Alaska Airlines' door-dropping flight was missing bolts The door plug that fell out of Alaska Airlines flight 1282 last month wasn’t properly bolted into place, according to a preliminary investigation. Seven passengers and one flight attendant suffered minor injuries during the January 5 incident, when a Boeing 737-9 Max bound for Ontario, California, experienced a rapid …
Quite funny, and I upvoted, but it's not anything to do with under-tightening the bolts. They were not installed, and if they had been they wouldn't have been very tight. They're there to stop the door from moving in exactly the way that it's meant to move if it was operating as a door, i.e. up and out. The bolts are long affairs with a castellated nut and cotter pin, simply in place to prevent movement by being strong in shear. Nothing to do with tension. </pedant>
Cheers!
Not diectly to do with tension, but....
I work in an automative-adjacent industry. Some of our fasteners are considered to be safety-critical items. On the production floor, our techs tighten those with automated torque wrenches. The wrenches log the applied torque for each fastener. If you don't put the fastener in, you won't get a torque value, and the unit can't move to the next station.
There are checks to make sure you're tightening one bolt N times when you're supposed to be tightening N bolts one time.
I'm somewhat surprised a similar requirement isn't in place for aviation.
Data for each fastener needs to be retained for something like 10 years.
I've worked on flightlines before, any decent QA would be literally screaming about FOD (Foreign Object Debris) risk. They've removed 4 bolts. Those bolts should have been placed somewhere very safe, and very visible, and then at the end of the maintenance, someone should have been asking some very big questions, about why the f%&k are there 4 bolts still sitting here.
You also would NEVER throw old bolts directly in the Bin, UNLESS there was 4 new shiny bolts standing there ready to be inserted. It is just not done, because it is so easy for exactly whats happened here to happen. Bolts go in bin. A while later, someone asks did you put back those bolts, someone else thinking of another part of the job, says of course. And there you have it, a plane released for service, without any locking bolts.
What you can say is that the initial design engineers did a pretty fantastic job, the plane flew multiple times without the locking bolts, triggered the pressure loss light (3 times!), but didnt lose the door in any of those occasions. Yes it finally did come out, but I still find it unbelievable that you can have a pressure loss light come on 3 times, and not pull the plane out of service for inspection. After the first time, you'd make sure that it's not a faulty sensor, after the second time, you'd make sure you can identify where the sensor is triggering. After the third time, you bloody well take the plane out of service and investigate!
Cock-ups all round on this one! What QA should have been doing in this case ----->
It's unclear though where the work was done. A work order was raised, but by whom? Boeing or Spirit? Where was the work done? Whose employees removed the bolts prior to doing the work?
If all this was done at Spirit by their employees then everything should have been tracked and new bolts fitted as they also manufacture the entire fuselage sections so it should have been known about and inspected afterwards.
If there were things being done by both Boeing and Spirit employees in that same area then there was obviously a massive breakdown in communication between them but the final post-work inspection again should have ensured everything was in order. Either way, this indicates a huge QA issue here for both companies.
As for the rivet holes, these should have been picked up during manufacture and fixed at the time: There is absolutely no excuse for anything like this to ever make it into a production aircraft.
"As for the rivet holes, these should have been picked up during manufacture and fixed at the time:"
Possibly this is related to recent reports about rivet holes being drilled in the wrong place by Spirit and retrospective checks and remedial action being taken after the planes had entered service.
doesnt matter who or where work was done. Even we recreational pilots and maintainers know that all fasteners and components come out into clean containers for each kind. Replaced components are placed into tray away from new components. On reassembly at least one other person confirms each component has gone back into correct location. Never been around when bits were "left over". Maybe only decade of experience explains that. OTOH, watching a diesel mechanic rebuild a 330 KW turbo diesel engine for gen set decades ago I noted the same practices. Culture of doing it right first time seems to be necessary in training maintenance staff, unlike, I regret to say, IT.
" Even we recreational pilots and maintainers know that all fasteners and components come out into clean containers for each kind. Replaced components are placed into tray away from new components."
I was trained to write things down. Every bolt that comes out is noted and when something is reassembled, there is a cross list going the other way to check things off. Used parts that will not be reinstalled are bagged with a note and saved. The repair is written up in the log. One of the Mars Exploration Rovers nearly went unlaunched as they had to find some explosive bolts that were set off to make last minute repairs and check that they did not wind up in a shorted condition which would have damaged internal electronics. Getting to Mars and not being able to deploy the solar panels would have been more embarrassing and expensive than just cancelling the launch. Even with all of the protocols NASA has in place, there are cock-ups. I would hope there were spankings all around for the crew that did the work.
I think he's making an oblique reference to the DIY experience of ending up with more bits than you started with. I think we may all have experienced this at home, but in a workshop, it should set off red lights. In The Meaning of Liff (Douglas Adams and John Lloyd) said that <a href="http://tmoliff.blogspot.com/2011/08/exeter-n.html>Exeter</a> could be used to describe this.
"I think he's making an oblique reference to the DIY experience of ending up with more bits than you started with."
I've had that plenty of times. If it's from working on the vacuum, whatever, if I've just done something major on the car before a long trip, that's a concern. When I was working on rockets, it would have been inexcusable. Since I got schooled in aerospace, I'm much more methodical about tear downs and reassembly so I rarely wind up with an Exeter. When I do, it's often by choice, as in Hobson's choice. The part that got left out was damaged and there was no replacement part available so something got glued. When the glue fails, it's into the bin with it since there will be no hope in getting parts at that point.
" triggered the pressure loss light (3 times!), but didnt lose the door in any of those occasions. Yes it finally did come out, but I still find it unbelievable that you can have a pressure loss light come on 3 times, and not pull the plane out of service for inspection. After the first time, you'd make sure that it's not a faulty sensor, after the second time, you'd make sure you can identify where the sensor is triggering. After the third time, you bloody well take the plane out of service and investigate!"
This issue seems to be unrelated to the plug loss. See http://www.b737.org.uk/pressurisation.htm AFAIU the warning light indicated the control system had a fault, and the alternate system (successfully) took over: at no time until the plug came off the aircraft, was the pressurisation incorrect (I'm speculating, but if the warning light was as a result of a leak making the pressurisation system unable to "keep up", the alternate system would have immediately failed in the same way).
We'll have a much more detailed explanation in the final report, but that's at least a few months away.
It mainly comes down to people, in this forum there is a ton of management speak... procedures, checklists and what more red tape that is supposed to make good on what is lacking on the factory floor. In the end there should only be motivated, skilled and experienced people doing these things if we want to prevent major risks to airline passengers.
It is not far fetched to assume the quality and qualifications of the workforce was sacrificed on the altar of diversity, next quarter profits and other factors resulting in a loss of skills, pride and motivation to make an excellent product. If people are unmotivated, mentally unfit for skilled assembly work or treated badly on the factory floor, managers shouldn't be surprised when subpar products roll out, why should the worker care about it if nobody else does.
Boeing, and many others, need CEO's like Ferdinand Piëch who would unexpectedly show up on Monday morning to beat up people when panels were 1mm out of line.
Why do some people always have to throw “diversity” into it?
Look, I am one of those “dirty foreigners”. I find myself fighting with management to do things right, to no avail, of course.
And yet, as soon as things done wrong catch up with them, others quickly line up and point at ME for the reason why it wasn’t done properly.
Really?
Boeing, and many others, do not need CEO's like Ferdinand Piëch who create a workplace culture resulting in the systematic corruption of test results, in that case Volkswagen diesel emissions, causing harm to people, the environment, company profits and shareholders' pockets.
"What you can say is that the initial design engineers did a pretty fantastic job, the plane flew multiple times without the locking bolts, triggered the pressure loss light (3 times!), but didnt lose the door in any of those occasions."
Boeing hasn't been especially good at not cutting corners so something like this is going to be blamed on them regardless of who did what to whom. The pressure fault light was there to denote a fault. It's a pain in the ass to bring in the gear and do a pressure check, but it's a hell of a lot cheaper than winding up with a load of criminal and civil lawsuits just in lawyer fees. Having the fault show up multiple times (logged) and removing the plane from overwater service due to repeated faults is the airline hammering in coffin nails as fast as they can. I've watched the same sort of thing happen where I worked once. We had a device under test go boom and management made the decision to test again without any analysis of why it happened the first time for a second boom of the day and $30k down the crapper. Nobody was going to listen to my concerns about not doing the work to understand why the first one went off bang. The big problem is a couple of the parts take a fair amount of time to machine and the machinist that made them can take time to schedule the work in. That added another month to the project. There was enough left of the second device to see that there was a error in the design that meant too much slop between two parts meant to index very precisely together.
Boeing decided a while ago that making planes wasn't their business. So they spun-off the part of the business that did the core manufacturing and it became Spirit AeroSystems. I think the idea was that Spirit would make parts for other companies. But I believe Spirit get most of their business from Boeing and Boeing only buy from Spirit. (Basically, if one company fails, they both fail)
I'm sure some clever MBA can explain why this separation is a good thing. Being a lowly engineer, it's beyond my capacity to understand these complex business/financial topics.
A couple of reasons for the spin-off: new contracts with the new company can help reduce future pension liabilities; new contracts can mean lower starting wages for new employers; keeps the plebs workers further from decision-making. But I think the main reason would be to mask capital costs as operational expenditure, thus "freeing up" capital either for acquisitions or gifts to investors.
You missed one; compartmentalization of liability. If losing the door plug had sucked several passengers out, Boeing could have passed the liability to Spirit. Or if they accidentally drop a rocket in a populated area, their space business won't kill their plane business. Remember when Ford and Firestone had their big fight over Explorer tires exploding? Even if it's not a supplier's fault, its good to muddy the water because stock prices are driven by emotion, not facts.
Something similar has worked for AMD and Global Foundries. (And could we argue Intel's failure to do so has cost them?) So it's not a complete no brainer.
But obviously they are very different industries - who else were Boeing going to buy from? Who else would buy from the spin off?
Actually Spirit have both Airbus and bombardier as customers as well, but I think that at least for Airbus it's smaller components being made and not entire fuselage sections.
From what I have read / seen on youtube (so truly authoritative sources scouts honour) some years ago Boing considered the option of buying back and in housing spirit again, but given the external contracts it would be almost impossible to do and on top of that todays boeing don't have the funds to do so without taking on debt in a way that will not pay for itself.
Pretty sure it was called Boeing Wichita before being spun out. Apparently one of the reasons was the quality was so bad and it was thought that a supplier would be easier to control....
And replies to others:
NTSB had said the pressurization warnings were not relevant.
Also in Leeham by a "whistleblower" posted that an another "Boeing Jedi mind truck" was used to record removing the door plug as mere "opening" of the door plug and thus avoid costly processes that would, for example, ensure reinstallation of the 4 stop bolts that were missing.
Also note the lack of bolts *but* a single white zip-tie holding the door to a stop pad. In the photo taken before insulation and interior panels were reinstalled...
"Also note the lack of bolts *but* a single white zip-tie holding the door to a stop pad. In the photo taken before insulation and interior panels were reinstalled..."
Problem solved: <jk>
The bolts were not the problem ..... should have used *more* zip ties .... cheaper than bolts and quicker to fit !!!
:)
P.S. Glad I don't fly on any Boeing Aircraft .....
Think a few days ago someone at Spirit AeroSystems flagged poorly riveted holes on a few planes currently in assembly. So it's interesting to read this interim report knowing this has been raised recently. Almost as if they knew it would be something that would be coming out.
What's more concerning for me is that the CVR wasn't saved by the pilots. At one end of the scale it screams poor pilot training. At the other, it feels they may have had to hide something (or felt they had to).
I would be interested to read why the CVR wasn't retained like it should've been.
You have to wonder why, in today's world of constant communication, CVRs and FDRs aren't transmitting their data continuously. The FAA should regulate, at a minimum, all commercial passenger carrying planes should have a satellite uplink for this critical data. We shouldn't be searching for 'black' boxes to determine the cause of a crash. And data from all in-flight incidents should be safely captured off of the affected aircraft.
For the C levels;
"We have AI constantly monitoring the health of our fleet so that we can proactively address any issue that might affect our position as the safest airline in the industry."
The same bullshit excuse automakers use for transmitting telematics (including GPS) on cars today.
I find it even more interesting why in this day and age of "infinite storage"
Because the rules were probably written 20 or 30 years ago, when two hours of storage was a lot. Plus they figure 99% of the time everything important will have happened in the last few minutes of the flight anyway.
They could change the rule to require 24 hours but that's going to cost the airlines a lot to have all their planes refitted, because you know whoever makes these replacement modules that are FAA certified etc. is going to charge a fortune. So the airlines would resist that rule change as unnecessary, because they'll say 99% of the time two hours is plenty.
why in this day and age of "infinite storage", 2 hours is considered sufficient recording time
As you say, developments in technology mean that much longer times are probably easily available. But I suspect that there's an element of "the rules say X, so we'll provide X unless the customer pays extra". It might even be that the storage already holds much more, but the software is configured not to use it. I.e, instead of "record till storage is up to <some percentage> then delete the older files", it's configured to "delete files older than X regardless of whether there's still 80% empty storage still available".
As to the pilots not pulling the breaker, I can think of two reasons.
Firstly, as someone else has said, in all the "excitement" they may well have just forgotten.
Secondly, had they not forgotten, they may have decided a permanent recording of some "colourful" language is best not preserved.
And there's a third reason that now comes to mind. What if they'd pulled the breaker to preserve the first incident, but then crashed later ? They really be getting some blame for having disabled the device that could have told investigators what was going on.
I think the issue is more that modern CVRs can hold much more than 2 hours, but Boeing have been so focused on keeping commonality in between all 737s that they haven't felt the need to make the disk any bigger. If you look at modern airliners (not rehashings of 1960s ones like the 737 Max), they usually retain CVR for more than 25 hours.
It is a not uncommon occurrence, and quite understandable, for traumatised flight crew to forget to pull the circuit breaker at the end of an incident flight. The technology should protect against this.
CVR disk??? This device is designed to survive a fscking plane crash! [1] It's almost certainly solid state, and could trivially be made to store many more than two hours without compatibility issues.
[1] First time ever that the euphemism is close to on-topic
"Okay, I have one question now : Boeing, do you still know how to make planes ?"
Answer:
Yes, they do but it is (supposed to be) cheaper if they subcontract the work to Spirit AeroSystems (spin-off from Boeing).
This has simply resulted in the spin-off being under more pressure to deliver on-time (has one major customer .... guess who !!!) and consequently quality has/is falling.
Cheaper vs Quality vs timely delivery ..... the usual you can have any two out of the three !!!
:)
It's much more serious than that. There's actually a Boeing-originated photo (DCA24MA063 report, figure 16) of the MED plug as installed with the bolts missing at the stage where they were about to restore the interior linings. So the record shows that nobody spotted this omission right up to the end of the job.
I think that pretty much backs up what I am saying. If the work procedure states.
1) fit frame
2) ...
3) ...
4) ...
.......
25) fit bolts
.......
51) take picture of the finished job and file with work sheet XYZ-123.
The unskilled worker doesn't realized he hasn't fitted the bolts. The picture is there for reference at a later date if something requires it, this report required it so it was dragged out of filing, then a skilled worker looked at it and spotted the error. I bet nowhere is there a procedure that says "All pictures must be inspected by a skilled worker before filing". The picture is a replacement for a sheet full of tick boxes, to save yet more money.
To be fair, unless there is a list of checkpoints for each picture, it would have been missed in a manual review as well. If I hand you a picture and tell you to point out anything that might be wrong, you'll miss anything non-obvious that you aren't specifically reviewing. Having said that, we use automated photo analysis for quality control in lots of industries that are less critical. Even painting critical fasteners in a contrasting color would help.
I'm not going to argue skilled vs unskilled. Humans make mistakes. In this case, potentially a series of them by two different teams. Because it's looking like the bolts weren't installed after rework to fix the rivets. Where the bolts missing from the original assembly, or did the team doing the rework fail to reinstall them?
The same NTSB photo does show a single “approved” zip tie (bottom right) that reduced both cost and weight. I imagine the fact that it managed to hold the doorplug in/on for 154 flights has been noted internally and a second redundant zip tie will now be offered (cost plus) on any new airframes…
Naively I would have thought that a plug in a pressurised aircraft would have been shaped so that it can never move outward being effectively wedge shaped so that pressure only increases the sealing force.
That way the worst that happen would be the plug falls into the cabin when the plane is unpressurised (and in theory on the ground)
It's a good point; but I think the plug sits in an opening designed for an emergency exit door. It would be bonkers to have to certify two versions of the fuselage with a different frame structure at this location, so the plug is very likely to be compatible with the way the emergency exit door is attached to the aircraft.
I read somewhere that emergency doors are designed with this kind of protection by design, but the plugs are an option (not offered by Airbus) which allows even more seats to be squeezed in.
MBAs despise the kind of overengineering that became standard in the airline industry precisely to save lives: the engineer must assume there is a risk he hasn't thought of; the MBA wants a to be able to price risks in order to determine which are acceptable.
It (sort of, without the "wedge" part) is designed that way. When pressurised, the main forces operating on the plug are the aircraft internal pressure pushing the door against the frame (specifically through structures called "stop pads", presumably because they "stop" it departing the aircraft). This stops the plug moving out but (other than from friction) does nothing to stop it moving up, so if the plug moves up to an extent that the stop pads are no longer matching up, it's on its way. This upward movement is how it would be removed during checks/maintenance and is prevented by the bolts (which in this case were missing). Others alluded to this, but the reason emergency exits (and therefore also other-things-designed-to-go-in-the-same-hole) aren't simple plugs is because the new thinking is to throw them out the aircraft by the person opening it, rather than being pulled in and placed on seats, dropped on the floor, etc., possibly causing obstruction.
None of this is a problem if you put the bolts where they're meant to go.
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There are large springs at the bottom of the door to take its weight and help it move up. There are also guide tracks and rollers on the side of the door/aperture to move it out when it slides up. The whole thing is designed to easily move up and out.. when required. Ie. when it’s an emergency exit door .. as opposed to a when it’s a plug that’s bolted (or zip tied in this case) permanently closed.
I’m not getting on a Boeing again, unless it’s old.. really old
"But.. why would the plug move up? I haven't looked at the altitude/pressure details when the door fell out, but.. Presumably to move up, it'd have to overcome any outward presssure from the interior being higher than the exterior. So moving up would need something to overcome that force, so maybe turbulence, or the aircraft becoming inverted and gravity doing it's thing. If the bolts had been correctly installed, the uppity door would have been prevented from departing the aircraft, but it did. So how was there enough force to defeat the stop pads?"
The forces from the pressure difference are perpendicular to the force required to move the plug up; it doesn't seriously resist or assist any upwards movement (there will be friction on the stop pads, which increases as the pressure difference increases, but given they're smooth metal, it probably isn't much). The springs at the bottom however, will be (constantly) exerting an upward force on the door, which is intentionally less than the door's weight. I believe the springs are to assist workers removing and replacing the plug: it will require less effort to lift it, and when replacing it, it won't drop into place as fast (possibly avoiding damage). It probably doesn't take much turbulence to provide the necessary force to "help" the springs push it up enough.
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Doors haven't been these types of "plug doors" in a long, long time. It's a common misconception.
In this case it's a "door plug" which is not a door at all. It is a permanent "cover" for a "portal" in the fuselage which exists for high-density seating configurations that require emergency exit in that location.
It is not an emergency exit either.
But also solid state drives have more storage cells than their stated capacity.
When something is over-written, the underlying storage block is not erased/written - a spare erased block is used and the address-storage map updated. The now "unused" block is put in a queue to be erased as the drive gets round to it. Also, at the filesystem level, deleted files aren't erased, the space they previously occupied is marked as free to be used later when a new file is written. Thus, especially when the storage is significantly larger than the stored data, old files can hang around for a bit and recovered with software that understands the intricacies of the file system structures. Recovering data in the "blocks waiting to be erased" queue means getting low level access ot the underlying storage - i.e. not via the translation mechanism that makes it look like an addressable disk (or whatever).
This changes if the system support TRIM. If TRIM is supported (at all level in the chain), then when the system deleted a file, it can tell the storage "these [list of addresses] blocks are no longer used and can be erased - thus allowing them to go into the erase queue and gives the drive a much larger pool of spare blocks to play with.
Responsibility hasn't yet officially been apportioned but the statement by the CEO makes this almost a formality. It wouldn't surprise me to see civil suits, which is how America disciplines its companies in lieu of effective regulation, coming on this, and the C-suite might have to worry about ones from investors who will have a good case to make about the company trashing their investment.
NOTHING will happen this year. Remember that it is Election Year in the USA (every year is an election year somewhere in the USA). Those [cough][cough] good folks across the pond, will spend more than the entire GDP of some nations just to elect 'yes' men and woman into jobs that most of them are totally unqualified for. (Boebert and MTG are good examples of those)
Because it is election year, no critical decisions will be made for fear of being called out for 'Election Interference'. Those Corporate Donors don't want to get pissed off. If they are then their $$$$$$$$$ will be spent elsewhere.
Mind you our bunch of twats in Westminster are not much better. Even the opposition who once had morals and you knew where they stood, are spinless corporate shills these days.
By some stroke of good fortune, there was nobody sitting in the seat row next to the plug. It will have been terrifying for the people in the row in front and the row behind, but nobody actually was in danger of being sucked out or beaten to death in their seat by being next to a gaping hole.
Nobody seems to have discussed the possibility of the door (a bloody great piece of hardware) striking the elevators or tailplane, rendering the aircraft unflyable. At least it was aft of the wings and engines.
"optional emergency door"
Optional secret exit/entrance for the CEO or super villain that has everything. I'm kinda curious if there's maybe too much flexibility in designs, ie the plug was there because the aircraft could be ordered in multiple configurations. So cargo, number of seats/passengers or exec jet. Saves on manufacturing I guess, but perhaps introduces too much risk.
It's for different configurations of passenger plane. The configuration of the plane that includes the most seats possible would have required a door to be fitted there. The configuration of the alaska plane had fewer seats/passengers, to the point where it was within regulation for fewer emergency exits to be needed. So a plug was fitted instead of a door to save some weight and maintenance costs.
If this had failed due to some design flaw you might have a point about risk - instead this one just gets chalked up to bad quality assurance during manufacture/maintenance. This didn't fail because it was a plug rather than a door, it failed because someone (more likely multiple people) didn't do their job properly when it was fitted. If they hadn't bolted in a door properly you can bet your ass that would have failed too.
Flight crews would prefer that only conversations related to an incident be available; they don't want every single thing they say in the cockpit to be available to review and dissect later. The 2 hours is a compromise. There's an FAA proposal to extend to 25 hours, but there's some resistance from the pilots' unions.
As far as I know, no, it's just a continual 2 hour loop. This used to be done with an endless loop of magnetic tape.
Keep in mind the main purpose of these things originally is to have some information in the event of an "everyone's dead" kind of accident, where there are no witnesses to interview.
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