitted, but I don't see evidence that they were ever fitted. Perhaps they were, but then removed by people working for a company that day to day doesn't fit bolts, or perhaps they were never there and the people working for the non-bolt-fitting company didn't see the problem with that.
    - inemesitaffia 3y ago
      Maybe you're in a company where you have to record the process of making instant coffee. You have your screwed container of coffee you have a cup and a kettle of hot water. Someone later finds the coffee container open and spilled by the resident cat. There's no record of the container opened but there's requests for coffee and completed work orders for coffee have been billed which you can't do without opening the coffee container
  - wongarsu 3y ago
    The conclusion is still pretty spot on. The company known (to Boeing) for shoddy work does a warranty repair as a follow-up for a failed warranty repair, and while Boeing QA caught the first repair going wrong it didn't catch the second repair going wrong because those bolts weren't tagged as having been touched. Still sounds like a clear case of an unbelievable amount of bad quality from Spirit, and Boeing not pressing the issue until something finally slips through the cracks
    - mardifoufs 3y ago
      Even that could've been believable. But , and correct me if I'm wrong, the comment claims that Boeing's systems clearly show that the bolts were never installed. Like, they knew about it even after all of that, and knew about it upon delivery. Again, that just doesn't even make sense from incompetence, greed, laziness or any other angle. It's not like the same people on the factory floor who would want to sweep the bad repair under the rug[0] also gets to control the delivery process, the massive paperwork, checks, automated checks, etc that are inherent to massively complex manufacturing. Again, this is claiming that the system knew about it, and that it was written there all along. So we are way beyond manufacturing issues here. [0] (not that they would for what is claimed to be literally just painting over the plugs, without installing anything. that's just dumb, it's not something you can just get away with, it would've been visible from the very first flights and would he basically a world's first)
      - anotherhue 3y ago
        Stupid metaphor but please help me understand, if I ordered a chicken-sandwich and was served with raw-meat, I would not politely return it and request a correction, I would flee the scene. How are they in any sense whatsoever still working with a company or process that would 'paint over the plugs'? That was the warning sign. I'm sure the answer is money somehow but is that even accurate? Surely this is more costly? Different budget maybe?
        tatersolid 3y ago
        > How are they in any sense whatsoever still working with a company or process that would 'paint over the plugs'? Because there is no alternative supplier that could supply the same components in a shorter-than-years timeframe. And they don’t want to halt all production as it would bankrupt the company. To the HN crowd, this is like AWS becoming broken and unreliable, but your entire build and architecture has AWS baked in. Moving to Azure or Google or whatever would take years of engineering and data migration. So you paper over the holes as best you can to keep the lights on.
- mardifoufs 3y ago
  I don't know, that's very very unlikely. I'm mostly familiar with the 787 inspection process though. still the events listed here are basically harder, longer and involve more bickering than just doing the repair. but who knows... as I said, I just know that this would be impossible with the 787 and way way harder than what is in relative term a simpler repair. Spirit might be shoddy, incompetent, etc but not putting bolts at all and fraudulently tampering with records? Painting over them? Why? Airplanes take longer to repair, or ship routinely, 737 parts are extremely available especially for the literal manufacturer, it's not some sort of insane repair... Again, even assuming sheer incompetence this is too competent
pxeboot 3y ago
If this is true, it is impressive the door stayed attached to the plane as long as it did. If they really forgot to install all of the bolts intended to hold it in place, I would have expected to to fail much sooner.
- jurassicfoxy 3y ago
  One thing I don't understand is the why the door isn't designed so that pressure doesn't seal it tighter. Like a manhold cover. It seems at least the door needs to be "lifted" to be removed, so the missing bolts hold it down (but presumably do not hold against outward pressure). I guess that's why it doesn't immediately fall out. Has anyone seen mechanical or assembly drawings of these things?
  - TaylorAlexander 3y ago
    My guess is a combination of it would be harder to install that way and designers never considered people would leave the bolts out! Hard to design a plane for such serious assembly oversight.
    - uoaei 3y ago
      Competent designers do think about those things.
      - icegreentea2 3y ago
        Competent designers and engineers consider the risks of incorrect assembly, and depending on risk assessment (probability vs severity of failure), and cost-benefit assessment (cost of redesign vs cost of inspection), and based on that decide on if further mitigations are required.
        TaylorAlexander 3y ago
        Sure that makes sense.
gnabgib 3y ago
Do we need another duplicate posting? First post was 12 hours ago[0] (469 points, 362 comments), and a dupe was 3 hours ago (116 points, 7 remaining comments - was merged into the first) [0]: https://news.ycombinator.com/item?id=39102021 https://news.ycombinator.com/item?id=39102021
- dheera 3y ago
  I wasn't awake 12 hours ago and it fell off the front page, so yes.
  - metadat 3y ago
    Try https://news.ycombinator.com/front https://news.ycombinator.com/front
- Mathnerd314 3y ago
  This is the better URL, as it is the original source.
  - m463 3y ago
    much better url
  - gnabgib 3y ago
    It is, and that was suggested/linked to in both the other discussions before this was posted.
- deleted 3y ago
  [deleted]
jimmaswell 3y ago
It's not very typical, I'd like to make that point.
- deleted 3y ago
  [deleted]
- kyralis 3y ago
  Built to very rigorous aerospace engineering standards.
- davidhyde 3y ago
  At least the front didn't fall off. https://www.youtube.com/watch?v=3m5qxZm_JqM https://www.youtube.com/watch?v=3m5qxZm_JqM
- CodeWriter23 3y ago
  A QA/SOP-based company either has a culture where nobody would dare violate SOP or it doesn’t.
- deleted 3y ago
  [deleted]
nntwozz 3y ago
I don't trust bike shops to take care of my mountain bike, I don't want to break my neck because of some mechanic. That's why I do my own service. I don't fly anymore but I guess next time I'm going to have to build my own aircraft.
- deleted 3y ago
  [deleted]
inamberclad 3y ago
In my opinion, the fact that this airplane isn't legally an airplane yet, just a collection of parts, is part of the problem. Boeing and Spirit should be criminally liable for mismanaged production, or at the very least have their production certificate for the type revoked.
deleted 3y ago
[deleted]
morcheeba 3y ago
Related question: I've seen news reports that the plane had experienced three recent pressurization issues (cabin pressure warnings). Does anyone know what kind of warning this was? Was it: - too low pressure, meaning that the door might have been leaking before it blew out. - too high pressure, meaning that the door had extra force on it.
- ars 3y ago
  Neither. The pressure was fine, the sensor or controller was not working correctly.
deleted 3y ago
[deleted]
deleted 3y ago
[deleted]
Redoubts 3y ago
Can someone contextualize this link? On its face, I'm seeing the equivalent of someone posting a big-tech expose on this HN, only for PG himself to reply saying "pls email me at pg@ycombinator.com"; and then another reply suggesting how to avoid being outed just like Journalist X's source was, only for Journalist X to reply with "if you know how my source was outed, please text me at <cell>" Like what is this site even?

215 points by jslezak 3y ago

tony2016 3y ago

American airline companies should just buy Airbus planes until Boeing gets its act together.

jslezak 3y ago

What a mess

dboreham 3y ago

Ah, so the mystery is solved: the doors were never bolted. Inspections done in Renton caught this in 99% of cases but nobody thought to follow the defect to source and get it fixed there. Classic case of "you can't inspect-in quality".

deleted 3y ago
[deleted]
avalys 3y ago
That’s not what is stated in the linked posts.
- monocasa 3y ago
  > With that out of the way… why did the left hand (LH) mid-exit door plug blow off of the 737-9 registered as N704AL? Simple- as has been covered in a number of articles and videos across aviation channels, there are 4 bolts that prevent the mid-exit door plug from sliding up off of the door stop fittings that take the actual pressurization loads in flight, and these 4 bolts were not installed when Boeing delivered the airplane, our own records reflect this.
  - avalys 3y ago
    Did you read the whole thing? Boeing removed the bolts to fix another issue around the door and neglected to reinstall them.
    - mardifoufs 3y ago
      Sure, that's not unbelievable. Tampering with the records is the weird part. I can't think of any reason why spirit or Boeing would be willing to do that when they can just... fix the repair if they knew about it? And if they didn't, then why tamper with the process management systems?
    - dboreham 3y ago
      Spirit removed them, not Boeing.
    - monocasa 3y ago
      I read 'they were never bolted' as 'upon delivery of the aircraft, the bolts holding in the plug were not installed' in order to differentiate from the case of 'the bolts loosened during use of the aircraft after delivery to customer'. But I can see how we could read to different statements from the parent.
  - jacquesm 3y ago
    Pretty wild because such a delivery would normally include at least one flight.
  - k1t 3y ago
    Although TFA doesn't explicitly say the bolts were there to begin with, the bigger issue is that repairs were required on this door, the repair team lied about what they did, which bypassed a QA check that would have likely caught the missing bolts. Given the awful (criminal?) behavior of the repair team, it seems reasonable to assume the bolts were initially present and they just forgot to put them back - rather than that they were missing from the start.
- dboreham 3y ago
  It says two things: > has in the past 365 calendar days recorded 392 nonconforming findings on 737 mid fuselage door installations which prompted my comment. then it says that the door in question was re-worked by Spirit employees. It implies that the bolts were removed and not re-fitted, but I don't see evidence that they were ever fitted. Perhaps they were, but then removed by people working for a company that day to day doesn't fit bolts, or perhaps they were never there and the people working for the non-bolt-fitting company didn't see the problem with that.
  - inemesitaffia 3y ago
    Maybe you're in a company where you have to record the process of making instant coffee. You have your screwed container of coffee you have a cup and a kettle of hot water. Someone later finds the coffee container open and spilled by the resident cat. There's no record of the container opened but there's requests for coffee and completed work orders for coffee have been billed which you can't do without opening the coffee container
- wongarsu 3y ago
  The conclusion is still pretty spot on. The company known (to Boeing) for shoddy work does a warranty repair as a follow-up for a failed warranty repair, and while Boeing QA caught the first repair going wrong it didn't catch the second repair going wrong because those bolts weren't tagged as having been touched. Still sounds like a clear case of an unbelievable amount of bad quality from Spirit, and Boeing not pressing the issue until something finally slips through the cracks
  - mardifoufs 3y ago
    Even that could've been believable. But , and correct me if I'm wrong, the comment claims that Boeing's systems clearly show that the bolts were never installed. Like, they knew about it even after all of that, and knew about it upon delivery. Again, that just doesn't even make sense from incompetence, greed, laziness or any other angle. It's not like the same people on the factory floor who would want to sweep the bad repair under the rug[0] also gets to control the delivery process, the massive paperwork, checks, automated checks, etc that are inherent to massively complex manufacturing. Again, this is claiming that the system knew about it, and that it was written there all along. So we are way beyond manufacturing issues here. [0] (not that they would for what is claimed to be literally just painting over the plugs, without installing anything. that's just dumb, it's not something you can just get away with, it would've been visible from the very first flights and would he basically a world's first)
    - anotherhue 3y ago
      Stupid metaphor but please help me understand, if I ordered a chicken-sandwich and was served with raw-meat, I would not politely return it and request a correction, I would flee the scene. How are they in any sense whatsoever still working with a company or process that would 'paint over the plugs'? That was the warning sign. I'm sure the answer is money somehow but is that even accurate? Surely this is more costly? Different budget maybe?
      - tatersolid 3y ago
        > How are they in any sense whatsoever still working with a company or process that would 'paint over the plugs'? Because there is no alternative supplier that could supply the same components in a shorter-than-years timeframe. And they don’t want to halt all production as it would bankrupt the company. To the HN crowd, this is like AWS becoming broken and unreliable, but your entire build and architecture has AWS baked in. Moving to Azure or Google or whatever would take years of engineering and data migration. So you paper over the holes as best you can to keep the lights on.
mardifoufs 3y ago
I don't know, that's very very unlikely. I'm mostly familiar with the 787 inspection process though. still the events listed here are basically harder, longer and involve more bickering than just doing the repair. but who knows... as I said, I just know that this would be impossible with the 787 and way way harder than what is in relative term a simpler repair. Spirit might be shoddy, incompetent, etc but not putting bolts at all and fraudulently tampering with records? Painting over them? Why? Airplanes take longer to repair, or ship routinely, 737 parts are extremely available especially for the literal manufacturer, it's not some sort of insane repair... Again, even assuming sheer incompetence this is too competent

pxeboot 3y ago

If this is true, it is impressive the door stayed attached to the plane as long as it did. If they really forgot to install all of the bolts intended to hold it in place, I would have expected to to fail much sooner.

jurassicfoxy 3y ago
One thing I don't understand is the why the door isn't designed so that pressure doesn't seal it tighter. Like a manhold cover. It seems at least the door needs to be "lifted" to be removed, so the missing bolts hold it down (but presumably do not hold against outward pressure). I guess that's why it doesn't immediately fall out. Has anyone seen mechanical or assembly drawings of these things?
- TaylorAlexander 3y ago
  My guess is a combination of it would be harder to install that way and designers never considered people would leave the bolts out! Hard to design a plane for such serious assembly oversight.
  - uoaei 3y ago
    Competent designers do think about those things.
    - icegreentea2 3y ago
      Competent designers and engineers consider the risks of incorrect assembly, and depending on risk assessment (probability vs severity of failure), and cost-benefit assessment (cost of redesign vs cost of inspection), and based on that decide on if further mitigations are required.
      - TaylorAlexander 3y ago
        Sure that makes sense.

gnabgib 3y ago

Do we need another duplicate posting? First post was 12 hours ago[0] (469 points, 362 comments), and a dupe was 3 hours ago (116 points, 7 remaining comments - was merged into the first) [0]: https://news.ycombinator.com/item?id=39102021 https://news.ycombinator.com/item?id=39102021

dheera 3y ago
I wasn't awake 12 hours ago and it fell off the front page, so yes.
- metadat 3y ago
  Try https://news.ycombinator.com/front https://news.ycombinator.com/front
Mathnerd314 3y ago
This is the better URL, as it is the original source.
- m463 3y ago
  much better url
- gnabgib 3y ago
  It is, and that was suggested/linked to in both the other discussions before this was posted.
deleted 3y ago
[deleted]

jimmaswell 3y ago

It's not very typical, I'd like to make that point.

deleted 3y ago
[deleted]
kyralis 3y ago
Built to very rigorous aerospace engineering standards.
davidhyde 3y ago
At least the front didn't fall off. https://www.youtube.com/watch?v=3m5qxZm_JqM https://www.youtube.com/watch?v=3m5qxZm_JqM
CodeWriter23 3y ago
A QA/SOP-based company either has a culture where nobody would dare violate SOP or it doesn’t.
deleted 3y ago
[deleted]

nntwozz 3y ago

I don't trust bike shops to take care of my mountain bike, I don't want to break my neck because of some mechanic. That's why I do my own service. I don't fly anymore but I guess next time I'm going to have to build my own aircraft.

deleted 3y ago
[deleted]

inamberclad 3y ago

In my opinion, the fact that this airplane isn't legally an airplane yet, just a collection of parts, is part of the problem. Boeing and Spirit should be criminally liable for mismanaged production, or at the very least have their production certificate for the type revoked.

deleted 3y ago

[deleted]

morcheeba 3y ago

Related question: I've seen news reports that the plane had experienced three recent pressurization issues (cabin pressure warnings). Does anyone know what kind of warning this was? Was it: - too low pressure, meaning that the door might have been leaking before it blew out. - too high pressure, meaning that the door had extra force on it.

ars 3y ago
Neither. The pressure was fine, the sensor or controller was not working correctly.

deleted 3y ago

[deleted]

deleted 3y ago

[deleted]

Redoubts 3y ago

Can someone contextualize this link? On its face, I'm seeing the equivalent of someone posting a big-tech expose on this HN, only for PG himself to reply saying "pls email me at pg@ycombinator.com"; and then another reply suggesting how to avoid being outed just like Journalist X's source was, only for Journalist X to reply with "if you know how my source was outed, please text me at <cell>" Like what is this site even?