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

[TURIN]

Originally Posted by tdracer

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]

Originally Posted by lateott

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]

Originally Posted by Big Pistons Forever

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]

Originally Posted by 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.

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]

Originally Posted by tdracer

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

[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]

Originally Posted by 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.

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]

Originally Posted by Consol

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...oLargeAt2X.jpg

[runner1021]

Originally Posted by GlobalNav

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]

Originally Posted by 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.

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]

Originally Posted by runner1021

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]

Originally Posted by procede

Ryanair would probably charge extra for the view.

And priority exiting....

[MLHeliwrench]

How it is supposed to look. (Not my photo, credit to whomever took it!)

[fdr]

Originally Posted by 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.

Originally Posted by powerjets

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]

Originally Posted by Chronic Snoozer

And priority exiting....

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

[tdracer]

Originally Posted by WHBM

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]

Originally Posted by OldnGrounded

"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.