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Alaska Airlines 737-900 MAX loses a door in-flight out of PDX

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Alaska Airlines 737-900 MAX loses a door in-flight out of PDX

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Old 25th Jan 2024, 11:18
  #1361 (permalink)  
 
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A door plug isn't a door.

Any more than a bath plug is a bath.
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Old 25th Jan 2024, 11:33
  #1362 (permalink)  
 
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AWST isn't bullish on Boeing at the moment.

https://aviationweek.com/aerospace/m...ers-be-stopped

As 2023 ended, the company’s strategy department was abolished. Unit strategy functions were also reduced. The company no longer wants a plan for company-wide new technology development, new product development or, most crucial, restoring the links between the people who design and build aircraft and the people who manage the company. There are also no plans to promote technical people to senior management positions. Stephanie Pope’s recent appointment as chief operating officer means another finance person has been made Calhoun’s heir apparent.

The future, if it can be called that, is simply to run the company for cash—deliver legacy jets, try to make existing defense programs profitable, and resume converting cash flow into shareholder returns. Management may also try to sell off parts of the company—or perhaps all of it. The implications of this for the U.S. aerospace industry, defense industrial base and even the broader economy are potentially enormous.
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Old 25th Jan 2024, 11:39
  #1363 (permalink)  
 
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Originally Posted by DaveReidUK
A door plug isn't a door.

Any more than a bath plug is a bath.
If you really want to go there with grammar and semantics, a "door plug" is a plug that goes in a door, like a plug that goes in a bath(tub). But where's the door? It's actually a "door opening plug" or a "door frame plug."

It's like the difference between a divot (gouged out turf) and a divot hole (where the divot came from): When you take a divot, it leaves a divot hole.
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Old 25th Jan 2024, 11:50
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Originally Posted by DaveReidUK
A door plug isn't a door.

Any more than a bath plug is a bath.
True. But the point is that they may have treated it like a door on the factory floor.

We now return to our incident aircraft, which was written up for having defective rivets on the LH mid-exit door.
(…)


However, more critical for purposes of the accident investigation, the pressure seal is unsurprisingly sandwiched between the plug and the fuselage, and you cannot replace it without opening the door plug to gain access.

(…)

the damning entry which reads something along the lines of “coordinating with the doors team to determine if the door will have to be removed entirely, or just opened. If it is removed then a Removal will have to be written.”

(…)

If you have been paying attention to this situation closely, you may be able to spot the critical error: regardless of whether the door is simply opened or removed entirely, the 4 retaining bolts that keep it from sliding off of the door stops have to be pulled out. A removal should be written in either case for QA to verify install, but as it turns out, someone (exactly who will be a fun question for investigators) decides that the door only needs to be opened, and no formal Removal is generated in CMES (the reason for which is unclear, and a major process failure). Therefore, in the official build records of the airplane, a pressure seal that cannot be accessed without opening the door (and thereby removing retaining bolts) is documented as being replaced, but the door is never officially opened and thus no QA inspection is required.
This entire sequence is documented in the SAT, and the nonconformance records in CMES address the damaged rivets and pressure seal, but at no point is the verification job reopened, or is any record of removed retention bolts created, despite it this being a physical impossibility. Finally with Spirit completing their work to Boeing QAs satisfaction, the two rivet-related records in CMES are stamped complete, and the SAT closed on 19 September 2023. No record or comment regarding the retention bolts is made.
If that's the language used on the factory floor, then that is significant.
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Old 25th Jan 2024, 11:55
  #1365 (permalink)  
 
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Originally Posted by helispotter
So what constutes "closure"? Some measures for improvement of quality and compliance would clearly need to be continuous while ever Boeing are building aircraft, so there is no "closure" in those cases... or is this mainly about public appearance?
Literally the only thing Boeing management cares about is squeezing the remaining cash from its aging, weary, shriveling cash cow. You have to hear everything they say through that filter.

They don't build aircraft; they build durable goods. They aren't an aviation company. They are a liquidation business devoted to shutting down the former world leader in commercial aviation industry as profitably as possible.
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Old 25th Jan 2024, 12:07
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Was paneling in place?

Did Spirit fix the rivets and door plug seal before or after the interior paneling was installed? Would a Spirit rework person have had permission to remove interior paneling to complete the task?

Am I correct in understanding that after the interior was initially installed, the interior panel would have to be removed to gain access to the four bolts--the only way to partially open the door plug or to prepare it for removal from the plane?

Finally, at the time the paneling was initially installed, was there a step to inspect the door plug to insure that the bolts were present before the door was obscured by paneling?

Last edited by fotoguzzi; 25th Jan 2024 at 12:35. Reason: clarity
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Old 25th Jan 2024, 12:31
  #1367 (permalink)  
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Originally Posted by tsumini
If it were me I would just call it whatever the blueprint calls it. QED
Blueprint?
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Old 25th Jan 2024, 13:13
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Not trying to shift blame but could there have been a better response to the pressurisation warnings on this newly delivered aircraft?
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Old 25th Jan 2024, 13:56
  #1369 (permalink)  
 
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Originally Posted by DaveReidUK
A door plug isn't a door.

Any more than a bath plug is a bath.
And a -900 isn’t a MAX…
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Old 25th Jan 2024, 13:58
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Travel Agent sees 15-fold increase in customers filtering out Boeing 737 Max planes
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Old 25th Jan 2024, 16:31
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Door Closure

Originally Posted by SRMman
Going back to my earlier post 1257, I'd facetiously suggested that Boeing should increase the lift springs rate such that the door guide track fittings MUST be forcibly held down to insert the locking bolts . . .In other words, the door physically couldn't be closed without the locking bolts.
Excellent - almost certainly idiot proof mechanical interlock. On the subject of door mechanics, I think we're almost certain that there were no bolts and as far as I can see there is no convincing explanation for why the door / plug lasted as long as it did before it detached. Change analysis would ask “what was different about the condition of the door on the event flight”?

Last edited by Europa01; 25th Jan 2024 at 16:34. Reason: Tweak
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Old 25th Jan 2024, 16:47
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Originally Posted by helispotter
So what constutes "closure"? Some measures for improvement of quality and compliance would clearly need to be continuous while ever Boeing are building aircraft, so there is no "closure" in those cases... or is this mainly about public appearance?
Sounds like what happens in any kind of review - you get a bunch of action item assignments with varying degrees of specificity and then do whatever the assignment is and provide documentation that it's done in order to close it. But they really seem to need some actions assigned from outside the company to make some high level changes, as well as some detailed changes to how they work.
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Old 25th Jan 2024, 17:34
  #1373 (permalink)  
 
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The door can be secured closed without the locking bolts by tightening the adjustable stops no matter how strong the springs are.

The better answer is to use a mechanism that doesn't require bolts at all - the latches on car doors and hood are examples of cheap and reliable mechanisms. Even pieces of spring steel that is attached to the door frame to hold against the tops of the door stops or some specifically created bracket.
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Old 25th Jan 2024, 17:45
  #1374 (permalink)  
 
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Originally Posted by C2H5OH
Don't have that hole in the fuselage in the first place or permanently close it forever.
There are plenty of posts in the thread about the perceived advantages of having a single fuselage design for the MAX 9, in other words all aircraft having the MED opening, filled by either the E/E or the door plug.
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Old 25th Jan 2024, 17:54
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Jon Ostrower summarises. https://theaircurrent.com/aviation-s...ality-failure/

127 Days: The anatomy of a Boeing quality failure

extract

…Boeing staff on Aug. 31 discovered (and later fixed) loose fasteners on the right-hand side plug exit.

…On the opposite side of the aircraft, next to the left-hand plug that failed on Alaska 1282, Boeing made another quality discovery. Rivets installed at Spirit in the fuselage structure just forward of the plug exit door frame weren’t installed properly in five locations and required rework. In documenting the defects, the quality control report observed four properly installed bolts were fitted to the exit plug, preventing its movement.

…On Sept. 7, the rivets in question were found to be painted over and the underlying issue with their improper installation not addressed. It is not clear at this point who specifically painted over the rivets, but Boeing quality control sent the fasteners back for rework to Spirit…

…On Sept. 12, Boeing conducted a standard test on the aircraft to confirm its structural integrity and its ability to be safely pressurized. 8789 passed successfully, TAC is told. During this period the damaged rivets remained unfixed and an additional five days passed while a final resolution was being planned by Boeing and Spirit.

The key moment, The Air Current has learned, came on Sept. 18 when the plug exit was opened by Boeing to give Spirit contracted staff access to fix the rivets. Whether the plug was removed or just opened remains unknown…

Regardless, the four key bolts that hold the plug in place must be removed to either open or remove the 63-pound plug. The whereabouts of the bolts, according to the NTSB, remain central to understanding what caused the explosive decompression aboard Alaska 1282.

The rivets were fixed fully the following day on Sept. 19. What happened next in the factory is not entirely clear, yet is just as essential to understanding the quality failures that led to the accident…

…Airplane 8789, now fully assembled, was seen outside the Renton factory on Oct. 8 and later moved to the flight line for its Oct. 15 maiden flight…

Last edited by joe_bloggs; 25th Jan 2024 at 18:49. Reason: Added extract
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Old 25th Jan 2024, 18:12
  #1376 (permalink)  
 
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Originally Posted by MechEngr
The door can be secured closed without the locking bolts by tightening the adjustable stops no matter how strong the springs are.

The better answer is to use a mechanism that doesn't require bolts at all - the latches on car doors and hood are examples of cheap and reliable mechanisms. Even pieces of spring steel that is attached to the door frame to hold against the tops of the door stops or some specifically created bracket.
Latches can also fail - example: my car has had a couple recalls related to latches. And safety critical latches normally have some additional active mechanism to keep them closed - cars have locks, climbers use locking carabiners, even with knots it's common to throw an extra locking half-hitch behind them to keep them from coming undone. It's not obviously safer or more reliable to replace something that once installed correctly has extremely unlikely failure modes with something that automatically latches and appears safe but still requires some active locking mechanism (more parts => more steps => more ways you can mess it up).
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Old 25th Jan 2024, 18:27
  #1377 (permalink)  
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Originally Posted by MechEngr
The door can be secured closed without the locking bolts by tightening the adjustable stops no matter how strong the springs are.

The better answer is to use a mechanism that doesn't require bolts at all - the latches on car doors and hood are examples of cheap and reliable mechanisms. Even pieces of spring steel that is attached to the door frame to hold against the tops of the door stops or some specifically created bracket.
If you mean the 12 adjustable pins that abut the stop pads I believe it was mentioned that they were rigged with a slight clearance that got closed up when pressurised.
Please correct me if I have that wrong, but if so the the stop pads would not restrict movement till a positive hull pressure differential was present

....or do you mean that they might be tightened in error?, that's another scary thought to add to the list
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Old 25th Jan 2024, 19:53
  #1378 (permalink)  
 
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Originally Posted by A30yoyo
Not trying to shift blame but could there have been a better response to the pressurisation warnings on this newly delivered aircraft?
It's been repeatedly reported (including statements from the NTSB) that there was NO relationship between the pressurization warnings and the door plug.
In short, the pressurization warnings were related to an electrical hiccup in the pressurization system, not a leak or lack of pressure.
Please quit with that dead end...
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Old 25th Jan 2024, 19:56
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United Airlines chief executive, Scott Kirby, also told CNBC that he is "disappointed".

"The Max 9 grounding is probably the straw that broke the camel's back for us," he said, adding that "we're going to build a plan that doesn't have the [Boeing] Max 10 in it".
737 Max 9: Boeing jets cleared to fly after mid-air incident - BBC News

I didn't see this discussed elsewhere. I believe United have 250 orders for the MAX10. Can it be that they are cancelling them ?
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Old 25th Jan 2024, 19:58
  #1380 (permalink)  
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Originally Posted by remi
AWST isn't bullish on Boeing at the moment.

https://aviationweek.com/aerospace/m...ers-be-stopped

That is a disturbing report. It puts the future of BCA into question, and that would rapidly convert to a further loss of confidence in the product range. It is essentially doubling down with the problem that exists from the corporate strategy to milk the cow dry, hasn't worked since 1997. Not a brilliant strategy, but then nor is the short sighted structure strategy of the investors
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