Boeing Keep your seatbelt low and tight in flight, especially when seated next to a plugged door

[berkeman]

Yikes...

https://mentourpilot.com/incident-alaska-air-737-max-9-loses-plugged-door-in-flight/

 

[Vanadium 50]

Thankfully, it appears that the seat that was closest to this plugged door of the Alaska MAX-9 was empty.

Sure, it's empty now.

 

[Greg Bernhardt]

A kid next to the door got his shirt ripped off

 

[russ_watters]

Awesome, I think I fly one of those next month.

 

[DaveE]

A new -9, about 145 flights since it entered service about 9 weeks ago. Good news for Airbus.

 

[Vanadium 50]

Good news for Airbus.

If it's Boeing, I ain't going.

 

[DaveE]

"Spirit AeroSystems Holdings, based in Wichita, Kansas, United States,[2] is an American aerostructure manufacturer, and is the world's largest first-tier aerostructures manufacturer. The company builds several important pieces of Boeing aircraft, including the fuselage of the 737, and 787, as well as the flight deck of the fuselage (referred to as "Section 41" by Boeing) of nearly all of Boeing airliners. Spirit also produces fuselage sections and front wing spars for the Airbus A350."

https://en.wikipedia.org/wiki/Spirit_AeroSystems

 

[DaveE]

 

[DaveE]

 

[dlgoff]

Spirit AeroSystems Holdings, based in Wichita, Kansas, United States,[2] is an American aerostructure manufacturer

I went through that place when it was Boeing. One of my uncles was a chemist there.

 

[Vanadium 50]

It's a "door plug" not a "plug door". They are not doors.

The 737MAX has space for two pairs of aft doors. In a very high density configuration there needs to be more doors. On non-ULCC carriers, this is not required. In this case, there is no "deactivated" door. It won't open, period (well, that's the plan).

My friend at Boeing sent me some information. The plug is held by four bolts, one in each corner. Somehow multiple bolts failed.

 

[Greg Bernhardt]

My friend at Boeing sent me some information. The plug is held by four bolts, one in each corner. Somehow multiple bolts failed.

I'm not an engineer, but maybe it needs 4 or more, shoot, just put a dozen in.

 

[berkeman]

I'm not an engineer, but maybe it needs 4 or more, shoot, just put a dozen in.

Or give all the passengers an extra shirt.

 

[Vanadium 50]

hoot, just put a dozen in.

Adds weight. Why make it a plug at all? Why not leave it a door? Adds weight and costs two seats.

I suspect counterfeit bolts. There was a case not long ago about a guy in London whose company was selling random parts and forging their certification.

IMHO, the person in question (a former DJ in Venezuela, so not at all sketchy) should be duct-taped to one of these doors, and wished a hearty "good luck!". If the parts aren't fake, he doesn't have anything to worry about, does he?

 

[gmax137]

forging

I see what you did there.

 

[DaveE]

I'm not an engineer, but maybe it needs 4 or more, shoot, just put a dozen in.

Bolts don't work if bolts aren't installed properly. It's not too hard for an engineer to design a sound structure on paper. Getting it built correctly is another story. Of course we don't know yet, but if there's a lottery, I've got dibs on a QA failure in the last installation of that door. It wouldn't be the first time there were issues with Boeing assembly quality.

 

[Vanadium 50]

I have not visited the Boeing factory, but I have visited the airbus factory, and the amount of QC is really impressive. They spend as much time on QC as they do on the actual assembly. While it is possible that all four bolts were put in incorrectly and that the QC team didn't notice. my money is on a part failing. And since everything needs to be certified, that leads me to start thinking about counterfeit parts.

 

[Tom.G]

Many, many years ago I worked in Quality Control at a Boeing plant. One day I failed 3 circuit boards for the cabin environmental controls, due to poor workmanship / bad solder joints.

Two days later I was confronted by two irate mid-level folks from Production. They chewed me out for failing the defective boards and stated they " ... didn't want the [assembly] line shut down...".

I wrote a report to my supervisor, but he was not in that day. I happened to see the facility Senior Manager in a hallway, so I handed him the report.

A week later I was 'layed off'.

An 'Enlightening Experience'; pay attention to who you work for!

 

[Greg Bernhardt]

Well if this doesn't give you confidence in flying...

Plane was restricted from flying over water amid auto pressurization fail lights
Alaska Airlines had restricted the plane from flying from over the ocean to Hawaii to ensure the plane could “return very quickly to an airport” in case any warning lights in the aircraft went off, according to Homendy.

https://www.cnn.com/2024/01/08/us/alaska-airlines-plug-door-found-investigation-monday/index.html

 

[berkeman]

It looks like all the folks in Portland are treasure hunting now. In addition to the door plug, they have found a couple of phones that got sucked out during the depressurization...

https://abcnews.go.com/US/passenger...-alaska-airlines-emergency/story?id=106186623

 

[berkeman]

So now I'm a little more confused (what's new?)...

The reports and the pictures of the opening seem to show little structural damage, other than the missing door plug:

https://www.phonearena.com/news/iPh...flight-that-lost-a-door-plug-mid-air_id154105

But the Wikipedia article seems to suggest that the door plug should have been mostly inside the fuselage, sealed by the higher pressure inside the cabin compared to outside at 10k+ feet:

https://en.wikipedia.org/wiki/Plug_door

So if the Wikipedia sketch is accurate, shouldn't there be a lot of torn up fuselage left behind as the Plug Door was ripped off of the airframe? Or is the Wikipedia drawing incorrect for the Boeing aircraft, and there were literally only 4 bolts holding that Door Plug against the difference in air pressure?

 

[difalcojr]

Looks to me like it needed about 4 bolts top and bottom, 8 on a side: 20 total! Wouldn't add much more weight.

Overengineer it. So, if fake, counterfeit parts of poor quality, if poor workmanship, and if dangerous company QC practices are in place, as all 3 causes are in most engineering disasters, you need to increase the design safety factors accordingly. Radically. Double them?

See how many customers want window seats now.

 

[gmax137]

As mentioned above, it is not a plug door. We need a different drawing.

 

[berkeman]

As mentioned above, it is not a plug door. We need a different drawing.

Better link please?

 

[DaveE]

Better link please?

This is all explained in the video in post #9. The bolts don't hold the door horizontally, they keep the door from moving vertically to "unlatch" from the structures that resist the horizontal Δp force.

 

[berkeman]

Oh crap...

https://www.cnn.com/2024/01/08/us/alaska-airlines-plug-door-found-investigation-monday/index.html

 

[gmax137]

This is all explained in the video in post #9. The bolts don't hold the door horizontally, they keep the door from moving vertically to "unlatch" from the structures that resist the horizontal Δp force.

I just watched that video. It is 18 minutes long, but is very clear with some good photos and explanation of how the plug works.

 

[gmax137]

Oh crap...

That's a good read, too!

 

[berkeman]

Awesome, I think I fly one of those next month.

Just take your Leatherman tool through the security checkpoint and use it on the plane to check the tightness of the bolts. I heard somewhere that TSA will be allowing Leatherman tools on flights going forward, as long as you can show that you are an ME and have a boarding pass for a "plugged door aisle".

 

[Greg Bernhardt]

Can they just check all the aircraft bolts for tightness please

 

[Vanadium 50]

Can they just check all the aircraft bolts for tightness please

They have grounded these planes already. This is causing major disruptions.

However, depending on the problem, maybe they will find it, and maybe they won't. If the bolts are bad, but correctly installed, that's a harder problem to catch than if they were installed correctly.

 

[berkeman]

Can they just check all the aircraft bolts for tightness please

'Scuse me mam, just checking your bolts here today. Okay, you're good. Have a nice flight.

 

[Vanadium 50]

Is not plug door. Is door plug.

As far as being restricted from flying over water, would you feel better if it weren't so restricted?

I flew on a 777s first flight with passengers. ORD-CDG. There were still bits of plastic covering various things, like the TV controls. Not sure how I felt about being over an ocean on a brand new plane.

 

[berkeman]

I flew on a 777s first flight with passengers. ORD-CDG. There were still bits of plastic covering various things, like the TV controls. Not sure how I felt about being over an ocean on a brand new plane.

Did you pay extra for that?

 

[Greg Bernhardt]

As far as being restricted from flying over water, would you feel better if it weren't so restricted?

I'd feel better if they'd take it out of service and get it air worthy. If they are so nervous about getting to an airport in time, it aint air worthy.

 

[Vanadium 50]

I'd feel better if they'd take it out of service and get it air worthy.

How is this possible?

One can say "We want 500 hours (or whatever) of overland flying before we take it over the ocean." I think that may even be reasonable. But you can't say "We want 500 hours of overland flying before we take it over the land."

Every US aircraft with that plug is out of service pending inspection. What more do you want?

 

[DaveE]

Alaska and United Airlines found loose bolts on the door plugs on several of its grounded 737 Max 9 planes days after a door plug blew out of an Alaska Airlines plane while it was in-flight.

https://www.seattletimes.com/busine...olts-on-door-plug-when-inspecting-its-max-9s/

Also, Juan Browne reported that Boeing removes and reinstalls the door plug after they receive the fuselage from Spirit to install the aircraft interior.

 

[Tom.G]

Sounds like a case of RTFM.

"Read the fuc**ng err, fine, manual!"

 

[russ_watters]

How is this possible?

One can say "We want 500 hours (or whatever) of overland flying before we take it over the ocean." I think that may even be reasonable. But you can't say "We want 500 hours of overland flying before we take it over the land."

Every US aircraft with that plug is out of service pending inspection. What more do you want?

Passengers. It's about the passengers.

 

[nsaspook]

Bob has his 15 min of fame.

 

[Greg Bernhardt]

Every US aircraft with that plug is out of service pending inspection. What more do you want?

How about inspected before the door blows off in flight if they were so nervous?

 

[Borg]

It's like opportunity.

 

[Vanadium 50]

How about inspected before the door blows off in flight if they were so nervous?

It's not a door. It's a plug.

It surely was inspected. Somewhere there is some paperwork which states how tight the fasteners. Clearly that wasn't enough.

Would more inspections help? Maybe, ,maybe not. Depends on what the problem was - were the bolts too loose? Or were they too fragile? Or is there something else: say a resonance issue causing them to work their way loose. I am unsure that doing more of what didn't work in this case is the solution.

It's also worth pointing out that taking these planes out of service is causing passengers to seek alternatives. Alaska flies about 40 billion passenger-miles per year, and driving kills about 5 people per billion passenger miles. So while they are flying, they save about 200 lives a year. If they lose 40% of their capacity for a week, the expectation value of fatalities due to alternative transportation approaches 1. And that's just Alaska.

I'm not suggesting ignoring the issue. But I am pointing out that overreacting also has its costs.

 

[difalcojr]

Bolting a plug? With all that wind pressure and vibration?! Think of bridges.

 

[gmax137]

"Since we began preliminary inspections on Saturday, we have found instances that appear to relate to installation issues in the door plug – for example, bolts that needed additional tightening," United said in a statement..."

The bolt physically traps the guide roller, preventing it from moving "down" in the track. Looks like it will perform this function regardless of how "tight" it is -- as long as it is present. Were they even present? Or maybe the cotter pins were missing and the castle nut vibrated off, and then the bolt escaped. All four of them.

 

[berkeman]

Alaska and United Airlines found loose bolts on the door plugs on several of its grounded 737 Max 9 planes days after a door plug blew out of an Alaska Airlines plane while it was in-flight.

https://www.seattletimes.com/busine...olts-on-door-plug-when-inspecting-its-max-9s/

Also, Juan Browne reported that Boeing removes and reinstalls the door plug after they receive the fuselage from Spirit to install the aircraft interior.

Great video, thanks @DaveE

And "loose bolts"? The Cotter pins would have to have been missing for that to happen, no? I suppose if Boeing reused the Cotter pins after the reinstallation, they could have failed and allowed the nuts to back off, but I can't imagine the technicians reusing Cotter pins.

@Flyboy -- You aren't allowed to reuse Cotter pins during maintenance, right?

 

[nsaspook]

Great video, thanks @DaveE

And "loose bolts"? The Cotter pins would have to have been missing for that to happen, no? I suppose if Boeing reused the Cotter pins after the reinstallation, they could have failed and allowed the nuts to back off, but I can't imagine the technicians reusing Cotter pins.

@Flyboy -- You aren't allowed to reuse Cotter pins during maintenance, right?

No, never.

You use a bent nail instead.

 

[Vanadium 50]

Or maybe the cotter pins were missing

When they replace them, it will be "Welcome back, Cotter."

 

[russ_watters]

And "loose bolts"? The Cotter pins would have to have been missing for that to happen, no? I suppose if Boeing reused the Cotter pins after the reinstallation, they could have failed and allowed the nuts to back off....

This is what caused my in-flight incident...

 

[berkeman]

This is what caused my in-flight incident...

I missed the memo, but am glad you are still with us...