Author Topic: Boeing 737 Max again, it would be nice if the windows [door plugs] stayed in!  (Read 99405 times)

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Offline MT

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Re: Boeing 737 Max again, it would be nice if the windows stayed in!
« Reply #125 on: January 10, 2024, 11:50:24 pm »
 

Offline floobydust

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Re: Boeing 737 Max again, it would be nice if the windows stayed in!
« Reply #126 on: January 11, 2024, 01:08:40 am »
He's a bit out to lunch, the stop fittings are not only for the plug door. It had to traverse up and out, so it's obvious the locking bolts were not there. Never mind the lower hinge bracket bolts being loose on United...

People expect the NTSB to be on top of a shady manufacturer and they can't be, it's impossible - their job is finding incident root cause, not babysitting Boeing.
People expect the FAA to be on top of a shady manufacturer and they can't be, it's impossible - they would need to be as technically capable as Boeing.  That is very expensive for engineers and such, just for regulatory oversight, when that team could simply build planes with their knowledge and expertise.

At some point Boeing needs to be accountable and get their shit together, instead of people expecting agencies to find all mistakes. Like I said, you can't inspect-in quality.

The rudder fasteners were found loose, missing washers etc. some time ago. Clearly nothing was fixed up over at Boeing after that.
Having a bean counter for CEO - great idea  :-DD
 
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Offline amyk

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Re: Boeing 737 Max again, it would be nice if the windows stayed in!
« Reply #127 on: January 11, 2024, 02:42:54 am »
It's even worse for Boeing if one considers that four fasteners had to be omitted for this to happen. This isn't even an inspection problem (which should ideally be finding very little errors, maybe one in a few dozen planes) --- I think it's either deliberate sabotage or a total lack of competence.
 

Offline floobydust

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Re: Boeing 737 Max again, it would be nice if the windows stayed in!
« Reply #128 on: January 11, 2024, 03:53:08 am »
That looks like a configuration error, where somebody put it together as "the usual" emergency exit door, not a plug door.
Or maybe getting those bolts out of inventory had an exception occur and they got forgotten. Many things can happen. It might be very difficult to work on the inside on your hands and knees with the two rows of seats over a bit too.
The planes are fucking sardine cans, I'm not fat or obese but do not fit in a seat at all- super cramped and uncomfortable. It really hurts after many hours. Hail hail MAX profit.
Imagine putting in those locking bolts, not a lot of room and the last two seat rows might even be in the way.

The bottom hinge bracket using split lockwashers over the slot is IMHO a design error. There should be a flat washer or more. I could see them working loose.

This door accident is showing so many gross errors by Boeing. Like it rolled out of Detroit circa 1976 or something.
 

Offline bdunham7

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Re: Boeing 737 Max again, it would be nice if the windows stayed in!
« Reply #129 on: January 11, 2024, 04:16:59 am »
The bottom hinge bracket using split lockwashers over the slot is IMHO a design error. There should be a flat washer or more. I could see them working loose.

I haven't actually seen a split, but if there is one I agree that is problematic IMO.  I can't imagine it being the design, and if it is we can conclude that it isn't working well since they appear to be coming loose on a regular basis.
A 3.5 digit 4.5 digit 5 digit 5.5 digit 6.5 digit 7.5 digit DMM is good enough for most people.
 

Offline floobydust

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Re: Boeing 737 Max again, it would be nice if the windows stayed in!
« Reply #130 on: January 11, 2024, 04:46:05 am »
Pic shows two loose bolts (one at the far back) and I didn't like the lockwasher over a slot. I thought this is United Airlines? The castellated nut (locking bolt) gets a flat washer.
This piece is flopping outside the Alaska Airlines plane, so the bolts fell out or they broke.

I realized every car, some Canadian airplanes and Airbus - have a door ajar switch and indication light. It might have been useful here?
Hail hail MAX profit Boeing  >:D
« Last Edit: January 11, 2024, 04:49:45 am by floobydust »
 

Offline pickle9000

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Re: Boeing 737 Max again, it would be nice if the windows stayed in!
« Reply #131 on: January 11, 2024, 05:25:54 am »
- The loose bolts all appear to be in line, not flopping around. So into a threaded hole or insert.
- Green lower pic behind the plastic appears to have at least one bolt and is still on the lift pin so at least one of the four retaining bolts are there.
- The green lift bracket attaches to the door so the door was hanging by that one point until it was sheared off.

I wonder if the other green bracket is still attached to the door?
 

Offline jfiresto

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Re: Boeing 737 Max again, it would be nice if the windows stayed in!
« Reply #132 on: January 11, 2024, 07:30:19 am »
Hail hail MAX profit Boeing  >:D
It is just good old shareholder value and executive talent retention in action. The 737 [profit]MAX. I like that.
-John
 

Online tom66

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Re: Boeing 737 Max again, it would be nice if the windows stayed in!
« Reply #133 on: January 11, 2024, 08:11:21 am »
That looks like a configuration error, where somebody put it together as "the usual" emergency exit door, not a plug door.
Or maybe getting those bolts out of inventory had an exception occur and they got forgotten. Many things can happen. It might be very difficult to work on the inside on your hands and knees with the two rows of seats over a bit too.
The planes are fucking sardine cans, I'm not fat or obese but do not fit in a seat at all- super cramped and uncomfortable. It really hurts after many hours. Hail hail MAX profit.
Imagine putting in those locking bolts, not a lot of room and the last two seat rows might even be in the way.

The bottom hinge bracket using split lockwashers over the slot is IMHO a design error. There should be a flat washer or more. I could see them working loose.

This door accident is showing so many gross errors by Boeing. Like it rolled out of Detroit circa 1976 or something.

I think the seats are usually put in by the airlines, because they tend to be customised to the airline's requirements.  Either way they can be one of the last things to go in, after the interior trim is put on, so they shouldn't have blocked the assembly of the plug. 
 

Offline mendip_discovery

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Re: Boeing 737 Max again, it would be nice if the windows stayed in!
« Reply #134 on: January 11, 2024, 11:28:46 am »
I think the seats are usually put in by the airlines, because they tend to be customised to the airline's requirements.  Either way they can be one of the last things to go in, after the interior trim is put on, so they shouldn't have blocked the assembly of the plug.

Unless the plug is the one being used to get the units in.
Motorcyclist, Nerd, and I work in a Calibration Lab :-)
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So everyone is clear, Calibration = Taking Measurement against a known source, Verification = Checking Calibration against Specification, Adjustment = Adjusting the unit to be within specifications.
 

Offline GyroTopic starter

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Re: Boeing 737 Max again, it would be nice if the windows stayed in!
« Reply #135 on: January 11, 2024, 11:48:36 am »
Ok, I think I have a mental picture of what has been going on here (from the fitting problems, loose bolts etc.perspective) but please bear with me, this is going to get wordy!

Fundamentals (which might not be immediately intuitive):

1. The bottom hinge pins and guides, and the top guide castings, are not responsible for keeping the door closed under cabin pressure differential. This function is performed by the Stop Pads and Stop Fittings. There are 12 of these, 6 on each side. The top and bottom edges are obviously rigid enough to resist cabin pressure without further local support.

2. As a 'plug' door, the stop pads and fitting interlock - The stop fittings on the door must pass inside the stop pads on the frame when the door moves downwards to the locked position. With them interlocked, there's no way the door can open under pressure differential (again, it is a plug design). The clearance between the pads and fittings must necessarily be close - you don't want the door moving out significantly as the cabin is pressurized.

3. Everything else - the hinge pins and guides and the upper roll pins and castings are only there to keep the 12 stop pads and fittings interlocked before the cabiin is pressurized. After this, they play no role in holding to door closed. Their only other function is to facilitate insertion and removal, which only happens on assembly, and probably, major inspection.

3. Fitting the hinge pin guides is part of the door manufacture. Their bolts will have been torqued up during assembly.


What I think is possibly happening at the factory (I've used 'door' for 'plug door' from now on), resulting from poor moral and time pressure:

1. The door must first be lowered onto the hinge pins at the bottom of the door frame. This isn't necessarily easy, the pins must be set parallel and introduced into the guide fittings on the door. First you have to slip on two uncompressed lifting springs onto the pins, then you have to get the ends of the pins into the guide fittings. The pins don't have alignment tapers, instead they have the threaded portion for travel stop washer and lock nuts, followed by a hard shoulder to the full diameter. The door itself weights 36kg. Damn, I can't get both pins in! First possible alignment issue - the spacing hings pins and guides might not match exactly: Possible bodge solution, loosen off the bolts on one of the hinge guides, there, that's better, both pins go in now.

2. Hinge the door in and try to push it down to the closed position. Firstly it needs to be pushed down against the spring pressure that holds it in the lifted position. Compressing the springs will increase the pressure to higher than the 36kgf needed to support it open - probably requires a boot pressure down on the bottom of the door.

3. Damn, the stop pads and fitting won't pass and interlock! Second possible alignment issue: The clearances are tight and something isn't sufficiently aligned - maybe the hinge pin guides, maybe the hinge mounts themselves to the airframe (I wonder if any of those bolts have been found loose!), maybe the roll pin guide fittings at the top of the door. Possible bodge solution, loosen the bolts on the upper guide fittings or hinge pin guide fittings to make the stop pads interlock.

4. Fitting the locking bolts (lower): The door needs to be pushed down against spring pressure, whilst bending right over and trying to push the bolts through from the rear (skin side) of the pin guide casting, whilst trying to align the holes in the casting with the one in the hinge pin (bugger this!). Hopefully it eventually goes in and the assembler isn't too pissed off to fit the castellated nut and pin. Now the other side, trying to do the same thing, only with the other (non favored) hand. Damn, I can't get the second bolt through! Third possible alignment issue: With the door is sitting in the frame, maybe it is impossible to get the other bolt to go through - the assembler is pushing against two springs and effectively trying to move the whole height of the door from side to side! Possible bodge solutions: 1) loosen the pin guide mounting bolts or 2) leave the bolt out - the other one and the top ones will hold it!

5. Top roll pin guide fitting casting locking bolts. This one I find most difficult to understand. At this stage, the door ought to be held down sufficiently by the hinge pin bolt(s). Maybe not if the pin guide mounting bolts have been loosened. Even if not, some downward foot pressure on the door ought to be enough to pull it down low enough for the roll pin to clear the bolt holes. I can't work this one out - worst case, the door is slightly tilted by the shenanigans at the bottom of the door I suppose. Maybe they were forgotten on that one plane and present on all the others under inspection. I'm sure the airlines would have flagged it damned quickly if the had found any of those missing, but up to now it mainly seems to be loose bolts.

6. Have every intention of tightening the awkward to access loose bolts whilst be pressured to get on with the next job.

All of the above might also have been complicated by the door being stuffed with fibreglass insulation. It's not shown in any of the pictures but the rest of the cabin is, so presumably the door too.
 
I don't think any of the four lock pins bolts need to be torqued up by the way, they are there to block side force and the castellated nut and split/cotter pin will prevent them from coming out, they would need to be backed off until the drilled cotter pin hole is accessible anyway. Worst case, overtigntening could crack the casting.


P.S. The movement stop washers and lock nuts on the ends of the hinge pins may or may not have been forgotten. Possibly one of them was on the lost door. One was certainly there because the ripped off pin guide (rear) was still with the plane. The front one was either not present of was ripped off, if so, there will be stripped threads on the pin and a hell of a witness mark on the plane door. Worst case, they aren't essential, although they could give some engineer a hell of a shock as the door jumps out on him when he opens it!
« Last Edit: January 11, 2024, 12:31:42 pm by Gyro »
Best Regards, Chris
 
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Online Andy Chee

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Re: Boeing 737 Max again, it would be nice if the windows stayed in!
« Reply #136 on: January 11, 2024, 12:15:59 pm »
All of the above might also have been complicated by the door being stuffed with fibreglass insulation. It's not shown in any of the pictures but the rest of the cabin is, so presumably the door too.
The fiberglass insulation should not be installed until the bolts have been inspected and signed off.
 

Offline GyroTopic starter

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Re: Boeing 737 Max again, it would be nice if the windows stayed in!
« Reply #137 on: January 11, 2024, 12:23:04 pm »
At the first fitting, yes. But what about when the door is subsequently removed to aid internal fit-out at the Boeing factory? Do they pull it all out again in practice?
« Last Edit: January 11, 2024, 12:25:02 pm by Gyro »
Best Regards, Chris
 
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Online Andy Chee

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Re: Boeing 737 Max again, it would be nice if the windows stayed in!
« Reply #138 on: January 11, 2024, 12:37:54 pm »
At the first fitting, yes. But what about when the door is subsequently removed to aid internal fit-out at the Boeing factory? Do they pull it all out again in practice?
To gain access to the bolts for plug removal, yes, the fibreglass insulation would have to be pulled out.
 

Offline GyroTopic starter

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Re: Boeing 737 Max again, it would be nice if the windows stayed in!
« Reply #139 on: January 11, 2024, 01:22:20 pm »
[deleted] too much added complication.
Best Regards, Chris
 

Offline MT

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Re: Boeing 737 Max again, it would be nice if the windows stayed in!
« Reply #140 on: January 11, 2024, 02:21:49 pm »
 

Offline GyroTopic starter

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Re: Boeing 737 Max again, it would be nice if the windows stayed in!
« Reply #141 on: January 11, 2024, 04:26:36 pm »
Lucky for Boeing that one was an Airbus.
Best Regards, Chris
 

Offline pickle9000

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Re: Boeing 737 Max again, it would be nice if the windows stayed in!
« Reply #142 on: January 11, 2024, 05:11:31 pm »
I wonder if this whole thing could be an order of operations change?

Even if it had engineering approval without testing it's risky. Of course things like this instigated
by an efficiency expert.
 

Offline SiliconWizard

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Re: Boeing 737 Max again, it would be nice if the windows stayed in!
« Reply #143 on: January 11, 2024, 09:06:12 pm »
I wonder if they will change CEOs again? Maybe that will help? :-DD
 
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Offline coppercone2

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Re: Boeing 737 Max again, it would be nice if the windows stayed in!
« Reply #144 on: January 11, 2024, 10:36:59 pm »
I wonder if they will change CEOs again? Maybe that will help? :-DD

I swear thats like a decoy flare at this point they need to make him fix it

the CEO makes a decision because someone tells him we are not making money doing this or that and you need to put your foot down. Who is saying it?
They probobly ask for financial analysis and no matter who asks the question they get the same result. There is some kind of problem some where. Clearly if they replace the man again then it will have the same results. Someone must have a very unrealistic view of the  process that keeps making these suggestions.

They need to look at the base information gathered used to make the recent bad decisions and determine why its either gathered incorrectly or processed incorrectly. Do analysis as if the CEO was the same person both times since the same thing keeps happening.

The company seems to be trapped in a time loop like time squared in startrek TNG.
« Last Edit: January 11, 2024, 10:42:02 pm by coppercone2 »
 

Offline pickle9000

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Re: Boeing 737 Max again, it would be nice if the windows stayed in!
« Reply #145 on: January 11, 2024, 10:37:39 pm »
I wonder if they will change CEOs again? Maybe that will help? :-DD

Yup, 80 million severance and gone in a cloud of smoke. Off to next job.
 

Offline schmitt trigger

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Re: Boeing 737 Max again, it would be nice if the windows stayed in!
« Reply #146 on: January 11, 2024, 10:57:17 pm »
I wonder if they will change CEOs again? Maybe that will help? :-DD

What happened to “the buck stops here”?
IMHO, they should make the CEO stay and clean up the mess created under his/her watch. And reduce the salary to $1 a year.

Yeah, keep on dreaming.
 

Offline pickle9000

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Re: Boeing 737 Max again, it would be nice if the windows stayed in!
« Reply #147 on: January 11, 2024, 11:06:13 pm »
The biggest problem I have with this incident is it's old tech and they know how to do it.

Reputation must have a dollar value.
 

Offline Stray Electron

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Re: Boeing 737 Max again, it would be nice if the windows stayed in!
« Reply #148 on: January 11, 2024, 11:17:04 pm »
I wonder if they will change CEOs again? Maybe that will help? :-DD

What happened to “the buck stops here”?


    He left office in 1953.  https://en.wikipedia.org/wiki/Harry_S._Truman The current CEO of Boeing probably wasn't even alive then.
 

Offline floobydust

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Re: Boeing 737 Max again, it would be nice if the windows stayed in!
« Reply #149 on: January 11, 2024, 11:58:23 pm »
Boeing's been missing or has loose fasteners on many occasions. Too many occasions.
Surely a multi-million dollar paycheque: "VP of Total Quality for Boeing Commercial Airplanes, chair of the Boeing Quality Operations Council and a member of the company’s Executive Council." Executive Carole Murray "... previously was senior director of Quality for the 787 Program".
We could promote her to CEO, add a few committees, that would fix everything  :palm:

Top heavy, big bucks executives are like parasites that drain all the cash and blood out of the lower workers.

It reminds me of the old "pop bottle in the door" stunt union workers in Detroit were pulling. My dad his '75 or '76 Ford F150 had that rattle and here I thought somebody just forgot their soda bottle there. Snopes says it's a myth (Cadillac door) but it really was happening back in the day.

If this is a pushback by disgruntled employees, and it's looking like that because a bolt is not terribly difficult to install, it's what you do all day... Boeing has pissed off the worker bees.
Soviet Union was like this too I thought, quality problems and nobody fixing it because those in charge make all the money, flog workers and do little else.
 
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