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

[logansi]

An almost brand new AS Max 9 has lost an entire window section during an explosive decompression event just out of Portland. Photos below show reported damage

https://cimg4.ibsrv.net/gimg/pprune.org-vbulletin/1280x1707/gdh_jfhaqaa2wxp_ccf6832b834277ac96435580f0ee73898a8d73af.jpg

https://twitter.com/bricaul/status/1743455513113969131

[MechEngr]

Looks like an emergency exit went. The hole is designed to be there - but it is supposed to have an exit door remain inside of it until a more normal emergency happens.

I hope the cause is found quickly.

[logansi]

Looks like an emergency exit went. The hole is designed to be there - but it is supposed to have an exit door remain inside of it until a more normal emergency happens.

I hope the cause is found quickly.

Confirmed

https://twitter.com/avgeekjake/status/1743462030366085387

[MLHeliwrench]

It’s gonna be something like the wrong material rivets or hiloks used at factory to put the plug in. Just took this many cycles to happen. If smoking was allowed in planes still it may have been prevented ;)


Video from inside while flying -

Video from inside

[cooperplace]

Ouch. Another reason to keep seat belts fastened.

[MechEngr]

The plug will be an exit door with an internal panel to cover access to the release mechanism so no rivets or hiloks. In that case I'd guess the exit door wasn't properly latched before the interior panel was installed. Queue up an inspection of all such installations.

[fdr]

The plug will be an exit door with an internal panel to cover access to the release mechanism so no rivets or hiloks. In that case I'd guess the exit door wasn't properly latched before the interior panel was installed. Queue up an inspection of all such installations.

That would seem to follow with the image of the striker plates for the panel to secure against. It would follow that there is a set of locks somewhere along the sides to hold the plug in place. Not a good look. EAD to follow...


https://cimg9.ibsrv.net/gimg/pprune.org-vbulletin/1602x752/screenshot_2024_01_06_at_3_49_02_pm_693969aa8254f0df39a90578 a1512056dddb2650.png


https://cimg7.ibsrv.net/gimg/pprune.org-vbulletin/2000x621/screenshot_2024_01_06_at_3_54_52_pm_5bcb3b0c53bce1d78d3d0b6f 6d123fe040766075.png


From FR24, Airliners

[JohnnyRocket]

An Alaska Airlines flight from Portland, Oregon to Ontario, California was forced to make an emergency landing after suffering depressurization after takeoff.
Alaska flight 1282 left Portland just after 5pm local time on Friday when a window blew out at 16,000 feet, ripping a child's shirt off.
The Boeing 737-9 MAX rolled off the assembly line just two months ago, receiving its certification in November 2023, according to FAA record posted online.

How could this happen? I thought they were plug doors that open inwards...

Footage from inside the cabin... you can see the lights of Portland below!

https://www.tiktok.com/@strawberr.vy/video/7320798084869393710?lang=en

One Twitter user suggesting that the door is actually deactivated for carriers such as Alaska and not used - therefore anyone sitting there would not have even known that it was a door of sorts.

https://twitter.com/jonostrower/status/1743466899869147549

[aeromech3]

If it is a plug, then it would need to be brought inside slightly and turned to go outward; the stops are still visible so unlikely it just blew out, more to the story?

[chucko]

It looks like an entire panel blew out, including the emergency exit.
https://katu.com/news/local/alaska-airlines-flight-1282-returns-to-pdx-after-a-depressurization-just-after-takeoff-boeing-737-max#

[lucille]

Wow. At 16,000 ft the cabin differential surely wouldn’t be more than say 5psi. The passenger were lucky it occurred so low, at FL390, it might have been somewhat less amusing.

Anyhow, a happy ending, which is always good.

[MechEngr]

It is to plug the hole, not a plug style door, though there is flexibility as to what marketing term is used. The same arrangement pictured here, on an Airbus, has been referred to as a plug style door.

The original design was true plug design, requiring passengers to manhandle the door from a sideways position back into the cabin. This was seen as a problem and seems to have been replaced with an outwardly opening door, hinged at the top and counterbalanced, that has an electromagnetically operated catch to prevent just this sort of operation. Since this wasn't intended for emergency evacuation I wonder if it had the top hinge or the catch. I suspect not.

Looks like a lot of forest to search to find the door. Start checking eBay and Craigslist.

[hec7or]

How could this happen? I thought they were plug doors that open inwards

Mid Exit Doors open outwards and downwards.

[logansi]

AS to ground entire Max 9 fleet for inspection

https://news.alaskaair.com/alaska-airlines/operations/as-1282/

[hec7or]

The original design was true plug design, requiring passengers to manhandle the door from a sideways position back into the cabin. This was seen as a problem and seems to have been replaced with an outwardly opening door, hinged at the top and counterbalanced, that has an electromagnetically operated catch to prevent just this sort of operation.

The Mid Exit Door is hinged at the bottom.

[andrasz]

Can someone confirm if AS actually has an exit door installed, or it is just a fuselage plug ? This door is required to meet certification standards for high density seating, but many airlines with lower density seating opt not to have it installed (saving on cost, weight and maintenance), and the hole is covered with a fixed plug. To me the picture suggests that there was no door but a covering wall panel on the inside, and the seat row pitch also does not look like an exit row.

[DaveReidUK]

Mid Exit Doors open outwards and downwards.

Oh, no, not the "semi-plug-door" discussion yet again ...

[V_2]

Can someone confirm if AS actually has an exit door installed, or it is just a fuselage plug ?.

“The section of fuselage involved appears to be an area that can be used as an additional emergency exit door by some operators of the aircraft type, but not by Alaska.”

source BBC news: https://www.bbc.co.uk/news/world-us-canada-67899564

keep those seatbelts loosely fastened

[milhouse999]

An Alaska Airlines flight from Portland, Oregon to Ontario, California was forced to make an emergency landing after suffering depressurization after takeoff.
Alaska flight 1282 left Portland just after 5pm local time on Friday when a window blew out at 16,000 feet, ripping a child's shirt off.
The Boeing 737-9 MAX rolled off the assembly line just two months ago, receiving its certification in November 2023, according to FAA record posted online.

How could this happen? I thought they were plug doors that open inwards...

Footage from inside the cabin... you can see the lights of Portland below!

https://www.tiktok.com/@strawberr.vy/video/7320798084869393710?lang=en

One Twitter user suggesting that the door is actually deactivated for carriers such as Alaska and not used - therefore anyone sitting there would not have even known that it was a door of sorts.

https://twitter.com/jonostrower/status/1743466899869147549

Not an expert but it looks like a door from the outside, have they just stuck a panel over it internally? Online seatmaps for the Alaskan 737 Max 9 don't show a door here so this appears correct.

[EDLB]

Another reason to buckle up during the complete flight time.

[Voodoo1977]

Boeing has sent a team of 20 accountants to investigate. 🤣

[DaveReidUK]

From Flight:

Provision for the new exits – which boost the exit limit capacity from 189 to 215 passengers – “will be structurally installed as standard in all -900s, and will allow operators to decide if the door should be activated or deactivated”, says 737 chief project engineer Mike Delaney.

The deactivation feature will enhance the aircraft’s remarketability, says Delaney, adding that, when not used, the mid-exit area will be covered with a standard sidewall and overhead bin interior.

That sounds to me like it's a genuine door, only deactivated (and which can be reactivated), rather than a dummy one.

[Less Hair]

On a positive note: It makes the middle seat more attractive.

[andrasz]

That sounds to me like it's a genuine door, only deactivated (and which can be reactivated), rather than a dummy one.

It is a genuine door frame, stripped of the slide, internal paneling and opening mechanisms. The locks are bolted in place and in principle should not be able to move. (Of course if any of those bolts were missing...). 'Reactivation' is a tad more than pulling a safety inhibitor pin, but still much less effort than cutting a hole in the fuselage and installing the required hardpoints.

[Auxtank]

From the Beeb:

https://www.bbc.co.uk/news/world-us-canada-67899564

[Ollie Onion]

Wouldn’t go near a 737 Max if you paid me to fly on it. Between MAS, dodgy rudder fastenings and now this.

[MechEngr]

On a positive note: It makes the middle seat more attractive.
Think of the view and the additional arm room. Plus it ends boring conversations with the middle seater. Maybe start writing notes to toss out: "I've been trying to contact you about your automobile warranty insurance" and let people guess how it got on the roof of their house.

[Whenwe]

On a positive note: It makes the middle seat more attractive.

with the appropriate increase in price.....,, sic!

[rog747]

The previous 737-900NG-ER series also had this option for an extra aft emergency exit door behind the wing to enable high-density seating.
It is more of a hatch, that drops down, has a window, and is fitted with a slide.
This exit can be used when Ditching, unlike the 2 rear main doors that must not be used when landing on water.
It's not like the larger 757 Type 1 door (doors 3L/R) with a slide.
UK's Excel Airways were the first airline to order two of the -900ER type in 2006 for delivery for summer 2008, but the airline went under soon after.

Some airlines choose not to use this extra exit option on the 737-900ER, and on the 737 MAX-9 and will have it deactivated as Alaska have done here.

Although the actual door/hatch is still fitted, but when seen on the inside (in the cabin) it is blanked off with a wall panel with a window, and Pax would not know there was a door/exit there.
It can be reactivated if the airlines want it.

The A321N cabin-flex also has this option to use the extra aft exit for high density seating, along with a choice of overwing exit hatches too, which can also be blanked off if not required.

[MechEngr]

Ahh - bottom hinge - now that I have a name for them: https://youtu.be/WLfT5WJz-6s?t=2322
I would not expect the bottom hinge to be in place for the substitute fixed door.
Seeing in the video that they don't have moving latches, the exit version of the doors are slid up to unalign the retaining features. Without the operating lever having someone pry the door up against the pressure it should not have moved.

Putting on a speculators cap - there were fatigue cracks in the retaining features / fingers on the door. Had only one let go I would not expect the door to do more than leak loudly. But if several had cracks then when one finally crossed the finish line the rest go in a rapid cascade.

[Alwaysairbus]

Assuming the door is fully installed but deactivated and the aircraft hasn’t been through a heavy mx check then it looks like a Quality issue from build. It would be interesting know if any reports previously of door indication / noise/ pressurisation problems. Maybe even a certification issue with the length of the fuselage flexing on landing. Going to be an interesting investigation with as always a lot of Swiss cheese hazards leading to the event. Luckily the seat was empty as could have been far worse.

[DaveReidUK]

Putting on a speculators cap - there were fatigue cracks in the retaining features / fingers on the door. Had only one let go I would not expect the door to do more than leak loudly. But if several had cracks then when one finally crossed the finish line the rest go in a rapid cascade.

I'm struggling to imagine fatigue cracks on an aircraft that's less than 3 months old.

[Timmy Tomkins]

"On a Wing and a Prayer" by Al Jazeera, years ago......subcontraced construction by lowest bidder

[aox]

I'm struggling to imagine fatigue cracks on an aircraft that's less than 3 months old.

There could be, if it was just a sheet of vinyl over the outside.

[FUMR]

Another reason to buckle up during the complete flight time.

Not much good if the seat you're in gets sucked out too!

[Auxtank]

There was this debate during the 777 development about doors - having a potential weak spot and either being redesigned to include a re-inforcing plate internally - or to wait, tell the end user to inspect the outside periodically for cracking and then face the prospect of fitting the plate externally with the concomitant delays and additional parasitic drag, etc.
In the end they just got on and redesigned the damn door to be stronger in the first place.

[MechEngr]

There are two sorts of fatigue - low cycle and high cycle.

Low cycle fatigue is typically a material issue where the material strength is far below the requirement, such as from an improper heat treatment or incorrect alloy. It can also happen if the manufacturing process has left a fatigue initiator such as using a sharp corner end mill instead of a fillet end mill. Low cycle is found in the 5.0 -100 cycle range. This can be typified by flexing a paper clip. It is from a load near or above the yield strength.

High cycle fatigue is the more typical for manufactured goods. It is typified by a load that is far below the yield strength and is nearly independent of yield strength and can run from 100,000 cycles to well into the millions. If there is a manufacturing process problem it can be as simple as a surface texture that's a bit rougher or an internal inclusion of contamination.

At only 3 months - that is no bueno.

[remi]

Wouldn’t go near a 737 Max if you paid me to fly on it. Between MAS, dodgy rudder fastenings and now this.
The quality and safety genes acquired from McAir in 1997 have time and again been proven robust and utterly dominant, and the Boeing genotype is essentially extinct.

[scampo]

Hopefully they can locate the missing door as the aircraft was over land for the duration but unfortunately the area is heavily forested, thankfully though no reports of injuries on the ground.

[ozbiggles]

It’s a good workout for Boeings PR machine, how many times you hear 737-9 vs 737 Max…

[alacrity11]

Was there a pressurization problem? High differential?

[A0283]

Some thoughts

What we appear to know :
-low hr low cycle aircraft
​​​​-low pressure differential
-no passenger (fumbling) next to the door
-escape door blown out (photos from in and outside needed to know what went with it)…

What we do not exactly know in this thread or ever:
-the exact configuration(s) of a deactivated door and its mounting and cabin interior… (which includes the way it was designed AND engineered)…
-which configuration actually was in place ..
-the manufacturing and installation procedures, and if these have been changed much, and if there is a difference between the MAX 8,9,10,7…
- if procedures where followed (parts required, tooling required, could procedure be followed… did they (need) to force anything to install…)

The loss of Safety Culture and level of QC/QA standards at Boeing will take years to rebuild (consultants often use 10 years for that) … investigation in this failure may shed a light on if Boeing (and FAA) have really started with this process.

[EDLB]

Looks that all hinge bolts are still there so they should be able to figure what happened without the missing door. Strange that the door blew so low with little pressure differential. There must have been something serious amiss. Not a crack or single bolt failure, more like no bolt nuts at all and hold in place by luck and paint.

[DaveReidUK]

Looks that all hinge bolts are still there so they should be able to figure what happened without the missing door. Strange that the door blew so low with little pressure differential. There must have been something serious amiss. Not a crack or single bolt failure, more like no bolt nuts at all and hold in place by luck and paint.

I don't think there are any hinges involved when the dummy door is fitted (obviously there are when it's an actual downwards-opening exit).

Looks like a pretty clean departure - those appear just to be seat trims/seat belts hanging out the opening:

https://cimg8.ibsrv.net/gimg/pprune.org-vbulletin/434x575/n704ala_179a99bbbc30d4f63be8d42189be03df659ac951.jpg

[A0283]

My impression… they will need everything they can get their hands on … including the door…

[arf23]

could save on airport aggro for skydivers, passing over your house 50km from the airport, just jump out and land on your front lawn. I've often wanted to do this when coming from US to Heathrow and going over my house in Leeds, just jump out now and skip the 200mile/5 hour train ride home...

[A0283]

Would be interesting to have a photo by a spotter or even better of a passenger entering during boarding… to see if the door was flush with the skin…

[remi]

Looks that all hinge bolts are still there so they should be able to figure what happened without the missing door. Strange that the door blew so low with little pressure differential. There must have been something serious amiss. Not a crack or single bolt failure, more like no bolt nuts at all and hold in place by luck and paint.
In the photos I've seen so far there is no obvious damage other than some plastic and insulation. It looks like the door just fell out. The interior isn't even in disarray. One wonders how the plane could have flown at cruising altitude on earlier flights.

Looks like it arrived from JFK at ~230P and was back in the air at 506P. Before that it had been in the air every day since being parked at SEA the whole day of the 1st.

Indications of pressurization issues appeared on the 4th:

https://theaircurrent.com/feed/dispatches/alaska-737-max-9-that-lost-deactivated-exit-had-recent-pressurization-issues/

[DTA]

I don't think there are any hinges involved when the dummy door is fitted (obviously there are when it's an actual downwards-opening exit).

Looks like a pretty clean departure - those appear just to be seat trims/seat belts hanging out the opening:


Could the door have been damaged on the ground? Just looking at the white marks either side of the opening in the above photo.

[Thruster763]

Makes me think of a BAC 1-11 windscreen and wrong sized fastners. Looks a lot like an assembly issue and the panel was only held in wth sealant and incorrect fastners or several fastners missing.

[waito]

I am really tired of this Boeing "Shareholder Value" Enterpri$e!

[JHPaulo]

Putting on a speculators cap - there were fatigue cracks in the retaining features / fingers on the door. Had only one let go I would not expect the door to do more than leak loudly. But if several had cracks then when one finally crossed the finish line the rest go in a rapid cascade.

The bird was almost brand new. Improper installation would be my guess.

[procede]

The loss of Safety Culture and level of QC/QA standards at Boeing will take years to rebuild (consultants often use 10 years for that) … investigation in this failure may shed a light on if Boeing (and FAA) have really started with this process.

I would argue that dependance on consultants is a large part of the problem. Disposable personel that can take away the responsibility from management or (best case) take all their knowledge with them when they leave.

[Auxtank]

Footage in flight YT.

https://www.youtube.com/watch?v=iu2kLu3xMdY&t=33s

[DaveReidUK]

The bird was almost brand new. Improper installation would be my guess.

Unconfirmed reports that Alaskan had previously had to do work on the door.

[procede]

Footage in flight YT.

Ryanair would probably charge extra for the view.

[A0283]

I would argue that dependance on consultants is a large part of the problem. Disposable personel that can take away the responsibility from management or (best case) take all their knowledge with them when they leave.

Consultants never take away the responsibility of management. Managers decide.
Consultants bring knowledge and experience and are able to adapt to industry and company or come from them. Those that don’t should get a different label.

As far as I know in the whole 737MAX saga there have been no references to consultants….

[AirScotia]

From the Beeb:

https://www.bbc.co.uk/news/world-us-canada-67899564
From that report: ":"They said there was a kid in that row who had his shirt was sucked off him and out of the plane and his mother was holding onto him to make sure he didn't go with it.""

This incident could easily have involved fatalities.

[DaveReidUK]

Could the door have been damaged on the ground? Just looking at the white marks either side of the opening in the above photo.

The original photo from which I cropped that image shows that they are just reflections from the hangar lighting, visible all along the fuselage.

[msbbarratt]

Not much good if the seat you're in gets sucked out too!

Pretty sure that it's only the seat back cushion that's departed, in the first post's photo it looks like the seat frame itself is still there.

Still somewhat interesting that it could come loose like that; how are they attached, Velcro?

[msbbarratt]

Wouldn’t go near a 737 Max if you paid me to fly on it. Between MAS, dodgy rudder fastenings and now this.

Not to mention oval holes drilled in the rear bulkhead...

Likewise not keen on going on a MAX, or anything.

Every thing like this suggests QC failings are being found by chance, not as a result of a thorough QC process review. Given how far down the QC cliff the company has fallen, and incidents like this demonstrating that they've not yet climbed back up, one wonders what other horrors are lurking. It's hard to believe that these QC failings affect only one model; and indeed 787 has had its share of QC problems of late too.

So, how long does one give the company before declaring them not competent to make any airframe? And if one did make such a declaration, how retrospective would that have to be?

[procede]

Consultants never take away the responsibility of management. Managers decide.
Consultants bring knowledge and experience and are able to adapt to industry and company or come from them. Those that don’t should get a different label.

As far as I know in the whole 737MAX saga there have been no references to consultants….

That is the theory. In reality is is much easier to make a decision if you can point to a consultancy report (that is not publicly available) where you took some parts completely out of context. I have seen that way too often.

Technical consultants are a different issue, where often retention of knowlegde is an issue. In theory everything has been documented, in reality hardly anyone is able to go through the documentation, if they can still find it after a few years...

Didn't Boeing have some junior employee responsible for quality control with no actual power to take any action?

[DTA]

The original photo from which I cropped that image shows that they are just reflections from the hangar lighting, visible all along the fuselage.
Yes, accepted. I posted after another comment to that effect. My question/comment about damage on the ground still remains though again I saw your post about maintenance having been done on that door. If one was looking for a reason why it failed early on this flight and not on previous flights then one explanation could be that the cause was not present on previous flights.

[Rebus]

Pretty sure that it's only the seat back cushion that's departed, in the first post's photo it looks like the seat frame itself is still there.

Still somewhat interesting that it could come loose like that; how are they attached, Velcro?
Yes velcro.

[Sue Vêtements]

How do you get your shirt "sucked off"?

I'm not saying it didn't happen, but I saw this as part of a magician's trick once, the whole point being that it was "impossible" because your arms go through the sleeves and hold it in place

Given Boeing's reputation, maybe the child won't be the only one to lose his shirt

[MechEngr]

I suspect the 200 mph gust might have had some influence, however short a time that was. For a moment the child likely resembled the car lot inflatables with their arms flailing in the air.

So, someone on the ground gets: A door. An inner panel. A child's shirt. A seat cover. And, per the BBC, a cellular phone.

Amazingly the nearby tray table remained in place.

I picture a rural location where someone, looking up into a tree, says "Bob? What the hell did you get up to last night?"

[msbbarratt]

That is the theory. In reality is is much easier to make a decision if you can point to a consultancy report (that is not publicly available) where you took some parts completely out of context. I have seen that way too often.

Technical consultants are a different issue, where often retention of knowlegde is an issue. In theory everything has been documented, in reality hardly anyone is able to go through the documentation, if they can still find it after a few years...

Didn't Boeing have some junior employee responsible for quality control with no actual power to take any action?

If there was a period in Boeing’s history when QC had no authority, I’m somewhat unnerved by the thought that anything that they built in this period is allowed to fly.

[Tango and Cash]

I'm all for the window seat view, but that's taking things a little too far!

[VHOED191006]

Can we talk about how 5 of their MAX 9s just departed? How long does a "full maintenance and safety inspections" take for one aircraft. Something tells me that you can't do that all within one night..........

[Flughafenn]

The seat to the right of the window looks a little bent out of shape!

Also, presuming these won't actually be back in the air at Alaska until they've actually found the root cause of the issue? I read above the CEO said there would be a safety inspection in next few days but one assumes that won't be enough to get them flying again?

[digitaria]

interesting that it could come loose like that; how are they attached, Velcro?

If doors are only secured by sealant, then anything is possible :)

[Sailvi767]

If it is a plug, then it would need to be brought inside slightly and turned to go outward; the stops are still visible so unlikely it just blew out, more to the story?

If the plug was never installed properly or latched it could shift position when the aircraft was unpressurized until it was able to blow out. It appears the aircraft had pressurization issues the day prior.

[Airbanda]

Makes me think of a BAC 1-11 windscreen and wrong sized fastners. Looks a lot like an assembly issue and the panel was only held in wth sealant and incorrect fastners or several fastners missing.

Me too!!

[DaveReidUK]

How do you get your shirt "sucked off"?

I'm not saying it didn't happen, but I saw this as part of a magician's trick once, the whole point being that it was "impossible" because your arms go through the sleeves and hold it in place.

Maybe file with the other reports I've seen that an entire seat departed ... :O

[Sailvi767]

Unconfirmed reports that Alaskan had previously had to do work on the door.

They are going to offer row 26 to adventurers and thrill seekers for just 30 euros!

[OpenCirrus619]

Ryanair would probably charge extra for the view.
... except Ryanair don't fly 737-MAX - they fly "Gamechangers".

[ACW342]

And yet again we see the reluctance for U.S. pilots to declare MAYDAY!! MAYDAY!! MAYDAY!! that gets EVERYBODYS immediate attention rather than a mumbled call and where a controller had to ask "are you an emergency or do you just wish to return to Portland" that was after he stopped their descent at 7000' from what I could hear on the R/T recording, posted earlier. Unless, of course, you don't consider having a piece of your aeroplane falling off causing an explosive decompression (or should that be an unplanned pressure operated, gravity assisted, removal of a fuselage panel and internal atmosphere) A342

[OpenCirrus619]

Just seen this, from yesterday: https://www.seattletimes.com/business/boeing-aerospace/boeing-wants-faa-to-exempt-max-7-from-safety-rules-to-get-it-in-the-air/

Looks like Boeing have learnt nothing over the past few years (and the FAA are still "bending over" for them).

Just reinforces my view: If its Boeing I ain't going

[procede]

And yet again we see the reluctance for U.S. pilots to declare MAYDAY!! MAYDAY!! MAYDAY!! that gets EVERYBODYS immediate attention rather than a mumbled call and where a controller had to ask "are you an emergency or do you just wish to return to Portland" that was after he stopped their descent at 7000' from what I could hear on the R/T recording, posted earlier. Unless, of course, you don't consider having a piece of your aeroplane falling off causing an explosive decompression (or should that be an unplanned pressure operated, gravity assisted, removal of a fuselage panel and internal atmosphere) A342
In their defence: the pilots probably would not have noticed the hole, if not for the cabin pressurisation warning.

[RevMan2]

Doesn’t help if - as reported - the adjacent seat was defenestrated…..

[MAN777]

What potential outcome could there have been had the plug/door/window struck the rear control surfaces ?

[Tech Guy]

An almost brand new AS Max 9 has lost an entire window section during an explosive decompression event just out of Portland. Photos below show reported damage

https://cimg4.ibsrv.net/gimg/pprune.org-vbulletin/1280x1707/gdh_jfhaqaa2wxp_ccf6832b834277ac96435580f0ee73898a8d73af.jpg

I think anyone sitting there would likely suffer explosive evacuation of their bowels immediately afterwards adding to their suffering.

[SLF3]

Just seen this, from yesterday: https://www.seattletimes.com/business/boeing-aerospace/boeing-wants-faa-to-exempt-max-7-from-safety-rules-to-get-it-in-the-air/

Looks like Boeing have learnt nothing over the past few years (and the FAA are still "bending over" for them).

Just reinforces my view: If its Boeing I ain't going

Does EASA have to accept this?

[Consol]

https://cimg2.ibsrv.net/gimg/pprune.org-vbulletin/1280x1707/gdh_jfhaqaa2wxp_ccf6832b834277ac96435580f0ee73898a8d73af_1__ cb07cec013dcb742290b676f362d8e91507fb9ea.jpg
Shouldn't there be bolts in these holes? Anyone got any fancy enhancement apps to see if the holes have any stubs left in them?

[Fright Level]

I often read comms transcripts from US events and there seems a reluctance to use ICAO standard phraseology. "We are an emergency" doesn't have the gravitas of a mayday call which I thought was what it should have been.

https://www.bbc.co.uk/news/world-us-canada-67899564

[DaveReidUK]

Doesn’t help if - as reported - the adjacent seat was defenestrated…..

As reported ...

The photos clearly show that didn't happen. If triple seats start to separate, it's a sign that you have far bigger problems.

[Auxtank]

In their defence: the pilots probably would not have noticed the hole, if not for the cabin pressurisation warning.

Except for;

https://cimg4.ibsrv.net/gimg/pprune.org-vbulletin/499x200/unnamed_5b7c30cfdab41785ac059eaf1970363258728688.jpg

[Matt2725]

I often read comms transcripts from US events and there seems a reluctance to use ICAO standard phraseology. "We are an emergency" doesn't have the gravitas of a mayday call which I thought was what it should have been.

https://www.bbc.co.uk/news/world-us-canada-67899564

From the audio I heard, even after the pilot declared they were an emergency, the next controller on approached asked again if they were an emergency aircraft (not sure why this wasn't passed on. I can only assume the Alaska wasn't squawking 7700 for some reason). The pilot reponsed in the affirmative, and gave the souls and fuel onboard. Yet soon after, ATC asked for souls and fuel onboard, which required the same readback again.

Not sure what we going on with the controllers, but the communication seemed pretty poor throughout.

[fdr]

https://cimg2.ibsrv.net/gimg/pprune.org-vbulletin/1280x1707/gdh_jfhaqaa2wxp_ccf6832b834277ac96435580f0ee73898a8d73af_1__ cb07cec013dcb742290b676f362d8e91507fb9ea.jpg
Shouldn't there be bolts in these holes? Anyone got any fancy enhancement apps to see if the holes have any stubs left in them?

Those aren't holes, those are striker plates to fair the alignment of the outer panels. the bolts would go laterally, and the recess for those appears top left and right I believe. I've owned earlier B737's this is new to me...

[DaveReidUK]

Those aren't holes, those are striker plates to fair the alignment of the outer panels. the bolts would go laterally, and the recess for those appears top left and right I believe. I've owned earlier B737's this is new to me...

Yes, they're the stops that prevent the door moving outwards unless it first moves vertically to clear them. The lock bolts are, of course, intended to prevent that happening unintentionally.

[unmanned_droid]

https://cimg2.ibsrv.net/gimg/pprune.org-vbulletin/1280x1707/gdh_jfhaqaa2wxp_ccf6832b834277ac96435580f0ee73898a8d73af_1__ cb07cec013dcb742290b676f362d8e91507fb9ea.jpg
Shouldn't there be bolts in these holes? Anyone got any fancy enhancement apps to see if the holes have any stubs left in them?

If you mean the permanent attachment points for the panel, there are blind fastener heads in the holes. It is interesting that one of the fastener heads (right hand side 2nd down) is tilted like it suffered a head/shank failure. This could be the last fastener to fail, although it seems less likely as it's on the forward edge. Since this was a 'new' aircraft I suspect that this panel was not secured correctly during manufacture, allowing air pressure leaks and fretting type failure of a fastener that then allowed dynamic pressure under the panel and pry it off.

[Big Pistons Forever]

Except for;

https://cimg4.ibsrv.net/gimg/pprune.org-vbulletin/499x200/unnamed_5b7c30cfdab41785ac059eaf1970363258728688.jpg

If the door is missing all its hardware because it is just intended to fill the hole would the door unlocked sensors still be there ?

[Bbtengineer]

If the plug was never installed properly or latched it could shift position when the aircraft was unpressurized until it was able to blow out. It appears the aircraft had pressurization issues the day prior.

Yeah I was thinking that too.

So looking on the bright side, maybe ASA just got a free diagnosis of the pressurization problem!

[Matt2725]

If the door is missing all its hardware because it is just intended to fill the hole would the door unlocked sensors still be there ?

Whilst I deal with much smaller and faster aircraft than the 737, I'd imagine there'd be numerous microswitches or similar around the door frame, which once released would send an illumination signal to the lighting controller or similar computer.

Although if the theory of the door not being installed correctly holds true, then I guess I'm way off the ball with that theory.

[welshwaffu]

What potential outcome could there have been had the plug/door/window struck the rear control surfaces ?

That's what I was thinking, I assume the aircraft still has all of its empennage intact?

[Auxtank]

If the door is missing all its hardware because it is just intended to fill the hole would the door unlocked sensors still be there ?
Good question. They should also have had a Master Caution with DOORS on the right hand annunciator panel as well but as you say; if the thing had taken it's hardware with it then possibly no.

[procede]

If the door is missing all its hardware because it is just intended to fill the hole would the door unlocked sensors still be there ?
I would be very surprised if they were still there.

[DaveReidUK]

It's not just the regular E/E door that's been deactivated (hence the absence of the operating lever and the vent panel). It's a purpose-designed blank and likely has no electrical connections at all.

[MLHeliwrench]

Can we talk about how 5 of their MAX 9s just departed? How long does a "full maintenance and safety inspections" take for one aircraft. Something tells me that you can't do that all within one night..........

unless the inspection is simply making sure the bolts to secure the plug are installed properly or installed at all!

[BFSGrad]

Alaska must think they have a handle on the issue as there are plenty of ASA MAX 9s in the air right now, including an ETOPS bird.

[ACW342]

I often read comms transcripts from US events and there seems a reluctance to use ICAO standard phraseology. "We are an emergency" doesn't have the gravitas of a mayday call which I thought was what it should have been.

https://www.bbc.co.uk/news/world-us-canada-67899564

From the audio I heard, even after the pilot declared they were an emergency, the next controller on approached asked again if they were an emergency aircraft (not sure why this wasn't passed on. I can only assume the Alaska wasn't squawking 7700 for some reason). The pilot reponsed in the affirmative, and gave the souls and fuel onboard. Yet soon after, ATC asked for souls and fuel onboard, which required the same readback again.

Not sure what we going on with the controllers, but the communication seemed pretty poor throughout.

Flight Level, Matt2725, please see my post no. 78. Not only does it give every one notice that you're in a baaaad way but your clearances can be sorted very quickly, nearby airfields will be wanting to offer you runways and the tower controler will press the big button on the red phone in the tower to scramble the crash crew. If I remember correctly captain Sullenberger didn't "I want to declare an emergency" He used "Mayday, mayday, mayday Cactus xxx double birdstrike (or similar) See this as an example: https://www.youtube.com/watch?v=RPkZBR89y_M

[JG1]

Except for;

https://cimg4.ibsrv.net/gimg/pprune.org-vbulletin/499x200/unnamed_5b7c30cfdab41785ac059eaf1970363258728688.jpg

Hard to believe an aircraft equipped with this pinball game technology had just been built and delivered. There's a lot wrong in this industry.

[Mr Mac]

Well this just enforces my view re 737 Max and indeed makes me question my whole view of Boing as a company. I spent most of my working career on their products, but now actively avoid their products. I dont like the 787 and avoid 737 Max for pretty obvious reasons, though I was on a LH 747 up from Singapore at the end of last year, and she was fine and felt at ease. The new Boeings are a shadow of their predecessor's. To put in context I fly probably 2-3 times a week long and short haul over the year. If I am thinking like this and I am only humble SLF, how many others are taking this view re Boeings new products ? Get the company base back to Seattle, kick the accountant's back to where they belong, and let engineers design things. Accountancy is a support function in a business, not the defining thing unless you are an accountancy practice. There will be books written in the future about the demise of this business !!

Rant over
Cheers
Mr Mac

[Big Pistons Forever]

Hard to believe an aircraft equipped with this pinball game technology had just been built and delivered. There's a lot wrong in this industry.

That sir is an insult to pinball machines everywhere!

Too bad Boeing thinks “QA” stands for Quality Avoidance,…..

[canard68]

I remember a HS 748 crashing near East Midlands in the UK that lost a door and it wrapped itself round the leading edge of the tailplane.
Control lost and straight down. The swept tail of a 737 may prevent the door from staying put but I would not bank on it.

[runner1021]

All things considered, Boeing had a very lucky day. Had this happened on a flight halfway to PHNL at FL390, Boeing would no longer be in the commercial aircraft business.

[Voodoo78]

From the audio I heard, even after the pilot declared they were an emergency, the next controller on approached asked again if they were an emergency aircraft (not sure why this wasn't passed on. I can only assume the Alaska wasn't squawking 7700 for some reason). The pilot reponsed in the affirmative, and gave the souls and fuel onboard. Yet soon after, ATC asked for souls and fuel onboard, which required the same readback again.

Not sure what we going on with the controllers, but the communication seemed pretty poor throughout.

Exactly my first thought when I heard the ATC comms.

Declaring mayday is an unambiguous, worldwide recognised statement that gets everyone’s attention.

The Thomson incident from the early 2000’s that someone posted here is a clear example of how to communicate.

Friend of mine recently had to call the coastguard on the telephone as his boat was on fire and he couldn’t get to the VHF. Even on the phone, he went through the mayday sequence because it told the coastguard two important things:

1- All the relevant info
2- The person on the phone knows what they are talking about.

[Thruster763]

Hard to believe an aircraft equipped with this pinball game technology had just been built and delivered. There's a lot wrong in this industry.

You would probably be surprised how many parts on a 737 have identification starting "707"......

[MLHeliwrench]

VAS aviation video summary with ATC comms



Video VAS aviation

[brak]

Amazingly the nearby tray table remained in place.

And the safety card in the pocket in front. Better attached than that door.

All things considered, Boeing had a very lucky day. Had this happened on a flight halfway to PHNL at FL390, Boeing would no longer be in the commercial aircraft business.

They had 2 no-survivor crashes in a row of the same type, and are still in business.

[ImbracableCrunk]

Good question. They should also have had a Master Caution with DOORS on the right hand annunciator panel as well but as you say; if the thing had taken it's hardware with it then possibly no.
The lights are marked INOP and are not wired to the "doors". The lights will test, but don't function as a warning.

[Ancient-Mariner]

Is it me, or have most window incidents been on the Left Hand side?
Even the BAC 1-11 incident was on the LH side, albeit the Captain's windscreen.

[AirScotia]

FAA orders grounding of 171 Boeing planes
https://www.bbc.co.uk/news/world-us-canada-67903655

[scr1]

Grounded in the US by the FAA

https://www.bbc.co.uk/news/world-us-canada-67903655

[Ivor_Bigunn]

To be accurate it is a no-fly until completion of an inspection that takes 4 to 8 hrs:


https://cimg0.ibsrv.net/gimg/pprune.org-vbulletin/1056x600/737_door_1_1b89af01d3ffb4f2e6fbe81ed22e8f167a91866b.jpg
IB

[Maninthebar]

To be accurate it is a no-fly until completion of an inspection that takes 4 to 8 hrs:
IB
This implies to me that a specific issue has been identified as THE cause of this event.

Which, without the door present is remarkable and points to some gross failure of assembly

[Orange future]

Why do I feel uncomfortable everytime I hear an airline crew from the US demonstrating a complete lack of RT awareness?

As for Boeing, its not a good look.

Along with the issues over 777x certification, the issues with the 767 tanker, the issues with the 787, the issues with the Max (tail bolts), the issues with the Max (bulkhead), the issues with the Max (MCAS).

In fact, one could argue the aerospace industry in the US has taken its eye off the ball.

V-22, F-22, F-35.......

The realities of a bean counters financialised economy.

[Ancient-Mariner]

I suspect the 200 mph gust might have had some influence, however short a time that was. For a moment the child likely resembled the car lot inflatables with their arms flailing in the air.

So, someone on the ground gets: A door. An inner panel. A chilhttps://theaircurrent.com/feed/dispatches/alaska-737-max-9-that-lost-deactivated-exit-had-recent-pressurization-issues/d's shirt. A seat cover. And, per the BBC, a cellular phone.

Amazingly the nearby tray table remained in place.

I picture a rural location where someone, looking up into a tree, says "Bob? What the hell did you get up to last night?"

I wonder if that cellular phone rings out if called? Would give a rough location of the "door" maybe?

[JapanHanuma]

I can't imagine an airline using the Boeing MAX brand to sell a ticket to their customers.
"Take a ride with use on our brand new A350s! Luxuries mile high!"
or
"Take a ride with us on our brand new Boeing 737 MAX'S! This airline cares more about money than your safety".

[Quantz]

And now all Max's in the US. How these bricks are still allowed to fly is beyond me. https://www.nytimes.com/2024/01/05/business/alaska-airlines-flight-portland-landing.html?campaign_id=60&emc=edit_na_20240106&instance_id=0&nl=breaking-news&ref=cta&regi_id=69311528&segment_id=154471&user_id=f91c764e792dfc80ec4e81acd2ee83fc

[OldnGrounded]

This implies to me that a specific issue has been identified as THE cause of this event.

Which, without the door present is remarkable and points to some gross failure of assembly

171 airplanes of the 218 total delivered are covered by the EAD. The ones not covered are the comparative few that have been in service long enough to have already been subject to an inspection including the door plug.

I other words, you're probably right.

[Europa01]

This implies to me that a specific issue has been identified as THE cause of this event.

Which, without the door present is remarkable and points to some gross failure of assembly

I’d like to bet that someone in engineering at Boeing will have looked at the photos and already worked out exactly what happened.

[Maninthebar]

Yup

So not a failure of design (would be all in series with no inpection)

Not a fatigue failure (would require much greater diagnosis)

Points to failure of assembly e.g. missing bolts or other fixings that are on the design

[freshgasflow]

https://cimg6.ibsrv.net/gimg/pprune.org-vbulletin/790x452/boeingmaxjumpseat_49afe5e3be08c7e89f9c7bdcaed6e8914143db3a.j pg

[VM325]

Judging by where the altitude drops on the FR24 track, the door may well be here somewhere.
It's a well populated area, so I'd have thought someone will eventually find it...

https://cimg5.ibsrv.net/gimg/pprune.org-vbulletin/2000x1198/screenshot_2024_01_06_at_19_24_05_79966c808ab866bf8e936a9741 e856dde9c5fc82.jpg

[procede]

171 airplanes of the 218 total delivered are covered by the EAD. The ones not covered are the comparative few that have been in service long enough to have already been subject to an inspection including the door plug.

I other words, you're probably right.

Or they have the high density config with a real door installed?

Non max 737-900 also seem have these plugs.Why are these not affected?

[remi]

Meanwhile, if you're looking for a completely deranged hot take completely divorced from fact, here you go:

https://www.thedailybeast.com/boeings-alaska-airlines-mid-air-emergency-very-similar-to-2011-southwest-airlines-blowout

[remi]

Judging by where the altitude drops on the FR24 track, the door may well be here somewhere.
It's a well populated area, so I'd have thought someone will eventually find it...

A metal door sized object at 12,000 feet should have left clear primary radar returns. It shouldn't be too difficult to find in the "tapes," if someone hasn't already found the door lying on top of Rudolph in their front yard.

[ReggieMoto]

The plug will be an exit door with an internal panel to cover access to the release mechanism so no rivets or hiloks. In that case I'd guess the exit door wasn't properly latched before the interior panel was installed. Queue up an inspection of all such installations.
Assuming the exit door is the cause, who would have configured the door to be properly latched and secured prior to the installation of the panel, Alaska or Boeing?

[MechEngr]

Informative video: https://www.youtube.com/watch?v=nw4eQGAmXQ0

Indicates a non-functional door was used rather than in-oping an exit door and suggest retaining bolts were missing. If so, then there will be a paper trail back to whoever signed off that the bolts were installed.

[Eutychus]

All things considered, Boeing had a very lucky day. Had this happened on a flight halfway to PHNL at FL390, Boeing would no longer be in the commercial aircraft business.

I think I see what you did there (https://en.wikipedia.org/wiki/Aloha_Airlines_Flight_243).

[procede]

Indicates a non-functional door was used rather than in-oping an exit door and suggest retaining bolts were missing. If so, then there will be a paper trail back to whoever signed off that the bolts were installed.

If this true, then there is a very serious quality control issue extending much further than just these plugs.

[MLHeliwrench]

That it was removed from ETOPS schedules with the prior pressurization issues shows that the system at least filled some of the Swiss cheese holes.

if it was anywhere at FL39 instead of 16,000 feet the decompression would have been much more dramatic - probably sucking that kid out the hole that lost only his shirt. Lots of ‘lucky’ elements to this.

The fact that the FAA did a mass grounding points to it being a factory install issue - not an Alaska maintenance issue - such as troubleshooting the pressurization snag.

[scifi]

Just to put some figures on the forces involved. If the door is 4ft by 3ft, then its area is 4x3x144, = 1728 square inches.
If the differential pressure is 5 psi, then the total force on the door is 8640 pounds, or about 4 tons.
As the door would weigh much less than 1/4 ton, it would experience an acceleration of over 16G., if all the fasteners failed at once.

[Liffy 1M]

There's what looks like quite an informative contribution by a former Boeing engineering guy (jimpalmer1969) in the comments section below Juan Browne's initial analysis.
https://www.youtube.com/watch?v=I9EvHpf8jZg

[incompleteness]

The emergency airworthiness directive has been issued, just now

https://drs.faa.gov/browse/excelExternalWindow/DRSDOCID122693486620240106201913.0001

[Plane Watcher]

Misread what you wrote as "Boeing has sent a team of 20 accountants" which would make sense for the company, post Stonecipher.

[MLHeliwrench]

The emergency airworthiness directive has been issued, just now

https://drs.faa.gov/browse/excelExternalWindow/DRSDOCID122693486620240106201913.0001


FAA emergency AD grounds all MAX 9 with dummy plug door installed. Those airframes with operational emergency exit at that cabin location are not affected by AD.

The AD basically says no further flight until a yet to be specified inspection is carried out.

id imagine this inspection will be released very shortly.

[DaveReidUK]

The emergency airworthiness directive has been issued, just now

https://drs.faa.gov/browse/excelExternalWindow/DRSDOCID122693486620240106201913.0001

Though unhelpfully it doesn't contain any details of the required inspection/rectification action.

[incompleteness]

Though unhelpfully it doesn't contain any details of the required inspection/rectification action.

I feel like that's because they don't know the exact root cause. They give a contact person in para j, I imagine he and his people will be up for a few days looking at all the feedback from inspections and coordinating with Boeing. Then there will be a final AD.

[MechEngr]

There's what looks like quite an informative contribution by a former Boeing engineering guy (jimpalmer1969) in the comments section below Juan Browne's initial analysis.


jimpalmer is describing the other door system. What was installed here has no linkage.

[D3pro]

And yet again we see the reluctance for U.S. pilots to declare MAYDAY!! MAYDAY!! MAYDAY!! that gets EVERYBODYS immediate attention rather than a mumbled call and where a controller had to ask "are you an emergency or do you just wish to return to Portland" that was after he stopped their descent at 7000' from what I could hear on the R/T recording, posted earlier. Unless, of course, you don't consider having a piece of your aeroplane falling off causing an explosive decompression (or should that be an unplanned pressure operated, gravity assisted, removal of a fuselage panel and internal atmosphere) A342

Or perhaps "Pan Pan"?

[Intecler]

Stupid question but..

Have a question about the plug.

In the video that MechEngr linked to, you don't see if the stop fittings will be on the inside of the stop pads or no.

If you compare with the door model, you can clearly see that it is on the inside in the closed position.

Can't link but search for "Climb on board Boeing's new 737 Max 9" on Google, it's the first link from Cnet, picture no.12.

[MAN777]

Any discussion from other regulators outside the US re groundings ?

I presume there must be non US examples of this low density fit ?

[crewmeal]

I guess this will put back the certification of the Max 10 by a few months. Also I wonder how many carriers use that as a proper emergency exit complete with slide equipment.

[JanetFlight]

Is this the same also used by Ryanair high density pax dubbed the 8-200?

[DaveReidUK]

I feel like that's because they don't know the exact root cause. They give a contact person in para j, I imagine he and his people will be up for a few days looking at all the feedback from inspections and coordinating with Boeing. Then there will be a final AD.

But the 737-9 is free to fly once the inspection that relates to the AD has been carried out.

[procede]

Is this the same also used by Ryanair high density pax dubbed the 8-200?

It looks like the same solution, except they have the doors installed, so apparently not an issue.

[DaveReidUK]

Is this the same also used by Ryanair high density pax dubbed the 8-200?

No, the plug is only available on the -9. Ryanair have a functioning door.

[spornrad]

Informative video: https://www.youtube.com/watch?v=nw4eQGAmXQ0

Indicates a non-functional door was used rather than in-oping an exit door and suggest retaining bolts were missing. If so, then there will be a paper trail back to whoever signed off that the bolts were installed.
Thanks, that explains in detail the working of the plug type door. Door must slide upwards to de-align the stop fittings. Door was thus creeping up by vibration during ground ops until it popped open after some cycles. So a massive quality problem in assembly, since they most likely forgot to install the four safety bolts (no damage to the fittings)

[lateott]

Facts and speculations:

1) This aircraft included a bottom-hinged mid-cabin plug, there was no mid-cabin door (fact)
2) At altitude the plug is normally retained against pressure differential by its 12 stop fittings positioned inside the frame's 12 stop pads (fact)
3) The plug design is spring loaded to lift itself 1.5 inch, clear its stop fittings from the frame's stop pads, swing down, and eject itself from the plane at flight speeds (facts with hyperbole)
4) Only 4 horizontal bolts are in place to counteract the spring-and-eject action of this plug design, 2 in the lower hinge brackets and 2 in the upper guide fittings* (believed to be fact)
5) 1 to 3 of the 4 bolts must have been missing, loose, over torqued, defective, wrong size, etc.** (speculation)
6) The 1 to 3 remaining bolt(s) loosened or sheared during the flight, allowing the plug to lift and eject (speculation)
7) Either the aircraft came from the factory that way or Alaska Air performed some improper maintenance on the plug in the last 2 months (speculation)

* Not entirely true, because if the plug is properly positioned during pressure differential there is also friction of the stop fittings against the stop pads which acts against the lifting spring force. Therefore, there may have been only a narrow window of pressure differential in which the plug lift-and-eject could have occurred. It's possible at higher altitude this could not have occurred, thereby somewhat limiting the potential consequences from (more) explosive decompression, altitude plunge, etc.
**I will speculate 2 bolts were missing, either the top 2 in the upper guide fittings, or the bottom 2 in the lower hinge brackets. Otherwise 2 or all 4 were over torqued or wrong size. If 4 bolts were missing, they never would have had any cycles, and it is unlikely a random defect would hit 4 bolts in the same plug. Therefore, human error during assembly or less likely maintenance.

IMO 4 bolts is not enough redundancy for this design when you consider the risk.

[lateott]

Thanks, that explains in detail the working of the plug type door. Door must slide upwards to de-align the stop fittings. Door was thus creeping up by vibration during ground ops until it popped open after some cycles. So a massive quality problem in assembly, since they most likely forgot to install the four safety bolts (no damage to the fittings)
Yes, except it looks like Boeing retained the bottom hinges for attachment of this plug design, and the hinges are spring loaded to lift the plug/door and clear the stops.

I think you can see the hinges hanging out of the doorframe in post-incident photos at the gate.

If we knew assembly or maintenance procedures we might be able to better guess whether the top 2 or bottom 2 bolts were missing. You would need to put 1 or 2 bolts in just to hold the plug in the frame. Seems like for installation, the plug must be pulled into the frame from the mid/top of the plug, pushed down at the hinges to counteract the spring and align the stop fittings, then a bolt installed to hold it against the upward spring force while the remaining bolts placed and tightened.

[Quantz]

Comments section is very instructive. Boeing gaining criminal reputation by the minute. Justifiably so.
https://www.nytimes.com/2024/01/05/business/alaska-airlines-flight-portland-landing.html#commentsContainer

[spornrad]

Spring-eject is disabled at pressure difference by friction and on ground was probably avoided via glue by paint / stickiness of seals. These plugs are never opened. Maybe the springs not installed? Vibration in ground ops overcame the sticking after some cycles. At least the upper two bolts were clearly not installed or fell out, since the stop fitting eyes are completely undamaged on the pics.

[ThreeIfByAir]

Stupid question from SLF... if this design is the same as the 900ER, why haven't they grounded any 900ERs? Delta, United and Alaska have about 400 of those between them...

[OldnGrounded]

Or they have the high density config with a real door installed?

Non max 737-900 also seem have these plugs.Why are these not affected?

1. Right. 2. Good question, but we don't know, yet, whether they are or are not affected.

[krismiler]

Fortunately the area around door frames is strengthened, this is why a rear door is a least risk bomb location for a suspect package. It looks like a quality control issue.

[BFSGrad]

I guess this will put back the certification of the Max 10 by a few months.
From the video in post #131, the MAX 10 does not use the plug-type mid-cabin exit door that is central to this accident. Regardless, the MAX 7 is in the on-deck circle, not the MAX 10. Even though unrelated, this accident will make it much more politically problematic for the FAA to grant the engine anti-ice exemption for MAX 7 certification.

[wheelsright]

As has been alluded to, it looks like the most likely explanation is Boeing neglected to put any bolts in! Of course, there will have to be detailed investigation to confirm if any bolts were fitted, but the pictures do not appear to show any evidence that any bolts were there at all. Other unlikely possibilities could be that the bolts were severely over torqued and fractured after a few pressurization cycles. The evidence may have been blown out the door. It highlights the importance of finding the dummy door plug to see if there are any remaining bolt stems or none at at all. Either way, it is likely the Boeing will have further explaining to do in respect of their procedures, safety and quality control. It is incredibly lucky that the incident happened at relatively low altitude. It is worrying that there have been a series of issues on this type that have, or could have, resulted in fatalities. I avoid these aircraft as a matter of principle. In my opinion, Boeing have got away with knowingly putting peoples lives at risk and there have been insufficient consequences. Passengers should vote with their feet and simply stop flying 737 Max as a protest.

[unmanned_droid]

There's what looks like quite an informative contribution by a former Boeing engineering guy (jimpalmer1969) in the comments section below Juan Browne's initial analysis.
https://www.youtube.com/watch?v=I9EvHpf8jZg

He assumes the door is an active exit rather than a deactivated/non-op exit from factory.

[chucko]

A metal door sized object at 12,000 feet should have left clear primary radar returns. It shouldn't be too difficult to find in the "tapes," if someone hasn't already found the door lying on top of Rudolph in their front yard.
Watch for it to turn up on eBay.

[lateott]

Spring-eject was probably avoided via glue by paint / stickiness of seals. These plugs are never opened. Maybe the springs not installed? Vibration in ground ops overcame the sticking after some cycles. At least the upper two bolts were clearly not installed or fell out, since the retainer eyes are completely undamaged on the pics.
Maybe :)

I speculate the springs are present even in the plug adaptation (to aid install and maintenance of the plug and frame.)

I cannot see a good photo of the upper attachment points in the doorframe through which bolts in the upper guide fittings would install horizontally towards the fore and aft. But I would agree it is likely the upper bolts were missing or stripped or (maybe) sheared.

If I were working on my boat or RV I would pull the plug in from the top or middle for leverage, step on both hinges to counteract the spring, shove at least 1 bolt in the top to hold it against the spring force, then go about installing all the bolts.

But I suppose the installation/maintenance SOP may be more prescriptive in where to grab/pull/push for proper positioning. ;)

These kinds of adaptations need to consider human factors in install/maintenance. If it were a door, that door would have a proper handle and latch and a logical "closing" sequence that naturally counteracts the springs. The fact that this is a plug adapted to the airframe may cause the technician to improvise.

[fdr]

All things considered, Boeing had a very lucky day. Had this happened on a flight halfway to PHNL at FL390, Boeing would no longer be in the commercial aircraft business.

Not quite, but it would be somewhat more embarrassing. The overwater flights are EDTO/ETOPS operations, and the depressurised fuel case has to be covered. Thats the good news. The bad news is that sitting at 10,000' for 2.5 or more hours, even near the tropics is going to be coolish for the fare payers. Needs lots of coffee. ~-5C outside (new inside temp for convertible model) There is a minor constraint that the range at the depressurised altitude is going to be a fair bit faster than desired for flight with a door open. Above 200KIAS gets pretty impressive buffet inside, but in this case, the guys were around 16,000' so the panel departed the plane at somewhere between 250-280KCAS, the usual climb speed for the 737. They could end up having to shut an engine down if limited by buffet to lower speeds.

Boeing would survive that, the pax would be pretty irritated.


Seat Guru probably just got a big increase in traffic....

[lateott]

Stupid question but..

Have a question about the plug.

In the video that MechEngr linked to, you don't see if the stop fittings will be on the inside of the stop pads or no.

If you compare with the door model, you can clearly see that it is on the inside in the closed position.

Can't link but search for "Climb on board Boeing's new 737 Max 9" on Google, it's the first link from Cnet, picture no.12.
Good question. Yes, the stop fittings would be on the inside of the stop pads when properly aligned. However, as noted before, the plugs (and doors where used) are mounted on spring-loaded hinges which force the plug up 1.5" and forces the stop fittings up above the stop pads until there is no more retention.

Edited to add: Also, that CNET photo 12 shows an actual door in the test aircraft, not a plug as was in this Alaska Airlines aircraft. However, the stop fittings are the same. The plug has no latch, only the 4 bolts to keep it in place.

[lateott]

All things considered, Boeing had a very lucky day. Had this happened on a flight halfway to PHNL at FL390, Boeing would no longer be in the commercial aircraft business.
True, however I speculated that it may not have been possible for this failure mode to occur at a higher altitude and pressure differential. More pressure differential means more friction on the stop fittings and less likelihood of shifting enough such that the plug would be shifted enough to be ejected.

Chain of events. There was surely a root cause, but multiple circumstances and contributing factors likely needed to align for this failure.

[JamaicaJoe]

Looks that all hinge bolts are still there so they should be able to figure what happened without the missing door. Strange that the door blew so low with little pressure differential. There must have been something serious amiss. Not a crack or single bolt failure, more like no bolt nuts at all and hold in place by luck and paint.


So that was where that bag of ten big bolts was supposed to go, -my bad,,, -- said some Boeing technician last night....

https://www.cnet.com/a/img/resize/bfdc11109f18f1d65081e2acc33c5d74f549470b/hub/2017/06/20/d37d15e6-76b8-473d-8c01-d8f7c5aa0f05/boeing-737-max-9-pas-4.jpg?auto=webp&width=1200

[MAN777]

This sounds like the door was designed by IKEA, doesn't fit properly and you end up with extra bits.

[tdracer]

Before you all get too wrapped up in your anti-Boeing crusade, you might want to consider this little inconvenient fact: The fuselage isn't built by Boeing - all 737 fuselages are assembled in Wichita by Spirit AeroSystems. The fuselages are shipped to Renton by rail as basically complete structures with the plug (or door) already installed. Assuming that this was an assembly issue (as seems likely based on the lack of associated damage from the departed plug, as well as the AD'ed inspection), the blame should fall squarely on Spriit, not Boeing.
While Spirit was "Boeing Wichita" at one time, that hasn't been the case for nearly 20 years (Boeing sold them in 2005) and it has operated as an independent subcontractor since. Spirit is also a major supplier to Airbus.
While an alert inspector at Boeing might have picked up on missing fasteners, given that fuselage portion arrives as a compete, approved assembly, it is very unlikely that there is any task at Boeing Renton to verify that the appropriate fasteners are installed on that door plug.
Unfortunately, QA at Spirit has been an on-going issue for some time - especially with the 737 fuselages (the often-mentioned issue with the miss-drilled aft bulkhead holes also traces back to Spirit.
Interestingly, there was an article in the Seattle Times recently regarding Boeing and Spirit re-negotiating the contract for the 737 fuselages to include improved quality and QA inspections (presumably with an increase in price to Boeing, although I don't think the article specifically said that).

While I doubt it's feasible at this point for Boeing to bring in a new subcontractor for the 737 fuselage, I think Spirit badly needs to step up their game if they expect to receive any future new business (Boeing, Airbus, or anyone else). No airframer wants to be associated with the sort of liability (not to mention bad press) that the recent Spirit screwups have caused Boeing.

[helispotter]

Unconfirmed reports that Alaskan had previously had to do work on the door.

I have read about prior pressurisation problems on this aircraft but where are the unconfirmed reports on what "work" (post #55) may have been performed on the plug? That is important since it may point to whether this is an issue related to manufacture or to maintenance activities.

[cooperplace]

Before you all get too wrapped up in your anti-Boeing crusade, you might want to consider this little inconvenient fact: The fuselage isn't built by Boeing -.
Hi TD,
Thank you for your as always detailed knowledge of Boeings, and it's good to know where the problem lies. Nonetheless, if a wheel fell off your Ford, you'd go back to the Ford dealer. If they said "that's not us, that's the fault of the sub-contractor that makes that part" you'd be unimpressed. You'd say "I paid my money to Ford, and I expect Ford to have better QC, and I might not buy a Ford next time".

Maybe selling Boeing Wichita was a mistake?

[Big Pistons Forever]

Before you all get too wrapped up in your anti-Boeing crusade, you might want to consider this little inconvenient fact: The fuselage isn't built by Boeing - all 737 fuselages are assembled in Wichita by Spirit AeroSystems. The fuselages are shipped to Renton by rail as basically complete structures with the plug (or door) already installed. Assuming that this was an assembly issue (as seems likely based on the lack of associated damage from the departed plug, as well as the AD'ed inspection), the blame should fall squarely on Spriit, not Boeing.
While Spirit was "Boeing Wichita" at one time, that hasn't been the case for nearly 20 years (Boeing sold them in 2005) and it has operated as an independent subcontractor since. Spirit is also a major supplier to Airbus.
While an alert inspector at Boeing might have picked up on missing fasteners, given that fuselage portion arrives as a compete, approved assembly, it is very unlikely that there is any task at Boeing Renton to verify that the appropriate fasteners are installed on that door plug.
Unfortunately, QA at Spirit has been an on-going issue for some time - especially with the 737 fuselages (the often-mentioned issue with the miss-drilled aft bulkhead holes also traces back to Spirit.
Interestingly, there was an article in the Seattle Times recently regarding Boeing and Spirit re-negotiating the contract for the 737 fuselages to include improved quality and QA inspections (presumably with an increase in price to Boeing, although I don't think the article specifically said that).

While I doubt it's feasible at this point for Boeing to bring in a new subcontractor for the 737 fuselage, I think Spirit badly needs to step up their game if they expect to receive any future new business (Boeing, Airbus, or anyone else). No airframer wants to be associated with the sort of liability (not to mention bad press) that the recent Spirit screwups have caused Boeing.

Spirit is a product of the Boeing culture, Cheap, Fast, Nasty. Boeing contractually incentivizes the quantity over quality mindset that virtually guarantees the pickle fork debacle, extra holes in the pressure bulkhead, departing exit EE plugs etc etc all of which are a direct result of bean counter management that knows the price of everything and the value of nothing.

Boeing is the poster child of an organization that never has the time, people, or money to do the job right, then has to scramble to find the time, people, and money to do the job over.

What a sad end to a company that was the world leader in commercial aviation.

[CMM]

Before you all get too wrapped up in your anti-Boeing crusade, you might want to consider this little inconvenient fact: The fuselage isn't built by Boeing - all 737 fuselages are assembled in Wichita by Spirit AeroSystems. The fuselages are shipped to Renton by rail as basically complete structures with the plug (or door) already installed. Assuming that this was an assembly issue (as seems likely based on the lack of associated damage from the departed plug, as well as the AD'ed inspection), the blame should fall squarely on Spriit, not Boeing.
While Spirit was "Boeing Wichita" at one time, that hasn't been the case for nearly 20 years (Boeing sold them in 2005) and it has operated as an independent subcontractor since. Spirit is also a major supplier to Airbus.
While an alert inspector at Boeing might have picked up on missing fasteners, given that fuselage portion arrives as a compete, approved assembly, it is very unlikely that there is any task at Boeing Renton to verify that the appropriate fasteners are installed on that door plug.
Unfortunately, QA at Spirit has been an on-going issue for some time - especially with the 737 fuselages (the often-mentioned issue with the miss-drilled aft bulkhead holes also traces back to Spirit.
Interestingly, there was an article in the Seattle Times recently regarding Boeing and Spirit re-negotiating the contract for the 737 fuselages to include improved quality and QA inspections (presumably with an increase in price to Boeing, although I don't think the article specifically said that).

While I doubt it's feasible at this point for Boeing to bring in a new subcontractor for the 737 fuselage, I think Spirit badly needs to step up their game if they expect to receive any future new business (Boeing, Airbus, or anyone else). No airframer wants to be associated with the sort of liability (not to mention bad press) that the recent Spirit screwups have caused Boeing.

I don’t see any relevance to this argument.

The aircraft has Boeing written on the side of it. Customers pay Boeing. Boeing selects its contractors. If they’re crap it is still Boeing’s problem and reflects badly on Boeing as a company.

That is really all there is to it IMO. They are going the same way as all companies in other safety critical industries that cut costs because quality processes are expensive, then cut too much and it all blows up in their faces and costs way more than doing things properly in the first place would.

The sad thing is the public and the workers (who usually turn up to work to try and do a good job) suffer. The people who set the policies get away with it.

I would like to see large numbers of senior managers fired over this; not the factory fitters. That would send a message.

[tdracer]

Spirit is a product of the Boeing culture, Cheap, Fast, Nasty. Boeing contractually incentivizes the quantity over quality mindset that virtually guarantees the pickle fork debacle, extra holes in the pressure bulkhead, departing exit EE plugs etc etc all of which are a direct result of bean counter management that knows the price of everything and the value of nothing.


No first hand knowledge, but scuttlebutt at the time Boeing spun off Wichita to Spirit was that Seattle was sick and tired of their lack of control over what Wichita was doing. Wichita was where many of the engine nacelle bits were produced, and the issues we had with those components was legend - and when Wichita was part of Boeing, taking the contract away and giving it to a non-Boeing supplier was a non-starter. The hope was that, making Wichita a non-Boeing supplier would actually increase our leverage by giving us the ability to take our business elsewhere.
The rot in Wichita dates back to long before you could blame the MacDac effect.

[tdracer]

I don’t see any relevance to this argument.

The aircraft has Boeing written on the side of it. Customers pay Boeing. Boeing selects its contractors. If they’re crap it is still Boeing’s problem and reflects badly on Boeing as a company.

That is really all there is to it IMO. They are going the same way as all companies in other safety critical industries that cut costs because quality processes are expensive, then cut too much and it all blows up in their faces and costs way more than doing things properly in the first place would.

The sad thing is the public and the workers (who usually turn up to work to try and do a good job) suffer. The people who set the policies get away with it.

I would like to see large numbers of senior managers fired over this; not the factory fitters. That would send a message.
Funny, I don't recall similar "Airbus Sucks" threads when the A350 had issues due to the Rolls engine shutdown rate, or A220/A320s ending up AOG because of issues with the Pratt geared turbofan...
Yes, it all reflects badly on Boeing, and the general public don't know the difference. But I expect a little better from aviation 'professionals'.

[Easy Street]

Funny, I don't recall similar "Airbus Sucks" threads when the A350 had issues due to the Rolls engine shutdown rate, or A220/A320s ending up AOG because of issues with the Pratt geared turbofan...
Yes, it all reflects badly on Boeing, and the general public don't know the difference. But I expect a little better from aviation 'professionals'.

That's a weak response considering that professionals understand very well how customers choose their engine manufacturer and have their engines supported independently of the airframer.

[CMM]

Funny, I don't recall similar "Airbus Sucks" threads when the A350 had issues due to the Rolls engine shutdown rate, or A220/A320s ending up AOG because of issues with the Pratt geared turbofan...
Yes, it all reflects badly on Boeing, and the general public don't know the difference. But I expect a little better from aviation 'professionals'.

I don’t think the problems related to quality that Boeing are having are in any way comparable with other aircraft manufacturers. I realise there will be some sentimentality based on your location, but the proof really has to be in the eating.

It appears there is a vast difference in Quality Culture between organisations.

[Tobin]

Facts and speculations:
3) The plug design is spring loaded to lift itself 1.5 inch, clear its stop fittings from the frame's stop pads, swing down, and eject itself from the plane at flight speeds (facts with hyperbole)

This seems consistent with the videos explaining it, but it immediately raises the questions:

Why is the plug door, which is never meant to be opened, designed such that it can be raised out of its stop fittings, as if to open? Why is so much of the opening mechanism apparently present in this non-opening plug? Why is opening only prevented by a few bolts? Why is the plug not fundamentally shaped so that it cannot move at all, and certainly not beyond the stop fittings, under any circumstance?

[tdracer]

That's a weak response considering that professionals understand very well how customers choose their engine manufacturer and have their engines supported independently of the airframer.
Curious, what non-Rolls Royce engine option is there on an A350 (or non-GE option on a 777x)?
While the airframer has some control over their suppliers, in the end all they really do is pull the contract and give it to someone else who will do a better job.
Not overly practical for an A350 (or 777) engine or the 737 fuselage.
Oh, and what makes you think the bits Spirit supplies to Airbus are of any better quality than what they supply to Boeing?

[ve3id]

And yet again we see the reluctance for U.S. pilots to declare MAYDAY!! MAYDAY!! MAYDAY!! that gets EVERYBODYS immediate attention rather than a mumbled call and where a controller had to ask "are you an emergency or do you just wish to return to Portland" that was after he stopped their descent at 7000' from what I could hear on the R/T recording, posted earlier. Unless, of course, you don't consider having a piece of your aeroplane falling off causing an explosive decompression (or should that be an unplanned pressure operated, gravity assisted, removal of a fuselage panel and internal atmosphere) A342

Mayday sounds like French to the Yanks! I cleaned up on French wine in a US store once when they were having a snit with them, as they sold it cheaper than local vintages and seemed glad for me to take it!

[OldnGrounded]

While an alert inspector at Boeing might have picked up on missing fasteners, given that fuselage portion arrives as a compete, approved assembly, it is very unlikely that there is any task at Boeing Renton to verify that the appropriate fasteners are installed on that door plug.

Unfortunately, QA at Spirit has been an on-going issue for some time - especially with the 737 fuselages (the often-mentioned issue with the miss-drilled aft bulkhead holes also traces back to Spirit.


"It's not our fault, it was the subcontractor!" Not a very persuasive defense argument.

Perhaps, since there is a known, ongoing QA problem at Spirit, someone at Renton should be doing those inspections.

[TURIN]

Funny, I don't recall similar "Airbus Sucks" threads when the A350 had issues due to the Rolls engine shutdown rate, or A220/A320s ending up AOG because of issues with the Pratt geared turbofan...
Yes, it all reflects badly on Boeing, and the general public don't know the difference. But I expect a little better from aviation 'professionals'.
It may be that we all know that engines are treated as independent entities, own log book etc.

[MarcK]

IMO 4 bolts is not enough redundancy for this design when you consider the risk.
I heard there are spare bolts in the rudder area.

[Chris2303]

Spirit is a product of the Boeing culture, Cheap, Fast, Nasty. Boeing contractually incentivizes the quantity over quality mindset that virtually guarantees the pickle fork debacle, extra holes in the pressure bulkhead, departing exit EE plugs etc etc all of which are a direct result of bean counter management that knows the price of everything and the value of nothing.

Boeing is the poster child of an organization that never has the time, people, or money to do the job right, then has to scramble to find the time, people, and money to do the job over.

What a sad end to a company that was the world leader in commercial aviation.

I'll bet that William Boeing is spinning in his grave right now

[GlobalNav]

All things considered, Boeing had a very lucky day. Had this happened on a flight halfway to PHNL at FL390, Boeing would no longer be in the commercial aircraft business.

Not sure yet about Boeing’$$ luck, but the passengers certainly were lucky.
Hard to judge this without knowing a valid engineering answer to what happened to the hardware,

[WHBM]

The fuselage isn't built by Boeing - all 737 fuselages are assembled in Wichita by Spirit AeroSystems. The fuselages are shipped to Renton by rail as basically complete structures with the plug (or door) already installed. Assuming that this was an assembly issue (as seems likely based on the lack of associated damage from the departed plug, as well as the AD'ed inspection), the blame should fall squarely on Spriit, not Boeing.
But although the sheet metal items may be built by a subcontractor, they don't also install the cabin linings, do they ? These are commonly customer-specific anyway. These would have been fitted across where the bolt positions we now see in the photographs are, as part of the interior fitout. This picture seems to show the interion Boeing receive
https://cimg8.ibsrv.net/gimg/pprune.org-vbulletin/859x415/boeing_6966ebfd5cb06668e3ff5237dcfd14cc0ce2279f.jpg

[aeromech3]

Discussion as to whether the stop fitting/bolts were not fitted; I cannot see a way for this semi plug to stay in position without some retention, even whilst the cabin trim panel is being fitted. Plain cabin windows can be temporarily held by tape whilst the clamping device is fitted, but a 'door' this size nah!
And certainly not whilst being ground transported from the manufacturer as a complete assembly, if that is the case mentioned earlier thread.
Sad to say, as a proud retired BAC1-11 licensed engineer, but short bolts seem a likely cause.

[Loose rivets]

BAC 1-11. Do you remember the g lock on the front door?


The door had a myriad flat plates, as did the frame. To open outwards the door lifted first and thus required the g lock for safety.

[Ranger One]

Before you all get too wrapped up in your anti-Boeing crusade, you might want to consider this little inconvenient fact: The fuselage isn't built by Boeing - all 737 fuselages are assembled in Wichita by Spirit AeroSystems. The fuselages are shipped to Renton by rail as basically complete structures with the plug (or door) already installed.

tdracer, there's an old joke (but also a truism) that used to say something along the lines of... the best airliner in the world would be designed by Lockheed, marketed by MD - and built by Boeing.

The last nail in the coffin of that old saw appears to be an aircraft that was designed by Boeing, marketed by Boeing, and built by no-one in particular...

[Taddles]

Just wondering how forceful a suck hole would that have been?

Still remembering the New Zealander sucked out over the Pacific when an improperly closed cargo door ripped some fuselage with it.

[powerjets]

Please calculate the lateral displacement as it passed the tailplane

[jimjim1]

Anyone got any fancy enhancement apps to see if the holes have any stubs left in them?

Pretty hi-res here. Included link in case pPrune does something to image.

https://static01.nyt.com/images/2024/02/05/multimedia/05xp-plane-Le/05xp-plane-Le-threeByTwoLargeAt2X.jpg

https://cimg9.ibsrv.net/gimg/pprune.org-vbulletin/2000x1333/05xp_plane_le_threebytwolargeat2x_73752cc840e1e6b96a880b35e9 54da12ac7c0d44.jpg

[runner1021]

Not sure yet about Boeing’$$ luck, but the passengers certainly were lucky.
Hard to judge this without knowing a valid engineering answer to what happened to the hardware,
No matter what the cause of this incident was, in a worst case scenario and a passenger ejected, Boeing would
be facing an unprecedented PR nightmare.

[jetrc]

Before you all get too wrapped up in your anti-Boeing crusade, you might want to consider this little inconvenient fact: The fuselage isn't built by Boeing - all 737 fuselages are assembled in Wichita by Spirit AeroSystems. The fuselages are shipped to Renton by rail as basically complete structures with the plug (or door) already installed. Assuming that this was an assembly issue (as seems likely based on the lack of associated damage from the departed plug, as well as the AD'ed inspection), the blame should fall squarely on Spriit, not Boeing.
While Spirit was "Boeing Wichita" at one time, that hasn't been the case for nearly 20 years (Boeing sold them in 2005) and it has operated as an independent subcontractor since. Spirit is also a major supplier to Airbus.
While an alert inspector at Boeing might have picked up on missing fasteners, given that fuselage portion arrives as a compete, approved assembly, it is very unlikely that there is any task at Boeing Renton to verify that the appropriate fasteners are installed on that door plug.
Unfortunately, QA at Spirit has been an on-going issue for some time - especially with the 737 fuselages (the often-mentioned issue with the miss-drilled aft bulkhead holes also traces back to Spirit.
Interestingly, there was an article in the Seattle Times recently regarding Boeing and Spirit re-negotiating the contract for the 737 fuselages to include improved quality and QA inspections (presumably with an increase in price to Boeing, although I don't think the article specifically said that).

While I doubt it's feasible at this point for Boeing to bring in a new subcontractor for the 737 fuselage, I think Spirit badly needs to step up their game if they expect to receive any future new business (Boeing, Airbus, or anyone else). No airframer wants to be associated with the sort of liability (not to mention bad press) that the recent Spirit screwups have caused Boeing.

That's something Boeing has to deal with since the 737Max is marketed as a product of Boeing and not of Spirit or any other subcontractor. With regards to your complaint that Boeing gets more heat than Airbus, well unfortunately the 737Max's previous run-ins don't do it any favors from the general public's viewpoint. If the A320neo family had successive fatal incidents due to alleged negligence then they would also be subjected to the same heat that Boeing now faces. The ball is in Boeing's court to change this public perception --- whatever method they use.

[GlobalNav]

No matter what the cause of this incident was, in a worst case scenario and a passenger ejected, Boeing would
be facing an unprecedented PR nightmare.
Of course, but as with the two Max accidents, the true tragedy is what happened to the passages and crew.

[Chronic Snoozer]

Ryanair would probably charge extra for the view.

And priority exiting....

[MLHeliwrench]

https://cimg1.ibsrv.net/gimg/pprune.org-vbulletin/1164x1612/img_0996_f071d65219c4d7829b7f0fcf742573f39baa9b1e.jpeg
How it is supposed to look. (Not my photo, credit to whomever took it!)

[fdr]

Just wondering how forceful a suck hole would that have been?

Still remembering the New Zealander sucked out over the Pacific when an improperly closed cargo door ripped some fuselage with it.

Please calculate the lateral displacement as it passed the tailplane

There's somewhere around 450 cu mtrs of air that is going to go venting, the gap is initially a bit more than 0.2 sq mtrs. once the panel departs fully, there is a larger exit area, but the pressure is going to be far lower already. The area that had to open up to release the door is larger than needed to be considered an explosive decompression, so the pressure will equalise pretty quickly, most of the differential will be gone by the time the door was fully released. Thereafter, buffet will be the main airflow issue in the cabin.

The doors trajectory is going to have a complex solution, and that won't have a high probability of being correct. There will be a probabilistic solution giving likelihood of any given outcome, wild guess, the probability of impact with the tail is going to be somewhere around 5-6%, and then the probability of severe damage from that is going to be another complex solution, but it will be about 30-45% or somewhere near that. Worst case outcome is not good at all, and the pax have obviously had good clean living that was paying off, the chance of someone going skydiving (sadly not Putin) was pretty high. Debris impacts are not unknown and can range from expensive to catastrophic, remember what a chunk of foam can do to a space shuttle leading edge. When released, it's not going to go far out laterally from the fuselage, and it will slow down rapidly. The panel will be unstable initially which would tend to make it follow close to the upwash of flow to the airframe, so it is not going to be so far from the stabiliser, wild guess, still passing below it and at part span. Presume the forward lower hinge will fail first, but the dudes at NTSB will be interested in the stresses on those to get an idea of where it went. Overall, it is irrelevant, once departed it was not a desirable state, lots of opportunities for dragons to rear their heads. As a problem to solve, it is far more demanding than assessing the probable trajectory of a burst disk. Good luck working that out.

[fdr]

And priority exiting....

and blankets, and charge for the removal of safety cards.

[tdracer]

But although the sheet metal items may be built by a subcontractor, they don't also install the cabin linings, do they ? These are commonly customer-specific anyway. These would have been fitted across where the bolt positions we now see in the photographs are, as part of the interior fitout. This picture seems to show the interion Boeing receive

As aeromech notes, something was holding that door in place prior to the failure. The ability to detect that it wasn't properly installed is a direct function of what was holding it in place. If, as aeromech suspects, it's something like 'short bolts', then it would be next to impossible to detect without a detailed inspection. OTOH, if bolts were completely missing, and it was being held in place by something like sealant - then yes, I'd expect a competent mechanic to notice the defect prior to installing the interior panels. Problem is we don't know - condemnation of the Renton workforce is premature.
We'll only know the answer to that until the investigation is done (or, if another improperly installed is detected during the mandated inspections).

[EEngr]

"It's not our fault, it was the subcontractor!" Not a very persuasive defense argument.

Perhaps, since there is a known, ongoing QA problem at Spirit, someone at Renton should be doing those inspections.

That was the policy years ago. Incoming parts and assemblies were subjected to test and inspection. But a decision was made to rely more upon vendors' QA processes, suitably audited by Boeing. In the event the vendor was not "up to the job" and remedies were not forthcoming, it was not out of the question for Boeing to acquire the subcontractor outright and put their own people into management positions. That's part of the reason they ended up with Boeing South Carolina. When their sub on the 787, Vought, ran into difficulties. The same might be in store for Spirit AeroSystems. Only there, some Boeing people might end up with egg on their face, having spun that operation from Boeing about 20 years ago.

[aeromech3]

That picture shows a cam style track in the exit plug and roller with a lock bolt between the top and second stop pad bracket which would require the semi plug to be slid in from the outside from above and then the locking bolt inserted (? lock bolt and nut or bolt into thread raises ? which direction should it be inserted); at floor level some sort of claw and pip pin.
In the actual post event picture I can see the roller!
The community picture on Reddit, has a seat config which would suggest the use as an emergency exit when required?

[Edoil17]

Hi. I have just heard on a news broadcast in Aus, that the two seats adjacent to this panel / Door plug, 26A, and 26B were not occupied on this flight???
Maybe a lucky coincidence or suspicious. Maybe some noise from this area during previous cabin pressure incidents? Who knows?
Anyway no one injured good outcome inn the end.

[Feathered]

Well this just enforces my view re 737 Max and indeed makes me question my whole view of Boing as a company. I spent most of my working career on their products, but now actively avoid their products. I dont like the 787 and avoid 737 Max for pretty obvious reasons, though I was on a LH 747 up from Singapore at the end of last year, and she was fine and felt at ease. The new Boeings are a shadow of their predecessor's. To put in context I fly probably 2-3 times a week long and short haul over the year. If I am thinking like this and I am only humble SLF, how many others are taking this view re Boeings new products ? Get the company base back to Seattle, kick the accountant's back to where they belong, and let engineers design things. Accountancy is a support function in a business, not the defining thing unless you are an accountancy practice. There will be books written in the future about the demise of this business !!

See: "Flying Blind The 737 MAX Tragedy and the Fall of Boeing," by Peter Robison, Penguin Random House, 2022.
https://www.penguinrandomhouse.com/books/646497/flying-blind-by-peter-robison
Great book about Boeing's loss of its safety oriented culture, especially after McDonnell Douglas used Boeing's money to purchase Boeing. Some weird political detours, but the book is solid.

(the accountants can stay in Chicago or Arlington or wherever, but the leadership should return home).

[msbbarratt]

That's something Boeing has to deal with since the 737Max is marketed as a product of Boeing and not of Spirit or any other subcontractor. With regards to your complaint that Boeing gets more heat than Airbus, well unfortunately the 737Max's previous run-ins don't do it any favors from the general public's viewpoint. If the A320neo family had successive fatal incidents due to alleged negligence then they would also be subjected to the same heat that Boeing now faces. The ball is in Boeing's court to change this public perception --- whatever method they use.

And that touches on a fundamental truth; Mother Nature will not be fooled by PR. One can perhaps talk people round into a more positive frame of mind with a barrage of slick presentations and enducements. But if one is building a duff product then real world operations will ensure that those weakness get exposed regardless.

Mother Nature doesn't listen to politicians either (ref: MAX 7 exemption, FAA funding reductions down the decades, etc).

[Feathered]

Before you all get too wrapped up in your anti-Boeing crusade, you might want to consider this little inconvenient fact: The fuselage isn't built by Boeing - all 737 fuselages are assembled in Wichita by Spirit AeroSystems. The fuselages are shipped to Renton by rail as basically complete structures with the plug (or door) already installed. Assuming that this was an assembly issue (as seems likely based on the lack of associated damage from the departed plug, as well as the AD'ed inspection), the blame should fall squarely on Spriit, not Boeing.
While Spirit was "Boeing Wichita" at one time, that hasn't been the case for nearly 20 years (Boeing sold them in 2005) and it has operated as an independent subcontractor since. Spirit is also a major supplier to Airbus.
All technically correct, but Boeing will proudly say that they are responsible for the entire aircraft delivered. I believe Boeing owns the type certificate for the entire airframe,not just parts not built by Spirit.
If Spirit is building junk and delivering it to Boeing Renton without proper QA, why is Boeing accepting junk without proper QA?

What other flaws, problems, defects, missing fastener nuts, oval bulkhead holes, flawed flight control software, extra wrenches, bonus rags, and other rubbish is Boeing also accepting and happily delivering as-is to customers?

[ThreeThreeMike]

As aeromech notes, something was holding that door in place prior to the failure. The ability to detect that it wasn't properly installed is a direct function of what was holding it in place. If, as aeromech suspects, it's something like 'short bolts', then it would be next to impossible to detect without a detailed inspection. OTOH, if bolts were completely missing, and it was being held in place by something like sealant - then yes, I'd expect a competent mechanic to notice the defect prior to installing the interior panels. Problem is we don't know - condemnation of the Renton workforce is premature.
We'll only know the answer to that until the investigation is done (or, if another improperly installed is detected during the mandated inspections).

Would an interior panel installer be interested in or competent to evaluate part of the airframe structure he was about to cover with a snap in plastic panel?

[incompleteness]

As aeromech notes, something was holding that door in place prior to the failure. The ability to detect that it wasn't properly installed is a direct function of what was holding it in place. If, as aeromech suspects, it's something like 'short bolts', then it would be next to impossible to detect without a detailed inspection. OTOH, if bolts were completely missing, and it was being held in place by something like sealant - then yes, I'd expect a competent mechanic to notice the defect prior to installing the interior panels. Problem is we don't know - condemnation of the Renton workforce is premature.
We'll only know the answer to that until the investigation is done (or, if another improperly installed is detected during the mandated inspections).

I can't post pictures, but you can see the problem area in reply 199 (from reddit r/aviation) on the upper left and right where there are fittings that trap the silver pins on the frames that are visible in the indicent photos we've seen. Those capture-fittings didn't work, they seem to be 2-piece fittings with a piece that's attached with a (pin?) after plug installation to prevent upward movement of the plug. 99% sure those are the fittings that are being looked at with magnifying glasses all over the country tonight.

[msbbarratt]

This implies to me that a specific issue has been identified as THE cause of this event.

Which, without the door present is remarkable and points to some gross failure of assembly

Indeed, seems like there is something specific to go looking for. It'll be interesting to see if this turns into a full root cause investigation, the "why did this specific issue occur, and what else might be related to it?" line of questioning. I fear not...

[remi]

All technically correct, but Boeing will proudly say that they are responsible for the entire aircraft delivered. I believe Boeing owns the type certificate for the entire airframe,not just parts not built by Spirit.
If Spirit is building junk and delivering it to Boeing Renton without proper QA, why is Boeing accepting junk without proper QA?

What other flaws, problems, defects, missing fastener nuts, oval bulkhead holes, flawed flight control software, extra wrenches, bonus rags, and other rubbish is Boeing also accepting and happily delivering as-is to customers?
There are two serious vendors of civil air transport aircraft in the world today and the one that just had a piece fall off one of its aircraft unprompted was not Airbus.

If the guys across the Sound from me can't get their act together, we're all going to need to get used to overhead luggage compartments that barely fit a wallet.

[Taddles]

Stripped thread?

[msbbarratt]

Judging by where the altitude drops on the FR24 track, the door may well be here somewhere.
It's a well populated area, so I'd have thought someone will eventually find it...

https://cimg5.ibsrv.net/gimg/pprune.org-vbulletin/2000x1198/screenshot_2024_01_06_at_19_24_05_79966c808ab866bf8e936a9741 e856dde9c5fc82.jpg

Anyone know the glide angle of a door plug?

[PuraVidaTransport]

According to the NTSB briefing tonight, there were only SEVEN (7) empty seats so just 4%. Alaska had 178 seats on the aircraft and the spokesman said there were 171 passengers. It is an official accident with lead investigator John Lovell (NTSB investigator in MAX crash in Ethiopia) leading the investigation. She said they have a general location based on primary radar for the door. Aircraft delivered to Alaska on November 11, 2023. Row 25 and 26 seats A missing headrests. On 26A, the back of the seat is missing. Clothing items in the area. Stops on door frame still intact. Door is not an emergency exit but can be opened for inspection.

https://www.youtube.com/watch?v=NGC0z8HgrTU

[PuraVidaTransport]

Anyone know the glide angle of a door plug?

NTSB spokesman tonight said that primary radar gives them the area around Barnes Road near I-217 and the Cedar Hills neighborhood.

[aeromech3]

Ref: back to Reddit pic in post 199, the floor fitting looks substantial enough to prevent the plug from lifting sufficiently to disengage the roller to cam track, unless the grey fitting is an open claw and not an eye, I do concede the top guide rollers seem a little thin, I am guessing a mere 5mm engagement with the track bracket.
I am sum-what surprised, after having years of dealings with a pedantic QA department, that some have not pointed out that production failings are not their remit, and so on behalf of them, please refer to Quality Control in issues of production or maintenance failings :rolleyes:

[tsumini]

tdracer

"As aeromech notes, something was holding that door in place prior to the failure. The ability to detect that it wasn't properly installed is a direct function of what was holding it in place."

Kinda wondering the same thing. Something held it in place for 2-3 months. I would speculate that it may have been the stop fittings serving as guides that held the door until they wore out/sheared then released the door all while upper bolts were missing. Also may have leaked just prior causing previous pressurization reports.

[Flipfrog]

Looking at two pictures showing the plug in installed vs the opening you can see the pin that's mounted on the aircraft frame is pretty short. The plug has a retaining bolt that seems to hold the door down under this pin.Could it be that the pin is infact too short and allows the door/plug to move past the pin if the frame expands or the door moves left or right it seems very close to being able to move upward?

[aeromech3]

In days of old, with a difficult to find pressurisation leak (no visible tobacco stains or window condensation) we would do a ground pressurisation run, mostly it required an engine supply as the APU would only give about 0.5psi diff. a mechanic would go around outside feeling windows and doors for air escape.
The same could be done with a down route / on ramp ADC change to confirm, by watching rate of climb/decent indicator, whether the hose had been connected leak free, external ports were plugged for this!
I believe now, best safety practices and all that, almost a steel net is required over the aircraft, hence finding leaks nowadays must be quite a task?

[MechEngr]

That's something Boeing has to deal with since the 737Max is marketed as a product of Boeing and not of Spirit or any other subcontractor. With regards to your complaint that Boeing gets more heat than Airbus, well unfortunately the 737Max's previous run-ins don't do it any favors from the general public's viewpoint. If the A320neo family had successive fatal incidents due to alleged negligence then they would also be subjected to the same heat that Boeing now faces. The ball is in Boeing's court to change this public perception --- whatever method they use.

After the Lion Air crash there was zero heat on Boeing. It was only after false statements immediately after the ET-302 crash, that the pilots doing the exact in-sequence operations given in the Emergency AD and the FCOM update, that the crap hit the fan. The plane was painted as uncontrollable, but that was far from the truth. By the time the actual actions taken by the ET-302 came out more than a year later the PR damage to Boeing had been done. Had Airbus been subjected to the same flack over knowingly not grounding all their planes when the pitot de-icing issue connected to AF447 was found, an issue they had a fix for prior to the crash that they didn't install, then there would be some equal footing. In both cases a situational sensor failed and the crews mishandled the aircraft because the software was inadequate to stop them from doing so.

It becomes a problem for a prime contractor to have to put into place a parallel and even larger QA system to over see all the QA systems of the subcontractors. It defeats a large amount of the reason to have subcontractors if their every action on the factory floor and every action by the QA/QC workers/engineers has to be double checked.

No one died from this, but it wasn't for lack of effort to do so - perhaps there is some criminal charge that can be brought against the Spirit QA/QC team and anyone who signed off that the installation was correctly done.

Also concerning to me about Alaska is they took a new plane off the ETOPS list for a pressurization defect they couldn't diagnose but kept it in service. The plane should be in full working order from the factory, and it appears that it was. Then that changed and didn't send up a giant red flag? No call to Boeing to figure out why the plane was leaking?

The sucky thing about this is the door has to be able to be removed to check for corrosion around the opening. Which means there is the chance, as in another 10,000 locations, to not assemble it correctly. And all of those locations are flight-safety critical to a similar extent as this door. There is no good design solution to an item that has to be removable to be unremovable. Even if one puts in redundant features, that just means when the primary feature isn't there you are down to one, but have increase the odds that some feature won't be installed correctly.

The best I can get is re-purposing the indicators that the conventional exit door has in place for this door. If it moves up even a millimeter, that's too far, and a switch would indicate that. I suspect someone in human factors decided that it would confuse pilots to have an indicator for a door that no one can use. That would be an interesting investigation to make. Had that light been flickering every time there was a pressure problem it might have been a better diagnostic. Still, the maintainers should not have shrugged the pressurization problem off and allowed it to remain in service.

For personal experience, I was once seated at a 737 over wing exit row and noticed the engine sound was extremely harsh as the plane started and got pushed back, not muffled at all. It appeared to be coming from the door and, after a short investigation, it was clear there was daylight from about 1/8th of an inch gap at the seal. This was the old style actual plug exit door, so I knew it could not be departing. Soon after takeoff, when the plane was pressurized, the door moved the slight amount and the seal did its job. I did mention this to the flight attendant. I don't know if it got passed to the airline; maybe I should have called them with the tail number. I expect a similar thing was happening on this aircraft, but it was behind the interior panel that would muffle the sound and prevent a view of the seal. It still should have been louder at that seat than anywhere else in the plane.

Perhaps add that to the maintainer's tools - that if air can leak out, so can sound. Put a high-pitched (8kHz), high volume (100dB) sound source inside the unpressurized fuselage and, if it can be more clearly heard outside with the doors shut at some location over the others, that may be a place a leak is happening. Move the source down the fuselage at the same time the people outside listening for it are moving. I know, I know - keep the hanger doors closed and avoid trying this during engine run-ups of neighboring aircraft.

[Rebus]

https://cimg1.ibsrv.net/gimg/pprune.org-vbulletin/1164x1612/img_0996_f071d65219c4d7829b7f0fcf742573f39baa9b1e.jpeg
How it is supposed to look. (Not my photo, credit to whomever took it!)
To my old eyes, the latch cam lock bolts look like they go from outer to inside, a hard job for someone to fit with restricted access. Also, it's hard to tell but the retainer nuts on the lock bolts look castellated, if they are, perhaps the split pins/ cotter pins weren't fitted.

[MechEngr]

This seems consistent with the videos explaining it, but it immediately raises the questions:

Why is the plug door, which is never meant to be opened, designed such that it can be raised out of its stop fittings, as if to open? Why is so much of the opening mechanism apparently present in this non-opening plug? Why is opening only prevented by a few bolts? Why is the plug not fundamentally shaped so that it cannot move at all, and certainly not beyond the stop fittings, under any circumstance?


All good questions. The plane is built with this opening because it was certified to have this opening for certain seating capacities to provide additional exits and certifying a second configuration without this opening is stupid expensive. It's also cheaper (OK, also stupid expensive) if the owner wants to add the exit later rather than having to saw a hole.

Because of the opening a door has to be there, whether the conventional exit door or this door, either blanked off by the interior panel in the event that a seating arrangement doesn't require the exit.

They have to be able to be opened because there is a gap between the door and the fuselage that cannot dependably be filled with sealant or easily examined, so the door has to be able to be opened to inspect that gap and door opening for corrosion and for the possibility of crack formation. As a result it has to be able to be moved up so that it can be opened for inspection and is the reverse of how it is installed, by moving it down.

There may be some other option, but typically the one that has the fewest parts is the best and this has a door and 4 bolts. It is also a good practice to make as few changes from a baseline design as possible so that new defects, such as this one appears to have had, don't creep in, so it duplicated a lot of the features of the exit door, but without the operating linkages and inflatable slide.

Why this one may have been installed incorrectly, as so far appears to be the case, is not clear. NTSB will be looking into that and will gain access to more information than the general public can get.

[A0283]

Credit to MLHeliWrench for that Reddit photo ! Would be interesting to get more of those… and more if details.
Would also be interesting to have a comparable photo of an activated door configuration.

Trying to picture both the installation sequence and an emergency operation sequence. Plus remarks made by other posters. And photos of the accident aircraft.

For me only questions at this stage.

Question - do we have 6 shear pins (??????) per side here (on the accident aircraft photos the holes seem still filled up), plus 1 per side cam roller high up, and 1 per side cam below?

Question - do we have 1 (black top) spring element here per side below? And do these assist in shearing??? So apparently, not only moving the door/hatch up,but also shearing.

Question - does this mean (is that what other posters mean) that we only have 2 locking elements high up and only 2 below 2+2=4 (if we exclude the 6+6=12 shear pins)???

Appears to be a built-up door and less integrated than I would expect at this day and age.
Question - Does someone know if they use this structure assy as the basis for the manufacture of an active door (machining/drilling/bushing this assy and adding emergency operating mechanisms)?

Appears they do a solid paint job on this door.

If the HS-748 case from long ago would be predictive, then you would expect more aircraft having had installation and/or pressurisation problems (apart from this one).
Might be that a structural door cause would not be the type of cause (platform/ gate based) maintenance would look for at the start, when confronted with pressurisation problems.

[DaveReidUK]

The community picture on Reddit, has a seat config which would suggest the use as an emergency exit when required?

The massive amount of legroom does indeed make it look like that, but the plug door cannot be used as an E/E (no opening mechanism, no slide, no vent panel, etc).

It is, however, possible to substitute a functioning door to increase the passenger limit, but if that happens it's only likely to be done once during the life of the aircraft.

[procede]

The massive amount of legroom does indeed make it look like that, but the plug door cannot be used as an E/E (no opening mechanism, no slide, no vent panel, etc).

It is, however, possible to substitute a functioning door to increase the passenger limit, but if that happens it's only likely to be done once during the life of the aircraft.

My guess is that they removed a row of seats to do the inspection.

[DaveReidUK]

Question - Does someone know if they use this structure assy as the basis for the manufacture of an active door (machining/drilling/bushing this assy and adding emergency operating mechanisms)?

Almost certainly not, I can't see any advantage in doing that compared to building an actual E/E door from scratch.

[A0283]

Anyone know the glide angle of a door plug?
As usual in aerospace… there is at least one (NTSB or FAA) paper on that… if I remember correctly it had different formulas for different shapes and sizes… don’t remember if it had a formula for cleanly departing doors …

[MLHeliwrench]

My guess is that they removed a row of seats to do the inspection.

yes, a row would need to be removed to pull the interior panels with relative ease.

below is I picture with what I would guess as the only ‘lock bolts’ keeping the plug from sliding up and out off the retention fittings. This is only speculation. I’m not familiar with how the lower part works. If it’s actually a hinge or just hooked in there.


https://cimg3.ibsrv.net/gimg/pprune.org-vbulletin/661x927/img_0996_86f5532344a917532e9ea49747e782eb7503bb11.jpeg
Blue circles highlight possible lock bolts.

[aeromech3]

The massive amount of legroom does indeed make it look like that, but the plug door cannot be used as an E/E (no opening mechanism, no slide, no vent panel, etc).
It is, however, possible to substitute a functioning door to increase the passenger limit, but if that happens it's only likely to be done once during the life of the aircraft.
Didn't mean to imply the plug would be used in an exit config; worked on a VC10, with cargo door which we could re-config the interior to full pax in a shift; if I recall the hydraulic ram had to be removed; another a HS748 remove passenger seats and install canvass ones for the task; perhaps this airline has the E/E door in storage, not ascertained where the slide would be fitted but as the E/E door has to open outward it might be part of the door and deploy split seconds before the door, as there is no fairing below the aperture for a stowage, interesting!

[kghjfg]

I noticed those too, on the picture with the door missing the pin that comes out of the fuselage to engage into the sliding socket on the door looks very short.

It doesn’t look long enough to properly engage and the lock bolt to stop the door sliding back up.

[rog747]

AFAIK
There have not been any previous issues before with this type of exit door (which is a drop down hatch with a Slide, added aft of the wing) as fitted on the 737-900ER,
and to the latest 737M8-200, and as seen here on the 737M-9
(a door will also be fitted on the M-10 but it is, I think larger)

This type of hatch (once called the hat rack door) was first fitted to the Boeing 707-320C first delivered 60 years ago in 1963.
AFAIK there were no issues with these doors that I can recall.
That old design may still today be a legacy from that 707 door design?
I do not know if this maybe the case sorry, but worth a Pprune ponder?

FYI
They were also fitted to the DC-8 Super Sixty series as well as the -55F series.

In the case of yesterday's incident I expect that both installation and/or quality control to be at the fore of the Investigations.

[fenland787]

I noticed those too, on the picture with the door missing the pin that comes out of the fuselage to engage into the sliding socket on the door looks very short.

It doesn’t look long enough to properly engage and the lock bolt to stop the door sliding back up.

I agree, zooming in on the higher res image of the failed door/plug in post #194 (it's still very hard to be sure I'm not just seeing artefacts in the image) but it almost looks like the visible end of the pin is showing an axial counterbore hole and an uneven surface at about the point that cross bolt would have been?
However if that were the issue then a quick visual inspection of the pins would not find it and the inspection of the other aircraft would surely take longer than it seems to......

[Edoil17]

Maybe the panel installer wouldn't be particularly interested, but someone (whom, is really interested in what is going on at this opening) should have "inspected" the area behind this panel prior to installing the trim panel. That was always due process when closing up any panel / door. Cheers

[WHBM]

According to the NTSB briefing tonight, there were only SEVEN (7) empty seats so just 4%. Alaska had 178 seats on the aircraft and the spokesman said there were 171 passengers. The whole discussion here reminds one of the old joke : "When is a door not a door ..."

The fortuitous chance of the adjacent seats not being occupied may be linked to this particular flight, in previous days, always being operated by a lesser capacity 737-MAX8, which is presumably the scheduled type. Accounts describe this particular airframe having been removed from ETOPS usage by Alaska (principally their routes to Hawaii) due to outstanding pressurisation issues, but was still felt capable of internal US flights. One imagines this latter decision by Alaska will come under some review.

It will be interesting to track down passengers seated there on immediately previous flights, and ask them if there was any excessive noise from the cabin wall, given that it was losing sufficient pressurisation to be noticed. Then ask the flight attendants what was reported about that.

[DogTailRed2]

On the failure door and the one above why is the edge trim missing? Is that normal when deploying the escape hatch? To an untrained eye to see the packing in the fuselage looks weird.

[AirScotia]

It does seem surprising to me that an airframe with known pressurisation issues wasn't taken out of service right away. It also seems odd to me that two seats next to the relevant window were apparently empty, two of only seven unoccupied seats in a full flight - including a window seat at that. That suggests that these seats were not bookable, which further suggests that something was known about that area of seating. Whistling noises? Rattling? Cold breeze?

[Thruster763]

The "pins" visible in the high res picture of the incident door and parts highlighted in blue in the post by MLHeliwrench are the guide mechanism, not the locking pins. The lock pins are lower down. The guides take the load as the door moves up so the striker pad support structure is not damaged as the door or plug moves out.

https://cimg4.ibsrv.net/gimg/pprune.org-vbulletin/380x207/737_9_door_b3b5633ff47a0a60b0104175a998e4846d0ecfad.png

That said I agree with MLHeliwrench and MechEngr that missing or loose upper bolts are the most likely cause.
The bolts do not carry any pressurisation forces they just stop the plug moving up to disengage the striker pads.
I don't know how the hinge bolts operate, but guess that they are just locking the lifting spring loads.
If the lower bolts take the spring loads and the door was closed with no upper bolts then the sealant on the outside would be able to hold the plug in place for some time. before finally giving way and allowing the door to move.

[aeromech3]

The "pins" visible in the high res picture of the incident door and parts highlighted in blue in the post by MLHeliwrench are the guide mechanism, not the locking pins. The lock pins are lower down. The guides take the load as the door moves up so the striker pad support structure is not damaged as the door or plug moves out.
Is your picture of a lower freight door which opens inwards and swings up into a freight bay ceiling and has a handle mechanism which extends pins into the door aperture frame when closing?
I don't see such a mechanism in the E/E semi plug pictures.
Am I missing the point of your post?

[Jetstream67]

tdracer , 7th Jan 2024 00:25
Before you all get too wrapped up in your anti-Boeing crusade, you might want to consider this little inconvenient fact: The fuselage isn't built by Boeing -
———————————-//-/

Boeing, Apple, Ford, Samsung. Almost every large manufacturer today is a systems integrator. Their job is to specify, test and integrate the many elements of their design of end product

When it goes wrong they can blame their supplier publicly or privately but their customers are being let down by the final product /brand’s defects.

[Thruster763]

The "pins" visible in the high res picture of the incident door and parts highlighted in blue in the post by MLHeliwrench are the guide mechanism, not the locking pins. The lock pins are lower down. The guides take the load as the door moves up so the striker pad support structure is not damaged as the door or plug moves out.
Is your picture of a lower freight door which opens inwards and swings up into a freight bay ceiling and has a handle mechanism which extends pins into the door aperture frame when closing?
I don't see such a mechanism in the E/E semi plug pictures.
Am I missing the point of your post?

It is a picture of a door guide and striker plates. The point of my post is the parts ringed in blue in the image by heliwrench and "pins" in pictures of incident fuselage frame (silver coloured) are NOT the locking pins or bolts, they are the door / plug guides on door / plug and guide pins on frame.

EDIT,
Just looked again and it appears that the guide pin and lock pin are combined on the mid emergency exit door. So the bolts do go intor the center of the guide pins. Sorry for the confusion.

[EXDAC]

In the image of post 223 I see a wire loop on each side of the door (about level with the top of the window). These look similar to the wire tethers used on pip pins.

Are pip pins used to lock the door in place?

[aeromech3]

In the image of post 223 I see a wire loop on each side of the door (about level with the top of the window). These look similar to the wire tethers used on pip pins. Are pip pins used to lock the door in place?
I imagined these were just lanyards much like ceiling panels and others have to facilitate opening without uncontrolled dropping, the adjacent structure does not looked beefed up for a pip pin type lock, but I stand to be corrected!

[DuncanDoenitz]

On the failure door and the one above why is the edge trim missing? Is that normal when deploying the escape hatch? To an untrained eye to see the packing in the fuselage looks weird.
Its not an escape hatch; its a non-functioning plug-door. The trim in this photo has been removed for access/inspection/photography. That's what the inside of a fuselage looks like when the trim has been removed.

[Tobin]

After the Lion Air crash there was zero heat on Boeing. It was only after false statements immediately after the ET-302 crash, that the pilots doing the exact in-sequence operations given in the Emergency AD and the FCOM update, that the crap hit the fan. The plane was painted as uncontrollable, but that was far from the truth. By the time the actual actions taken by the ET-302 came out more than a year later the PR damage to Boeing had been done. Had Airbus been subjected to the same flack over knowingly not grounding all their planes when the pitot de-icing issue connected to AF447 was found, an issue they had a fix for prior to the crash that they didn't install, then there would be some equal footing. In both cases a situational sensor failed and the crews mishandled the aircraft because the software was inadequate to stop them from doing so.

There is a huge difference between a sensor temporarily failing with the pilot making completely unwarranted inputs commanding the plane into a stall, versus a system that actively and repeatedly degraded the plane's flight characteristics because of a failed sensor.

In the first case, the pilots needed to do almost nothing and the problem would correct itself. Just "don't do anything stupid". In the second the pilots needed to take immediate action to maintain controllability.

These issues are nowhere near being equal in severity.

[Europa01]

I agree, zooming in on the higher res image of the failed door/plug in post #194 (it's still very hard to be sure I'm not just seeing artefacts in the image) but it almost looks like the visible end of the pin is showing an axial counterbore hole and an uneven surface at about the point that cross bolt would have been?
However if that were the issue then a quick visual inspection of the pins would not find it and the inspection of the other aircraft would surely take longer than it seems to......

Looks very much as though this and flipfrog’s earlier post are correct. The roller pins in the fuselage frame clearly do engage in the door guide tracks although maybe not as far as you might expect given the available depth of the fitting) BUT the engagement of the lock bolt which stops the plug lifting up the track with the roller pin looks marginal.

Given this event had a direct (not root) cause of a mechanical engagement fault I’d have to say I’m surprised at the woolly terms of the AD. Surely we should expect specific dimensions to be checked and recorded. Against a Boeing specification? - perhaps there wasn’t one.

[WHBM]

It also seems odd to me that two seats next to the relevant window were apparently empty, two of only seven unoccupied seats in a full flight - including a window seat at that.
It's normally just a trivia - though of relevance here - that USA passengers, have a strangely different perspective to Europe, and go on about getting an Aisle Seat. Noticeable on carriers with free seating like Southwest that those first in take aisle seats, whereas comparably on Ryanair they more commonly take window seats first. It leads to considerable inefficiencies in boarding as the aircraft fills up and there needs to be making way for others to pass by, sometimes with reluctance, Given these incident seats are at the rear, they are the ones, fortunately, likely to go unused where the aircraft is not full.

[EXDAC]

I imagined these were just lanyards much like ceiling panels and others have to facilitate opening without uncontrolled dropping, the adjacent structure does not looked beefed up for a pip pin type lock, but I stand to be corrected!

Yes, that's correct. They support the plug in the partially open position as seen here in the video posted by MechEngr- Informative video:

Indicates a non-functional door was used rather than in-oping an exit door and suggest retaining bolts were missing. If so, then there will be a paper trail back to whoever signed off that the bolts were installed.https://www.youtube.com/watch?v=nw4eQGAmXQ0

[C2H5OH]

So how are those bolts installed then?
Tool/Screw inserted through the plug fitting and fastened in the axial bore of the bolt, then pulled in place and secured with a safety pin?

[EXDAC]

So how are those bolts installed then?
Tool/Screw inserted through the plug fitting and fastened in the axial bore of the bolt, then pulled in place and secured with a safety pin?

The (intended) location of the 4 retaining bolts is explained in the annotated photos at 2:27 and 24:26 of the video linked in my post above

[Ivor_Bigunn]

Yes I agree this video is excellent and seems to be definitive about how the Plug works. (And only the Plug has a full-size window in it. Doors have small circular Portholes).

There is 3-4 minutes right at the end about the Alaska Airlines incident.

In the absence of any visible frame distortion or tearing, I would deduce that all 4 securing bolts must have been U/S or missing, so the door could slide upwards 4" under the fitted bottom springs pressure, become completely clear of the retaining devices, and be fired out into space by cabin pressure. But how that could come about I do not have a theory.

IB

[AirScotia]

According to Reuters, the last body to amend the door would be Boeing themselves.

Spirit made blowout part but Boeing has key role (https://www.reuters.com/business/aerospace-defense/spirit-aero-made-blowout-part-boeing-has-key-role-sources-2024-01-07/)


As part of the production process, Spirit builds fuselages for 737s and sends them by train with the special door assembly “semi-rigged,” one of the people said. “They are fitted but not completed," the person said.

At its Renton, Washington, plant, Boeing typically removes the pop-out, or non-functioning, door and uses the gap to load interiors. Then, the part is put back and the installation in completed. Finally, the hull is pressurized to 150% to make sure everything is working correctly, the person said.

[DTA]

They appear to have very quickly known the cause of this incident without even finding the missing door/plug. Would photos have been taken of the plug during production or later maintenance? I would presume the only thing you could tell from a photo is if the (upper) securing bolts/pins were missing? Damage or the wrong type/length would not be obvious.