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Looks as though the 2 parts that guide the door up and off of the retention pads are gone. That is the location that have the upper 2 "lock" bolts in the door

https://www.ar15.com/media/mediaFiles/180908/1000001578_jpg-3085321.JPG

https://www.ar15.com/media/mediaFiles/180908/1000001577_jpg-3085322.JPG

ETA for clarification, there is most likely a roller on the ship side and a track on the door with the lock bolt in it keeping the door from moving up and out if that makes any sense

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The lower hinge fittings are used for retention, too.

Check out this drawing and photo of a emergency door installation -

https://www.ar15.com/media/mediaFiles/348/1000000528-3085467.jpg

https://www.ar15.com/media/mediaFiles/348/1000000529-3085468.jpg

I don't understand the function of a cable assembly on the plug door unless it's used to rotate the roller assembly to lock and unlock.

The NTSB classified this as major damage.  We're not seeing something critical.

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Looks to be a limiting strap to keep it from going full open during maintenance

https://www.ar15.com/media/mediaFiles/180908/1000001581_jpg-3085509.JPG

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But, this what I don't get.  The stop fittings of the door sit inboard of the respective fuselage stop fittings.  The door has to move up the whole height of the frame/fuselage stop fitting before it can translate outboard.

https://www.ar15.com/media/mediaFiles/203937/blS259f-2806399.gif

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... We're not seeing something critical.

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It is a limiting strap for a door plug install.  You would not want a limiting strap on an emergency door for obvious reasons.

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And, you wanna know something else? This very well could've been on Alaska Airlines too. They put all their aircraft into heavy maintenance immediately upon delivery. The only time a plug door comes off would be during that time. Someone probably just didn't put it back on well

— Trystan (@astro_zeus_) January 7, 2024

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Looks to be a limiting strap to keep it from going full open during maintenance

https://www.ar15.com/media/mediaFiles/180908/1000001581_jpg-3085509.JPG

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2019 - https://www.heraldnet.com/business/citing-audit-boeing-quality-inspectors-question-job-cuts/


2021 - https://www.wenatcheeworld.com/news/congress-demands-records-from-boeing-to-investigate-production-quality/article_3a5338cc-b89f-11eb-b126-bb0d2d70d678.html

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That just doesn't seem right..... not sure I believe that.

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Images taken by passengers show no damage to the frame around the neat rectangular hole. It appears that the plug, which is fastened to the airframe with just four bolts, came loose and fell away.

On Saturday, Alaska Airlines said that in the days before Friday's in-flight incident pilots had filed several reports of intermittent warning lights that indicated some loss of cabin pressure on the jet.

Jason Lai, Alaska's managing director of engineering, said these pressurization warnings were written up and "resolved per approved maintenance procedures."

As a result of those write-ups, the plane was then restricted from long-distance flying out over water, he said, but otherwise allowed to fly.

There is no immediate explanation as to why the plug blew out.

Photos and videos made by passengers inside the jet show clean metal brackets where the plug would be fastened, with no visible breaks, structural damage, deformations or tears in the metal.

In an interview Saturday, independent airline industry consultant Bob Mann said, "that makes me wonder if it was ever properly fastened."

If not, he said, repeated pressurizations and depressurizations each time the jet flew could have gradually loosened it.

Chris Brady, an experienced pilot who runs the "Boeing 737 Technical Site" website, on Saturday posted a video showing a photo of the door plug and describing how it is installed. Brady's technical assessments were cited in the U.S. House report into the two fatal MAX crashes.

His video, citing the 737 maintenance manual, states that the door plug is fastened with just four bolts to fittings inside the fuselage. The Seattle Times confirmed with an industry source that this is accurate.

"For this incident to have happened, something must have been amiss with at least one of those bolts, probably more," Brady states in the video.

The entire fuselage of the jet, including this plugged door, is assembled in Wichita, Kan., by Spirit AeroSystems and arrives by train at Boeing's Renton plant.

In Renton, Boeing mechanics and quality inspectors complete the cabin interior, adding the wiring, insulation and sidewalls that would cover the plug before adding the seats, galley, lavatories and other interior elements.

Investigators will hope to find the piece that fell somewhere south of Portland and will comb the manufacturing assembly and inspection records.

Mann said the lack of any deformation around the hole in the fuselage makes it look like the initial cause may be "a Spirit quality control issue."

However Boeing has ultimate responsibility for the aircraft. The plug should have been inspected in Renton before the sidewall was installed to cover it.

And Alaska Airlines will also face questions about how it handled the indications of depressurization the days before, allowing the plane to continue to fly.

News of the depressurization warnings was first reported late Friday on The Air Current website.

Lai, Alaska's managing director of engineering, said via email that "these types of aircraft pressurization system write ups are typical in large aircraft commercial aviation operations."

"In every case, the write up was fully evaluated and resolved per approved maintenance procedures and in full compliance with all applicable FAA regulations," he added.

Nevertheless, he said, "out of an abundance of caution," Alaska Airlines has an internal policy to restrict aircraft with multiple maintenance write ups on certain systems from flying long distances over water, even when the reported faults are resolved.

That was the case for this aircraft. It was restricted from flying to Hawaii but cleared to fly to California.

"This internal policy is not required by any FAA regulation but is an additional 'above and beyond' safety precaution," Lai said.

https://www.seattletimes.com/business/boeing-aerospace/boeing-737-max-9s-grounded-after-alaska-airlines-in-flight-blowout/

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This scares the living shit outta me.  Still allowed to fly, just short distances over land.  You can still die, it just won't be over water.  

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Will be interesting to see how much Boeing stock takes a hit on Monday

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The lower hinge fittings are used for retention, too.

Check out this drawing and photo of a emergency door installation -

https://www.ar15.com/media/mediaFiles/348/1000000528-3085467.jpg

https://www.ar15.com/media/mediaFiles/348/1000000529-3085468.jpg

I don't understand the function of a cable assembly on the plug door unless it's used to rotate the roller assembly to lock and unlock.

The NTSB classified this as major damage.  We're not seeing something critical.

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Thankfully I don't have to worry about that.
I'm so fat and already wedged in the bathroom that a rapid decompression would cause me to expand and be even further stuck in place in the bathroom.

Kharn

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Would a rapid decompression suck the contents of the tank up through the toilet like a geyser?  

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So if I'm understanding this correctly, it looks like there are roller pins on either side of the opening near the top that index into those slotted brackets on either side of the plug. When the roller pins enter the grooves, the 12 lugs along the sides of the plug have clearance to move past the ones on the fuselage. At the bottom of the plug are hooks that grab and cinch to the bottom of the opening. As the hooks are tightened, the whole plug gets pulled down and against the fuselage skin into it's fully sealed position. Once there, the lugs on either side are aligned and get what looks like grub screws threaded into them that further press the plug's and fuselage's sealing surfaces together.

Seems like it should be impossible for that to come apart mid flight. I'm guessing someone didn't put the grub screws in correctly or at all.

https://www.ar15.com/media/mediaFiles/203945/GDN4W5IXAAAUcVt_jpg-3085840.JPG

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It was long ago, and I'm making these numbers up just to illustrate...but after that firefighting C-130 wing fold we started doing rainbow fitting inspections on the entire fleet. Those fitting have "teeth" that determine their structural integrity. After they found a couple of problems, an engineer got up in front of the wing commander and started explaining the probability of failure from a single tooth through consecutive teeth. One tooth was a 1 in 10,000,000 chance of catastrophic failure. Two consecutive teeth didn't double the risk...it went to 1 in 100,000. At three teeth when the odds of a crash hit 1 in 1,000 missions everybody in the room got really quiet. We inspected those damn fittings for a LONG time after that.

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The rainbow fittings at wing station 220 had nothing to do with that wing separation, which occurred inboard of BL65 under a lower surface doubler hiding an 8+ inch crack in the skin and 2 severed hat stringers. The lug or flange cracks on the rainbow fittings are a separate issue but C-130's have never lost a wing there.

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Based on the spacing of the remaining windows, leg room in that isle, and huge hole, I would say that is an emergency exit.

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What derivative would have a live door as opposed to a plug?

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What derivative would have a live door as opposed to a plug?