Alaska Airlines 737-900 MAX loses a door in-flight out of PDX
Attorney Timothy A Loranger told the BBC the litigation process could take "a couple of years" as there are a lot of people involved.
"His [Mr Tran] leg was almost sucked out of the airplane if it wasn't for his seatbelt," Mr Loranger said. "It is just terrifying."
"His [Mr Tran] leg was almost sucked out of the airplane if it wasn't for his seatbelt," Mr Loranger said. "It is just terrifying."
That BBC video needs to be played a few times at aircraft maker facilities and repair depots to move the understanding from the abstract to the concrete.
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Ta! to @Hot 'n' High & @A0283 for the insightful comments.
I'm not sufficiently into the things of FAA's AC 25.1309-1 nor the subsequent "Arsenal" draft to comment, beyond the fact that since the 900ER (with the plug) was introduced in 2007 extending to almost 500 currently flying around, so far no plug has separated on any of them. From that point of view, the likelihood of a "fatal accident" is therefore to be considered negligible. And another thing we can conclude is that, at least in Boeing's perception, the opening of the plug (15° on its straps/retainers) is not a "door" issue, while the plug's removal is. So, it depends if its "structural" or a "door".
While I agree that on the occasion of the second rivet repair on 714AL any informal and/or fleeting involvement of the Boeing "door" team cannot be fully excluded, I presume that in particular Boeing had a strong incentive to just "open" the plug and not to remove it (in their "logic", opening doesn't need to be recorded, removing does). Remember that on 12 Sept, 714AL had already gone through its structural integrity and pressurisation test. Removing the plug would in all likelihood necessitate a new test, which would take time. When a week later, the plug was opened on 18 Sept for the second rivet repair, 714AL was already delayed and naturally parked on the platform outside the assembly hall. This might explain why, in stead of removing the plug, Boeing went through extraordinary efforts to "open" it far beyond its standard 15° by removing its connections with the straps and putting it resting at least at 45° on an external (improvised?) support structure on the outside platform, as can be clearly seen behind the cabin window in a photo sourced from Spirit and reproduced as "Figure" 15 in the NTSB's preliminary report.
I'm not sufficiently into the things of FAA's AC 25.1309-1 nor the subsequent "Arsenal" draft to comment, beyond the fact that since the 900ER (with the plug) was introduced in 2007 extending to almost 500 currently flying around, so far no plug has separated on any of them. From that point of view, the likelihood of a "fatal accident" is therefore to be considered negligible. And another thing we can conclude is that, at least in Boeing's perception, the opening of the plug (15° on its straps/retainers) is not a "door" issue, while the plug's removal is. So, it depends if its "structural" or a "door".
While I agree that on the occasion of the second rivet repair on 714AL any informal and/or fleeting involvement of the Boeing "door" team cannot be fully excluded, I presume that in particular Boeing had a strong incentive to just "open" the plug and not to remove it (in their "logic", opening doesn't need to be recorded, removing does). Remember that on 12 Sept, 714AL had already gone through its structural integrity and pressurisation test. Removing the plug would in all likelihood necessitate a new test, which would take time. When a week later, the plug was opened on 18 Sept for the second rivet repair, 714AL was already delayed and naturally parked on the platform outside the assembly hall. This might explain why, in stead of removing the plug, Boeing went through extraordinary efforts to "open" it far beyond its standard 15° by removing its connections with the straps and putting it resting at least at 45° on an external (improvised?) support structure on the outside platform, as can be clearly seen behind the cabin window in a photo sourced from Spirit and reproduced as "Figure" 15 in the NTSB's preliminary report.
Last edited by D Bru; 18th Mar 2024 at 15:57.
Since that photo was taken by Spirit and the installed door is part of the Spirit supply of the fuselage and Spirit replaced the door seal, I'd say that the door was opened by Spirit as part of the Spirit task to replace the defective rivets. Spirit had been dinged repeatedly on quality problems so Spirit would rather not include the additional task of opening and closing the door, but at least they did not hide the defective seal. The rivet replacement was work done under a deficiency notice to Spirit; it's not clear why anyone on the Boeing side would touch that door. Boeing doesn't have a factory floor installation procedure for it; Spirit does. And Spirit has been very, very quiet. If Spirit comes back with names of Boeing employees that they know aided the riveters, that will be interesting, but who knows until then?
Interesting question on the pressurization test. Another reason Spirit might have to be quiet about the process, though the replacement of the door seal could have been a pressure test trigger and wasn't.
Interesting question on the pressurization test. Another reason Spirit might have to be quiet about the process, though the replacement of the door seal could have been a pressure test trigger and wasn't.
Long retired engineer here, but I suggest that you cannot "open" a plug, it nust be either fully in situ, or effectively "removed", however small the displacement/angle from in situ.
As stated several times, it is not a door, so cannot be opened.
As stated several times, it is not a door, so cannot be opened.
I wonder how often the fixings are looked at. It obviously doesn't feature in the pilots' walkaround. Is it ever looked with the interior cabin lining taken off before a D-check ?
Anyone who has followed this thread and read the NTSB report will know that the plug can be opened after 4 bolts, if fitted, have been removed.
I think it's clear that this door/plug has at least 3 possible major states:
Closed (subdivided into secured and not secured)
Open (subdivided into tethered and not tethered)
Removed (subdivided into intentionally and unintentionally)
The Alaska incident illustrates that a rapid transition between states is possible.
Last edited by EXDAC; 18th Mar 2024 at 23:43. Reason: fix typos
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Background situation at Renton
What isn’t to be ignored IMO is the reported background situation at Renton against which the rivet repairs took place. As we know, the 714AL rivets issue was identified end of August '24 and the first “repair” (overpainting the rivets) took place on 7 Sept. Finally, the rivets were redone properly on 19 Sept.
The background situation at that very same time I’m referring to is about the massive and no doubt frantic additional activity at Renton, following the August '24 discovery of the elongated 737 Max bulkhead holes. Apart from some 40 airframes at Spirit Wichita, there was a massive 220 737’s at Renton (in most cases nearly completed aircraft, like 714AL), most of them requiring inspection of about half of about 1000 holes, plus re-fastening the suspect but OK ones and re-drilling the out-of-specs holes. There was mentioning of "eight repair lines" and "armies of people" involved. See source below.
So, I’m not mentioning these background circumstances as an excuse for what happened (and what apparently didn’t) with the rivet repair and the opening and closing of 714AL’s plug, but it could explain a certain pressure on the teams involved.
Regards
===
Source:
Court case documents in a class action against Spirit, Case 1:23-cv-03722-PAE Document 25 Filed 12/19/23 (https://www.documentcloud.org/docume...t-aero-systems), quote Boeing CFO Brian West as interviewed by Jefferies LLC analyst Sheila Kahyaoglu on 7 Sept ’24 at Jefferies Industrial Conference:
"It is the aft pressure bulkhead section of the airplane. We know how to fix it, but it’s early in the rework process and the rework hours will likely be higher and the cycle time longer than the vertical fin NOE [notice of escapement], we had earlier in the summer. This is different. It’s a bit more complicated, it’s more involved. There’s hundreds of holes that get inspected. There’s an X-ray inspection process step that’s required, and it’s a very critical part of the airplane. So we have to make sure we do this right and we will.
It will impact about 75% of the 220 airplanes that were inventory – at inventory as the – as of the end of the second quarter. So it’s large.
In terms of our focus with our supplier, it is a 100% the most important thing we’re working on right now. We’ve got literally armies of people from Boeing and the supplier working on this issue."
The same court documents quote Spirit CEO at the time, Tom Gentille, interviewed on the same occasion as West:
"What we have to do is about 1,000 holes in the aft pressure bulkhead, 500 of them are machine-enabled, so could be suspect. So we X-ray all of those and then we look to see on the X-ray could they be suspect. And if they are, what we do is drill out the fastener, inspect the hole. If there’s no issue with the hole and often there isn’t, we just put in the same-sized fastener.
If there is an oblong hole, what we do is we oversize it, drill it out again so it’s a little bit bigger, and then put it in a larger fastener. So we expect to be done with the repairs of the units in our factory by the end of November.
Now, for Boeing, it may take a little bit longer because they have, in many cases, completed aircraft. The 250, there’s maybe 65% or 70% of those that could require inspection and repair.
We set up essentially a separate factory across the street where we’re going to have eight repair lines and we’ll do X-ray on two of those and then repair on six."
The background situation at that very same time I’m referring to is about the massive and no doubt frantic additional activity at Renton, following the August '24 discovery of the elongated 737 Max bulkhead holes. Apart from some 40 airframes at Spirit Wichita, there was a massive 220 737’s at Renton (in most cases nearly completed aircraft, like 714AL), most of them requiring inspection of about half of about 1000 holes, plus re-fastening the suspect but OK ones and re-drilling the out-of-specs holes. There was mentioning of "eight repair lines" and "armies of people" involved. See source below.
So, I’m not mentioning these background circumstances as an excuse for what happened (and what apparently didn’t) with the rivet repair and the opening and closing of 714AL’s plug, but it could explain a certain pressure on the teams involved.
Regards
===
Source:
Court case documents in a class action against Spirit, Case 1:23-cv-03722-PAE Document 25 Filed 12/19/23 (https://www.documentcloud.org/docume...t-aero-systems), quote Boeing CFO Brian West as interviewed by Jefferies LLC analyst Sheila Kahyaoglu on 7 Sept ’24 at Jefferies Industrial Conference:
"It is the aft pressure bulkhead section of the airplane. We know how to fix it, but it’s early in the rework process and the rework hours will likely be higher and the cycle time longer than the vertical fin NOE [notice of escapement], we had earlier in the summer. This is different. It’s a bit more complicated, it’s more involved. There’s hundreds of holes that get inspected. There’s an X-ray inspection process step that’s required, and it’s a very critical part of the airplane. So we have to make sure we do this right and we will.
It will impact about 75% of the 220 airplanes that were inventory – at inventory as the – as of the end of the second quarter. So it’s large.
In terms of our focus with our supplier, it is a 100% the most important thing we’re working on right now. We’ve got literally armies of people from Boeing and the supplier working on this issue."
The same court documents quote Spirit CEO at the time, Tom Gentille, interviewed on the same occasion as West:
"What we have to do is about 1,000 holes in the aft pressure bulkhead, 500 of them are machine-enabled, so could be suspect. So we X-ray all of those and then we look to see on the X-ray could they be suspect. And if they are, what we do is drill out the fastener, inspect the hole. If there’s no issue with the hole and often there isn’t, we just put in the same-sized fastener.
If there is an oblong hole, what we do is we oversize it, drill it out again so it’s a little bit bigger, and then put it in a larger fastener. So we expect to be done with the repairs of the units in our factory by the end of November.
Now, for Boeing, it may take a little bit longer because they have, in many cases, completed aircraft. The 250, there’s maybe 65% or 70% of those that could require inspection and repair.
We set up essentially a separate factory across the street where we’re going to have eight repair lines and we’ll do X-ray on two of those and then repair on six."
Last edited by D Bru; 19th Mar 2024 at 09:09.
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Words
The recent discussion on the words plug, door, etc, prompted a search for the meaning or misuse of words in safety.
'Words mean something'
WORDS MEAN SOMETHING
'One word multiple meanings'
https://www.linkedin.com/pulse/one-w...aign=share_via
'Words mean something'
WORDS MEAN SOMETHING
'One word multiple meanings'
https://www.linkedin.com/pulse/one-w...aign=share_via
Can of Worms..?
I think all this talk about if you can, or can not, 'Open' a plug is just so much semantics.
You can open many things; Windows can be opened, so can Boxes, even Discussions can be opened.
Being 'Open' is not the just limited to Doors.
You can open many things; Windows can be opened, so can Boxes, even Discussions can be opened.
Being 'Open' is not the just limited to Doors.
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If a term means something different to different people it can influence what behaviour they consider appropriate/acceptable.
To me - as slf - door plug is a remarkably unhelpful term.
- door as they can usually be opened and closed with little or no thought (when they are closed they usually latch automatically, or with just a turn of a visible handle).
- plug because they usually "stay in" once they are put in place (bath-plugs don't just pop-out in use).
For me -- and perhaps others -- a term such as "inspection hatch" would give a more appropriate mental image, and perhaps give a clearer indication of the need for paperwork when opened or secured. (Fastened or unfastened?)
PS IIRC this thread has also seen the offending "door plug" referred to as a "door plug", a "plug door", a "door" & a "plug". So the term does also seem to lead to terminological confusion.
Last edited by Peter H; 20th Mar 2024 at 13:50.
Last edited by EXDAC; 21st Mar 2024 at 20:02.
Semantics: the branch of linguistics and logic concerned with meaning.
If a term means something different to different people it can influence what behaviour they consider appropriate/acceptable.
If a term means something different to different people it can influence what behaviour they consider appropriate/acceptable.
Outsiders have to learn what those terms mean in context.
There's a reason legislation defines terms. It specifies the meaning when a term has/could have multiple meanings.
Sorry, hit keyboard before engaging brain.
Try "dismantle" rather than open or remove.
You need tools to remove a plug, but not to open a door.
Remove just one split pin from one of four bolts, and you have started to dismantle the plug, even if the plug itself is still (moderately) securely in situ.
Try "dismantle" rather than open or remove.
You need tools to remove a plug, but not to open a door.
Remove just one split pin from one of four bolts, and you have started to dismantle the plug, even if the plug itself is still (moderately) securely in situ.
Sorry, hit keyboard before engaging brain.
Try "dismantle" rather than open or remove.
You need tools to remove a plug, but not to open a door.
Remove just one split pin from one of four bolts, and you have started to dismantle the plug, even if the plug itself is still (moderately) securely in situ.
Try "dismantle" rather than open or remove.
You need tools to remove a plug, but not to open a door.
Remove just one split pin from one of four bolts, and you have started to dismantle the plug, even if the plug itself is still (moderately) securely in situ.
What you can do with a plug, or door, depends on the context, and the experience of the person doing the action. The fact that people have different views on what the thing put in the hole in the side of the airframe is called illustrates precisely why unambiguous defined terms are needed in technical documentation.
For me, if an item can be removed, and its lack of replacement could endanger the aircraft in normal operation, then I would suggest that would be a good candidate for having the removal and replacement documented formally.
For anyone that hasn't had a chance to see it - here is the video clip of Jennifer Homendy's testimony to the Committee on the 6th March, where she describes Boeing's ... procrastinating 
Given enough tools, I can remove practically anything.
Back in my days at Boeing (long before plugs began popping out), engineering was responsible for defining functional tests and procedures for doing any sort of out of sequence work. LRUs (Line Replaceable Units) often had pre-written procedures for removal and replacement. These served as checklists to ensure the part was removed (properly, without damaging surrounding structure) and reinstalled without missing a step or part. For infrequently performed work, one-time work orders were generated. Which also served as the checklist. And a record of work performed. Which it seems is missing for this incident.
It's not so much a question of when the next door plug will blow out. It's what happened to the old process. It, as well as a few bolts, appear to have gone missing. And the next time some out of sequence work needs to be done, the overall template for doing/documenting the work won't be there.
Back in my days at Boeing (long before plugs began popping out), engineering was responsible for defining functional tests and procedures for doing any sort of out of sequence work. LRUs (Line Replaceable Units) often had pre-written procedures for removal and replacement. These served as checklists to ensure the part was removed (properly, without damaging surrounding structure) and reinstalled without missing a step or part. For infrequently performed work, one-time work orders were generated. Which also served as the checklist. And a record of work performed. Which it seems is missing for this incident.
It's not so much a question of when the next door plug will blow out. It's what happened to the old process. It, as well as a few bolts, appear to have gone missing. And the next time some out of sequence work needs to be done, the overall template for doing/documenting the work won't be there.
........ Back in my days at Boeing (long before plugs began popping out), engineering was responsible for defining functional tests and procedures for doing any sort of out of sequence work. LRUs (Line Replaceable Units) often had pre-written procedures for removal and replacement. These served as checklists to ensure the part was removed (properly, without damaging surrounding structure) and reinstalled without missing a step or part. For infrequently performed work, one-time work orders were generated. Which also served as the checklist. And a record of work performed. Which it seems is missing for this incident. ..........
