Alaska Airlines Boeing 737 Max 9 incident

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gounion
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Alaska Airlines Boeing 737 Max 9 incident

Post by gounion »

So. A window blew out? WTF?

Details are still sketchy and hard to come by. Some news reports says it was a door, but it looks to me like a panel with a window blew out. At first, I thought it was like years ago, when an airliner in Hawaii lost most of the top half of the plane, but was able to land. That was because the old airplane, with the fuselage weakened after years of pressurizing and depressurizing, fell apart. That’s why today’s jets have a limited lifespan, unlike the much older airplanes that didn’t go as high and weren’t pressurized.

But nope, the plane is two months old.

Now, I’m no expert, I’m only a toolmaker, but I’m the most expert in this area on the board. But I’m educated in the metallurgy and construction of airplanes. So I’ve got some semi-educated guesses.

First, the 737 is a very old design, and the design is well tested and safe. The Max planes, however, have some big differences. Airliners like to stretch models, instead of making a whole new design of an airplane, as they don’t have to train pilots on new airplanes. And there’s only so much stretching you can do, and the manufacturers push the limits of what can safely be done. The Max is one such design. They have to have computer software do a lot because they plane reacts quite differently being stretched, and that’s what caused two crashes some years ago that caused the loss of all aboard.

Now, metal fatigue sure as hell isn’t the issue. And the plane wasn’t even up to cruising height.

So now it comes to the two main points. Either design or workmanship. Now, here’s where I admit that since I’ve been out of the trade for 25 years, there’s things I don’t know. I worked at Beechcraft on the Beech Starship in the late eighties, in the composite department, and it was a shit show, because no one really had a clue as to how composites worked, and what was the long-term ramifications of them, and the state of the art has moved forward a lot since then. While the original 737 was an all-aluminum craft, I don’t know how much composites are being used today.

I don’t see how this could happen in an aluminum assembly, as the rivets are inspected many different ways to make sure the work is done correctly. I’ve seen where a whole part of the plane had to be torn apart and re-done because the x-rays detected problems - and this is during the manufacturing process, before it goes out the door, so I don’t see that being the problem here.

If composites are used, there could have been mistakes in the process, not baked correctly, and the composites came apart.

The other problem is a systemic one. When I was in the business, most everything except for the avionics, computer systems and engines was done in-house. That way the company and the inspectors had complete control of the product. But now everything but final assembly is done by other companies and in other countries. You lose control of the product in that way. Boeing has had trouble with sub-assemblies from other countries. Wire harnesses are an issue still, with most of them made in Mexico now.

So it could be a sub-assembly problem from a sub-contractor.

I suspect they’ll be moving quickly on this one. This is where inspection stamps are important. All this assembly has a paper trail a mile long, and those whose stamps are on this plane are going to have some rough days ahead. That’s why I kept complete control of my stamp and refused to stamp anything I didn’t do myself, no matter how much pressure from however high up I got. Because you never know when a plane will have a problem.

But flight is still extremely safe. Thousands go up every day and come down safely. That’s because of government regulations. I’d feel just as good getting on an airplane today.
Glennfs
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Re: Alaska Airlines Boeing 737 Max 9 incident

Post by Glennfs »

gounion wrote: Sat Jan 06, 2024 11:46 am So. A window blew out? WTF?

Details are still sketchy and hard to come by. Some news reports says it was a door, but it looks to me like a panel with a window blew out. At first, I thought it was like years ago, when an airliner in Hawaii lost most of the top half of the plane, but was able to land. That was because the old airplane, with the fuselage weakened after years of pressurizing and depressurizing, fell apart. That’s why today’s jets have a limited lifespan, unlike the much older airplanes that didn’t go as high and weren’t pressurized.

But nope, the plane is two months old.

Now, I’m no expert, I’m only a toolmaker, but I’m the most expert in this area on the board. But I’m educated in the metallurgy and construction of airplanes. So I’ve got some semi-educated guesses.

First, the 737 is a very old design, and the design is well tested and safe. The Max planes, however, have some big differences. Airliners like to stretch models, instead of making a whole new design of an airplane, as they don’t have to train pilots on new airplanes. And there’s only so much stretching you can do, and the manufacturers push the limits of what can safely be done. The Max is one such design. They have to have computer software do a lot because they plane reacts quite differently being stretched, and that’s what caused two crashes some years ago that caused the loss of all aboard.

Now, metal fatigue sure as hell isn’t the issue. And the plane wasn’t even up to cruising height.

So now it comes to the two main points. Either design or workmanship. Now, here’s where I admit that since I’ve been out of the trade for 25 years, there’s things I don’t know. I worked at Beechcraft on the Beech Starship in the late eighties, in the composite department, and it was a shit show, because no one really had a clue as to how composites worked, and what was the long-term ramifications of them, and the state of the art has moved forward a lot since then. While the original 737 was an all-aluminum craft, I don’t know how much composites are being used today.

I don’t see how this could happen in an aluminum assembly, as the rivets are inspected many different ways to make sure the work is done correctly. I’ve seen where a whole part of the plane had to be torn apart and re-done because the x-rays detected problems - and this is during the manufacturing process, before it goes out the door, so I don’t see that being the problem here.

If composites are used, there could have been mistakes in the process, not baked correctly, and the composites came apart.

The other problem is a systemic one. When I was in the business, most everything except for the avionics, computer systems and engines was done in-house. That way the company and the inspectors had complete control of the product. But now everything but final assembly is done by other companies and in other countries. You lose control of the product in that way. Boeing has had trouble with sub-assemblies from other countries. Wire harnesses are an issue still, with most of them made in Mexico now.

So it could be a sub-assembly problem from a sub-contractor.

I suspect they’ll be moving quickly on this one. This is where inspection stamps are important. All this assembly has a paper trail a mile long, and those whose stamps are on this plane are going to have some rough days ahead. That’s why I kept complete control of my stamp and refused to stamp anything I didn’t do myself, no matter how much pressure from however high up I got. Because you never know when a plane will have a problem.

But flight is still extremely safe. Thousands go up every day and come down safely. That’s because of government regulations. I’d feel just as good getting on an airplane today.
In all seriousness I personally believe that Boeing is cutting costs and cutting quality to make more profit
Didn't you once tell me the current ceo is a bean counter not a plane builder.
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gounion
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Re: Alaska Airlines Boeing 737 Max 9 incident

Post by gounion »

Glennfs wrote: Sat Jan 06, 2024 11:48 am In all seriousness I personally believe that Boeing is cutting costs and cutting quality to make more profit
Didn't you once tell me the current ceo is a bean counter not a plane builder.
They have been for some time. Aircraft design is an afterthought to current leadership. That’s why they moved their HQ to Chicago, far away from any manufacturing facilities.

That’s why I included design in the possibilities.

I really do want to know how this shakes out. It’s got my old toolmaker problem-solving juices going. I love process investigations.
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Re: Alaska Airlines Boeing 737 Max 9 incident

Post by ZoWie »

This is addressed in a post I made at pretty much the same time. Maybe we both saw the same report on CNN. (MSNBC is much more interested in drumpf to bother with little things like air disasters.)

Oddly, the best story I've seen is in the Daily Mail. A London tabloid.

It's pretty clear that something is not right with the door frame. The pins that hold the door closed, as you know, could go on a bank vault. The door opens in, not out, and it appears from photos making the rounds that the entire frame detached from the fuselage. Everything's gone. There's just a big rectangular hole in the back of the cabin. You'd know more about what holds those frames in than I do, but I would assume they're riveted or bolted in pretty securely.

The question of union labor vs right to work is not relevant. The question of the CEO being a bean counter is marginally relevant, because cost cutting can cause lapses in safety, as any railroad employee can tell you to the point where you'll never live near the tracks.

It seems that I cannot edit the OP any longer, so I'll note here that something's rotten in the state of Illinois, not Washington. Apparently Seattle isn't the Boeing HQ any more.
Last edited by ZoWie on Sat Jan 06, 2024 12:00 pm, edited 1 time in total.
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gounion
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Re: Alaska Airlines Boeing 737 Max 9 incident

Post by gounion »

ZoWie wrote: Sat Jan 06, 2024 11:53 am This is addressed in a post I made at pretty much the same time. Maybe we both saw the same report on CNN. (MSNBC is much more interested in drumpf to bother with little things like air disasters.)

It's pretty clear that something is not right with the door frame. The pins that hold the door closed, as you know, could go on a bank vault. The door opens in, not out, and it appears from photos making the rounds that the entire frame detached from the fuselage. Everything's gone. There's just a big rectangular hole in the back of the cabin. You'd know more about what holds those frames in than I do, but I would assume they're riveted or bolted in pretty securely.

The question of union labor vs right to work is not relevant. The question of the CEO being a bean counter is marginally relevant, because cost cutting can cause lapses in safety, as any railroad employee can tell you to the point where you'll never live near the tracks.
Some stories say it’s a door, some says it’s a window. I think it’s a window, from the photos. A teenager can’t sit in a door isle.

And a door can’t move when pressurized. The structure around a door is also FAR stronger than the rest of the fuselage.
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Re: Alaska Airlines Boeing 737 Max 9 incident

Post by ZoWie »

The hole shown (however reluctantly) on CNN is much bigger than a window, and you can see the clear edges of a cutout that used to have something in it. I don't know much about airframes, but I know that a door is larger than a window. CNN was speculating that it was an emergency exit.
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gounion
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Re: Alaska Airlines Boeing 737 Max 9 incident

Post by gounion »

ZoWie wrote: Sat Jan 06, 2024 12:01 pm The hole shown (however reluctantly) on CNN is much bigger than a window, and you can see the clear edges of a cutout that used to have something in it. I don't know much about airframes, but I know that a door is larger than a window. CNN was speculating that it was an emergency exit.
If it’s a door, it’s an emergency exit.

I think it’s the entire panel around the window, based upon my knowledge. Now, let’s be clear: my experience was with light aircraft, business jets and fighter jets, and not airliners, so I could be wrong. I think it’s the entire panel assembly. Remember the windows are tiny, and the immediate area around the window are very strong.

But I’ll admit the entire thing has me puzzled.
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Re: Alaska Airlines Boeing 737 Max 9 incident

Post by ZoWie »

Could be. The answer would be to see what the panel looks like on a cargo version of the 737 Max 9, except that there isn't one. They use wide-body jets retired from passenger service for that.
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Re: Alaska Airlines Boeing 737 Max 9 incident

Post by gounion »

ZoWie wrote: Sat Jan 06, 2024 12:08 pm Could be. The answer would be to see what the panel looks like on a cargo version of the 737 Max 9, except that there isn't one. They use wide-body jets retired from passenger service for that.
Had a lot of experience with one of our represented companies that took airliners and converted them to cargo. It was quite interesting. It’s a BIG hole that hey cut out and put the cargo doors in. Those guys were good.
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Re: Alaska Airlines Boeing 737 Max 9 incident

Post by ZoWie »

Cargo conversions ARE interesting. They really re-work those planes. There are some great 747s out there.
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Re: Alaska Airlines Boeing 737 Max 9 incident

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ZoWie wrote: Sat Jan 06, 2024 12:17 pm Cargo conversions ARE interesting. They really re-work those planes. There are some great 747s out there.
Yeah, this company mostly did 757s, though they did some 747 work. This was in the early 2000’s, before Amazon REALLY took off. You still see the smaller planes for FedEx, even puddle-jumpers. UPS uses 757s and up.
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Re: Alaska Airlines Boeing 737 Max 9 incident

Post by ZoWie »

Here FedEx uses mostly old DC-10s, which as we know were designed to have a large cargo door in all of their airframes. They seem to be phasing in other aircraft, since these are getting kind of old.
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Re: Alaska Airlines Boeing 737 Max 9 incident

Post by Number6 »

From the picture, it looks like it was an emergency exit that blew out. Notice, on the left side of the below picture is a window panel and to its right is where the section that blew out is. The outer frame is intact and the inner panels along the sides of the exit are gone exposing insulation. I have no idea of how it happened but grounding the planes for inspection is the correct step.

Image

I dunno, Six. The seats are too close together. That's why people like the exit rows - there's more leg room, as people have to be able to get through the door easily.

I think it is probably the full panel with the window. But again, I'm not sure.
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Re: Alaska Airlines Boeing 737 Max 9 incident

Post by gounion »

What I thought. Via CNN:
The planes were returned to service following "in-depth and thorough plug door inspections," Alaska said in a statement. The "plug door" refers to a portion of the plane's fuselage that the manufacturer can put in place instead of an emergency exit door, depending on the configuration requested by an airline. This is the portion of the plane that blew off Friday night, according to firsthand accounts and video from passengers, leaving a refrigerator-sized hole.
It wasn’t a door. Honestly, I hadn’t heard of a “plug”, but as I said, I hadn’t worked for an airliner manufacturer.
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Re: Alaska Airlines Boeing 737 Max 9 incident

Post by ZoWie »

Right, there was no door there, but the plug was still closing a hole in the fuselage. This hole is clearly shown in the photos.
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Re: Alaska Airlines Boeing 737 Max 9 incident

Post by Glennfs »

ZoWie wrote: Sun Jan 07, 2024 11:22 am Right, there was no door there, but the plug was still closing a hole in the fuselage. This hole is clearly shown in the photos.
I am guessing it would be similar to a freeze plug on an engine block
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gounion
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Re: Alaska Airlines Boeing 737 Max 9 incident

Post by gounion »

Glennfs wrote: Sun Jan 07, 2024 12:20 pm I am guessing it would be similar to a freeze plug on an engine block
No, not at all. It’s just a window assembly instead of a door assembly.
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