Better Things to Talk About.
January 8, 2024
POOR ALASKA Airlines. There they were, leisurely mulling the finer points of their merger with Hawaiian, wondering which visage to paint on the tail, when the 737 MAX-9 stole the show.
Pop went a fuselage plug on flight 1282, decompressing the jet and scaring the daylights out of everyone on board. The plane landed safely, but now a number of MAXes are grounded as regulators focus on attachment bolts.
The MAX can’t catch a break, either. This is the plane that spent two years on hiatus after the crashes of Lion Air flight 510 and Ethiopian Airlines flight 302, until its twice deadly stall-avoidance system was redesigned.
It looks bad, I know. Particularly for Boeing. But this is likely a lot more minor than the media spin suggests. I expect the plug attachments will get some sort of do-over and the planes will quickly be up and flying again.
A jetliner is pressurized so that its occupants can breathe without the need for supplemental oxygen. If the fuselage is breached, that squeezed-together air rushes out. The pilots will don oxygen masks and take the plane to a lower altitude in what we call, plainly enough, an “emergency descent.” The sensations of this drop might be alarming, but it’s an easy and straightforward maneuver.
Rarely are decompressions deadly. When they are, it’s usually because it happens explosively, such as when a bomb goes off, causing massive structural damage. In the Alaska incident, the big danger would’ve been the door plug colliding with the tail structure. But this didn’t happen, leaving the rest of it pretty routine.
I don’t mean to sound blithe, but it’s amusing how much attention this mishap is getting. One of the biggest news stories of the week is about a decompression in which nobody was killed or injured. The track record of the MAX, I figure, is part of the reason. A negligible malfunction, or a design flaw suggesting negligence? Let’s hope it’s not the latter, but either way, back in the Golden Age of Air Disasters, something like this would barely have made the papers.
Ironically, the amount of coverage we’re seeing serves to remind us of just how safe flying has become. In decades past, multiple airline crashes were the norm every year, with hundreds dead at a time. We’ve grown so accustomed to near-perfect safety that a minor event, without a single injury, wins as much attention in 2024 as a crash that killed two-hundred people would’ve gotten in the 1980s.
On the other hand, it’s better to be reading about a decompression than about a catastrophe. And it hardly needs saying that this could easily have been more serious. Had a passenger been sitting adjacent to that plug and not wearing a seatbelt, he or she would’ve been ejected. A hole opening up in the side of a plane, regardless of the reason, earns more than a shrug. Even more so if the problem is traced to a design defect or a quality control screw-up. People are skeptical, and let’s be honest, both Boeing and the 737 MAX deserve whatever scrutiny they’re getting.
I guess that’s the real, if obvious issue: It’s less about what happened than what could have happened. And will it happen again?
Incidents like this, and our focus on them, keep us on our toes. I get that. It’s a way of being proactive and careful, so that we maintain the levels of safety we’ve achieved.
UPDATES:
Some of you have wondered why section of the Alaska 737 that blew out was shaped like a door. The number of required doors depends on seating configuration. Alaska’s layout doesn’t mandate a door in this spot, so there’s a plug there instead, attached with bolts.
Meanwhile, a news outlet today asked me why, following the decompression, no announcement was made by the captain. It’s hard to know, but I imagine the cockpit crew was quite busy. There was an emergency descent to perform, as well as the necessary checklists, coordination with air traffic control, etc. Also the pilots would’ve been wearing oxygen masks, which makes communications more difficult.
It’s possible one of the pilots did make a PA but it wasn’t heard in the noise. Or, being as busy as I imagine they were, they may have relayed information to the flight attendants and left it up to them.
As a pilot I’ve experienced a handful of depressurizations over the years. One afternoon I was working a flight from South America to the United States when, high over the Caribbean, came a sudden whooshing sound that seemed to emanate from nowhere and everywhere at once. I could feel my ears popping, and sure enough, a glance at the instruments showed we were quickly losing pressurization. The captain and I put our masks on, took out the book and began troubleshooting.
Part of that troubleshooting involved one of those steep descents. To the passengers I’m sure it
felt like a roller coaster, but everything was carefully coordinated. The autopilot was engaged the whole time, and no limits were exceeded.
Should a pressure loss occur over mountains or other high terrain, pilots will follow predetermined routes, sometimes called “escape routes,” that allow for a more gradual descent, in stages. Even if crossing the Andes or the Himalayas, there’s always the opportunity to reach a safe altitude before supplemental oxygen runs out.
Related Stories:
MARRIAGE MINDED: THE ALASKA-HAWAIIAN MERGER.
THE MAX IS BACK
THE AIRPLANE THAT ISN’T
Photos courtesy of Michael Saporito and Unsplash.
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48 Responses to “Better Things to Talk About.”
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There doesn’t seem to be any record of the work that was done involving the door plug removal and reinstallation. If true, it was unauthorized rework, one of the highest crimes in aerospace manufacturing. 40 years as a mechanic, manufacturing engineer, and finally training instructor makes me suspect 1st shift began this illegal act and got as far as torquing the castle nuts prior to end of shift. Second shift took over and failed to install cotter pins in the castle nuts as they replaced insulation blankets and interior side panels. When the FBI completes its investigation, I hope the responsible parties and their line managers rot in federal prison. This could have been so much worse at 35,000 feet with a near maximum pressure differential and passengers in that row. Resignation of the Boeing CEO, Head of Commercial Airplane Division, and Head of 737 Division were a good start. For God’s sake, put engineers on the board and listen to their professional advice!
Patrick, Don’t leave us hanging! Tell us more about your depressurization outing…and the others.
Hmm… would the door being ejected at FL350 not also take a part of the fuselage from the sudden pressure change?
Aviation safety has come a tremendous long way, but this is certainly a step in the wrong direction, even if nobody died. That door could have also landed on someone and died unexpectedly.
Is there a cruising altitude at which a depressurization of this sort would be dangerous for passengers?
Apparently, for some Boeing reason or something, there are no plugs in the cockpits. SOLVED.
If I’m reading that AWST quot correctly, that means tha FOUR retaining bolts would need to fall out before that door plug could move.
Four bolts that should have been secured with nuts and cotter pins. Which they obviously were not, because the couldn’t have come out if the nuts had been retained with cotter pins.
This strikes me as a fairly Big Deal. As a kid, I crewed for a glider pilot. He impressed upon me that the wing bolts needed to be installed front to back, and he inspected this *every time*. For Boeing or their subcontractor not to have done similar due diligence seems…unthinkable. Are their assembly empooyees no longer required to have A&P certificates?
Have you ever seen someonwill never hear well again.e after an explosive decompression? They have AT LEAST a bad headache and
I have spent most of my life flying, as a passenger, enjoy it, and have until the past decade held Boeing in the highest regard. However, my confidence in Boeing has sunk to the lowest degree possible with the revelations about Boeing’s lack of proper training for pilots of the 737 MAX, and with stories about sloppy manufacturing practices. But it is the 737 MAX story that has led me, as a kind of protest, to avoid airlines that fly Boeing aircraft. Needless to say, I will not fly the 737 MAX ever, regardless of how many assurances Boeing makes, they have proven themselves to be an untrustworthy company. Fortunately, all of my flying now is only from the US to Europe, and I fly only European carriers, so it is fairly easy to give my business to Airbus. This is a very sad state of affairs for a company that once was the finest aeronautical engineering company in the world.
> asked why this “plug” was able to pop out of the fuselage when an airplane’s doors open inward to prevent popping out.
Because a “door plug” (term of art in the airline industry) is not the same thing as a plug door. Sorry to bork your counterfactual rant.
Thomas and Bruce Pierce have correctly asked why this “plug” was able to pop out of the fuselage when an airplane’s doors open inward to prevent popping out.
From AWST …
“The plug’s design includes 12 “stop-fitting” device fittings that keep the insert from moving outward (see diagram, page 14). When the plug is in place, fittings on it match up with stop pads around the frame. Two hinges along the plug’s bottom and two guide roller fittings—one on each side of the plug near the top that fit into rollers attached to the frame—allow the plug to move up so its fittings can clear the pads and swing outward. But upward movement is possible only if four bolts are removed, effectively unlocking the plug. The bolts, secured by castellated nuts and cotter pins, are installed horizontally near each hinge and through each roller fitting.”
Note, “But upward movement is possible only if four bolts are removed … ” and I suspect that the likelihood of four bolts spontaneously falling out is about as likely as an engine falling off because its retaining hardware came loose. This is why all the attention is aimed at Spirit — the airframe manufacturer and the words, “never tightened” are appearing in print.
https://aviationweek.com/air-transport/safety-ops-regulation/new-quality-problems-rock-boeing-trigger-faa-probe
Another commenter – Bruce Pierce – has already written this below, but I think it bears repeating: Aren’t the doors of pressurized airliners designed in such a way that they are held shut by the pressure inside of the cabin being higher than the outside pressure? That way if either the latching system fails or somebody tries to open a door during cruise flight at high altitude, it is impossible for a door to open. The doors are fail-safe.
Why isn’t the door ‘plug’ on the Max 9 designed to be fail safe?
Are there other pressurized airliners with door plugs? Are they fail-safe?
Thank you very much for your post about this.
Obviously, it was terrifying for all on board, but good to know that competent pilots can manage this sort of situation, without a bigger catastrophe.
Thank you Patrick for your clear practical assessment of the incident. And for not whitewashing it.
I normally like your takes on things but this seems very wrong. Door failures on airplanes have caused serious problems in the past up to and including loss of the aircraft and all aboard.
eg
AA96, TK981, UA811, etc.
Plus if anybody had been sitting in 26A or 26B it is very likely they would have died. Combine this with the fact that both United and Alaska have found planes with incorrectly tightened bolts on the same door plugs and it strikes me as a pretty big deal. Yes, once the pilots realized the door hadn’t severed part of the tail or compromised the airframe otherwise and that nobody had been sucked out of their seats it was probably a relatively routine return to the airport. But to me that misses the point of how serious this could have been.
I’m also more than a little disturbed by the fact that Alaska apparently didn’t consider the plane fit for flights to Hawaii but was still willing to fly it from Portland to Ontario.
When Boing moved its Corporate offices Chicago, it ceased being an airplane company.
I love your column, but like others I do think this is a little dismissive of the fear people feel when this happens. Not only for those on board…but those on the ground also! It’s a miracle the door and other objects that were sucked it out did not hurt or kill anyone on the ground. This “minor” happening could have been so much worse and the margins are not wide to have turned this into a major disaster.
@chandelle: “no chance”? You’re funny (not!). Nobody has anybody ever seen people getting up during ascent, sure. (We’re not talking the first 2min after the plane took off.)
And the difference to La Paz is obviously that in La Paz, you don’t have constant winds of several hundred MPH.
So I would be careful with totally ruling out any danger if I were you.
I’m with others here that rather find Patrick’s non-chalance (while very welcome in most cases) a bit off the mark here. I think Boeing and Alaska (and the passenger) had a hell of a lucky day there…
La Paz and its surroundings are located just below the altitude at which the door blew out, so I doubt if anyone would’ve actually experienced anything more than altitude sickness even if an emergency descent hadn’t been initiated. What’d have been disconcerting is the bang, because the pressure differential would’ve been double that in a car tire, and the sudden, exponential increase in decibel levels inside the cabin. Since the aircraft was in climb, there was no chance of any loss of life, with pax strapped in securely.
Whilst Boeing seems to have copped a fair bit of egg, AA has escaped scrutiny although we know now that it kept flying the same aircraft despite it having faced pressurisation snafus on previous flights.
For all those worried about flying on the 737 Max, just drive a car which is far safer.
“In the United States, there are around 1.13 fatalities per every 100 million vehicle miles traveled, compared to just 0.035 fatalities per every 100 million airplane miles traveled.”
Oh, wait. Never mind.
With respect to the similar 900ER, the last one was built in 2015 so all of them have gone through several cycles of maintenance that require opening and closing the plug doors with associated torquing of bolts and installation of new cotter pins so presumably they aren’t at risk. The worry here is about aircraft too new to have gone through that level of maintenance yet and those are all dash 9s.
I’ve always enjoyed your columns, Patrick, but this article is not calming my nerves. I still refuse to fly the 737-MAX. After the two crashes, everyone said, “you can fly on the MAX with confidence. The problem has been fixed and Boeing can’t afford another mishap so you can bet they’ve really inspected this plane up and down, so it is safe.” Well, apparently that isn’t true. At this point Boeing’s word means nothing. I imagine they’ll eventually rename the MAX so nervous flyers won’t know what they’re flying on.
I’m not a pilot or an engineer, but to nervous-flying layman it seems Boeing needed to rush a new model onto the market to compete with the Airbus A320Neo, so rather than take the time to design something from the ground up they slapped something together based on old designs. Add to that the scandal of the government letting Boeing inspect its own planes to save money and you see the problem.
The media does try to rile people up to increase ratings, but I don’t think they’re overreacting in this case.
Thinking back to the Southwest 737 incident that resulted in the death of a passenger after an uncontained fan blade struck the fuselage, I can fully understand how this event could very easily have turned into a disaster.
Various news stories reported that the Captain did make PA announcements but no one could hear them.
But ultimately this points out a possible serious problem with the Boeing subcontractor who built the fuselages of the planes. News stories reported that Spirit Aerosystems (a unit of Boeing until 2005, probably spun off in some bullshit financial maneuver to cut costs) has come under scrutiny before for poor workmanship. And United Airlines found missing and loose bolts on these plugs. This is quite disturbing.
I’m going to try to avoid MAX planes (and this is another utterly STUPID corporate name). BAD marketing.
https://www.dailymail.co.uk/news/article-12944821/Alaska-Airlines-Spirit-Aerosystems-door-plug-lawsuit-flight.html
I agree with those who point out that not finding out the cause of the pressurization problem warnings [four in two months, reportedly] is alarming. Rather like disregarding a smoke alarm until you are actually ablaze.
They don’t make them like they used to . . .
Rafael: the -900ER at United, at least, *was* also grounded. The FAA order applied to all 737 airframes with plug doors that had not yet reached their “B check”, normally performed after 24 months in service. I don’t know whether United found any issues on their -900ER fleet or if the loose bolts reported were on their MAX-9 fleet (they have 146 -900s and 80 MAX-9s).
Why do you think Spirit Aero systems which build these fuselages never comes up in the discussion? What about inspections at Boeing upon receipt of them? Seems as a lot of conjecture, but root causes, such as Boeing’s atrocious employee policies and continual outsourcing, fighting with Unions etc. is ignored as a possible starting point?
Re the cockpit door, I have read (& make of this what you will) that it’s >designed< to open in the event of explosive decompression.
That's what I mean about several aspects of this incident: getting clear information is hard.
I was very surprised to see that they had had some pressurization problems with the aircraft previously and because of this restricted the use of this aircraft to over land flying !!!
It should not have been flying at all. Alaska had a previous fatal accident due to improper maintenance and don’t seemed to have learned much and neither has Boeing. I wonder what is going to happen next to the 737 max.
Here’s something that seems to be glossed over in the reporting. Several news articles state the loss of pressure caused the cockpit door to fly open and slam into the lavatory door.
I thought after 9/11 all cockpit doors were securely locked and made bullet proof to prevent unauthorized access. So how did a pressure loss cause the door to spring open? Are they really as secure as we’ve been told they are? If not, seems rather pointless if a determined hijacker could gain access.
Thank you for the article. I always appreciate your calm commentary.
However, I agree with another commenter that this does seem a bit too nonchalant. I would not consider this as a minor incident in today’s day and age, and comparisons to yesteryears when fatal accidents were more common are pointless with the technical advancements and expectations of today. I feel like it’s getting just the right amount of attention per today’s standards so as to push those responsible to correct systemic issues that led to this and prevent it in the future. I don’t think it’s about how minor or easy the fix is. It’s about how it slipped in in the first place. You are right, our definitions of minor and major incidents have changed over the years. That seems like a good thing to me.
I read about the mother’s account who held onto her teenage son while his seat was reclining into the open hole and clothes were being sucked out until pressure stabilized and I’m sure she’d be hard pressed to call it minor also.
That said, I am just a paying passenger (not an aviation authority) so my sentiment doesn’t really amount to anything.
And what about the -900ER?? Nice detail to include a photo of it, instead of a Max9. Those -900ER with the plugs, should have been grounded as well…
It seems the more I read about this, the more confusing it gets. Was the departing object really a “plug”? My sink plug never goes down the drain no matter how fatigued the plug or sink might be. What exactly failed?
Also the business about the CVR. It overwrites itself! Yes, after two hours. But no two hours elapsed here between start-up & shut-down.
Was also amused to learn that Portland has a waypoint called HPSTR.
I’ve been following you for several years, and have your book, so you know I’m on your side, but I have to disagree with the notion that this was minor. Nothing but pure luck,averted a disaster. WE could easily have been reading about passengers sucked out, or complete loss of the plane.
Might be the airline’s fault–neglectful maintenance–not Boeing. Too bad…Boeing was once a great and respected company.
One more thing – one hopes that Alaska is shelling out for new clothes for everyone on the flight.
I know it’s something pilots are trained for, but it seems like it would be a serious Brown Trousers Alert in the back of the plane.
I agree that this could have been a whole lot worse, however there are a few things that concern me and point to a procedural problem we need to fix before something really serious happens:
1) As a result of the FAA-mandated inspections, loose bolts have been found on other MAX-9s in the same plug. Is something messed up in the manufacturing process? Is there something that is messed up in the plug design that lets the bolts work themselves loose? Do we need to tighten up inspection requirements on these bolts?
2) Related, the subcontractor, Spirit Aero Systems, has had a handful of other issues, including leaking bulkheads and other leaking hull plugs. At a minimum, Boeing needs to keep a more-careful watch on their subcontractors. If I were paranoid, I’d order a top-to-bottom inspection of all their work going back some period of time. (Spirit Aero Systems is no relation to Spirit Airlines. Is the name just unlucky?)
3) Per mainstream media reports (yes, I know), the specific airframe was prohibited by Alaska from making long-haul overwater flights after three recent depressurization warnings. It’s very new hull – completed in IIRC November. I’m not a professional in the industry, but that record would seem to have suggested that there’s something going on that needed inspection *before* the plug blew out. Seems like taking the hull out of service and inspecting it for either a leak or a faulty sensor could have prevented a huge PR nightmare for Alaska.
As Hugh has already eluded, it seems to me that the more disheartening piece of this story relates to the decline of Boeing as a company. It seems there have been alarming supression of reports about quality issues at Spirit, a key Boeing subcontractor (see details here: https://www.levernews.com/boeing-supplier-ignored-warnings-of-excessive-amount-of-defects-former-employees-allege/).
As Patrick and others have written, it seems to me the unholy monster that is the 737 Max is a symptom of a rotten corportate culture at a once great company. Le sigh.
On a more technical note, is there a reason why these door plugs wouldn’t be designed to fail safe like doors themselves (at least as I understand them)? That is to say, if someone tries to open a door when the plane is pressurized, they cannot because it is designed in such a way that the pressure of the cabin forces it to stay in place even if the latch mechanism is open. I’m not an engineer but this seems like a fundamentally good design and I wonder why they wouldn’t design plugs in the same way.
All passengers on any flight have the opportunity to listen and or read the before and in flight briefings. That little nugget of info can save you and who is sitting next to your lives and sanity
If you are like me a former nervous Nelly flier take a leaf out of my book. I took a free introductory flight lesson . Loved it and became a pilot . The FAA and NTSB don’t rely on pilots brains to methodically do everything correctly the only thing pilots have to remember is get the checklist and follow it. … Trust your pilots to do the right thing or get your commercial license and join the fleet. As for the 737 Max it’s a safe airplane to fly . Yes Boeing wanted to sell it without an expensive cost for airlines in retraining their pilots but we all know that story and the overlord corrected that. Things can happen on any flight just prepare yourself to do the best job as a passenger you can with all the knowledge you have.
Normally I’m with you on these things but not this time. I get your point that pilots are trained and completely capable of coping with a sudden decompression. It is tremendously lucky that there wasn’t someone seated right next to the window, someone who would have likely been napping with their head against the very part that left the airplane. Luck aside, the presence of loose bolts on other aircraft indicates a failure of both the manufacturing process and the quality inspection procedures. Lastly, it is disturbing to think that this “plug” is not at all a plug as we are accustomed to thinking, but rather short bolts in shear. So what we have are multiple fundamental failures:: manufacturing, quality assurance, and engineering design, any one of which could have caused the incident alone but instead we have all three.
What might be the bigger issue is that the cockpit door flew open, as it was designed, at the moment of depressurization but this was omitted from the pilots manual. Just like MCAS. Are Max pilots wondering what else is hidden from them?
In the fifties and sixties, engineers didn’t know enough to predict the behaviour of “an airliner”. Thus they designed as best they could and then watched what would happen. They learned about “metal fatique” and stuff like that.
We’ve gone from lets just fly and see what happens to “we should be able to make things fly without any casualties along the way”. We expect planes to be… not flawless, but without fatal issues. Explosive decompressions like this one have the risk of sucking not-strapped-in people overboard. Like the Hawaiian flight several decades ago.
The issue is that the stall issues were downplayed. Then an accident happened killing all aboard. Then they were downplayed again, and then another accident happened killing all aboard. Then boeing tried to downplay it again but independent organisations forced them to be serious.
If you keep ignoring the signs, you’re bound to continue until something serious happens. They ignored the signs before challenger… until one exploded. They ignored the signs before columbia… until it broke apart. They ignored the signs before the Lion and Ethiopian crashes.
Alaska ignored the signs on this specific airplane. This plane had several pressurization problems they couldn’t solve.
The FAA takes this somewhat seriously. They do consider this a safety risk that is worthy of a grounding / requiring inspections of the fleet. Good.
I understand your take on wanting to reassure the public that flying is safe, bus…
I think it is more about whether this is a symptom of a more widespread quality control issue, maybe the next loose bolt will be holding something more critical.
I’m sure some are wondering, how would this have been different if it occurred at 35,000 feet and 550 mph?
I also am struggling to think of this as a minor incident. It’s pretty easy to imagine myself seated in that row on some random flight where a random “minor incident” like this happens. It’s also pretty easy to imagine how frightening that would be.
It’s great that no one was seated there, but it’s also seemingly a coincidence. I mean, I would chalk that up to happy coincidence rather than to that flying is safer than ever.
Kudos to the crew.
Thanks for this voice of sanity in a sea of media lunacy!
This does seem a little too nonchalant to me. As a passenger, a hole opening up in the side of the fuselage with a not insignificant possibility of passengers being ejected from the aircraft is not a “minor incident” as you describe it. It was a stroke of good fortune that a passenger was not sitting closer to the rupture, or a flight attendant was not walking by at the wrong moment.
Shipe I generally appreciate your calm perspective on media coverage, this seems serious and indicative of a larger design and QA issue with Boeing and this particular aircraft.
It is lucky that one ‘window’ seat was empty…
On the subject of the lack of announcements made by the flight crew, a pilot’s priorities are: aviate, navigate, communicate — in that order. Considering the circumstances, the first two were certainly enough to keep the pilots busy, and I’d like to think that I’d be understanding of that if I happened to be a passenger (though it’s impossible to put myself in that mindset, and I’ll admit that it’s easy to “Monday Morning QB” the situation).