Alaska Airlines 737-900 MAX loses a door in-flight out of PDX
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@D_Bru on OR OR
Just thinking.
The production work involved by itself may be simple, the envelope of manufacturing processes encompassing them are not. Manufacturing defined as including manufacturing (engineering), tooling (engineering), production, logistics, configuration management, etcetera.
Not simple in a normal situation, and certainly not in a faulted airplane program with delays, restarts, backlog, ramp ups, redesign, unstructured and ad hoc management steering and prioritising by loss of safety culture, etcetera
In this situation it would not be either OR Boeing OR Spirit processes and systems and people, next to hired hands. Each phase/situation above adds process pieces either in sequence, in parallel, and in multiple layers. The top layer is Boeing, period. You might say that top layer has the label final responsibility, the other layers and their process are just contributory.
So it’s not a OR OR question, but AND AND with multiple LAYERS involved. There should be more information forthcoming on the manufacturing process layers above the layer with opening, closing, riveting, closing, (pressure testing). And for example how backlog and rework processes were set up and followed and paper/IT supported.
This last aspect is not the most complex situation that you can encounter by the way. Because as far as I know there has been no engineering design change work involved in this. Let alone any certification work. So just “recurring“ work with the “plug option”.
Also… scope and time … If I would have to look into it myself I would at least start looking into this starting on the fuselage assembly line at Spirit itself. The airplane design and manufacturing design are a bit unusual here, in the sense that the side frames of the plugpanel/escapedoor option stick out like horns during their final fuselage join assembly. Which makes me wonder if this … scroll fast forward … is the driver of the riveting issue. And if so, my first question would be, how often…. Because that would effect how manufacturing and production processes have to be set up. And how these are then subsequently covered in the QA/QC layer.
Was happy to read after March 6th that the NTSB changed strategy and widened the scope of the investigation beyond this specific airplane and event. As they won’t find the answer on the OR OR level alone.
The production work involved by itself may be simple, the envelope of manufacturing processes encompassing them are not. Manufacturing defined as including manufacturing (engineering), tooling (engineering), production, logistics, configuration management, etcetera.
Not simple in a normal situation, and certainly not in a faulted airplane program with delays, restarts, backlog, ramp ups, redesign, unstructured and ad hoc management steering and prioritising by loss of safety culture, etcetera
In this situation it would not be either OR Boeing OR Spirit processes and systems and people, next to hired hands. Each phase/situation above adds process pieces either in sequence, in parallel, and in multiple layers. The top layer is Boeing, period. You might say that top layer has the label final responsibility, the other layers and their process are just contributory.
So it’s not a OR OR question, but AND AND with multiple LAYERS involved. There should be more information forthcoming on the manufacturing process layers above the layer with opening, closing, riveting, closing, (pressure testing). And for example how backlog and rework processes were set up and followed and paper/IT supported.
This last aspect is not the most complex situation that you can encounter by the way. Because as far as I know there has been no engineering design change work involved in this. Let alone any certification work. So just “recurring“ work with the “plug option”.
Also… scope and time … If I would have to look into it myself I would at least start looking into this starting on the fuselage assembly line at Spirit itself. The airplane design and manufacturing design are a bit unusual here, in the sense that the side frames of the plugpanel/escapedoor option stick out like horns during their final fuselage join assembly. Which makes me wonder if this … scroll fast forward … is the driver of the riveting issue. And if so, my first question would be, how often…. Because that would effect how manufacturing and production processes have to be set up. And how these are then subsequently covered in the QA/QC layer.
Was happy to read after March 6th that the NTSB changed strategy and widened the scope of the investigation beyond this specific airplane and event. As they won’t find the answer on the OR OR level alone.
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Alaska Airlines Flight Was Scheduled for Safety Check on Day Panel Blew Off
The airline’s engineers had called for the plane to undergo a rigorous maintenance check on Jan. 5 to determine why the [pressurization] warning lights were triggering based on their use of “a predictive tool” rather than on the number of times the warning lights had gone off, the airline said.
https://www.nytimes.com/2024/03/12/u...-android-share
https://www.nytimes.com/2024/03/12/u...-android-share
"When asked about the report, Alaska Airlines said it could not find any record of a report of whistling coming from the plane."
Lots of documentation going missing.
The plot thickens.
Lots of documentation going missing.
The plot thickens.
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Now the planes start whistling… (after all) …
This was posted about earlier but denied by the parties involved.
Which again puts forward the questions…. Was the information there but disappeared, or was the information not there in the first place. In both cases it points to systemic negligence. Which is no surprise if you accept a loss of safety culture.
+
Some originally pointed to the Spirit Malaysia plug supplier. Then to contractors of three contracting parties.
Thinking about the latter… You would expect, based on the ‘beans’ focus of Boeing, that such contractors would have to thoroughly document their work … in detail, per work item. So documentation should be available at 3-6 parties on paper and in their IT systems.
This was posted about earlier but denied by the parties involved.
Which again puts forward the questions…. Was the information there but disappeared, or was the information not there in the first place. In both cases it points to systemic negligence. Which is no surprise if you accept a loss of safety culture.
+
Some originally pointed to the Spirit Malaysia plug supplier. Then to contractors of three contracting parties.
Thinking about the latter… You would expect, based on the ‘beans’ focus of Boeing, that such contractors would have to thoroughly document their work … in detail, per work item. So documentation should be available at 3-6 parties on paper and in their IT systems.
Last edited by A0283; 13th Mar 2024 at 08:22.
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If the flight data recorder does not show any issue with cabin altitude, isn't it likely that the warning light was due to an internal failure of the cabin pressure controller? And wouldn't the pilots have watched the cabin altitude gauge if they suspected a leak? The passengers who reported a whistling sound would not have known if it was the same aircraft, would they?
Last edited by MarineEngineer; 13th Mar 2024 at 09:24.
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Last edited by A0283; 13th Mar 2024 at 09:36.
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NTSB tightens the screws (no pun intended) on Boeing
https://www.ntsb.gov/news/Documents/...%20Blowout.pdf
Today NTSB chair Homendy wrote "To date, we still do not know who performed the work to open, reinstall, and close the door plug on the accident aircraft. Boeing has informed us that they are unable to find the records documenting this work." She even called CEO Calhoun, who was also aware the're absolutely no records.
Homendy further declared: "I have become increasingly concerned that the focus on the names of individual front-line workers will negatively impact our investigation and discourage such Boeing employees from providing NTSB with information relevant to this investigation. To that end, I have instructed NTSB to utilize our authority to protect the identities of the door crew and other front-line employees who come forward with information relevant to the investigation. We will also continue to actively encourage anyone who can provide our investigators with information relevant to this investigation to please reach out at [email protected]."
And it doesn't stop at that: "Additionally, today NTSB sent Boeing the enclosed reminder of the regulatory restrictions to which Boeing has agreed as a party to the NTSB investigation. For the public to perceive the investigation as credible, the investigation should speak with one voice — that being the independent agency conducting the investigation. Releasing investigative information without context is misleading to Congress and the public and undermines both the investigation and the integrity of the NTSB, which is recognized as the world’s leading accident investigation agency."
P.S.: for A0283 : yes, intuitively it should be AND/AND, but I presume that it's CMES (Boeing) that should be able to provide who's worked on the rivets (and in this case opened the plug). Even if it was Spirt's people (or subcontractor) who worked on the rivets, there's a Boeing "rivet" responsible who first assigned the deficit for rework and signed off the (ultimate) repair (remember that in the first attempt Boeing rejected the rivets as "just having been painted over"). Most likely no involvement of Boeing's "door" people at all, because the plug wasn't removed, just opened. And closed of course, minus the bolts apparently.
P.P.S.: I also read that NTSB is scheduling a public hearing in August 2024: https://www.ntsb.gov/news/press-rele...R20240312.aspx . To take out the popcorn....
P.P.P.S.: The current "cat and mouse Spiel" between NTSB and Boeing is ultimately likely to contribute to a better understanding of what constitutes a "record" demanded from aircraft builders to document their manufacturing processes.
Today NTSB chair Homendy wrote "To date, we still do not know who performed the work to open, reinstall, and close the door plug on the accident aircraft. Boeing has informed us that they are unable to find the records documenting this work." She even called CEO Calhoun, who was also aware the're absolutely no records.
Homendy further declared: "I have become increasingly concerned that the focus on the names of individual front-line workers will negatively impact our investigation and discourage such Boeing employees from providing NTSB with information relevant to this investigation. To that end, I have instructed NTSB to utilize our authority to protect the identities of the door crew and other front-line employees who come forward with information relevant to the investigation. We will also continue to actively encourage anyone who can provide our investigators with information relevant to this investigation to please reach out at [email protected]."
And it doesn't stop at that: "Additionally, today NTSB sent Boeing the enclosed reminder of the regulatory restrictions to which Boeing has agreed as a party to the NTSB investigation. For the public to perceive the investigation as credible, the investigation should speak with one voice — that being the independent agency conducting the investigation. Releasing investigative information without context is misleading to Congress and the public and undermines both the investigation and the integrity of the NTSB, which is recognized as the world’s leading accident investigation agency."
P.S.: for A0283 : yes, intuitively it should be AND/AND, but I presume that it's CMES (Boeing) that should be able to provide who's worked on the rivets (and in this case opened the plug). Even if it was Spirt's people (or subcontractor) who worked on the rivets, there's a Boeing "rivet" responsible who first assigned the deficit for rework and signed off the (ultimate) repair (remember that in the first attempt Boeing rejected the rivets as "just having been painted over"). Most likely no involvement of Boeing's "door" people at all, because the plug wasn't removed, just opened. And closed of course, minus the bolts apparently.
P.P.S.: I also read that NTSB is scheduling a public hearing in August 2024: https://www.ntsb.gov/news/press-rele...R20240312.aspx . To take out the popcorn....
P.P.P.S.: The current "cat and mouse Spiel" between NTSB and Boeing is ultimately likely to contribute to a better understanding of what constitutes a "record" demanded from aircraft builders to document their manufacturing processes.
Last edited by D Bru; 13th Mar 2024 at 21:55.
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Boeing might want to consider a couple of inspection hatches in the inner lining each side so at least the top two of such critical bolts can be inspected from time to time. And at least every time there is a pressurisation warning. Removing a row of seats and a whole inner panel to even see them seems to much of a palaver to it being done regularly or on just a faraway suspicion.
That would also show that Boeing is doing something physical with the problem that the airlines can assist in. Rather than another procedure in a sometimes shortcoming, flawed and not always followed Boeing quality control system. Boeing seems reluctant to do design fixes on the Max rather than just even more paperwork and training.
That would also show that Boeing is doing something physical with the problem that the airlines can assist in. Rather than another procedure in a sometimes shortcoming, flawed and not always followed Boeing quality control system. Boeing seems reluctant to do design fixes on the Max rather than just even more paperwork and training.
Back in the day that's happened countless times to me where I've been asked to unship/completely remove an avionics box so another trade could do stuff behind it - almost always non-standard work like survey work/survey rectification work - like this was. Standard work would usually(!) call up such removal/refit/test procedures as part of the work package - non-standard work definitely wouldn't and so it would be down to me to do that. First thing I'd have to do is raise an appropriate "move iaw" or "remove iaw" entry on the Work Recording system which would then require a "refit/re-test iaw" to close it off once the other guys had finished whatever they were doing. For a move, the "iaw" would specifically reference just those parts of the full removal process carried out as (for eg), if the LRU was not disconnected, there would be no need to sign off for the "disconnect" or a subsequent "connect" and, as a result, quite often there would be no need to do a full re-test either. I'd have expected the same for the door plug - only those steps for "opening" and "re-closing" to be called up rather than a full "removal/replace".
There could even have just been confusion as to who was going to raise the paperwork but, as the person doing the work, I'd have to sign it off so, either way, I'd know the entry had been opened so that's quite unlikely - but "Murphy" works in very strange ways at times.
Last edited by Hot 'n' High; 14th Mar 2024 at 10:26.
Boeing might want to consider a couple of inspection hatches in the inner lining each side so at least the top two of such critical bolts can be inspected from time to time. And at least every time there is a pressurisation warning. Removing a row of seats and a whole inner panel to even see them seems to much of a palaver to it being done regularly or on just a faraway suspicion.
That would also show that Boeing is doing something physical with the problem that the airlines can assist in. Rather than another procedure in a sometimes shortcoming, flawed and not always followed Boeing quality control system. Boeing seems reluctant to do design fixes on the Max rather than just even more paperwork and training.
That would also show that Boeing is doing something physical with the problem that the airlines can assist in. Rather than another procedure in a sometimes shortcoming, flawed and not always followed Boeing quality control system. Boeing seems reluctant to do design fixes on the Max rather than just even more paperwork and training.
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900ER checks probe
With Alaska 1282 we're of course looking at MAX-9 production (quality) issues. But following 21 Jan's FAA SAFO recommending also plug inspections on the 900ER, out of curiosity I ran a quick check in FAA's SDRS. For instance, for Delta alone it returned 31 anomaly reports on 15 of its 900ERs between 21 Jan and 2 Feb inclusive. That's an in my view at least not negligible nearly 10% of Delta's 160 900ER fleet. And I'm leaving out several separate reports which found torn plug seals while performing the inspections.
The 31 reports concern hardware anomalies, ranging from damaged, loose, wrong specs, but in most cases of missing cotter pins, washers, nuts and a good number of absent bolts (that is no hardware at all). There was also a case where an upper roller guide had cracked and a case where the upper roller guide bolts had been installed backwards/inverted. The most striking was that on two aircraft all four lower guide hinge bolts (and associated hardware) were missing completely (that is LH and RH).
IMO, such sample results show that this particular plug design would seem not only to be prone to production "escapes", but also to maintenance ones.
Regards
The 31 reports concern hardware anomalies, ranging from damaged, loose, wrong specs, but in most cases of missing cotter pins, washers, nuts and a good number of absent bolts (that is no hardware at all). There was also a case where an upper roller guide had cracked and a case where the upper roller guide bolts had been installed backwards/inverted. The most striking was that on two aircraft all four lower guide hinge bolts (and associated hardware) were missing completely (that is LH and RH).
IMO, such sample results show that this particular plug design would seem not only to be prone to production "escapes", but also to maintenance ones.
Regards
Last edited by D Bru; 15th Mar 2024 at 16:12. Reason: added time span for the reported anomalies
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D Bru Interesting check and find!
Some thoughts:
- You would expect these and other results to pop up somewhere in the NTSB reports/hearings.( In the old HS door case they had iirc about 27 earlier events/finds before the fatal accident. So the zero finds originally reported in this case surprised me ).
- Personally I would add the seal issues and numbers. Seals may turn out to be more important than people expect.
- Still not clear to me how the plug is perceived from Boeing design to Spirit Malaysia to Spirit Wichita to Boeing Renton to Boeing testing at KBFI to airline operations and maintenance.
- Is a (door-)plug structure or a door or should it be a ‘1309 system’ ?
- If it is structure, why would you ever open it? And if you (a structures team?) hardly ever open it, why would you find these seal and parts/fasteners anomalies.
- If it’s a door you would expect a doors team to handle it, a team of which you would expect that pressure checking and testing is their second nature.
- Naming it a door-plug would suggest it requires both teams, which creates what you might call an ‘organisational/process interface ‘. Murphy is fond of interfaces.
Working on something else I stumbled upon an old Boeing doors manual. It has old written notes in it covering questions and answers put forward by various people in this thread. For example on setting the pins in relation to pressurisation. The manual itself was not clear enough apparently.
Some thoughts:
- You would expect these and other results to pop up somewhere in the NTSB reports/hearings.( In the old HS door case they had iirc about 27 earlier events/finds before the fatal accident. So the zero finds originally reported in this case surprised me ).
- Personally I would add the seal issues and numbers. Seals may turn out to be more important than people expect.
- Still not clear to me how the plug is perceived from Boeing design to Spirit Malaysia to Spirit Wichita to Boeing Renton to Boeing testing at KBFI to airline operations and maintenance.
- Is a (door-)plug structure or a door or should it be a ‘1309 system’ ?
- If it is structure, why would you ever open it? And if you (a structures team?) hardly ever open it, why would you find these seal and parts/fasteners anomalies.
- If it’s a door you would expect a doors team to handle it, a team of which you would expect that pressure checking and testing is their second nature.
- Naming it a door-plug would suggest it requires both teams, which creates what you might call an ‘organisational/process interface ‘. Murphy is fond of interfaces.
Working on something else I stumbled upon an old Boeing doors manual. It has old written notes in it covering questions and answers put forward by various people in this thread. For example on setting the pins in relation to pressurisation. The manual itself was not clear enough apparently.
The recent postings on here referring to loose bolts, inappropriate practices for fastening things, deviations from standard procedures are to my mind, and I am a telecoms guy not aerospace , serious especially because of the special circumstances of the airiner business. This should be especially so in the USa because of the circumstances leading up to AA191 in 1979. 270 people died because AA maintenance people deviated from specified practices for changing engines. As has been pointed out another ten minutes into this flight , by that time at FL300 and we are talking another catastrophe with at best killing the passengers located by the door and at worst even more debris hitting the left stabiliser. So i hope the FAA really do act firmly and mandate very very through inspections of this door plug (BTW is there one on the other side? and look in more detail at issues that have been brought to light in other areas by these concerned.
Building airliners is one of those industries where you just have to do the right thing every single time because of the hostile environment the finished product operates in and unlike Cars trucks trains bikes etc aircraft cannot just stop and sort it out or x summon help
Building airliners is one of those industries where you just have to do the right thing every single time because of the hostile environment the finished product operates in and unlike Cars trucks trains bikes etc aircraft cannot just stop and sort it out or x summon help
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That's closing the stable door after the horse has bolted. This particular problem probably has a very specific cause, has never happened before (else we'd have heard of it) and is unlikely to happen again. Taken together with other happenings, such as mis-drilled holes and loose nuts on rudder linkages, what is very obviously missing is a competent quality system that will prevent and/or catch errors of this sort when (not if - we're all human) they occur. This is the direction I hope that the FAA will take and mandate very firmly.
That's closing the stable door after the horse has bolted. This particular problem probably has a very specific cause, has never happened before (else we'd have heard of it) and is unlikely to happen again. Taken together with other happenings, such as mis-drilled holes and loose nuts on rudder linkages, what is very obviously missing is a competent quality system that will prevent and/or catch errors of this sort when (not if - we're all human) they occur. This is the direction I hope that the FAA will take and mandate very firmly.
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fizz57 - loose bolts in general (example vertical fin) and in the plug locations have been found before … we don’t know yet if any plugs opened… the Alaska case is the only one as far as we know were a departure was reported…
@Hans … is right of course … the basic failure was on the production level …
Apart from that we don’t know yet if there was a failure on the manufacturing level which sits above the production level… you can ask serious questions on the configuration management level (on the manufacturing/engineering/marketing interface) … you can ask questions on the engineering design level ….
In my (aerospace) experience only after these levels (or layers) are clear you could start talking about the quality layer (QA/QC).
From that viewpoint the word quality gets far too much attention and weight, both in general, in the management speak coming from Boeing, and in the hearings in the US Congress. Quality is becoming a kind of layer that absolves management from solving issues down to the actual execution and floor level. In that sense the word “quality” starts to sound like the word “risk” in the financial world (before the 2008 global crisis). So beefing up QMS, SMS, RMS will take effort and responsibility away from where it is most needed. It will also negatively impact other US and international companies and the aerospace system in general.
An interesting and related parallel (already noted earlier) is that people speaking out within Boeing, for now more than a decade and till today (re FAA and NTSB investigations), have been dealt with in a way that instilled fear in them. Boeing management have now come up with the “Speaking Up” system. Interesting difference in choice of words … up and out … Speaking was and is not the problem (it is a long standing pillar of safety culture), fear is. And after you have solved the fear issue, start addressing the issues that are spoken about. Stop COYA and start getting (literally) back to basics.
@Hans … is right of course … the basic failure was on the production level …
Apart from that we don’t know yet if there was a failure on the manufacturing level which sits above the production level… you can ask serious questions on the configuration management level (on the manufacturing/engineering/marketing interface) … you can ask questions on the engineering design level ….
In my (aerospace) experience only after these levels (or layers) are clear you could start talking about the quality layer (QA/QC).
From that viewpoint the word quality gets far too much attention and weight, both in general, in the management speak coming from Boeing, and in the hearings in the US Congress. Quality is becoming a kind of layer that absolves management from solving issues down to the actual execution and floor level. In that sense the word “quality” starts to sound like the word “risk” in the financial world (before the 2008 global crisis). So beefing up QMS, SMS, RMS will take effort and responsibility away from where it is most needed. It will also negatively impact other US and international companies and the aerospace system in general.
An interesting and related parallel (already noted earlier) is that people speaking out within Boeing, for now more than a decade and till today (re FAA and NTSB investigations), have been dealt with in a way that instilled fear in them. Boeing management have now come up with the “Speaking Up” system. Interesting difference in choice of words … up and out … Speaking was and is not the problem (it is a long standing pillar of safety culture), fear is. And after you have solved the fear issue, start addressing the issues that are spoken about. Stop COYA and start getting (literally) back to basics.
Last edited by A0283; 18th Mar 2024 at 12:18.
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Passenger experience and law suits
https://www.bbc.com/news/world-us-canada-68583149
Experience of the man sitting next to the window in the row directly behind the gap.
Experience of the man sitting next to the window in the row directly behind the gap.