NTSB Preliminary Report Alaska

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[@domenickruttura5412]

I was an Airframe mechanic in the Navy, we never worked on any plane with out two inspections, Quality control and Quality inspection. We never did repairs by memory, we went by the book. So sad for such a great company.

[@quesopasso]

Formerly great, it would seem.

[@38911bytefree]

Boeing does not deserve its reputation and name anymore.

[@rockets4kids]

A much greater problem is the lack of FAA oversight as a result of reduced funding.

[@idanceforpennies281]

Even on GA you have an AME which needs to be signed off by LAME. The licenced aircraft engineer untilmately takes responsibility. The AME is qualified, but the LAME is the double check. Unless the AME is also a LAME (which many are) Lol.

[@richardlewis4288]

I was an airframe and powerplant mechanic for the major airlines for over 30 years. Some jobs are required inspection items (RII) and some aren’t. The airline can designated any job an inspection item if it deems nexsssary and I presume the plugs will now also probably on every Mx check even if the plug wasn’t opened. Increased FAA oversight won’t accomplish anything, it’s the airline itself that provides the oversight and the majors do a very good job of it.

[@greyjay9202]

That's a long flight from Sydney, but Juan took the time to make this video, before grabbing some shut eye. That's dedication, and we appreciate it, Juan. Boeing and Spirit have a lot to answer for. The FAA has to hold their feet to the fire.

[@prmath]

Dang good man…👍🏼

[@baomao7243]

I agree with the comment on Juan. Juan: You rock. You go above and beyond the call of duty. We appreciate it. Just be sure to get your rest !!

[@davidlang1125]

I think Juan no longer feels the affects of jet lag. Fifteen hours in the air is a walk in the park for him.

[@baomao7243]

@@davidlang1125 Next stop: Astronaut

[@pilotdane1]

@@baomao7243 FNA !!!

[@leokimvideo]

Juan often speaks about Swiss Cheese holes lining up to create a disaster, the way I see this door plug incident is reverse. So many Cheese holes have lined up not to have a major loss of the aircraft or lives lost. It's potentially Boeing's' biggest lucky break. No pun intended.

[@thetowndrunk988]

They melted the damned Swiss cheese into fondue……

[@the_expidition427]

@@thetowndrunk988 Saving this

[@sveinwiklund6972]

The Swiss Cheese Model was first used by James Reason - a professor at Manchester Universtity in the UK in his book 'Human Error' - whch was released in 1991. In the book, he elaborates on a theory that says that accidents cannot be traced back to a 'single root cause' - accidents are often the result of a combination of factors. You may remember Arthur Hailey's novel Wheels from 1971 - about the automobile industry in Detroit and the pressure 'to deliver'. If you had connections in the industry, you asked for a mid-week product. I remember from LA California back in the 1970-ties. Some friends had decided to switch to Japanese automobiles - they could get American produced ones 'on the day', but they instead waited five months for Japanese produced ones. The MCAS incident/accidents - two Lion Air and one Ethiopian Airlines, started with a Lion Air flight where the crew managed to fly the aircraft to its destination, but somehow their experience was not caught by their organization, so the next day the same aircraft crashed. Then, one should believe that every one flying B737 Max should know how to handle a similar upset - So back to James Reason - People do Mistakes!! - And they will continue to do so ' regardless how large a Swiss Cheese we bring in'. SO, our task is to reduce the events - I am not sure if it is appropriate - to an acceptable level.

[@PowderMill]

Fortunately ->> Swiss Cheese is not permitted at the new “WOKE” Boeing. Even the mention of it could cause additional Federal lawsuits and sanctions for “CULTURAL APPROPRIATION” or some other such nonsense. I refuse to fly until at least 50% of all commercial airline pilots and ATC workers are either Black, Womenz, Transgender, Low-IQ or any combination of the above. Forget SKILLS, MERIT, dedication, knowledge, etc…. I only want to place my life and the lives of my family in the tender and caring hands of some GRIFTER. 🤔 Btw - WHY PULL CIRCUIT BREAKERS ??!,?? It’s 2024, how about a few week’s worth of audio/video and telemetry data stored on a $200 buck solid-state storage device with multiple redundant back up devices.?

[@awboat]

@@AngelOfTheAbyss66 So you got a channel that does better? I really hope so we can see your awesomeness.

[@jimwells4240]

Just a note from a former structural mechanic on various Boeing products. The door frame is and EXTREMELY robust piece of structure, generally a single-piece 7075-T6 forging of approximately 5/16" or more in thickness. It would be truly unlikely for the doorframe itself fail.

[@jonathanbott87]

Honest/curious Q: Would door plug frames be the same? There's been so much info about how they're not doors and how hard it's to convert to a door, so honestly just curious. Thanks!

[@lairdcummings9092]

@@jonathanbott87 should be the same as the emergency exits or other doors; it's designed specifically to serve as an emergency door. @jimwells4240 Good info; thank you.

[@FreshTillDeath56]

Good to know, thanks

[@jamescole1786]

2/10/24... A+ Juan on this detailed, 3-D animation & layered responsibility of several manufacturers involved in this Alaska Airlines (plugged?) door blow-out while climbing to altitude. Fantastic video with EZ to understand graphics & comments. Thank God no fatalities! A+ to all flight crew & ATC for priorities followed. Special thx Juan for your attitude & efforts to collect & organize so many details for YT/Public video. 💪⚙️🔩🔧😊

[@Jamez3l]

If the bolts were installed and the plug broke away the damage would have been much worse correct?

[@rogerstephens2749]

I've been a inspector/ master mechanic since 1979. The mechanics that install and rig the doors have a close out inspection and then a final inspection. Now if you have to open or remove anything for rework inspection creates a removal record to re inspect all the parts and the surrounding area. I can't believe this happened

[@ParkerUAS]

Precisely. I e only worked around small GA fleets where the "big plane" was a King Air 350. Every one of those shops has meticulous process for removal and installation. They all went by the book, but each had added measures whether it was the small bags with screws and bolts that were labeled with where they went and then affixed to the part or to the aircraft area. Even our 172's would have a little bag of screws hanging from every inspection panel. Once work was done another mechanic NOT involved in the work would come do an inspection before it even went to the IA. If the IA was the one doing the main work, he had two mechanics separately look it over. Boeing's Quality Control never should have let this out the factory door.

[@rael5469]

I also have more than 40 years in aircraft maintenance and I can't believe it either Roger.

[@Bob-nc5hz]

As Juan mentions in closing the video, I assume the tool has an option allowing "opening" a door because there is little reason to reinspect a regular door (plug door) that's opened and closed in the course of maintenance, That that option was usable and used for a *door plug* is what's insane. Though from all the stuff that's been filtering out, it's definitely in keeping with the clusterfuck that is the 737's assembly lines.

[@ralphedelbach]

I would like to see the paperwork you describe for this specific aircraft as well as who signed-off on the work done. Why hasn't this issue been pushed more in news reports about this gross error by Boeing? It should have been IMO.

[@ParkerUAS]

@@ralphedelbach probably because until the NTSB report is finalized that information is kept pretty private because you have both civil and possibly criminal penalties on line. I think once the report is finalized you will see more on who exactly signed what and what the real process was.

[@jimgrant4348]

For the want of a nail, the shoe was lost. For the want of a shoe, the horse was lost. For the want of a horse, the rider was lost. For the want of the rider, the message was lost. For the want of the message, the battle was lost. For the want of the battle, the kingdom was lost. And all for the want of a horseshoe nail. I remember my mom reciting this poem when I was young. We discussed the meaning. It's the little things you overlook that have big consequences.

[@charlesfaure1189]

This wasn't about little things. It was about the gutting of an aerospace engineering company's core principles in favor of a "lean manufacturing" model to try to gain an advantage over Airbus. 'Lean manufacturing' is a euphemism for ruthless cost-cutting. Any activity judged judged not to add value is ruthlessly sheared down to 'minimum.' It's never really minimum. It alway ends up below, because somebody's quarterly performance review will always be based on saving more time, labor, money.

[@SubTroppo]

"Sire, nail making and horse shoeing was outsourced to the kingdom of CheapMcCheap and we invested in tulips instead". The king of WallStreetLandia's response: "How long did it take the last messenger to die?"

[@spvillano]

@@charlesfaure1189 and just think about the pure profit by omitting all of the bolts! Just used plastic wire ties, they're cheaper. "Just so long that it arrives good enough for them to sign and accept delivery". Then, when regulators step in after a few "incidents", "who knew, we'll fix it as it's really bad for our reputation!".

[@TornadoCAN99]

"A horse! A horse! My Kingdom for a HORSE!!!"

[@jeffreywonser3241]

For the want of money, safety is lost.

[@ajg617]

Attorneys have amended the suit to include the following: passengers on the earlier flight heard [ a whistling] sound “coming from the vicinity of the door plug.” They brought it to the attention of flight attendants, who then “reportedly informed” a pilot, according to the complaint. After the pilot checked cockpit instruments and found readings to be normal, no further action was taken, the complaint says. If true, your suspicion that it was hanging by a thread may well be correct.

[@gsdalpha1358]

Might that explain why no one was sitting next to the plug door? I would've requested moving if there was an annoying whistle right there!

[@brendanh8978]

​@gsdalpha1358 apparently the flight was otherwise full, which leads me to believe the airline itself opted to leave those seats empty. Did they suspect something?

[@LandYacht]

Yikes.

[@leepatton1180]

Very good info that leads me to believe there is some kind of cover up cabin pressure problem empty seats by the door plug lost recording sure smells fishy

[@alexrebmann1253]

I have heard that warning lights lit up in the cockpit to indicate a possible pressure problem days earlier and I also read about the whisting sound coming from that area from an earlier flight.

[@LauwersFreddy]

When I have screws left while assembling IKEA furniture: “OH NO, I’ll have to check everything and start over”. Boeing that has left over bolts while assembling a plane: “ Meh….”. Thank you for making these videos!

[@brendanh8978]

That's what hit me. Some tech at Boeing took those out. Either that tech or the next shift saw them still laying wherever they were left. Did nobody say anything? Safety really is a culture. Is the culture there to keep your mouth shut and the line moving to maintain output and profits?

[@greeneyesms]

@@brendanh8978 Unless they simply grab bolts out of a bin as they go along - then it wouldn’t be obvious for quite a while. I don’t know, I’m just wondering.

[@brendanh8978]

@greeneyesms I don't know either, but I certainly hope not. There should be a chain of custody for every part and every tool to make sure everything ends up where it is supposed to.

[@solandri69]

Yeah. I'm wondering what happened to the bolts. Did some worker get home, undress, find 4 bolts in his pocket, and decided not to report it? Did they place them in a ziplock bag, tape it to the window, and drew the graffiti around it so they wouldn't forget, but the bag fell off? I'm a stickler about carefully storing the screws when I open up a laptop to upgrade RAM / SSD. It's literally impossible for me to forget to reinstall a screw, as I'd have parts left over. It's hard to believe my procedures are more robust than an aircraft repair crew's.

[@greeneyesms]

@@brendanh8978 Agreed. Here’s a crazy idea I just had: what if they had someone examine and sign-off on critical work? They could call it something like Quality Assurance or Quality Inspection. Seriously, I cannot fathom how something this important could be so slip-shod.

[@c1d2e]

Passengers on the prior flight noticed a whistling sound coming from the door plug and notified the Flight Attendant. This door plug was likely already out position on the previous flight compromising the airtight seal around the door. Door seals that are leaking create a loud scream or whistle noise.

[@skynineUK]

We used to tip a little water in the gap that froze and stopped the noise.

[@JohnSmith-yv6eq]

Japan Airlines 747 freighters used to have dark brown stains "streaming" from the doors on the exterior of the aircraft near the cockpit. This was the nicotine from the pilots smoking cigarettes during the long freight carrying flights.....

[@andij605]

So sad to hear that they weren't taken seriously. When we fried some birds in an engine upon take-off, we still returned to the ground (with one engine), even though the pilots saw no indication of any issues on their instruments, because us passengers saw, and heard the extremely unusual vibration from the affected engine. (Well and the pilots phoned engineers as well who apparently said "that's interesting, we want to take a look asap".) edit: then again, that was KLM... they are quite serious about safety these days, and less repercussions to pilots for being late or whatever. When I flew LOT and a Dreamliner had water flowing down at passengers and into the ground from the airco... LOT flight attendants were like "that's normal, Dreamliners always have a lot of water running from the airco upon take-off". wtf

[@cremebrulee4759]

​@@andij605that's crazy.

[@gtdcov]

Someone held those 4 pins in their hand at some point in time and shrugged their shoulders because they didn’t care. Those 4 pins are somewhere whether it be in a tool bag,on a work bench or in the dump but the do exist.

[@andrewsnow7386]

Doors were NOT my area of expertise, but I was a mechanical engineer at Boeing for 10 years. Note how the stop fittings that hold the door in are just flat pads. The door doesn't engage the door frame in a way that supplies any support to the door frame -- the door only applies a load to the structure. That is the door leaving only reduces the load on the door frame. Thus, even of it failed at a higher pressure, it is very unlikely it would have compromised the structure of the airplane (assuming it still didn't hit the tail).

[@GWNorth-db8vn]

I think he meant the outrush of air bending the edges of the opening outwards.

[@persistentwind]

​@GWNorth-db8vn even so most doors and door frames are designed to handle this exact sort of failure.

[@GWNorth-db8vn]

@@persistentwind - It looks like it did handle it. The question is whether it would be able to handle it at a higher altitude.

[@persistentwind]

@@GWNorth-db8vn it would. The wind rush tearing out the edges is highly unlikely - it's been years since I've done the math on it but the forces involved are really not in tearing from wind but the structure surrounding the door itself.

[@joelaurieri9065]

Agreed /i also a mechanical engineer and responsible for design and manufacturing of air frame plug doors for a major aircraft manufacturer. in a worst case the door would blow out not affecting the surrounding structure of the aircraft.. hopefully the door would fly off without hitting any major aircraft components wings ,rear stab and empennage.

[@edgarmuller6652]

I am surprised that the aircraft flew 450 hours without the bolts. Having pressurization problems points to, that the problem had been coming along for a while.

[@edkeller8078]

Yeah, no way. The prelim DOES NOT CLAIM PROOF it left BA without those four retaining bolts, but it does have a picture of the door after it was tilted back in, but did not provide date/time or context of the picture. This has led a lot of people to conclude the picture is a smoking gun. It is not. Personally, I don’t believe bolts were not reinstalled, just as I don’t believe it made 150 flights without losing the door. I think an experiment would prove mean time to failure is a flight or two. I think this was sabotage, maybe the night of 2 January. It would be easy to do, with access.

[@MrPig40]

Oh well, just don't fly over water. Send it!

[@syx3s]

shows how good of a design it is. i wouldn't be surprised if it would have flown it's entire lifetime just fine with even one of those bolts correctly installed.

[@Tra-vis]

You also have to realize this wasn't the only aircraft this problem was apparent. There must be hundreds if not thousands of flight hours on aircraft with this same missing bolt

[@sk1996]

@@MrPig40We’ll do it live!

[@jamesw.123]

Great video Juan. I wish regular media could provide a little more depth than their usual superficial 30 second news bite. It’s nice to have an alternative, and many of us here really appreciate your dedication in getting these videos out on a timely basis despite your busy schedule. We salute you. So sad what the culture change at Boeing has done to the once great company.

[@johnharvey7913]

You must be thinking of cable or internet "news". But where did that graphic of the door come from? The New York Times. That was a lot of unglamorous work on their part (reporters and graphic designers, whose names you never heard of) to come up with that. They are one of the few news organizations left that can still afford to do that sort of thing. The internet and Google (and Craigslist) decimated newspaper advertising, which used to pay for the reporting. But the opinionated talking heads still get paid to talk about what they don't know about. Few will pay for the truth, but many will pay for entertainment. We are so lucky to have in one person, Juan, a person who knows so much and can also explain it clearly, like a great teacher. Being a pilot, not a know-it-all politico, he knows he must face reality, or he may die. And thank goodness the Seattle Times still manages to get solid reporting out on this, you can bet they are under lot of financial stress these days. They must have laid off so many people...By the way, we now know for sure that Boeing is not the company it used to be, but that might have been foreseen when they moved the execs away from the factory, thereby taking their eyes off the ball. And how about that former colossus GE, where the cost-cutting execs learned their trade from the master, "Neutron Jack" Welch? They recently bailed out of their vast former HQ in Connecticut after many years of problems of their own making. Reality has a funny way of making people pay for their mistakes, eventually. Sometime other people pay for them, too.

[@lisaproustresearch]

Regular media do not do research. They dont engage experts. They are paid to look nice & read from a script. This is why these amazing videos can help us understand what the regular TV will never dare to touch. They do superficial "reading" without understanding the meaning of words sometimes.

[@k9er233]

Truly nothing more than talking heads at best.@@lisaproustresearch

[@rogueninja1685]

Oh, without a doubt. Still so many questions even with the added coverage. Why were the hard to get to rivets not to spec? Just because something might be a pain to do right, doesn't mean that shouldn't be a consideration in engineering. Maybe a special tool is required for certain rivets. Why, when I have my cat sleeping, my car in the snow, and fireworks from 4 years ago on my phone, do we have a few hour over ride of critical data on every flight? Data can be dirt cheap in terms of storage capacity. Fix this. Is it disturbing to anyone else that a procedure that was so well documented, they had physical pictures of the mistake, was missed by an entire team of people? The complacency we all get but is supposed to be handled with redundancy, but it could be in any and all of these systems on an aircraft. Pretty terrifying And as someone else mentioned, WHERE ARE THE BOLTS???

[@glenwoodriverresidentsgrou136]

Structural engineer here who has designed aircraft structure, had the door released at a higher differential pressure it would not have caused a catastrophic failure of the fuselage structure. The failure mechanism would have been more violent, but the mechanism would have been the same. As you astutely calculated, the door was holding a force equal to the weight of several automobiles when it failed. The force of the decompression is best exemplified by the twisted seats that were empty at the time. You raise an interesting question at the end: were the empty seats luck, or had this area been flagged prior to the flight? As for the pilots head hitting the HUD, the decompression acted like a 9,000 lb push on the side of the AC (action/reaction), and this likely yawed the plane violently to the side potentially throwing the pilots around. Would be interesting to review the flight data recorder for evidence of this. Great work on this series, and thanks for your dedication to getting this video out after a long flight.

[@markevans2294]

Likely the combined effects of the escaping air and the hinged door being forced into the slipstream would apply rotational forces to the aircraft in all three axes. Faster than the autopilot and yaw damper could correct for.

[@FutureSystem738]

@@markevans2294No, not likely at all.

[@4af]

Another commenter pointed out: "According to an article in the Seattle Times, passengers on a prior flight reported noises eminating from the area of the door plug to the cabin crew who in due course reported it to the pilots. Supposedly the pilot(s)checked instruments, found all normal and no further action was taken."

[@davidhoekje7842]

"Flight attendant, it's drafty here, can you move me to another seat?"

[@FutureSystem738]

@@davidhoekje7842 Absolutely FANTASTIC view though, (as long as you have your seatbelt on).

[@Dazza-u4c]

My background, pilot. Former Aircraft technician Royal Australian Air Force ( F111) , Crew Chief BAE Systems ( Tornado ). We always had two sets of eyes signing off work carried out. The tech doing the job and a progressive inspector. On critical tasks we had three. The first two and then a independent inspector.

[@gdmonks1959]

Dazza we’re you in Saudi on Tornado? I was in Khamis and Dhahran

[@smokeless7774]

When I was in QC a two word mantra was drummed into us " Never Assume "

[@EleanorPeterson]

It makes an 'ASS' out of 'U' and 'ME'...

[@brucelytle1144]

"NA"

[@davecrupel2817]

​@@EleanorPeterson My dad always said that 😂 took it to heart.

[@tonywilson4713]

Samuel L. Jackson in the film the *Long Kiss Good Night* _"Everyone knows when you make an assumption you make an ass out of you and umption!"_

[@Old_B52H_Gunner]

In the military we used to say assumption is the mother of all F’ups

[@mvintrigue-trawlerdiy1101]

Unfortunately you are going to be quite busy. Hawker down and now a Challenger. Thanks for you great videos.

[@pookatim]

A clear explanation of why it is so necessary for passengers to keep their seat belts fastened at all times.

[@jamescollier3]

I'm the man-child that would have moved into the empty window seat

[@danielwinn7108]

@@jamescollier3I often do that too. It’s a good thing that I wasn’t on that flight in that row.

[@joeskis]

would 13k pounds of pressure rip a person through their seatbelt?

[@galacticminx]

@@joeskis That's the static force on the door plug. Force, not pressure. A person wouldn't feel that force unless their body was the size of the door and they were plugging the hole. They'd still feel a force due to the loss of pressure on one side of their body, but it would be nowhere near the force on the door plug. I'd say a seat belt would easily hold it. Whether the seat that it's attached to would hold the force is another story. They'd probably depart the airplane still strapped to their seat.

[@VoxOptimatium]

@@smacktard6051 Well done. 100% accurately described.

[@PeopleAlreadyDidThis]

The zip tie just visible at 19:01 must have had magical qualities. I believed at the beginning that there were no bolts in the door when it blew, but I couldn’t see why the door seemed to fail progressively; first OK, then leaking, then the departure. It was too long, too many flights for a spring loaded door to stay in place. It’s fascinating to think the zip tie might have kept the door from rising for so long. I’m surprised to see utterly virgin paint in the bolt hole. Even one initial bolt installation ought to have marked that paint slightly. Almost seems like the bolts were never installed. Did the magical zip tie hold the plug in place all the way from Spirit to the incident? That doesn’t square with the rivet repair event, but that’s the most pristine bolt hole in world history.

[@Bitterrootbackroads]

There is at least one photo of the door open during the rivet rework, so obviously no bolts and no zip tie at that point. If Spirit positioned the door knowing that it would be opened at Boeing during aircraft assembly, maybe one bolt was installed to keep it positioned? Someone mentioned blue painters tape on window that may have held a baggie with some or all of the bolts at one point. The pic with zip tie is apparently after the rivet rework & just before interior panels get put back in place.

[@hiscifi2986]

The door would have stayed on if they only used two Zip-Ties.

[@cremebrulee4759]

I would have expected some markings on the paint from the bolt being installed.

[@tonywilson4713]

HEY JUAN - on that question of what would happen if it had happened at altitude. I remember a documentary into the Lockerbie disaster regarding the Pan American 103 bombing. One of the reasons that plane did NOT survive the explosion was because of where the bomb was located which was just before the wing. When it went off it didn't simply blow a hole but ripped out part of the wing mounts near the leading edge which then tore the rest of the plane apart. This plug door in the Max is further back in the plane and also BEHIND the wing. I did my degree in aerospace and my professor's expertise was in Structural Analysis. This sort of destruction is not easy to simulate even with the most modern systems and software. We can back track from evidence or laboratory experiments but simulating catastrophic failures from basic and first principles is far more difficult than people realise. So its very hard to say if this might or might not cause a hull loss at higher altitude. Its certainly damning that its happened at Boeing. Somebody had to remove those 4 bolts so somebody SHOULD have known they needed to be put back. My bet would be is they'll find all 4 in the bottom of somebodies tool box or maybe in the trash or maybe in the "random bolts" box that every workshop has. FYI - I'm in Australia (Brisbane) and love the channel and what you do for aviation safety.

[@mikebarushok5361]

You're right about trying to do analysis by simulation. But novel designs usually do create some sort of testing to failure as part of certification. One example I was involved with involved over pressurizing a Lear jet fuselage in stages noting any leaking rivets, seal failure, etc and finally rupturing the pressure vessel catastrophically. Bets were that door hinges, an antenna mount, electrical bulkhead connectors or a skin splice would go first. But it was the entire forward bulkhead that blew out. At something like 96 psi. It was loud enough to be heard in the airport control tower about 1.5 miles distant. Being in the building, in an adjacent bay and wearing earplugs and muffs we all had ringing in our ears afterwards for a couple of days.

[@tonywilson4713]

@@mikebarushok5361 *AWESOME REPLY* Deserving of way more than a single thumbs up.

[@rowerwet]

Since this is a door opening with a normal reinforced frame around it, it should not have ripped the fuselage. Lockerby was an irregular hole torn out of the skin with no edge reinforcement, and it would have continued to tear like a sheet of paper. The crumled edges would catch the airflow and tend to rip further

[@lairdcummings9092]

​@@rowerwetthe question here, though, is would have losing the plug at full altitude have caused additional damage, creating just those kinds of jagged, exposed edges? Would it have damaged the surrounding structure? Also, what about the aerodynamics of the door, at higher altitude? Would it have been bounced back into the airframe? Possibly launched into the path of the tailplane? I can see there might be some future experiments in this area.

[@joshcarter-com]

@@rowerwetI believe you’re correct. Cracks tend to self-perpetuate but the door leaving cleanly also left a reinforced frame. But to the point of the original comment, it’s impossible to know for sure. Also, I’m glad to know I’m not the only person with a “random bolts and screws” bin. 😅 However I try not to have any leftovers when doing car maintenance.

[@WillN2Go1]

The helium balloon example only works if the pilots' heads are less dense than the surrounding air. Maybe if they were Boeing executives.

[@EWLR89]

Could the heads going forward be a reaction to the depressurization? Like when your head goes forward when you sneeze. If the depressurization pulls them back into the chair, their bodies would try and jerk forward instinctively.

[@oleran4569]

I wonder if the pilots were propelled forward ..after.. the initial depressurization. How rigid are their seats? Could the seat backs have slapped them from behind in a post flex recoil?

[@stevewausa]

Sudden deceleration due to the change in aerodynamics?

[@eugenepolan1750]

Did ther aircraft decelerate because of a sudden increase in drag?

[@MessOfThings]

My thought would be that the change in the aerodynamics caused sudden deceleration.

[@ChristisKing117]

Growing up working on cars, when we finished and had left over bolts, we took everything back apart. Inexcusable mistake!

[@DanEBoyd]

As soon as I get the part removed, all bolts get threaded back into their holes if the part is going to be off for an extended time, or if there are other areas of the component being disassembled, in order to avoid confusion. For something like a V8 intake manifold swap where there might be a bunch of different types of bolts, I'll put each bolt I remove into its hole on the new piece, and then transfer them back to the old one once it's off. Then the old manifold acts as a bolt server while the new one goes on.

[@charlesferry2092]

check the mechanics tool box, i think thats where the missing bolts are. if not WHERE ARE THOSE BOLTS........find the bolts........you find the person(s) responsible.

[@weldonyoung1013]

Yes, but in the aviation industry most fasteners are not re-used. New ones are required.

[@jlGenozzV]

​@@weldonyoung1013yes but the old bolt serves as a reminder that you need to install the new ones.

[@alanm8932]

At 19:01 we're ignoring the white zip tie that's holding the door closed?! Right (FWD) side of door, 2nd pair of lugs up from the bottom have a zip tie clamping the pin & pad firmly together. That's why the door is remaining pressed down against the springs in the photo. No doubt the cable tie was just to hold the door closed for the photo but obviously it just stayed like that & never got the 4 locking bolts fitted. (Made perfectly possible by there being no procedure/record required for "just closing" a door plug). After 150+ flights the zip tie broke or slipped off one of the lugs. The next flight starts with the door lifted by the springs, all 12 pins at or over the top edges of their pads, mostly just held by the rollers in the bottom part of their guides. Guides break at 15k ft. (Guides were never designed to withstand the differential air pressure on the door plug). What we want to know is, what brand of zip tie is that? If it's good enough for 150+ flights, it's good enough for anything I'd want a zip tie for!

[@Bitterrootbackroads]

Very interesting! I’ve wondered since the early discussion on the Chris Brady channel about the direction of push, up or down, required to open plug. In the end it seemed the written procedure calling for a downward push, was simply intended to take the spring / shear pressure off the lower bolts for easy removal. Since then I’ve wondered about how much force & travel those springs have? Best guess being at least enough to lift the door to the upper travel limit of the lower slides. That would have the door properly positioned for the roller pins to enter the upper guides, and also for stop pins to clear pads upon closing before door is lowered to final closed position. If the springs exert that level of tension, and the 4 locking bolts are missing, it seems the plug would simply flop up and open before plane was airborne. UNLESS there was something like that zip tie temporarily holding plug in position. The test I would like to see could be done on the plug directly opposite on the other side of the accident plane- pull the 4 locking bolts and see what the door does. Unless someone has a better explanation for that zip tie, its presence seems just as critical as the lack of the bolts in the same pic. If you are the first to spot it, NTSB needs to reassess and determine if your scenario has merit.

[@beo2009]

Just commented the same

[@DLWELD]

Good points, uplift springs meant for 150 lb door, not a 63 pound door - zip tie used to hold door down in place temporarily. All looked fine - cover it up. One zip tie.

[@T_Mo271]

Agreed, and the zip tie is a lot easier to see in Figure 16 in the prelim report. Figure 14 also shows that at least the top two bolts were installed before the rivet repair started.

[@donnaw9040]

I found myself lol on the floor with this comment, shared with many😂

[@CaptVirtual]

So lucky this occurred at this altitude otherwise this would have been a very sad tale indeed. The Pilots, FA's, ATC did a great job.

[@paulsherman51]

So did the FA in Naples, FL with keen knowledge and quick thinking of that escape hatch door; the pilots, posthumously, of same aircraft getting it down as safely as they could; and the two crew making most amazing glide onto a New Hampsire highway -- the "I-Hop Approach" Sure, there are risks associated with everything, but there are -- and will always be -- more angels than risks.

[@Airsally]

When ever we remove a panel we had to inspect, tag it with as good to reuse. And bag any fasteners,and counting bolts nuts and washers . And attach the tag and bag to the removed part. Yeah it's extra work. But that was our procedure. At Northrop Grumman flight test. You can't be too careful, and always had an inspector ck our work.

[@mikebarushok5361]

That, or some variant is pretty universal. It's possible that due to too many times that personnel didn't look hard enough and just put in new hardware that Boeing specifies loose parts to go to a staging area and the location noted instead. But, Boeing employees didn't do the rivet rework, because it was done by on site Spirit employees as warranty rework. And, very crucially, Boeing doesn't allow vendor employees access to the (computerized) system where the equivalent of 'removal' would be written up and (as you know) a step called 'OK to Install' and another called "Installation OK" would create sign offs and inspect points. It's my understanding that the Spirit employees working on site in Boeing Final Assembly have to use a different system that isn't intended for much more than shift status reporting and scheduling.

[@jonb8166]

In the original NTSB report, it is pretty clear there is a zip tie holding one of the pins to its pad. That suggests that somebody knew that something was needed to keep the door in place against the force of the springs pushing it upward. "Darn thing keeps sliding up, let's zip tie it until somebody puts in the bolts." That's about as smart as installing your car's wheels with the lug nuts loose, figuring somebody will remember to come back later and tighten them.

[@Bitterrootbackroads]

Agreed. I’ve yet to hear from anyone familiar with the pressure of those lift springs. If gravity keeps the door closed why would someone secure it with a zip tie? If mechanics are used to a closed door being a bolted door, they may also know that an unbolted door will slide up & open on its own? Curious that NTSB makes no mention of the zip tie. Did they not see it? Or do they consider it a non factor?

[@davidkranz9990]

As a former operations manager on the 787 production line in Charleston South Carolina I can tell you that the Wi-Fi installation is done on a platform that goes over the fuselage from the wing. Usually that does not require entry into the airplane through any of the door plugs or doors on the 787, however if entry is required to fish the cables through the fuselage, it would be unnecessary to have a plug door opened and a paperwork nightmare for access. You simply would use one of the main entry doors already open. This is especially important not to not disturb any seals unnecessarily because the next step will be to pressure test the fuselage to check for leaks (again, this is how it’s done on the 787). Access to the Wi-Fi gantry on the 787 was done by climbing on the wing and then using the ladder and platform on top of the gentry to access the upper fuselage. it over the wing and then climb the gantry and then on top of the airplane. Some of the time, travel work from vendors, the technicians and quality inspection teams will travel together to complete the work and sign off on the vendors documentation. Since the travel / rework is completed back to design configuration,since not necessarily required unless Boeing had an inspection check between leaving the vendor and then the interior sidewalls are installed. Travel work is common to fix Nonconformance work. Most of the time Boeing doesn’t have the engineering drawings to do the work. It is possible that Spirit considers the drawings proprietary. However, it’s possible for Boeing to request vendor drawings engineering for a particular part or assembly to xix the Nonconformance themselves. These engineering drawings are only good for 72 hours from approval. Since I no longer work at Boeing and I never worked on the 737 program it is possible they have the drawing information and the ability Complete the nonconformance themselves.

[@weldonyoung1013]

Make me wonder why Alaska Airline didn't at least run a pressure test after getting many alarms or falts. But that doesn't dismiss Boeing's complete disregard of manuals.

[@Rangerfan41]

Disregard of what? @@weldonyoung1013

[@davidkranz9990]

If memory serves me right, a certain percentage of air loss is aloud. I was never part of that production test so I don’t know how much. My guess is that a static test inside a factory without the vibration or continue wear on the fittings during flight might have something to do with it or the plug door was removed after test was completed. There should have been constraints to require retests but where talking vendor travel work. Please understand, I never worked on the 737 program and have no first hand knowledge of work completed or processes used. Just a former manager of the 787 program with general knowledge of processes and practices used.

[@cliffmathew]

This despite the fact that the whole idea of Wi-Fi is being wireless.

[@davidkranz9990]

@@cliffmathewYou still have to run power and fiber optic to make it function

[@robertfraser9551]

This is looking increasingly like a handover problem. Boeing and Spirit working their own NCR's and a second shift handover. If the disposition instructions were to remove and later install the door per AMM 53-..... a specific task for bolt removal, bagging, labelling, storage etc and one for the reinstallation, may not have been required (i.e the AMM standard practices are called out as accompanying the detailed door instructions. ) The second shift could have been led to believe the door reinstallation had been completed and their work content was just the interiors restoration. The QC system has very well developed handover processes embodying the lessons of decades of experience and the subject of continuous improvement. So this occurrence has somehow slipped through all the gates! Lot more of this story to go !

[@HaroldBrice]

@robertfraser9551 Absolutely correct Robert! See the information in the NTSB prelim report. They have a picture of said door on said airplane showing bolts not installed and attached to an email discussing the fact. Heads will roll. Handoff problem, fumble, they dropped the ball and could have been much worse that it was. Take it to benefit us in the future.

[@mbvoelker8448]

You nailed this from the start. Two "No excuses" points. 1. The cockpit voice recorder. Don't you pilots train on pulling that circuit breaker after bringing an emergency plane to the ground in the simulator? 2. The interior finishing crew. In my factory work I was RESPONSIBLE for not passing any errors from previous operations through my position. I was required to hand back any detective product rather than continue the assembly. No way the finishers didn't see that something looked weird about that door plug when they looked at it to determine what they had to do.

[@gmpltd114]

Thanks Juan. When is someone going to suggest that it is way past time that the FAA got audited as well, aren't they supposed to have oversight of maintenance standards? Greg, New Zealand.

[@Paul1958R]

Juan, Thank you for this! A big shout out to Chris Brady (The Boeing 737 Technical Channel) who also did an indepth YT video on this NTSB prelim report. It was pointed out that you can see in the NTSB report figure 16 (pg 17 of 19) that there is a tie strap installed around one of the stop fittings/pads (lower right, clearly visible if you download the report pdf and zoom in on the pic) which may be all that kept the door from opening/falling off much sooner that it did. It would be interesting the know whether installing that tie strap is 'standard procedure' to hold the door plug in place until the retention bolts are installed. The tie strap is not mentioned in the NTSB report. ps Im curious how much precip you got at BWHC in the last precip event? Paul (in MA)

[@GeneralDesignInnovation-es4zz]

The pristine paint confirms that the bolts were not there even before the rivet rework. That also explains why there were no "leftover" bolts. The techs who removed the door for rivet rework did not have to remove any bolts, so they would not expect to need to put any back.

[@oldcynic6964]

Yes, I was thinking that too. In my dumb mind it says that the door plus left Spirit (not the Boeing factory) with the bolts missing. But - as others have said - if the guys doing the work at Boeing had gone by the book, they would have found an instruction that said "Now replace the four bolts...." And the inspectors would (hopefully) have found an instruction that said "check all four bolts are in place and torqued to "

[@T_Mo271]

Figure 14 in the prelim report (showing the pre-repair location of the bad rivets) shows bolts in at least the top two fittings. Those holes clearly look different than the same top-right hole in Figure 16 (after repair).

[@andyloebrown8250]

​@@T_Mo271 You are right ! In First pic, sure looks like there might be a bolt tip with nut in view.

[@jamescollier3]

I'm confused. Who puts the door in? If Boeing did it, wouldn't there be a record with details down to the 15 minutes including names?

[@omgsrsly]

In the picture with the tape strips you can see the bolts installed, though. It was taken before the repair work on the rivets started.

[@paulbervid1610]

Thank God no one was lost in this incident. Great video Juan.

[@andyb6622]

I am not surprised about stuff with quality issues... I work at a huge machine shop.... And alot of dingle berries dont give a hoot anymore about taking pride in what they do.

[@geofiggy]

JB, a picture is worth a 1,000 words, and as with you, my motto is "Data Rules". Thanks for your time and resources. Take care and fly safe. 🤟🏼🖖🏼

[@georgeforall]

Thank you to the Captains and FOs that take care of the passengers and the FAs! You are appreciated!

[@poppyrowland1385]

They don’t want to die either…..🙄

[@georgeforall]

@@poppyrowland1385 Always one like you 🙄

[@bigdaddie40]

Juan, the 737 does have CAT3 autoland. You just have the additional capability to hand fly a CAT3 approach via the HUD. It is sporty, especially in the flare. Myself, I would prefer a 3 axis autopilot (the 737 has 2) and an additional autopilot like the 757/767. The HUD does allow very low takeoff minima.

[@TSKseattle]

The door surround structure is pretty substantial. I don't think the loss of the plug would have failed the structure. The door itself is not Primary Structure and would not carry any load, so losing it would not transfer load to the plug frame.

[@MrShobar]

Agree.

[@800fmoore]

Thanks!

[@cheesenoodles8316]

I rarely fly, but it is never lost on me a very complex machine made of lightweight materials going very fast. My Dad was an aerospace engineer and I worked at a high tech composit plastic aerospace manufacturer. There allot of interactions, human and mechanical that must be correct. Juan is a great resource

[@KevinBalch-dt8ot]

It’s the interfaces where the ball gets dropped.

[@Raelven]

My dad was also an aerospace engineer. On my birth certificate under "Father's Occupation" it says "Space Tech". I've always been really proud of that.

[@roflchopter11]

17:29 I'm an engineer, but not structures like this. If those door stringers were to take tension/compression loads, like they would see due to bending of the fuselage, the force would have to get to them through the friction of the stop pads or hinges and the pin and track, which seems highly unlikely. So I don't think they are structural in that sense. The bulkhead that forms the left and right sides of the door frame, and the stringers that form the top and bottom, ate likely the loaf paths. Fuselages are very well built. Remember that mid-air in the past year where an aircraft landed with something like 40% of the fuselage circumference missing? Very robust. Especially because they need to survive high loads in turbulence and heavy normal acceleration.

[@duanelundgren7985]

I'm not an Engineer... but the bulkheads adjacent to any door carry the structural and pressurization loads at all times. Without damage TO the bulkhead(s), the absence of a door doesn't, in my mind, cause the bulkheads any additional stress.... If a departing door rips a chunk out of a bulkhead, yeah, then all bets are off. Failure to meet Type Design is problematic!! Thanks Juan!!

[@markcalhoun8219]

yeah I think that was the risk, if the door ripped loose one of the bottom hinges damaging the bulkhead due to the extra force. That or the door hitting the tail section.

[@brianfhorton]

I am an aircraft structural engineer and these bulkheads, longerons, and stringers are designed to carry all flight loads as if the door is not installed. There is no risk of fuselage structural failure from a door departing the aircraft. The only risk is the door hitting something and causing damage.

[@markcalhoun8219]

@@brianfhorton oh sure if it just blew off, but if you look at the craft, the hinges which remained attached were rather bent, there's a hypothetical where they were ripped off with the door and those hinges are secured to the bulkhead presumably. There's a shear load eventually that rips the bulkhead no? Also yeah the door hitting the tail section could be bad, especially in a MAX.

[@jdencook]

Thanks for your dedication Juan especially after a long flight. After a plane accident you’re the one we want to hear first.

[@fredcanavan3864]

Nice job as usual, Juan. As a C141 crewmember in the 70s and 80s I went to altitude chamber at Andrews and Shaw. You may have gone on the West Coast. If you remember, when they blow the chamber at about 20,000 feet chamber altitude, the cushions under and behind you instantly inflate throwing you up and forward slightly. I believe that’s what happened to the crew in the cockpit.

[@thomasrapp2536]

Juan, you called it I the first video you did on this incident. NO BOLTS. You as a A&P had a very clear idea of what happend, unlike the MSM crowd. Keep up the great and truthfull reporting you do an all subjects.

[@danielcgomez]

my neck hurts ...from shaking my head. Thanks for the update Juan, It is much appreciated.

[@cheddar2648]

Off topic - fresh report of a twin jet downed near west coast of Florida. Double engine failure. Attempted emergency landing on a portion of I-75, but collided with a car and caught fire. Initial reporting was five on board with two fatalities. Three were able to escape the blaze.

[@pigdroppings]

A lot of videos on KZbin

[@pigdroppings]

There is a video on YT of the 3 survivors RUNING out of the plane.

[@GhettoWagon]

I-75 in FL is getting wild. Used to be on that part of the highway all the time

[@mikebarushok5361]

Challenger 600

[@pigdroppings]

The pickup driver, wearing a yellow shirt, was out of his smashed truck and walking around after being hit by the plane. He was taken to a hospital for observation.

[@DougGrinbergs]

1:45 New York Times door plug animation 4:08 door plug from Spirit Malaysia installed at Spirit Wichita

[@seriatim8527]

Just a minor correction. The somewhat elaborate design of the plug door is to ensure that it DOES NOT transmit fuselage loads, but only reacts the radial load due to pressure differential.

[@GH-oi2jf]

Regarding the seats closest to the opening, I have read that they had been booked, but the ticket holders were no-shows.

[@JeffCowan]

Juan, I flew into Portland that night on a later flight from the big island. Alaska 737 Max. There was moderate turbulence and wind shear between 3000 and 6000 on the way down. It might have been a factor for 1282, shaking the door loose. That's about the altitude they lost the door if I recall. Edit: i see now it was 16000. Still, possible factor.

[@kaspju21]

Wx was mentioned during one of the NTSB talks. They talked about rough weather in the area. While not the entire reason why, it certainly is a factor here.

[@css0076]

As a 20+ year A&P Mechanic, instructor, and inspector...this is a case of "undocumented maintenance ". Spirit Aerospace and Boeing need to remember the 18" rule and put EVERYTHING on paper......nothing is insignificant.

[@craigsowers8456]

Better you than me flying to Sydney ... long time in the Saddle Juan !!! As stated in my first comment on this series, would have been easy for NTSB to note lack of scuffing on the inner barrels of the 4 bolt holes on-site. But this appears to be a joint Spirit and Boeing QA escape ... AND the build mechanics too ... "Everybody is responsible for Quality" !!! Would first look at who stamped off on the bolt installation at Spirit (not installed ... big miss) and then the Boeing rework crew/QA AND "Production Planning Dept." !!! Planning is "supposed" to compare original build design to prepare their rework planning ... like "Remove 4 Bolts" ... when the mechanic read their rework planning, should have been first clue the bolts weren't there !!! OMG But guess all this BS with "DEI" is coming home to roost. Pity. P.S. ~ How the hell did those mis-formed AD rivets pass first inspection at Spirit before being shipped out ??? Question for the sub in Malaysia AND Boeing's QA that's supposed to be there overseeing the operation (Procurement QA) n'est ce pas?

[@cjmillsnun]

The bolts were fitted by Spirit in Wichita. They were removed in Renton. The first picture that shows the faulty rivets shows the bolts installed. And stop with the racism/misogyny We don't know the gender or race of the people who missed putting the bolts back in. DEI has nothing to do with this. This goes back to the basics of aviation. Someone should be signing off to say that every bolt has been checked.

[@michaelsturtevant7707]

I grew up in an aviation family. My father flew fighters in WWII & enjoyed 31 years with TWA during the golden age. Retiring as a 747 Captain in 1982. I remember all of the incidents & crashes we had back then. While these incidents are unacceptable & troubling, we have been blessed to have such a good safety record in U.S. aviation since 2009 Let’s pray that these issues are addressed & we continue to have the safety record we have enjoyed. Juan, Thank You for your leadership in accurately briefing all of us on these incidents on this channel.

[@ooshie1000]

Thank you Juan. Excellent analysis. I keep thinking of this substantial piece of structure leaving the aircraft at 280 kts and striking the horizontal stabilizer. Game over. So much luck and skill involved in a successful landing without loss of life.

[@Sugah_J]

Juan, just a technical note. At Alaska Airlines, they can do a CAT III auto land with and without the HUD. With the HUD, what they call a hybrid approach, the minimums are much lower (usually 400 RVR) than the 600 RVR required for just a standard HUD only approach.

[@kenmercer2721]

Fascinating how the air from the back of the fuselage rushed forward, bending seat 26A forward, and the forward air rushed backward bending seat 25A back as it exited the aircraft. Lucky the seats were unoccupied. Also really lucky the plug didn't damage the rear stabiliser as that is probably the more likely scenario leading to a total loss.

[@Charles802]

Actually, based on prior reporting 25A was occupied and the boy sitting there lost his shirt.

[@Elizabeth-tg7jo]

My hair stands on end anytime I hear an update on this. So close. Also, I live in AK. Flight attendants are not there to serve you drinks. They are trained safety officers.

[@johnscott5105]

Just shows how important it is for people working on these planes to be attention to detail oriented as to go over their work properly or have someone else do a inspection.

[@peterredfern1174]

Another great update on this incident Juan,now go and have a siesta mate,safe flights as always ,😴😴👏👏👍🇦🇺

[@matthewbeasley7765]

I hope that you're able to do an interview with these pilots some day. The interview you did with the captain of the United flight into Honolulu was incredible. I think this interview would be similar. Losing 5PSI through a door sized hole has to rank up there as one of the most violent depressurizations that an airplane has come back from. I image their first thoughts were along the lines "Is this airframe going to stay together?"

[@WayOutWardell]

I was flabbergasted when I saw that door photo in the report. Absolutely shocking.

[@MADHIKER777]

Proves that the whole is only as strong as the weakest link. Thanks for the detailed explanations, Juan.

[@NicolaW72]

Thank you very much for this Review of the Preliminary Report - and especially for pointing it out so plain clear: It was tremendous luck that this doesn´t became the third Hull Loss of a 737 MAX! Indeed a great Job by the Pilots!

[@EvDelen]

Contemporaneous reports from passengers was that they felt turbulence and a large bump before the MED blew out. It's likely that it was seated properly, although not secured to prevent vertical movement, but because it wasn't secured it became unseated and blew out. I doubt it would have been able to blow out at altitude given the forces pushing on the door to keep it in place. This happened because there was turbulence at just the right moment, when the door wasn't fully pressurized but pressurized enough to blow out.

[@Ice77Pilot]

Alaska does CATIII autolands in the 737. The HUD allows lower minimums than with the autoland alone.

[@AzzaTheGreat]

Amazing. I usually have a few screws and bolts left over from IKEA flat packs, it usually crosses my mind as to where these go.... I wonder what the person thought when they had 4 bolts left over after they finished putting the door back together ? So strange.

[@mudi2000a]

IKEA often puts too many screws or bolts in the bag. So certain parts are leftover most of the time. That’s why I count them and take away the superfluous ones before.

[@charlesferry2092]

please try to find out who is holding those bolts!!!!!!!!! find those bolts and you find out who is the weak link in this chain of events. i want you to be the next head of the FAA.that department would learn from you exactly how to straighten up and fly right. juan.....YOU THE MAN!!!! THX

[@davidsouthworth6246]

as the aircraft was on light duties due to pressurization issues, i'm going with the "door hanging on a thread for a while" scenario.

[@richardgraham1167]

Having the actual door plug, available to fit back into the side of the fuselage, is a great forensic resource.

[@k9er233]

Yes, there are a lot of areas south of the airfield where the door might have never been found. Landing in a suburban yard was fortuitous.

[@WjaKitch]

No mention of that plane's previous flights that exhibited cabin pressure abnormalities. They were reported but presumably not further investigated. It's possible this issue had been looming for sometime and possibly degenerating flight after flight. That inspection procedure needs to call out these plug door inspections. The problem for the carrier means that aircraft would be removed for quite some time for disassembly and inspection.

[@Thegonagle]

And pressurization errors need to be taken seriously, not assumed to be a “nuisance” or glitch to be reset and hope it doesn’t come back on the next flight. Because guess what? The error came back.

[@88Amps]

Absolutely fascinating and terrifying in equal measure. The flight crew was unaware that the cockpit door is designed to open in such a depressurization event. The backup is the pop out panels, but they all thought the panels were primary. The checklists flew away (except apparently the abbreviated form). I greatly appreciate what I’ve learned here (though I may go back to thumb-sucking on my next flight).✈️ TYSM

[@tirshk]

I caught that too, about the cockpit door. I was under the impression those doors were impossible to breach.

[@bruces3613]

He never went into details with me since I was very young but my father had both eardrums blown out from cockpit depressurization during USAF jet training. He landed with blurry vision, blood running down from both ears, and pain like his head in a vice.

[@MG-do2uq]

A C-141 had the aft cargo pressure door fail at 41,000 feet if memory serves, with a lot of interior panel damage but not structural and the aircraft landed safely. Happened in the early 80's possibly late 70's.

[@JohnSmith-yv6eq]

Aft cargo door is an opening door anyway so there will be a large frame right round it???

[@brianfhorton]

20 year aircraft structural engineer here. The fuselage structure is designed to carry all flight and ground loads without a door installed. This includes rapid decompression load cases. The only loads a door carries are its own weight and the cabin pressure directly acting on it. There is zero risk of structural failure from a door not being in place. The greatest risk to the aircraft as a whole from a door departing in flight is the damage it could cause by striking other parts of the aircraft.

[@HaroldBrice]

@brianhorton: Your comment is labeled "two days ago -edited". I wish I knew exactly what that means...Thank you for your comment. Can you explain exactly about what the pressurization does in terms of physical load? Will you please. I feel a pound of pressure is a lot of force but I am not sure how it is applied mathematically to an aircraft fuselage. I know I can hold my thumb on a garden water hose and stop at least 20psi so I am wondering about the action of 5 psi on the airplane. Over.........

[@aeromoe]

Thank you Juan for another great video on this topic. Learning more about those door stops with each vid. Buddy of mine flew aboard N704AL on 28 December 2023 PDX-PHX...I picked him up at PHX after arrival. As an avgeek I've photographed a LOT of planes over the past 45 years...including this one...arriving at PHX with my buddy aboard it. Boeing sure dodged the bullet on this one. Recovering that door in the Portland backyard was so fortuitous in this case. As you say had it occurred at altitude with potential total loss we'd likely never know the cause and probably not even suspect the missing plug door bolts were the culprit. Safe travels!

[@big_beak]

You may want to provide NTSB with your photo. Chances are the photo won't show anything amiss, but you never know - it just might.

[@patmcdermott4832]

@@big_beak I think the photos were from the NTSB report as shown on Chris Brady's channel.

[@HaroldBrice]

To @aeromoe: Nobody knows what would have been the result if this plane had been up higher. I refer you to the Hawaiin Airlines 737 back in 1988 I think it was. A flight between islands but it was still up at 24,000 feet when a large section of the roof forward of the wing left the aircraft. One flight attendant was pulled to her death. Numerous other injuries. The plane landed with no further complications. So I am guessing this Alaskan plane would have stayed together and landed just fine.

[@aeromoe]

​@@HaroldBrice​ Yeah it's hard to say but the Aloha Airlines 737 incident you refer to sure spoke volumes about the effects of many cycles imposed on airframes utilized on many short-distance sectors a day,

[@Shoulderdevil2023]

Amazing analysis Juan. Shows just how important Quality checks are on life threatening mechanisms, and how absolutely significant it is to have accurate checklists in place. The individual on production line and performing maintenance and inspections need to be reminded their own family could be affected as a result of negligence

[@AaronShenghao]

12:07 If Boeing's corner cutting haven't gone crazy, the structure should withstand it. Especially after what happened to that Aloha 737. 17:36 One thing us Engineers learnt after the DC-10 and 747 cargo door troubles is: Make sure when a door opened and blown out during a flight, it shall not damage the aircraft structure or control systems, such damage can and have lead to a fatal accidents in the past. This is not a Engineering defect, rather it's a poor QC and manufacturing defect. How can someone forgot to put the bolts and Pins, then whoever did the QC didn't spot it is beyond me.

[@alschafer4292]

One of the worst things you can see in a job order are the words "Gain access to". Ther may have been a work order to rivet an area that required the door to be removed. There was no specific work order to reinstall the door. Seems it was just considered to be part of the riveting process. A complete abandonment of a coordinated QA system & oversite between Boeing & Spirit.

[@JohnSmith-yv6eq]

It does not specify if the Spirit rectification crew working in the Boeing plant to rectify the rivets were THE ONES responsible for reinstalling the door.... and the bolts.... or who was responsible for the inspection and signoff re same....... Funny that...

[@Bitterrootbackroads]

I forget which video mentioned it, but it was pointed out there are different inspection procedures depending on if the door / plug is “opened” or “removed”. An ordinary exit door may not need inspection after a simple “opening”, but most likely would after being “removed”. I sense a disconnect between management, sales, accounting, engineering, manufacturing, QA, maintenance manual writers, and the mechanics who actually work on the planes. Somewhere along the line maybe someone got confused about what they were dealing with? Is it a plug, a door, a door plug, or a plug door? Commenters have argued endlessly over the terminology and the consequences of getting it wrong. Maybe someone wrote a procedure for a “door” instead of a “plug”, and someone else followed that procedure? In any case, to either “open” or “remove” the thing that blew off this plane, the 4 locking bolts need to come out, so the QA needs to be the same. If you get an organization full of people who just follow orders, do their job, cover their ass, and react to constructive criticism with “you’re not the boss of me” they will do all kinds of things that don’t make sense. The Swiss cheese holes all lined up, and here we are.

[@JMChladek]

The physics of the motion pushing the captain into the HUD might have something more to do with the pressure difference escaping the open door plug hole. When that door comes off, it becomes almost akin to a rocket thruster on a spacecraft puffing. Given where the door plug was on the fuselage and the orientation of the plane in it climb, I could see it causing a movement in the forward cabin. FDR analysis of the flight instruments might show if that was the case. If that door plug ripped off starting at the top, it could have pushed the tail down and the nose up, forcing the captain's head down and forward into the HUD. Boeing and Spirit are dang lucky that all this is is "embarrassing".

[@torben777]

Good point about the empty seats. Statistically it is extremely unlikely that with only 7 emply seats out of 184 seats, both seats closest to the door seals woyld be empty. This also makes me wonder if something was noticesable on the inside (noise?) that made the passengers or the stwardesses avoid to fill those 2 chairs.

[@4af]

Another commenter pointed out: "According to an article in the Seattle Times, passengers on a prior flight reported noises eminating from the area of the door plug to the cabin crew who in due course reported it to the pilots. Supposedly the pilot(s)checked instruments, found all normal and no further action was taken."

[@andrewjackson5127]

Best animation/illustration of the mechanism I have seen. Awesome! I believe the door popped at 14, 000 feet and they continued ascent to 16,000 following the door departure before their emergency descent.

[@Tomxman]

Well that’s only 35-45 seconds of time. And there’s a big rock near the flight path - Mt Hood 11,245 ft

[@hisnibs1121]

Door popped at 14,830 ft and 17:12:33. 1 minute 8 seconds later, at 17:13:41, the plane reached 16,320 and began to descend . (See vid at about 15:50 to 16:30.)

[@Thegonagle]

First, they’re just flying along like they’ve done for years, doing routine operations, thinking routine thoughts. Then BANG, something happens, they’re startled and at this point it could be anything-a bomb, a midair crash, the damn thing broke in half, anything! There’s weird physical sensations, waves of air pressure, ear-popping pain, sudden temporary deafness, etc. Now, they gotta take a few seconds to realize first and foremost they’re alive, and a few more seconds to realize they’re in a real emergency and to switch to emergency training mode. Then they need to realize that, OK, at least they’re still flying and not falling out of the sky, but they still need to check the alarms that are undoubtedly going off, then understand this is a sudden loss of cabin pressure emergency. Then they need to unstow their O2 masks and put them on along with their radio headsets that had fallen off during the bang. They now know, as every pilot would, they need to descend to the magic breathable 10,000 ft ASAP, but first they need to be sure that they can do so safely because they’re next to a mountain range, still within potentially crowded airspace, and they don’t yet know what’s broken and what still works. Therefore they need to find their checklists, which were suddenly blown all over the cockpit. Then, with ATC blessing, they can descend to 10,000 knowing no other aircraft are in their way. Given all that, they did great.

[@hisnibs1121]

@@Thegonagle Very well put. Amazing that the crew (and the training they'd been provided with) coped so well and so quickly with such a startling, confusing and very dangerous situation. (I wonder whether they'd even found out what had happened in the minute before the descent started.)

[@savagesteve5894]

Missing bolts is exactly what i mentioned in the original video you publicized. The pics u showed in your 1st video showed zero deformation in the door tabs an obvious sign that instantaneous decompression just blew the door clean out. The lower door compression spring strength eventually gave way. Glad nobody was unrestrained sitting in this window isle. great channel keep up the commenting fellow aeronautical engineers

[@HaroldBrice]

Yeah @savagesteve5894, I am going to have to go ahead and ask you to consider what the springs function actually is in this design we are discussing. The springs are to help position the plug in the correct position so the seal will fit properly and seal correctly. And to keep the door plug in the correct position for the duration. The springs will ensure the plug door does not move around, rattle, or otherwise misbehave. Kudos to whomever designed the dang thing in the first place. It apparently stayed in place (without the bolts) for quite a while. Sorta like shifting my 1946 Ford Ton and a Half without depressing the clutch (and not grinding those old square-cut gears). Disappointed someone(s) dropped the ball on this and super glad no one was injured.

[@realulli]

I don't think the airframe would have come apart like you described if the blowout had happened at cruise altitude. The reason is, the plug is under no tensile load, except the loads it carries internally from the air pressure. It's not carrying any load between the sides of the frame, it's just sitting on the stop pads, doing nothing but keeping air in. The only thing that might get damaged is a bit of skin around the door, but both bulkheads and stringers are designed to hold together plug or no plug since they can't depend on the plug to transmit load, except for pressing outwards on the stop pads. What might cause damage is the pressure differential becoming negative after all the air has rushed out, but I don't know how much of a factor that is.

[@_HMCB_]

The kid was actually sitting in seat 25A according to reports. I believe it was the two seats in the very row the door was in were the actual unoccupied seats.

[@PurpleCatAudio]

Juan, Great content! Much more alarming to me is the fact that the hardened cockpit door opens on depressurization... doesn't sound very safe if someone wanted to gain access and knows how all this works.

[@stuartatkins5425]

Boeing sure got lucky! Another great job of explaining this to us. Thank you.

[@davidzachmeyer1957]

Juan, the young man whose shirt was blown off was seated in 25A. Seats 26A & 26B were unoccupied.

[@georgedreisch2662]

For potential material fatigue over time, resulting from the locking lugs working progressively out, for the lack of the AN-6 locking cross / shear bolts, it’s probably fortunate this event occurred, sooner then later, as I’m thinking it could have resulted in a catastrophic failure of the frames adjacent the plug, and consequences of that.

[@MoMadNU]

What was lacking was "procedural continuity" This is where whatever you are working on cannot exceed a delta time limit to complete. So in this case, you would not have been able to set the door in place and then 3 hours later install the bolts. The entire procedure would have a delta time of 1 hour, which cannot be interrupted. Log entry start/stop times would have to indicate that it was completed under max delta time. If this process is already in place, and they are not following it, it's only a matter of time before the next big one happens.

[@NatalieMcDonnell-h9f]

Reference : Bolt witness marks:If the bolts were initially installed by Spirit ,should there be at least a witness mark inside the bolt hole or on the outer face from the washer? Seems TOO pristine....Do you know why they just don't PERMANENTLY fit a panel in this section , if it's designed never to probably never be opened during its lifetime, and Boeing advises customers that retrofitting an emergency escape is costly, I don't see rhe advantage of this design?..Lastly, the graffiti on the window, any company I worked always treated this behaviour as a sign of poor professionalism and low morale, perhaps confirming the atmosphere in Boeing workplace?...EXCELLENT analysis, as always, you give a great insight on all your videos, I learn a lot..THANKS. 🤓

[@lizj5740]

Reminds me of the graffiti on a blackboard shown on a cover of a Bechtel Corporation company magazine: the old light bulb turned into a rude picture. The mags were placed on employees' desks in the a.m. and retrieved (all of them?) by the afternoon.

[@cjmillsnun]

There were witness marks indicating washers had been fitted, washers need bolts so they must've been fitted too. Also the picture identifying the faulty rivets shows all 4 bolts in place.

[@Merv-Bob]

Super good report, with NO 'Hair-On-Fire' nonsense. Cheers, Mark

[@Larpy1933]

This is wonderful - answering all my questions and many I hadn’t thought of. Juan: Thanks for taking one for the (Patreon) team in making this so quickly and with such rigour. It occurred to me today - after watching you for years - that your clear thinking, succinct speech and critical reasoning gives me hope for humankind. Plus: I learn a lot. A LOT. Thank-you and good luck! (Victoria, BC).

[@mikeschultze3135]

Juan, I cant thank you enough for a highly detailed report on this Door Plug. Boeing has alot of explaining to do. I beleive the FAA needs to do daily audits of the entire assembly line. The CEO needs to be replaced. The workers need full protection from filiing unsafe working practices. A whistle blower form sent to Boeing and the FAA. Many years ago a entire top of a Boeing 747 blew off and sucked a flight attendant out. I recall this was in Hawaii. Boeing was very lucky passangers didnt get sucked out or complete loss of control of that Boeing 737 Max.

[@rael5469]

6:12 On the topic of the rivets being reworked......I even wonder about THAT aspect of it. They pulled the door seal out of it's retainer to access the rivets in question. This tells me that those rivets are for the seal retainer channel. Well when looking at all of the rivets on the other side of the frame where they marked them as being defective.......the "buck tails" of the seal retainer rivets WILL look smaller than the surrounding rivets. They might have flagged those rivets as being under bucked by mistake. I've seen it happen before. You have to go get the inspector and point this out to them so they will buy off their own write up as "No Defect Noted" or whatever. Also, even though it is the higher factory standards.....believe me.....ANYTHING that fills the hole of a seal retainer is going to stay put for the life of that aircraft. It's not a structural component. I've seen an aircraft 20 year old with an intercostal glued in place with piloted rivet holes but they were never drilled to final size or had fasteners installed. Flew around like that only glued in place for 20 years. Believe me.....these airliners are VERY overbuilt. Built to last. As long as a fastener was filling the hole on that seal retainer......ANY fastener.....it wasn't going anywhere for the life of the aircraft. They probably never needed to rework those fasteners at all. It's just a seal retainer. I say this because any mechanic or inspector has to look at things realistically. The fact is that the more mechanics touch an aircraft the more damage they do....and this is a scientific fact. So bottom line......being too picky about non-structural rivet bucktails could....and did....induce more damage than it was worth. Seal retainer? Rivet fills the hole? Walk away. Don't get me wrong....the rivets have to be tight. If they aren't tight they WILL chafe and fall out eventually. But as long as they are tight....and fill the hole.....leave them alone. What if you are reworking them down to spec and make a scratch on the main frame? Was it worth it? NO ! When I worked for a Boeing subcontractor we watched a Boeing video on quality. Boeing told us, "The customer is buying a new aircraft, not a repaired one."

[@MrWolfriver]

Welcome home JB. Thanks for getting such thorough report so soon off the stick. Top quality as usual.

[@gordonslippy1073]

Great video series on this incident. Now that we're all experts on door plugs, I'm concerned about the myriad other items that are much less visible and more technical, such as wiring and hydraulics. TWA 800 comes to mind, with its chafed center tank wiring.

[@budm9982]

This is absolutely amazingly detailed information. I don’t know why this incident captured me so but I’ve been following it through your reporting since the beginning. Good job Juan.

[@elizabethannferrario7113]

Thank you Juan . sleep tight , appreciate your video very much knowing your very tired.

[@AwestrikeFearofGods]

14:48 Taking the captain's report as fact, that's a tough one to explain: 1) Even at a minimum weight of 156,500, the plane would be subjected to a modest and rapidly-diminishing rightward lateral acceleration of only 0.06g, assuming the door instantaneously disappeared, for maximum leak rate. The location of the plug at the left rear (behind CG) of the aircraft indicates that the yaw acceleration would be left-turning. These two accelerations are opposite, but unequal, at most distances forward of the aircraft CG. They are negligible and in the wrong direction. Assuming the captain's seat is 50 feet forward of the aircraft CG, 1 g of centrifugal/centripetal acceleration (pulling the captains head forward) would require a yaw velocity of 46 degrees/second. Therefore, we can safely rule out acceleration-related phenomena as the cause. 2) Upon explosive depressurization and failure of the flight-deck door, it's obvious that airflow at the flight-deck-door opening would be aftward. What's not so obvious, is the direction of airflow at other locations within the flight deck. One can imagine forward airflow at some locations, analogous to forward airflow outside of a stationary (but powered) turbofan nacelle and bell-mouth inlet. Desk fans too.