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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

Old 24th Jan 2024, 07:31
  #1301 (permalink)  
 
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Don't loose bolts happen all the time ?

We know with good confidence that the door plug's four locking bolts where not present at time of the accident, because the structural elements holding the door are essentially intact, and would not allow ejection of the door plug if these locking bolts had been present: perhaps even one, and most certainly two, are enough to prevent the door from sliding up and detach. Thus loose structural bolts are not the direct cause of the plug's ejection.

Alaska reportedly found "many" loose bolts in their inspections of the door plugs of their 79 grounded 737 MAX 9. I assume it's mostly structural bolts, not missing bolts nor missing castellated nuts on locking bolts. These findings finding seem largely unrelated to missing/lost locking bolts that have caused the plug's loss.

I ask: is such finding so abnormal/alarming ? Don't loose bolts happen all the time, and aren't they factored in the design ?

Last edited by fgrieu; 24th Jan 2024 at 07:44. Reason: factored in the design
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Old 24th Jan 2024, 07:51
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Originally Posted by Pinkman
Throwaways' description makes perfect sense and like me many of us with knowledge of ISO and other QMS type systems probably had their face in their hands - its a classic. Yes, in the first instance the ship should have been delivered defect free but given the situation BAC found themselves in what should have happened is that the spirit warranty/re-work team should have been employed under contract arrangements that permitted them to use CMES even if through a designated BAC employee. There is so much more around culture and enforcement but we are not even close to that yet.
A production system doesn't have to cater for the normal only, it has to assume abnormalities will occur and is supposed to be robust enough in process to catch those. If not, then why waste the time and money on QA; just put it into slot machines at Vegas, at least they occasionally pay out.

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Old 24th Jan 2024, 07:59
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Originally Posted by fgrieu
We know with good confidence that the door plug's four locking bolts where not present at time of the accident, because the structural elements holding the door are essentially intact, and would not allow ejection of the door plug if these locking bolts had been present: perhaps even one, and most certainly two, are enough to prevent the door from sliding up and detach. Thus loose structural bolts are not the direct cause of the plug's ejection.

Alaska reportedly found "many" loose bolts in their inspections of the door plugs of their 79 grounded 737 MAX 9. I assume it's mostly structural bolts, not missing bolts nor missing castellated nuts on locking bolts. These findings finding seem largely unrelated to missing/lost locking bolts that have caused the plug's loss.

I ask: is such finding so abnormal/alarming ? Don't loose bolts happen all the time, and aren't they factored in the design ?
Simple answer to your 3 questions:
1. Very alarming
2. Certainly not
3. Absolutely not
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Old 24th Jan 2024, 08:10
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Rivet Rework

Another snippet from throwawayboeing's post I found astonishing was the bit about the rivets:

We now return to our incident aircraft, which was written up for having defective rivets on the LH mid-exit door."
"Spirit has teams on site in Renton performing warranty work for all of their shoddy quality, and this SAT promptly gets shunted into their queue as a warranty item."

"Once they have finished (the rivets), they send it back to a Boeing QA for final acceptance, but then Malicious Stupid Happens! The Boeing QA writes another record in CMES (again, the correct venue) stating (with pictures) that Spirit has not actually reworked the discrepant rivets, they *just painted over the defects*. In Boeing production speak, this is a “process failure”

"Presented with evidence of their malfeasance, Spirit reopens the package and admits that …. they did not rework the rivets properly


Am I being naïve in taking this at face value; that Spirit literally “painted over” the rivets instead of, presumably, replacing them? Just seems unbelievable....
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Old 24th Jan 2024, 08:15
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I wonder, when in maintenance, if we removed a panel or assembly we would bag the attaching hardware and tie to the item; if we removed say an FCU and had multiple similar bolts of different length, we would make up a cardboard pattern template and insert in groups, saves a lot of faffing around.
Those of you still working aircraft, is this a taboo practice now?
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Old 24th Jan 2024, 08:25
  #1306 (permalink)  
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Originally Posted by aeromech3
I wonder, when in maintenance, if we removed a panel or assembly we would bag the attaching hardware and tie to the item; if we removed say an FCU and had multiple similar bolts of different length, we would make up a cardboard pattern template and insert in groups, saves a lot of faffing around.
Those of you still working aircraft, is this a taboo practice now?
That simple expediency would have gone a long way towards precluding the embarrassment of this event.
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Old 24th Jan 2024, 08:45
  #1307 (permalink)  
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Originally Posted by SRMman
Another snippet from throwawayboeing's post I found astonishing was the bit about the rivets:

We now return to our incident aircraft, which was written up for having defective rivets on the LH mid-exit door."
"Spirit has teams on site in Renton performing warranty work for all of their shoddy quality, and this SAT promptly gets shunted into their queue as a warranty item."

"Once they have finished (the rivets), they send it back to a Boeing QA for final acceptance, but then Malicious Stupid Happens! The Boeing QA writes another record in CMES (again, the correct venue) stating (with pictures) that Spirit has not actually reworked the discrepant rivets, they *just painted over the defects*. In Boeing production speak, this is a “process failure”

"Presented with evidence of their malfeasance, Spirit reopens the package and admits that …. they did not rework the rivets properly


Am I being naïve in taking this at face value; that Spirit literally “painted over” the rivets instead of, presumably, replacing them? Just seems unbelievable....
Well, it worked on the B-17. where they only needed to last about 30 missions on average. Spirit heritage? BCA has noted that the problem with the quality of the door originated with the fabricator of that component, over the seas and far away in Malaysia. Which highlights the failings thereafter, at Spirit and at Renton. Deflection won't absolve BCA from the need to cogitate their navel and determine whether they are "in it for the huntin' ".
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Old 24th Jan 2024, 08:58
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Apologising in advance for thread drift, I don't think the Avro Lancaster had a "life" per se, but its survival rate averaged at 21 operational sorties. I was involved with one of the survivors PA474 in the early 80's !
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Old 24th Jan 2024, 09:12
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The issue for Boeing, the FAA and the NTSB is that this system failure is so fundamental to Boeing (and its subs) QA/QC that an analogue could happen anywhere on any 737. It is not unique to this ‘door’.

quadrupling the number of inspectors won’t make a difference if they don’t know what they are supposed to be looking at. They need to make fundamental changes to their production and quality systems. That’s a three year minimum project just for systems design followed by implementation with an associated learning curve and culture change.

what do you do in the interim? The pure answer is shut them down, but realistically that won’t happen.
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Old 24th Jan 2024, 09:29
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AFAIK, they much relied on external senior instructors teaching "external" standards.
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Old 24th Jan 2024, 09:53
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Originally Posted by aeromech3
I wonder, when in maintenance, if we removed a panel or assembly we would bag the attaching hardware and tie to the item; if we removed say an FCU and had multiple similar bolts of different length, we would make up a cardboard pattern template and insert in groups, saves a lot of faffing around.
You beat me to it, we used little drawstring bags whenever the same loose fasteners were to be reinstalled.
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Old 24th Jan 2024, 10:41
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Originally Posted by DaveReidUK
You beat me to it, we used little drawstring bags whenever the same loose fasteners were to be reinstalled.
Our engineers have been using “ziplock” plastic bags in recent years. They have several drawers of different sizes. They can be written on with marker pen and “nested” inside each other if required.
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Old 24th Jan 2024, 10:50
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Originally Posted by joe_bloggs
Our engineers have been using “ziplock” plastic bags in recent years. They have several drawers of different sizes. They can be written on with marker pen and “nested” inside each other if required.
We’re presuming that there isn’t a neat and tidy bag of bolts that was tacked to the door which decided it wanted to go skydiving when the opportunity presented itself.
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Old 24th Jan 2024, 11:35
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Originally Posted by joe_bloggs
Our engineers have been using “ziplock” plastic bags in recent years. They have several drawers of different sizes. They can be written on with marker pen and “nested” inside each other if required.
Or, basically anything that is the equivalent of a red lockout padlock that you use to indicate: Please do not turn on the power while I am working inside the high voltage cabinet (or please do not deliver this airplane until the bolts are back in).
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Old 24th Jan 2024, 11:48
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Originally Posted by SLF3
The issue for Boeing, the FAA and the NTSB is that this system failure is so fundamental to Boeing (and its subs) QA/QC that an analogue could happen anywhere on any 737. It is not unique to this ‘door’.

quadrupling the number of inspectors won’t make a difference if they don’t know what they are supposed to be looking at. They need to make fundamental changes to their production and quality systems. That’s a three year minimum project just for systems design followed by implementation with an associated learning curve and culture change.

what do you do in the interim? The pure answer is shut them down, but realistically that won’t happen.
This is when management puts workers through a bunch of slide shows and quizzes to fix the problem, with no change in management whatsoever.
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Old 24th Jan 2024, 12:20
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Originally Posted by aeromech3
I wonder, when in maintenance, if we removed a panel or assembly we would bag the attaching hardware and tie to the item; if we removed say an FCU and had multiple similar bolts of different length, we would make up a cardboard pattern template and insert in groups, saves a lot of faffing around.
Those of you still working aircraft, is this a taboo practice now?
I work in maintenance at a corporate flight department, and this is exactly how we do it. A 24-month inspection requires removing multiple panels on the wing and fuselage, and the fasteners (screws) can often be of several different lengths on any one panel. We have pattern templates for every panel on the aircraft, labeled with the panel number. We have a log sheet with all panels listed, with entries for “removed”, “ok to close” “installed” and “inspected”.

The person who inspects a given panel after reinstallation cannot be the same person who installed it.
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Old 24th Jan 2024, 13:02
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Originally Posted by Yancey Slide
We’re presuming that there isn’t a neat and tidy bag of bolts that was tacked to the door which decided it wanted to go skydiving when the opportunity presented itself.
Imagine finding that in your backyard.

I wonder, is there a formal process to document and deal with loose and excess parts found on an aircraft factory floor? After all, those bolts must have been found somewhere? They can’t just have disappeared in thin air, I’d imagine. (Barring some genuine Jedi tricks.)
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Old 24th Jan 2024, 13:55
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Seattle Times today:

"The fuselage panel that blew off an Alaska Airlines jet earlier this month was removed for repair then reinstalled improperly by Boeing mechanics on the Renton final assembly line, a person familiar with the details of the work told The Seattle Times.

If verified by the National Transportation Safety Board investigation, this would leave Boeing primarily at fault for the accident, rather than its supplier Spirit AeroSystems, which originally installed the panel into the 737 MAX 9 fuselage in Wichita, Kan."
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Old 24th Jan 2024, 14:11
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Originally Posted by DaveReidUK
Seattle Times today:
That’s not the same as what Throwaway wrote . . . And perhaps is more damning.
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Old 24th Jan 2024, 14:16
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Originally Posted by DaveReidUK
Seattle Times today:
https://www.seattletimes.com/busines...ska-max-9-jet/
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