21 ms·

A Matter of Millimeters: The story of Qantas flight 32

680 points by xenophonf 3y ago

wyldfire 3y ago
Raymond Babbit would be pleased to hear the passengers landed safely.
ghaff 3y ago
What an extraordinarily detailed writeup.
- rvnx 3y ago
  [flagged]
  - sammy2255 3y ago
    Are you seriously accusing Admiral Cloudberg of writing articles with ChatGPT?
    - jshier 3y ago
      It's an especially ironic accusation given she's currently dealing with YouTube channels stealing her write-ups and reading them into a video using AI. She even had a "if you read this you're an AI bot" section in an article a few weeks ago.
  - kergonath 3y ago
    Which adjectives specifically? And which sentence structure? I did not see anything out of the ordinary for such a technical discussion.
  - mango7283 3y ago
    I'd love to see you demonstrate "adjectives that no humans would use". Do tell.
  - pxmpxm 3y ago
    Not sure about GPT, but it's hella overwrought - it's like someone took the investigation PDF and tried to make the cheesiest Lifetime movie out of it. Far too many superfluous adjectives and embellishments; barely readable IMO. eg "The red-hot, wildly spinning disk instantly fractured into several sections, which rocketed outward in multiple directions at incomprehensible speed"
    - mango7283 3y ago
      Well the whole point of articles like this is that they are more "literary" than the investigation reports and therefore more entertaining and engaging to read. There's a time and place for reading dry technical investigation reports and this is not one of them. Also, none of the adjectives you highlighted are beyond human comprehension or usage or even rare so it's certainly not an example of what parent was trying to convey.
      - pxmpxm 3y ago
        Taking a sentence and doubling the world count with folksy-sounding adjectives does not actually make the prose more "literary". It's just bad copy...
        mango7283 3y ago
        It's a matter of taste. Clearly many of us here were entertained by the style of the blog vis a vis the wiki version or other sources of the same information.
quickthrower2 3y ago
Very lucky they had that mastermind crew. The facts they had to keep within 3 knots of an ideal landing speed indicates how hard this was to get out of. They landed 150m from end of runway (perfect for the scenario). Amazing.
tekla 3y ago
Engineering at its finest. Lots of problems but multiple layers and layers of redundancies that prevented a major issue from becoming a bigger issue involving souls
Cyberdog 3y ago
Reading articles and seeing videos about airline disasters tends to increase my faith in flying rather than making me more afraid of it. Terrorism or sabotage aside, so many failures have to compound to put a modern airliner in a truly irrecoverable state that it's effectively impossible to happen and not worth my time to even worry about. What times we live in that we can hurtle ourselves across oceans at hundreds of miles per hour and be in substantially no more danger than we would be walking down a sidewalk in our home town (in before HN commenters reply with information about all the dangers associated with sidewalks).
- RetroTechie 3y ago
  That assumes the environment the aircraft flies in, behaves predictable. Sometimes it does not. Turbulence is an obvious one. Downdrafts another. You can have a perfectly functional aircraft, but if the whole air column it's in goes down faster than the aircraft can climb, the aircraft will go down with the air column no matter what. Reminds me of an Air Crash Investigation episode: some volcano had erupted, ash was high up in the air, air traffic control wasn't aware of this, and iirc it didn't show up on weather radar or similar systems (or on the planes' systems). So it looked all clear. Meanwhile the whole plane was getting ash-blasted. To the point that paint was stripped, cockpit windows went from clear to matte, and ash attached itself to engine fan blades. Obviously trouble followed... Bottom line: the environment a vehicle moves through, is always a factor. Sometimes an unpredictable, uncontrollable and/or hazardous one.
  - Cyberdog 3y ago
    I'm not familiar with the volcano incident you referred to, but a bit of searching seems to indicate it was British Airways Flight 009 in 1982, where a 747-200 had all four engines fail due to volcanic ash… then glided safely out of the ash cloud and was able to restart three of the engines and land safely at a major airport. From a complete loss of power to all engines to on the ground with zero deaths, zero injuries. That's exactly the kind of story I'm talking about that gives me such faith in flying!
    - 3y ago
Agingcoder 3y ago
Incredible. That’s a fault tolerant system, operated by a highly knowledgeable crew. Congrats to all those involved, from system designers to pilots and crew.
ren_engineer 3y ago
there are some crazy talented pilots out there who are able to perform under massive amounts of pressure, United Flight 232 is a more extreme version of this article https://en.wikipedia.org/wiki/United_Airlines_Flight_232 https://en.wikipedia.org/wiki/United_Airlines_Flight_232 >Despite the fatalities, the accident is considered a good example of successful crew resource management. A majority of those aboard survived; experienced test pilots in simulators were unable to reproduce a survivable landing. It has been termed "The Impossible Landing" as it is considered one of the most impressive landings ever performed in the history of aviation plane lost all hydraulics and had to be steered and crash landed using only the engines
- mopsi 3y ago
  Errol Morris made an exceptional documentary about UA232. One of the pilots just looks into the camera and tells the story. https://www.youtube.com/watch?v=nf33RDu_D6M https://www.youtube.com/watch?v=nf33RDu_D6M
  - oh_sigh 3y ago
    Not just any camera - an Interrotron!
- macintux 3y ago
  That is an amazing story, thanks for sharing it. This part leapt out at me: > Rescuers did not identify the debris that was the remains of the cockpit, with the four crew members alive inside, until 35 minutes after the crash. I can't imagine spending a half hour waiting to be rescued, not knowing whether any of your passengers had survived.
- Sebguer 3y ago
  Article by the same author as the submitted one on this: https://admiralcloudberg.medium.com/fields-of-fortune-the-crash-of-united-airlines-flight-232-9cf65ae14c68 https://admiralcloudberg.medium.com/fields-of-fortune-the-cr...
- feerceKitteh 3y ago
sho_hn 3y ago
A turbine disc fragment ripped through the entire plane cross-section and exited on the other side. Stunning.
- olex 3y ago
  I like the pragmatic engineering point of view described in the article: > For engineering purposes, disk fragments are assumed to have infinite energy at the moment of release; they will cut through any reasonable material and cannot be contained.
  - cleansingfire 3y ago
    Also demonstrated by the picture in the op of the brick wall. Note that it wasn't smashed or knocked down, but looks as if it was cut.
    - finnh 3y ago
      That must have been the section that broke downward, so was traveling faster than terminal velocity.
metadat 3y ago
An amazing recovery, there's even an Air Crash Investigations episode about it: https://imdb.com/title/tt3234896/ https://imdb.com/title/tt3234896/
- MBCook 3y ago
  Love that show. Makes me wish we dealt with software even a tiny bit like that. Checklists alone for troubleshooting common customer problems would save so much hassle. But so many companies (including mine) still work on more of the “heroic” model where it’s up to individuals to just learn the hard way through helping lots of customers and noticing patterns.
  - ghaff 3y ago
    The thing is that you end up having to be very process heavy. From an efficiency, rather than safety perspective, I had an offer from (and interviewed with--in that order) Boeing many moons ago. The thing I remember from a long-ago dinner after that interview was a guy who had spent a couple of years on some design tweak that saved some fraction of a percent on fuel consumption. That's the sort of thing that most engineers do in aviation (where it's perfectly appropriate).
  - rswail 3y ago
    I'm trying to introduce SRE as a practice in to my organization. We don't have anywhere near the safety requirements of aviation or medical or power generation software, but our operations do affect thousands of people around the world. Getting people to understand that SRE is a code of practise and an overall approach has been very difficult, even with the so-called "QA" team, who think their job ends when the latest upgrade is deployed. We do work in public transport, and the best solution I've found so far, is when they say they're "done", I ask them whether they are willing to stand at the railway station at peak hour and explain to passengers why they can't get home on time (or to work). The usual result is that they go away and think about it and there is more testing done. But getting that to be a standard approach and way of thinking is very difficult, especially when product owners and project managers are only focussed on the next milestone/payment.
jandrese 3y ago
> Meanwhile on the ground, events were taking an unexpected turn. On Batam Island in Indonesia, debris from the №2 engine plunged into a populated area shortly after the failure, resulting in surprise and alarm. Among the debris was a large portion of the failed IP turbine disk, which fell with such force that it cleaved straight through a building, razing a brick wall. Thankfully, no one on Batam was hurt by the debris. However, photographs of locals holding airplane wreckage in what appeared to be Qantas livery were soon posted to Twitter, where they were taken as indications that a Qantas airplane had actually crashed somewhere over Batam. Qantas engineers already knew that the plane was still flying, but they were unable to contact the crew to find out more information. And outside that bubble, the news that a Qantas A380 had possibly gone down spread so quickly that even investors reacted while the plane was still in the air. In fact, the first time Qantas’s CEO learned of the situation was when he received a call asking why the company’s stock price was dropping. Information flies so fast in the modern world. There is a classic XKCD about learning about an earthquake via Twitter moments before the ground starts shaking.
- loloquwowndueo 3y ago
  Oh you mean https://xkcd.com/723/ https://xkcd.com/723/
- choilive 3y ago
  The crypto markets responded to Russia's invasion of Ukraine even faster than Twitter did. That was an interesting day
ulfw 3y ago
I was on the flight and took the picture referenced as "A passenger took this photo in flight, showing turbine fragment exit holes in the upper surface of the wing. (ATSB)" Forced myself on another A380 flight shortly after so I won't lose faith in it's engineering safety.
- saagarjha 3y ago
  Hopefully without incident that time?
  - ulfw 3y ago
    Thankfully yes! I lived in Singapore at the time and thought... my goodness. It's a small island. If you end up afraid of flying, what do you do!? Kudos to the Qantas crew on board as well as Captain de Crespigny and his co-pilots and two check captains. We happened to have a lot of experienced pilot power on board. A video from that time: https://youtu.be/U8Un2boLZD8 https://youtu.be/U8Un2boLZD8
- yukkuri 3y ago
  Good on you!
- gumby 3y ago
  Wow. I was (long ago!) in an engine fire emergency landing situation and though I did take a connecting flight to get home I didn’t fly for a while afterwards. Psychologically, your choice was probably the smarter one.
  - ghaff 3y ago
    I've been in a couple situations. - The main one was that I had a flight from Vancouver to Victoria and the weather was too bad for the helicopter to fly. So we took a prop. On takeoff, some cross-wind hit the plane and we tipped over. My colleague and I who were sitting across from each other thought that was it. - The other one was my plane was reported crashed when I was visiting my parents for some holiday or other. I got panicked call on drive back from airport.
unbindableisaac 3y ago
Coincidentally I just finished reading the self-authored book ("QF32") of the pilot's own recount of the day. The book leads in with many interesting life experiences that led him to make so many good life-and-death choices that day.
RcouF1uZ4gsC 3y ago
I wonder if there is any correlation with having been in the Air Force and handling these high stress civilian airline near disasters. Both this captain and the Sullenberger of thMiraclenon the Hudson were Air Force (RAF and USAF respectively). Since, you will be going against an enemy who may damage your aircraft, there is likely more training on how to assess and recover from damage as well as how to handle these types of situations.
- MBCook 3y ago
  From watching Air Disasters pilots with military training has helped out a number of times. However such pilots being very authoritarian or having bad crew resource management and not listening/refusing to let the copilot help has caused a number of accidents (or been a contributing factor) numerous times too.
Syzygies 3y ago
I am addicted to a fault to Mentour Pilot's studies of flight incidents. Again, here, he goes into greater depth: https://www.youtube.com/watch?v=JSMe1wAdMdg https://www.youtube.com/watch?v=JSMe1wAdMdg
- MBCook 3y ago
  I was going to mention him! I found his channel in the last year and have loved watching his coverage, especially from the point of view of a pilot. If you like this article you’ll also likely like the show Air Disasters too (also known as Air Crash Investigations and Mayday, depending on where you are). It goes into a lot of detail based on crash reports without sensationalizing things too, though not quite as far as this article.
  - DiggyJohnson 3y ago
    Another great channel is "Green Dot Aviation". I think he's the best in class, personally. Him and Admiral Cloudberg are the best aviation content out there.
- bambax 3y ago
  I like Mentour Pilot but the outcome of the incident is only revealed at the end. Admiral Cloudberg's articles are more like Columbo: they start with what happened, and then go back in time to find out and explain all the little details that caused it. In a way it's much more logical that way. Mentour Pilot constantly has to say "remember this, it will prove important later". But we don't know why it's important, and so we don't remember, and as a result the narrative is much less clear.
yukkuri 3y ago
So did he pass his check flight? ;)
- kQq9oHeAz6wLLS 3y ago
  I know airline regs and reality would never allow it, but I like to think the check pilot tore up the assessment form, and just walked into the CEO's office and plunked down the cockpit audio. "Yeah, he passed."
  - matheusmoreira 3y ago
    > What happened in there? > Emergency landing. > You look like you've been through it. > The engine... exploded. > So is he a pass or a fail? > He's a pass.
XorNot 3y ago
The one thing which sticks out to me is the ECAM system including a baked corrective message of "open fuel transfer valves" due to the imbalance. That seems like an odd message to include in an emergency action system, which by definition is only active in unexpected situations. Is there really no system to confirm if a fuel leak is happening?
- stevepeg 3y ago
  A320/330/340/350 driver here (can't get away from Airbus apparently). Nope, there is no system to confirm a leak apart from a camera around the tail if you're lucky enough to have one, my previous airline had a flight where an engine leak was detected this way. Think about it, how would you design such a system? So this falls on the crew. The procedure to determine if you have a leak is pretty much the same across types: add the fuel on board (FOB) to the fuel used (FU) and make sure that the number you get is the same as what you started the flight with. If it's less by some margin then you probably have a leak. You can confirm further by looking at tank quantities (but they take time to reduce depending on the size of the hole). If you get an engine or pylon leak then you might also see increased fuel flow on that engine. If the leak is elsewhere in the system then you might notice a smell. If you can't work it out then the procedure (at least on Airbus types) usually involves turning an engine off to see if the leak stops (yep, really). As for the ECAM "open fuel transfer valves" message, I don't know for sure on the 380 but all the other Airbus types I've flown have something like: .IF NO FUEL LEAK FUEL IMBALANCE....MONITOR So it doesn't really instruct you to open the transfer valves but leads you into the fuel imbalance procedure if you think you need it. The very first line of the fuel imbalance procedure says something like "Don't apply this procedure if fuel leak is suspected".
  - SkyPuncher 3y ago
    You could absolutely design a system that could detect a leak. I’m guessing that it’s just not common enough, or at least catastrophically common enough, to warrant. At its simplest you measure estimated volume delivered to the engines against estimated volume remaining in the tank. Both are things that should be digitally measurable. The problem seems to be that the only case it really matters is in a catastrophic accident where such measurements are going to be broken anyways.
nradov 3y ago
And this is why fully autonomous flight control systems won't be certified for airliners in our lifetimes. While autonomous systems are capable of taking off, navigating to a destination, and landing they are largely incapable of handling major emergencies. It's impossible for engineers to foresee every possible failure mode and program for it.
- cesarb 3y ago
  > It's impossible for engineers to foresee every possible failure mode and program for it. Playing devil's advocate: you don't have to. It just has to be better than a pair of experienced airplane pilots working together. Which is still very hard, and there's still a good chance we won't see it in our lifetimes, but at least it's not impossible.
  - lovemenot 3y ago
    Also, let's not completely discount remote pilots
    - nradov 3y ago
      Let's completely discount remote pilots. There is no technology on the horizon which would solve the network latency or sensor fidelity problems that prevent remote piloting from being adequate for handling in-flight emergencies.
      - lovemenot 3y ago
        I don't claim to be knowledgeable. It's just a hypothetical question. Surely, it depends on the nature of the emergency. As I understand it, in this Qantas example, the pilots did not need to fly the plane with real-time responses, just to make good decisions. Let's not completely discount remote pilots, while recognising they are not a universal panacea.
        mkl 3y ago
camkego 3y ago
This article highlights the dangers from fake/illegitimate/non-oem aircraft replacement parts that are being used to repair aircraft. https://www.reuters.com/business/aerospace-defense/engine-maker-cfm-says-up-96-planes-affected-by-fake-parts-probe-2023-09-20 https://www.reuters.com/business/aerospace-defense/engine-ma... Doesn't make me feel comfortable about flying.
- brutusborn 3y ago
  It doesn’t really specify the risk though, the parts may not be critical. I would hope regulations require independent certification for critical parts, but I’m scared to look.
  - ChickeNES 3y ago
    Sometimes non-critical parts can cause a disaster though, as in Swissair 111, where arcing in the in-flight entertainment system led to a fire that quickly doomed the plane.
Stratoscope 3y ago
It may be a cliché to call someone a "national treasure", but I would take it a step further for Admiral Cloudberg: she is a world treasure. Kyra has written so many great articles under her nom de cloud. Trust me, just pick any of them and you will learn something. https://news.ycombinator.com/from?site=admiralcloudberg.medium.com https://news.ycombinator.com/from?site=admiralcloudberg.medi...
- genewitch 3y ago
  there's a video podcast, too, which they should put on TV instead of whatever is on there now, overdramatized claptrap
pdonis 3y ago
One thing that jumped out at me was the narrow range of safe airspeeds on the landing approach--only three or four knots between stall and max speed not to overrun the runway. Quite a good piece of flying to get the plane down safely, not to mention all the other things the crew had to do.
- sundvor 3y ago
  Yep, they were very heavy and needed to land essentially at stall speed - which they basically did seeing as the stall warning chimed in moments before touch down - in order to allow for as much space as possible to stop the plane. I took from the article that their calculations were kind of hacked together with a number of overrides, so I guess they erred on the side of caution in case any of the assumptions needed a margin of error. Amazing article. So well written. Kudos to the Qantas flight team, especially the pilot - they know their stuff for sure. And also kudos to the Airbus engineering team, that was such an epic win for redundant systems. (It was interesting to see how stopping calculations were improved as part of the post mortem, for one.)
  - hugh-avherald 3y ago
    > especially the pilot Worth noting that there was an unusual flight crew: 3 captains (one to check the captain's proficiency, and another to check the checker's proficiency) plus the first and second officers.
    - Grimburger 3y ago
      Plus the off-duty one upstairs watching the tail camera on the entertainment console. Article says 140 years of combined experience between them which is more than impressive. Airbus really couldn't have hoped for a better crew for this to eventually happen to. One of my favourite things about the A380 is that in-flight live feed from the tail, surprised more planes don't do it. Offers visual detail of the entire topside and a lot of information that might not otherwise be available.
  - squidgyhead 3y ago
gumby 3y ago
30 years ago I was in an emergency landing due to engine failure situation (flight attendants take away your shoes, practice crash position, rearrange the passengers etc) and the thing that stuck out the most for me was that everybody did as they were told. No self righteous people; it was clear to everyone why there are flight attendants aboard and that they were key to your survival. The evacuation was orderly, though the follow up was lengthy (e.g. everybody’s passport was still on board). More recently I’ve seen pictures of people evacuating down the slides with their luggage! Seems incredibly dangerous, not just for the slide experience but in slowing down evacuation. We had no fire in the cabin but what if we had? Oh yeah, you know the stereotype of the press sticking their camera in your face to see how freaked out you are? It does happen in real life.
- MBCook 3y ago
  You’re not supposed to take anything on the slides. No luggage. No shoes. Just you. But it is ignored. Which is sad, people could really get hurt. Your right though the fact as many people comply as they do is kind of incredible given how people act in other situations.
  - deleted 3y ago
    [deleted]
  - dataflow 3y ago
    Why in the world do you have to take your shoes off before going down the slides? I could understand jackets or jewelry, but shoes?
    - resolutebat 3y ago
      High heels are not OK, for obvious reasons. Regular shoes are fine.
      - dataflow 3y ago
        Ahh that makes way more sense. Thanks.
aunty_helen 3y ago
My first job was working at a mro that overhauled engines a bit smaller than the Trent 900s but same principles apply. I built qa software to digitize the forms and signature process like what’s mentioned in the article as having not correctly been signed off on. I ate lunch with repair engineers that had dark wells of knowledge about the engines they worked on. They could talk so deep on a subject that lunch break was over and we’d resume conversation over weeks. There’s a paragraph in this post that hits a few points that are very subtle. The missing sign offs and engineers not knowing the process and and and. I think the criticism of RR is valid here. The qa manager at the mro I worked at was a force of nature. He was feared and uncompromising. He was also the signature that could cause an engine shutdown in flight. I admired this person and still do. There’s small issues like this that go on every day on every engine model all over the world. There’s thousands of engines flying right now that have little defects that could cause a shutdown. There’s issues that have been identified, signed off as low risk and will be checked next time the engine comes in for overhaul. There’s engineers out there that see the same fault, a premature cracked pipe, carbon buildup, abnormal corrosion, after a while of seeing this problem, they’ll raise the paperwork which will go up the chain and sit. It may be ignored, taken for information for future designs, identified as something that should be fixed or monitored or the frequency of monitoring increased. Maybe the part life will be reduced or you will be forced to NDT the part at each overhaul. The cheese wheel concept is great as these systems are so complex there’s always going to be some issues. As for Qantas, near the end it mentions the plane was repaired at great cost. It’s a source of company pride that they’ve never lost an airframe. They repair planes which are BER (beyond economic repair) just to keep this record.
- grecy 3y ago
  > As for Qantas, near the end it mentions the plane was repaired at great cost Indeed. Qantas has been ranked the safest airline int he world almost every year since forever [1] I clearly remember when QF32 happened and everyone was utterly shocked. That simply DOES NOT happen to Qantas. [1] https://www.forbes.com/sites/laurabegleybloom/2023/01/03/ranked-the-20-safest-airlines-in-the-world/?sh=42d1400e9f54 https://www.forbes.com/sites/laurabegleybloom/2023/01/03/ran...
V__ 3y ago
I'm wondering why the tolerances for the oil pipe were so small in the first place. Why not make the pipe one or two mm thicker?
- peteradio 3y ago
  Because its dead simple to machine a center and the designer did not factor in machinist/engineer/qa/facility incompetence.
  - SkyPuncher 3y ago
    I know very basic machining, but I know that part looks almost so simple I could manufacture it. It’s very interesting that there were not wall thickness measurements. That would have solved this whole issue.
  - kergonath 3y ago
    You don’t need any such incompetence in this case, as explained in the article, though it does help and that specific facility had several issues. The tube was built to spec, it’s the specs that were not what they should have been. The failures were more with the whole process (like the reference points with different tolerances and the inadequate paperwork) rather than machinist incompetence. They are just the guys at the bottom.
    - peteradio 3y ago
      The engineer documents did not match the design documents. Incompetence number one. The machinist would have seen with the naked eye very easily that the hole was not close to center, an old salt would have raised it up. Incompetence number 2. The machinist not being aware that moving the jig was ruining the setpoint. Incompetence number 3. There were clearly incompetent individuals working at the facility. I get what you are saying... Don't blame the individual but best thing you can do from a process perspective is hire good people.
      - kergonath 3y ago
modernpacifist 3y ago
I don't know about others, but I can't help but smile when I read the detailed series of events in aviation postmortems. To be able to zero in on what turned out to be a single faulty part and then trace the entire provenance and environment that led to that defective part entering service speaks to the robustness of the industry. I say that sincerely since mistakes are going to happen and in my view robustness has less to do with the number of mistakes but how one responds to them. Being an SRE at a FAANG and generally spending a lot of my life dealing with reliability, I am consistently in awe of the aviation industry. I can only hope (and do my small contribution) that the software/tech industry can one day be an equal in this regard. And finally, the biggest of kudos to the Kyra Dempsey the writer. What an approachable article despite being (necessarily) heavy on the engineering content.
- sylens 3y ago
  I think many of us are so used to working with software, with its constant need for adaptation and modification in order to meet an ever growing list of integration requirements, that we forget the benefits of working with a finalized spec with known constants like melting points, air pressure, and gravity.
  - abid786 3y ago
    Completely agree - I think it can go one of two ways. Software is more malleable than airplanes are and that also comes with downsides (like how much time and effort it takes to bring a new plane to the market)
    - RajT88 3y ago
      I was just thinking of this metaphor today. Try drawing the software monstrosity you work on / with as an airplane. 100 wings sticking out all different directions, covered with instruments and fins, totally asymmetrical and 5 miles long. Propellers, jets, balloons, helicopter blades. Yep, it flies. When it crashes, just take off again.
      - 3y ago
deleted 3y ago
[deleted]
dynjo 3y ago
Absolutely astonishing and riveting read.
nojs 3y ago
Fantastic write up, and amazing testament to the engineering in the A380. It’s extremely impressive that the pilots were able to safely land the plane with such extensive damage to so many separate systems.
zubairq 3y ago
Really interesting read
tgbugs 3y ago
My internal alarm bells started going off as soon as I read about datum AA and datum M. Shouldn't it be possible if not standard practice for the design software to issue a giant warning if you have a part that is defined by two datums that are almost but not quite the same? If they aren't the exact same datum then something like this will inevitably happen.
- brutusborn 3y ago
  It’s definitely possible, but the checking system was probably built under the implicit assumption that the sources of truth for the checks (datums, dimensions) were correct. 2 datums might need to be very similar but not quite the same, so checking for it might present a lot of hard to handle false positives and make the system very complex.
- Kosirich 3y ago
  There is nothing wrong with 2 datums, the issue is that during machining this is not "a part" but an assembly that moves. There are so many failings from my POV in the manufacturing process and verification of the part, which is summarized nicely by the following quote: . Furthermore, initial inspections at the start of the production run were supposed to verify that the manufacturing process was creating products that satisfied the “design intent,” but the initial products were checked against the manufacturing drawings, not the design drawings.
atemerev 3y ago
Given the sad state of the world in general, I am in awe of aviation industry because it actually works as designed, where all millions of potential points of failure are handled gracefully (and airlines are still profitable somehow). A true miracle.
Grimburger 3y ago
> By specifying an landing weight in excess of the maximum, the system logic changed to apply the operational coefficient only once — for unrelated and obscure reasons — and lo and behold, when he ran the numbers this time, the computer said they could just barely land on any of the 4,000-meter runways at Singapore Changi Airport, with only 100 meters to spare. It wasn’t much, but with no better runways anywhere nearby, it would have to do. Hacking overflows in an emergency, topnotch.
liendolucas 3y ago
It's so interesting to read on aviation postmortems even for people that don't fully understand all the technical details as explained in the article (great by the way, kudos to the author). I've always wondered if there is an authoritative database with all significant events in aviation to read and learn more about? Do pilots study past events as part of their training?
EVa5I7bHFq9mnYK 3y ago
With the engine ruptured, still operating and the fuel leaking, how did they know the whole thing is not gonna explode at any moment?
- aaronmdjones 3y ago
  They didn't, which is why they shut it down.
  - EVa5I7bHFq9mnYK 3y ago
    I've read the ruptured engine was still operating for 3 hours after the plane landed.
    - mauvehaus 3y ago
      Engine 1 was continuing to operate after landing because the fuel shutoff valves were inoperative. Engine 2 was the engine that had the uncontained failure.
    - aaronmdjones 3y ago
      The ruptured engine (#2) was shut down within a minute of the incident, in-flight. Two of the remaining engines (#3, #4) were shut down after landing. The last engine (#1) could not be shut down and had to be drowned in fire-fighting foam. This is in the article.
ogurechny 3y ago
The article is complex and well written, but I am a bit perplexed by the victorious tone and never-ending praise of safety. It resembles a sales pitch a bit too much, even though no one is selling anything. Maybe it's unintentional, and being around salesmen just does that to people. If you are like me, you've probably said “hmm…” to yourself multiple times when certain things were mentioned, because those were things that actually didn't work (that they were left intact really boosts the credibility of the author). From calculation software that had never ever been tested with out-of-ordinary data to the computer keeping the broken engine running. From pure luck with fuel tanks being almost full and unable to explode to absence of any physical kill switch to stop the engine. An hour being generously available to go through ALL the checklists to clear the notifications. An hour of passengers and crew staying on top of the poodle of fuel hoping that nothing would ignite it. Finally, pure randomness in debris flying the way it did. It's not a story of “layers of safety” overlapping, it's a story of “layers of randomness” overlapping. What would be really interesting is a distribution of outcomes for all possible trajectories of debris, i. e., how (un)lucky they actually were. I guess corporations don't release models like those to the public. Also, that special chamber for oil filter requiring precise drilling of a perfectly fine pipe seems “ewww” to me. It is not serviceable anyway without reinstalling everything from scratch, as far as I understand, why not make it a single piece?
- Neil44 3y ago
  I guess it's a glass half full type situation. There's a lot of universes where that plane did not make it back and a lot of decisions aligned to ensure that it did.
- Game_Ender 3y ago
  The author is positive because of all the safety layers that existed and staid intact, despite how flawed humans and companies are. The culture of looking at previous accidents like the UA232, where they lost ann engine and ALL controls with it, meant the A380 control system was engineered to take even more damage and it worked. I do agree though it did not spend enough effort focusing on the areas to improve: - A computer controlled engine that runs for 60 seconds while on fire, and lets a dangerous part spin too fast. It seems like something that should of been covered ahead of time. - An engine manufacturing process that is so complex it’s almost impossible to validate. - A fault management system that only shows you 1 or 2 at a time when you have 40.
class3shock 3y ago
Just throwing this out there, if anyone reading this knows of other writers/blogs/books/etc. similarly looking into aviation engineering/failures I would love some recommendations.
- throwaway290 3y ago
  https://avherald.com/ https://avherald.com/
- dezgeg 3y ago
  https://fearoflanding.com/ https://fearoflanding.com/
mrlonglong 3y ago
I applaud this article for being so thorough and informative on this subject. I hope Airbus changes their mind about building new ones. We like them even if airlines don't like the operating costs.
jdietrich 3y ago
To a half-competent machinist or manufacturing metrologist, half a millimetre of concentricity error on a part of that size might as well be half a mile. It's a huge, grievous error that can be seen with the naked eye. You don't get an error of that scale through normal variation, it's a clear sign of a serious problem with your setup. This part of the article really leapt out at me: The tolerance for this bore was supposed to be Ø 0.05 mm according to the design drawings, but was changed to Ø 0.5 mm in the manufacturing drawings without explanation. Even so, the non-conformance on the accident hub was between Ø 0.90 and Ø 0.98 (an offset of 0.45–0.49 mm), which should have been flagged by the machine. The CMM records from the accident hub were not retained, so it was not possible for investigators to confirm that the error was actually registered. The meaning might not be obvious if you've never worked in a machine shop, but it's crystal clear if you have. Many people at that plant knew that they were delivering out-of-spec parts. Everyone who handled that part could have told you at a glance that the counterbore was badly off-centre. Rather than going back to remake the parts, rather than figuring out why the parts were bad, they just went through the motions of QC, shipped them anyway, falsified documentation and discarded evidence. For all the complexity of the analysis, the root cause is blindingly simple - flagrant negligence, concealed by flagrant deceit.
- ambyra 3y ago
  The article said it wasn’t visible because that stub was machined after it was placed in the hub. Which begs the question “why would you weld a tube in place and then finish machining it after?” Maybe it was easier/faster to machine it while it was on a hub. Also, wasn’t there an oil filter that had to go in there? Wouldn’t the oil filter experience interference if the counterbore was offset? Closing comment: damn I thought people paid more attention when building turbines.
  - spacecadet 3y ago
    Yes, but what the poster meant is that it would be and that is confirmed in the images.
ardel95 3y ago
The story of what happened in the cockpit during the failure is just as interesting! The captain made a number of right decisions in a very challenging situation that allowed the plane to safely land. Mentour Pilot did a video on that: https://youtu.be/JSMe1wAdMdg?si=YSgbqFpR_EBe-FvX https://youtu.be/JSMe1wAdMdg?si=YSgbqFpR_EBe-FvX
YeGoblynQueenne 3y ago
>> The story of Qantas flight 32, as told herein, is therefore not only the tale of a dramatic emergency, but a testament to the safety of aviation today — a story that should make every reader feel a little less fearful of flight. I'm not afraid of flight. I'm afraid of fall. (Sounds much better in Greek: δεν φοβάμαι την πτήση, φοβάμαι την πτώση).
matheusmoreira 3y ago
> It goes without saying that if any of the turbine fragments had entered the passenger cabin, there would have been injuries, if not fatalities Understatement of the century. Somehow those spinning discs completely missed those passengers!! They were in such a state that when they disintegrated they went up and through the wing, towards the ground and one nearly missed the plane itself, striking its ventral section instead of passenger cabins. That near miss took out a huge number of aircraft systems so how catastrophic would the damage have been if they had gone through the plane?? I read the entire article and my conclusion is their luck was immeasurable from the very beginning. They were blessed with such tremendous luck even before the flight crew got the chance to demonstrate their badassery and heroism. One of those discs destroyed part of a building.
smdyc1 3y ago
Had to chuckle at this: "If you have made it this far, I first of all commend your patience, and/or your nerdiness." A thoroughly enjoyable write-up this was.
contingencies 3y ago
Many things failed, at least: (1) failure to identify safety-critical parts for review (2) failure in design drawings made without regard for fabrication (3) failure to make reference to original design goals when altering part designs (4) bad machining plan altering work-holding during the machining (5) failure to inspect finished parts
- contingencies 3y ago
  (5) was particularly bad: an off center hole should have been visible to the naked eye of any trained machinist, and at least one person should have inspected all safety critical parts. This would have been the final fail-safe to catch the combination of all prior errors. It was not made. There's actually another failure - (6) - which is the failure to perform visual inspection of the assembling mechanic which should have generated a query or note at the very least. While at this point the mechanic is probably given specific points to check, and an aggressive timeline for assembly, and has little motivation to extend critical thinking beyond the assembly task as they cannot possibly intuit all of the design intent for every part and subassembly, a better run assembly process with a culture of observation would have had this flagged for verification with designers.
Log_out_ 3y ago
The part out of tolerance could have been caught by comparing it to a master part within tolerance? Laserscan it or capacitor probe measure it and encounters the lack of material. In car part companies there is usually a qm-lab drawing samples from production. Does airplane turbine production not have this step?
xony 3y ago
[dead]
deleted 3y ago
[deleted]

680 points by xenophonf 3y ago

wyldfire 3y ago

Raymond Babbit would be pleased to hear the passengers landed safely.

ghaff 3y ago

What an extraordinarily detailed writeup.

rvnx 3y ago
[flagged]
- sammy2255 3y ago
  Are you seriously accusing Admiral Cloudberg of writing articles with ChatGPT?
  - jshier 3y ago
    It's an especially ironic accusation given she's currently dealing with YouTube channels stealing her write-ups and reading them into a video using AI. She even had a "if you read this you're an AI bot" section in an article a few weeks ago.
- kergonath 3y ago
  Which adjectives specifically? And which sentence structure? I did not see anything out of the ordinary for such a technical discussion.
- mango7283 3y ago
  I'd love to see you demonstrate "adjectives that no humans would use". Do tell.
- pxmpxm 3y ago
  Not sure about GPT, but it's hella overwrought - it's like someone took the investigation PDF and tried to make the cheesiest Lifetime movie out of it. Far too many superfluous adjectives and embellishments; barely readable IMO. eg "The red-hot, wildly spinning disk instantly fractured into several sections, which rocketed outward in multiple directions at incomprehensible speed"
  - mango7283 3y ago
    Well the whole point of articles like this is that they are more "literary" than the investigation reports and therefore more entertaining and engaging to read. There's a time and place for reading dry technical investigation reports and this is not one of them. Also, none of the adjectives you highlighted are beyond human comprehension or usage or even rare so it's certainly not an example of what parent was trying to convey.
    - pxmpxm 3y ago
      Taking a sentence and doubling the world count with folksy-sounding adjectives does not actually make the prose more "literary". It's just bad copy...
      - mango7283 3y ago
        It's a matter of taste. Clearly many of us here were entertained by the style of the blog vis a vis the wiki version or other sources of the same information.

quickthrower2 3y ago

Very lucky they had that mastermind crew. The facts they had to keep within 3 knots of an ideal landing speed indicates how hard this was to get out of. They landed 150m from end of runway (perfect for the scenario). Amazing.

tekla 3y ago

Engineering at its finest. Lots of problems but multiple layers and layers of redundancies that prevented a major issue from becoming a bigger issue involving souls

Cyberdog 3y ago

Reading articles and seeing videos about airline disasters tends to increase my faith in flying rather than making me more afraid of it. Terrorism or sabotage aside, so many failures have to compound to put a modern airliner in a truly irrecoverable state that it's effectively impossible to happen and not worth my time to even worry about. What times we live in that we can hurtle ourselves across oceans at hundreds of miles per hour and be in substantially no more danger than we would be walking down a sidewalk in our home town (in before HN commenters reply with information about all the dangers associated with sidewalks).

RetroTechie 3y ago
That assumes the environment the aircraft flies in, behaves predictable. Sometimes it does not. Turbulence is an obvious one. Downdrafts another. You can have a perfectly functional aircraft, but if the whole air column it's in goes down faster than the aircraft can climb, the aircraft will go down with the air column no matter what. Reminds me of an Air Crash Investigation episode: some volcano had erupted, ash was high up in the air, air traffic control wasn't aware of this, and iirc it didn't show up on weather radar or similar systems (or on the planes' systems). So it looked all clear. Meanwhile the whole plane was getting ash-blasted. To the point that paint was stripped, cockpit windows went from clear to matte, and ash attached itself to engine fan blades. Obviously trouble followed... Bottom line: the environment a vehicle moves through, is always a factor. Sometimes an unpredictable, uncontrollable and/or hazardous one.
- Cyberdog 3y ago
  I'm not familiar with the volcano incident you referred to, but a bit of searching seems to indicate it was British Airways Flight 009 in 1982, where a 747-200 had all four engines fail due to volcanic ash… then glided safely out of the ash cloud and was able to restart three of the engines and land safely at a major airport. From a complete loss of power to all engines to on the ground with zero deaths, zero injuries. That's exactly the kind of story I'm talking about that gives me such faith in flying!
  - 3y ago

Agingcoder 3y ago

Incredible. That’s a fault tolerant system, operated by a highly knowledgeable crew. Congrats to all those involved, from system designers to pilots and crew.

ren_engineer 3y ago

there are some crazy talented pilots out there who are able to perform under massive amounts of pressure, United Flight 232 is a more extreme version of this article https://en.wikipedia.org/wiki/United_Airlines_Flight_232 https://en.wikipedia.org/wiki/United_Airlines_Flight_232 >Despite the fatalities, the accident is considered a good example of successful crew resource management. A majority of those aboard survived; experienced test pilots in simulators were unable to reproduce a survivable landing. It has been termed "The Impossible Landing" as it is considered one of the most impressive landings ever performed in the history of aviation plane lost all hydraulics and had to be steered and crash landed using only the engines

mopsi 3y ago
Errol Morris made an exceptional documentary about UA232. One of the pilots just looks into the camera and tells the story. https://www.youtube.com/watch?v=nf33RDu_D6M https://www.youtube.com/watch?v=nf33RDu_D6M
- oh_sigh 3y ago
  Not just any camera - an Interrotron!
macintux 3y ago
That is an amazing story, thanks for sharing it. This part leapt out at me: > Rescuers did not identify the debris that was the remains of the cockpit, with the four crew members alive inside, until 35 minutes after the crash. I can't imagine spending a half hour waiting to be rescued, not knowing whether any of your passengers had survived.
Sebguer 3y ago
Article by the same author as the submitted one on this: https://admiralcloudberg.medium.com/fields-of-fortune-the-crash-of-united-airlines-flight-232-9cf65ae14c68 https://admiralcloudberg.medium.com/fields-of-fortune-the-cr...
feerceKitteh 3y ago

sho_hn 3y ago

A turbine disc fragment ripped through the entire plane cross-section and exited on the other side. Stunning.

olex 3y ago
I like the pragmatic engineering point of view described in the article: > For engineering purposes, disk fragments are assumed to have infinite energy at the moment of release; they will cut through any reasonable material and cannot be contained.
- cleansingfire 3y ago
  Also demonstrated by the picture in the op of the brick wall. Note that it wasn't smashed or knocked down, but looks as if it was cut.
  - finnh 3y ago
    That must have been the section that broke downward, so was traveling faster than terminal velocity.

metadat 3y ago

An amazing recovery, there's even an Air Crash Investigations episode about it: https://imdb.com/title/tt3234896/ https://imdb.com/title/tt3234896/

MBCook 3y ago
Love that show. Makes me wish we dealt with software even a tiny bit like that. Checklists alone for troubleshooting common customer problems would save so much hassle. But so many companies (including mine) still work on more of the “heroic” model where it’s up to individuals to just learn the hard way through helping lots of customers and noticing patterns.
- ghaff 3y ago
  The thing is that you end up having to be very process heavy. From an efficiency, rather than safety perspective, I had an offer from (and interviewed with--in that order) Boeing many moons ago. The thing I remember from a long-ago dinner after that interview was a guy who had spent a couple of years on some design tweak that saved some fraction of a percent on fuel consumption. That's the sort of thing that most engineers do in aviation (where it's perfectly appropriate).
- rswail 3y ago
  I'm trying to introduce SRE as a practice in to my organization. We don't have anywhere near the safety requirements of aviation or medical or power generation software, but our operations do affect thousands of people around the world. Getting people to understand that SRE is a code of practise and an overall approach has been very difficult, even with the so-called "QA" team, who think their job ends when the latest upgrade is deployed. We do work in public transport, and the best solution I've found so far, is when they say they're "done", I ask them whether they are willing to stand at the railway station at peak hour and explain to passengers why they can't get home on time (or to work). The usual result is that they go away and think about it and there is more testing done. But getting that to be a standard approach and way of thinking is very difficult, especially when product owners and project managers are only focussed on the next milestone/payment.

jandrese 3y ago

> Meanwhile on the ground, events were taking an unexpected turn. On Batam Island in Indonesia, debris from the №2 engine plunged into a populated area shortly after the failure, resulting in surprise and alarm. Among the debris was a large portion of the failed IP turbine disk, which fell with such force that it cleaved straight through a building, razing a brick wall. Thankfully, no one on Batam was hurt by the debris. However, photographs of locals holding airplane wreckage in what appeared to be Qantas livery were soon posted to Twitter, where they were taken as indications that a Qantas airplane had actually crashed somewhere over Batam. Qantas engineers already knew that the plane was still flying, but they were unable to contact the crew to find out more information. And outside that bubble, the news that a Qantas A380 had possibly gone down spread so quickly that even investors reacted while the plane was still in the air. In fact, the first time Qantas’s CEO learned of the situation was when he received a call asking why the company’s stock price was dropping. Information flies so fast in the modern world. There is a classic XKCD about learning about an earthquake via Twitter moments before the ground starts shaking.

loloquwowndueo 3y ago
Oh you mean https://xkcd.com/723/ https://xkcd.com/723/
choilive 3y ago
The crypto markets responded to Russia's invasion of Ukraine even faster than Twitter did. That was an interesting day

ulfw 3y ago

I was on the flight and took the picture referenced as "A passenger took this photo in flight, showing turbine fragment exit holes in the upper surface of the wing. (ATSB)" Forced myself on another A380 flight shortly after so I won't lose faith in it's engineering safety.

saagarjha 3y ago
Hopefully without incident that time?
- ulfw 3y ago
  Thankfully yes! I lived in Singapore at the time and thought... my goodness. It's a small island. If you end up afraid of flying, what do you do!? Kudos to the Qantas crew on board as well as Captain de Crespigny and his co-pilots and two check captains. We happened to have a lot of experienced pilot power on board. A video from that time: https://youtu.be/U8Un2boLZD8 https://youtu.be/U8Un2boLZD8
yukkuri 3y ago
Good on you!
gumby 3y ago
Wow. I was (long ago!) in an engine fire emergency landing situation and though I did take a connecting flight to get home I didn’t fly for a while afterwards. Psychologically, your choice was probably the smarter one.
- ghaff 3y ago
  I've been in a couple situations. - The main one was that I had a flight from Vancouver to Victoria and the weather was too bad for the helicopter to fly. So we took a prop. On takeoff, some cross-wind hit the plane and we tipped over. My colleague and I who were sitting across from each other thought that was it. - The other one was my plane was reported crashed when I was visiting my parents for some holiday or other. I got panicked call on drive back from airport.

unbindableisaac 3y ago

Coincidentally I just finished reading the self-authored book ("QF32") of the pilot's own recount of the day. The book leads in with many interesting life experiences that led him to make so many good life-and-death choices that day.

RcouF1uZ4gsC 3y ago

I wonder if there is any correlation with having been in the Air Force and handling these high stress civilian airline near disasters. Both this captain and the Sullenberger of thMiraclenon the Hudson were Air Force (RAF and USAF respectively). Since, you will be going against an enemy who may damage your aircraft, there is likely more training on how to assess and recover from damage as well as how to handle these types of situations.

MBCook 3y ago
From watching Air Disasters pilots with military training has helped out a number of times. However such pilots being very authoritarian or having bad crew resource management and not listening/refusing to let the copilot help has caused a number of accidents (or been a contributing factor) numerous times too.

Syzygies 3y ago

I am addicted to a fault to Mentour Pilot's studies of flight incidents. Again, here, he goes into greater depth: https://www.youtube.com/watch?v=JSMe1wAdMdg https://www.youtube.com/watch?v=JSMe1wAdMdg

MBCook 3y ago
I was going to mention him! I found his channel in the last year and have loved watching his coverage, especially from the point of view of a pilot. If you like this article you’ll also likely like the show Air Disasters too (also known as Air Crash Investigations and Mayday, depending on where you are). It goes into a lot of detail based on crash reports without sensationalizing things too, though not quite as far as this article.
- DiggyJohnson 3y ago
  Another great channel is "Green Dot Aviation". I think he's the best in class, personally. Him and Admiral Cloudberg are the best aviation content out there.
bambax 3y ago
I like Mentour Pilot but the outcome of the incident is only revealed at the end. Admiral Cloudberg's articles are more like Columbo: they start with what happened, and then go back in time to find out and explain all the little details that caused it. In a way it's much more logical that way. Mentour Pilot constantly has to say "remember this, it will prove important later". But we don't know why it's important, and so we don't remember, and as a result the narrative is much less clear.

yukkuri 3y ago

So did he pass his check flight? ;)

kQq9oHeAz6wLLS 3y ago
I know airline regs and reality would never allow it, but I like to think the check pilot tore up the assessment form, and just walked into the CEO's office and plunked down the cockpit audio. "Yeah, he passed."
- matheusmoreira 3y ago
  > What happened in there? > Emergency landing. > You look like you've been through it. > The engine... exploded. > So is he a pass or a fail? > He's a pass.

XorNot 3y ago

The one thing which sticks out to me is the ECAM system including a baked corrective message of "open fuel transfer valves" due to the imbalance. That seems like an odd message to include in an emergency action system, which by definition is only active in unexpected situations. Is there really no system to confirm if a fuel leak is happening?

stevepeg 3y ago
A320/330/340/350 driver here (can't get away from Airbus apparently). Nope, there is no system to confirm a leak apart from a camera around the tail if you're lucky enough to have one, my previous airline had a flight where an engine leak was detected this way. Think about it, how would you design such a system? So this falls on the crew. The procedure to determine if you have a leak is pretty much the same across types: add the fuel on board (FOB) to the fuel used (FU) and make sure that the number you get is the same as what you started the flight with. If it's less by some margin then you probably have a leak. You can confirm further by looking at tank quantities (but they take time to reduce depending on the size of the hole). If you get an engine or pylon leak then you might also see increased fuel flow on that engine. If the leak is elsewhere in the system then you might notice a smell. If you can't work it out then the procedure (at least on Airbus types) usually involves turning an engine off to see if the leak stops (yep, really). As for the ECAM "open fuel transfer valves" message, I don't know for sure on the 380 but all the other Airbus types I've flown have something like: .IF NO FUEL LEAK FUEL IMBALANCE....MONITOR So it doesn't really instruct you to open the transfer valves but leads you into the fuel imbalance procedure if you think you need it. The very first line of the fuel imbalance procedure says something like "Don't apply this procedure if fuel leak is suspected".
- SkyPuncher 3y ago
  You could absolutely design a system that could detect a leak. I’m guessing that it’s just not common enough, or at least catastrophically common enough, to warrant. At its simplest you measure estimated volume delivered to the engines against estimated volume remaining in the tank. Both are things that should be digitally measurable. The problem seems to be that the only case it really matters is in a catastrophic accident where such measurements are going to be broken anyways.

nradov 3y ago

And this is why fully autonomous flight control systems won't be certified for airliners in our lifetimes. While autonomous systems are capable of taking off, navigating to a destination, and landing they are largely incapable of handling major emergencies. It's impossible for engineers to foresee every possible failure mode and program for it.

cesarb 3y ago
> It's impossible for engineers to foresee every possible failure mode and program for it. Playing devil's advocate: you don't have to. It just has to be better than a pair of experienced airplane pilots working together. Which is still very hard, and there's still a good chance we won't see it in our lifetimes, but at least it's not impossible.
- lovemenot 3y ago
  Also, let's not completely discount remote pilots
  - nradov 3y ago
    Let's completely discount remote pilots. There is no technology on the horizon which would solve the network latency or sensor fidelity problems that prevent remote piloting from being adequate for handling in-flight emergencies.
    - lovemenot 3y ago
      I don't claim to be knowledgeable. It's just a hypothetical question. Surely, it depends on the nature of the emergency. As I understand it, in this Qantas example, the pilots did not need to fly the plane with real-time responses, just to make good decisions. Let's not completely discount remote pilots, while recognising they are not a universal panacea.
      - mkl 3y ago

camkego 3y ago

This article highlights the dangers from fake/illegitimate/non-oem aircraft replacement parts that are being used to repair aircraft. https://www.reuters.com/business/aerospace-defense/engine-maker-cfm-says-up-96-planes-affected-by-fake-parts-probe-2023-09-20 https://www.reuters.com/business/aerospace-defense/engine-ma... Doesn't make me feel comfortable about flying.

brutusborn 3y ago
It doesn’t really specify the risk though, the parts may not be critical. I would hope regulations require independent certification for critical parts, but I’m scared to look.
- ChickeNES 3y ago
  Sometimes non-critical parts can cause a disaster though, as in Swissair 111, where arcing in the in-flight entertainment system led to a fire that quickly doomed the plane.

Stratoscope 3y ago

It may be a cliché to call someone a "national treasure", but I would take it a step further for Admiral Cloudberg: she is a world treasure. Kyra has written so many great articles under her nom de cloud. Trust me, just pick any of them and you will learn something. https://news.ycombinator.com/from?site=admiralcloudberg.medium.com https://news.ycombinator.com/from?site=admiralcloudberg.medi...

genewitch 3y ago
there's a video podcast, too, which they should put on TV instead of whatever is on there now, overdramatized claptrap

pdonis 3y ago

One thing that jumped out at me was the narrow range of safe airspeeds on the landing approach--only three or four knots between stall and max speed not to overrun the runway. Quite a good piece of flying to get the plane down safely, not to mention all the other things the crew had to do.

sundvor 3y ago
Yep, they were very heavy and needed to land essentially at stall speed - which they basically did seeing as the stall warning chimed in moments before touch down - in order to allow for as much space as possible to stop the plane. I took from the article that their calculations were kind of hacked together with a number of overrides, so I guess they erred on the side of caution in case any of the assumptions needed a margin of error. Amazing article. So well written. Kudos to the Qantas flight team, especially the pilot - they know their stuff for sure. And also kudos to the Airbus engineering team, that was such an epic win for redundant systems. (It was interesting to see how stopping calculations were improved as part of the post mortem, for one.)
- hugh-avherald 3y ago
  > especially the pilot Worth noting that there was an unusual flight crew: 3 captains (one to check the captain's proficiency, and another to check the checker's proficiency) plus the first and second officers.
  - Grimburger 3y ago
    Plus the off-duty one upstairs watching the tail camera on the entertainment console. Article says 140 years of combined experience between them which is more than impressive. Airbus really couldn't have hoped for a better crew for this to eventually happen to. One of my favourite things about the A380 is that in-flight live feed from the tail, surprised more planes don't do it. Offers visual detail of the entire topside and a lot of information that might not otherwise be available.
- squidgyhead 3y ago

gumby 3y ago

30 years ago I was in an emergency landing due to engine failure situation (flight attendants take away your shoes, practice crash position, rearrange the passengers etc) and the thing that stuck out the most for me was that everybody did as they were told. No self righteous people; it was clear to everyone why there are flight attendants aboard and that they were key to your survival. The evacuation was orderly, though the follow up was lengthy (e.g. everybody’s passport was still on board). More recently I’ve seen pictures of people evacuating down the slides with their luggage! Seems incredibly dangerous, not just for the slide experience but in slowing down evacuation. We had no fire in the cabin but what if we had? Oh yeah, you know the stereotype of the press sticking their camera in your face to see how freaked out you are? It does happen in real life.

MBCook 3y ago
You’re not supposed to take anything on the slides. No luggage. No shoes. Just you. But it is ignored. Which is sad, people could really get hurt. Your right though the fact as many people comply as they do is kind of incredible given how people act in other situations.
- deleted 3y ago
  [deleted]
- dataflow 3y ago
  Why in the world do you have to take your shoes off before going down the slides? I could understand jackets or jewelry, but shoes?
  - resolutebat 3y ago
    High heels are not OK, for obvious reasons. Regular shoes are fine.
    - dataflow 3y ago
      Ahh that makes way more sense. Thanks.

aunty_helen 3y ago

My first job was working at a mro that overhauled engines a bit smaller than the Trent 900s but same principles apply. I built qa software to digitize the forms and signature process like what’s mentioned in the article as having not correctly been signed off on. I ate lunch with repair engineers that had dark wells of knowledge about the engines they worked on. They could talk so deep on a subject that lunch break was over and we’d resume conversation over weeks. There’s a paragraph in this post that hits a few points that are very subtle. The missing sign offs and engineers not knowing the process and and and. I think the criticism of RR is valid here. The qa manager at the mro I worked at was a force of nature. He was feared and uncompromising. He was also the signature that could cause an engine shutdown in flight. I admired this person and still do. There’s small issues like this that go on every day on every engine model all over the world. There’s thousands of engines flying right now that have little defects that could cause a shutdown. There’s issues that have been identified, signed off as low risk and will be checked next time the engine comes in for overhaul. There’s engineers out there that see the same fault, a premature cracked pipe, carbon buildup, abnormal corrosion, after a while of seeing this problem, they’ll raise the paperwork which will go up the chain and sit. It may be ignored, taken for information for future designs, identified as something that should be fixed or monitored or the frequency of monitoring increased. Maybe the part life will be reduced or you will be forced to NDT the part at each overhaul. The cheese wheel concept is great as these systems are so complex there’s always going to be some issues. As for Qantas, near the end it mentions the plane was repaired at great cost. It’s a source of company pride that they’ve never lost an airframe. They repair planes which are BER (beyond economic repair) just to keep this record.

grecy 3y ago
> As for Qantas, near the end it mentions the plane was repaired at great cost Indeed. Qantas has been ranked the safest airline int he world almost every year since forever [1] I clearly remember when QF32 happened and everyone was utterly shocked. That simply DOES NOT happen to Qantas. [1] https://www.forbes.com/sites/laurabegleybloom/2023/01/03/ranked-the-20-safest-airlines-in-the-world/?sh=42d1400e9f54 https://www.forbes.com/sites/laurabegleybloom/2023/01/03/ran...

V__ 3y ago

I'm wondering why the tolerances for the oil pipe were so small in the first place. Why not make the pipe one or two mm thicker?

peteradio 3y ago
Because its dead simple to machine a center and the designer did not factor in machinist/engineer/qa/facility incompetence.
- SkyPuncher 3y ago
  I know very basic machining, but I know that part looks almost so simple I could manufacture it. It’s very interesting that there were not wall thickness measurements. That would have solved this whole issue.
- kergonath 3y ago
  You don’t need any such incompetence in this case, as explained in the article, though it does help and that specific facility had several issues. The tube was built to spec, it’s the specs that were not what they should have been. The failures were more with the whole process (like the reference points with different tolerances and the inadequate paperwork) rather than machinist incompetence. They are just the guys at the bottom.
  - peteradio 3y ago
    The engineer documents did not match the design documents. Incompetence number one. The machinist would have seen with the naked eye very easily that the hole was not close to center, an old salt would have raised it up. Incompetence number 2. The machinist not being aware that moving the jig was ruining the setpoint. Incompetence number 3. There were clearly incompetent individuals working at the facility. I get what you are saying... Don't blame the individual but best thing you can do from a process perspective is hire good people.
    - kergonath 3y ago

modernpacifist 3y ago

I don't know about others, but I can't help but smile when I read the detailed series of events in aviation postmortems. To be able to zero in on what turned out to be a single faulty part and then trace the entire provenance and environment that led to that defective part entering service speaks to the robustness of the industry. I say that sincerely since mistakes are going to happen and in my view robustness has less to do with the number of mistakes but how one responds to them. Being an SRE at a FAANG and generally spending a lot of my life dealing with reliability, I am consistently in awe of the aviation industry. I can only hope (and do my small contribution) that the software/tech industry can one day be an equal in this regard. And finally, the biggest of kudos to the Kyra Dempsey the writer. What an approachable article despite being (necessarily) heavy on the engineering content.

sylens 3y ago
I think many of us are so used to working with software, with its constant need for adaptation and modification in order to meet an ever growing list of integration requirements, that we forget the benefits of working with a finalized spec with known constants like melting points, air pressure, and gravity.
- abid786 3y ago
  Completely agree - I think it can go one of two ways. Software is more malleable than airplanes are and that also comes with downsides (like how much time and effort it takes to bring a new plane to the market)
  - RajT88 3y ago
    I was just thinking of this metaphor today. Try drawing the software monstrosity you work on / with as an airplane. 100 wings sticking out all different directions, covered with instruments and fins, totally asymmetrical and 5 miles long. Propellers, jets, balloons, helicopter blades. Yep, it flies. When it crashes, just take off again.
    - 3y ago

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dynjo 3y ago

Absolutely astonishing and riveting read.

nojs 3y ago

Fantastic write up, and amazing testament to the engineering in the A380. It’s extremely impressive that the pilots were able to safely land the plane with such extensive damage to so many separate systems.

zubairq 3y ago

Really interesting read

tgbugs 3y ago

My internal alarm bells started going off as soon as I read about datum AA and datum M. Shouldn't it be possible if not standard practice for the design software to issue a giant warning if you have a part that is defined by two datums that are almost but not quite the same? If they aren't the exact same datum then something like this will inevitably happen.

brutusborn 3y ago
It’s definitely possible, but the checking system was probably built under the implicit assumption that the sources of truth for the checks (datums, dimensions) were correct. 2 datums might need to be very similar but not quite the same, so checking for it might present a lot of hard to handle false positives and make the system very complex.
Kosirich 3y ago
There is nothing wrong with 2 datums, the issue is that during machining this is not "a part" but an assembly that moves. There are so many failings from my POV in the manufacturing process and verification of the part, which is summarized nicely by the following quote: . Furthermore, initial inspections at the start of the production run were supposed to verify that the manufacturing process was creating products that satisfied the “design intent,” but the initial products were checked against the manufacturing drawings, not the design drawings.

atemerev 3y ago

Given the sad state of the world in general, I am in awe of aviation industry because it actually works as designed, where all millions of potential points of failure are handled gracefully (and airlines are still profitable somehow). A true miracle.

Grimburger 3y ago

> By specifying an landing weight in excess of the maximum, the system logic changed to apply the operational coefficient only once — for unrelated and obscure reasons — and lo and behold, when he ran the numbers this time, the computer said they could just barely land on any of the 4,000-meter runways at Singapore Changi Airport, with only 100 meters to spare. It wasn’t much, but with no better runways anywhere nearby, it would have to do. Hacking overflows in an emergency, topnotch.

liendolucas 3y ago

It's so interesting to read on aviation postmortems even for people that don't fully understand all the technical details as explained in the article (great by the way, kudos to the author). I've always wondered if there is an authoritative database with all significant events in aviation to read and learn more about? Do pilots study past events as part of their training?

EVa5I7bHFq9mnYK 3y ago

With the engine ruptured, still operating and the fuel leaking, how did they know the whole thing is not gonna explode at any moment?

aaronmdjones 3y ago
They didn't, which is why they shut it down.
- EVa5I7bHFq9mnYK 3y ago
  I've read the ruptured engine was still operating for 3 hours after the plane landed.
  - mauvehaus 3y ago
    Engine 1 was continuing to operate after landing because the fuel shutoff valves were inoperative. Engine 2 was the engine that had the uncontained failure.
  - aaronmdjones 3y ago
    The ruptured engine (#2) was shut down within a minute of the incident, in-flight. Two of the remaining engines (#3, #4) were shut down after landing. The last engine (#1) could not be shut down and had to be drowned in fire-fighting foam. This is in the article.

ogurechny 3y ago

The article is complex and well written, but I am a bit perplexed by the victorious tone and never-ending praise of safety. It resembles a sales pitch a bit too much, even though no one is selling anything. Maybe it's unintentional, and being around salesmen just does that to people. If you are like me, you've probably said “hmm…” to yourself multiple times when certain things were mentioned, because those were things that actually didn't work (that they were left intact really boosts the credibility of the author). From calculation software that had never ever been tested with out-of-ordinary data to the computer keeping the broken engine running. From pure luck with fuel tanks being almost full and unable to explode to absence of any physical kill switch to stop the engine. An hour being generously available to go through ALL the checklists to clear the notifications. An hour of passengers and crew staying on top of the poodle of fuel hoping that nothing would ignite it. Finally, pure randomness in debris flying the way it did. It's not a story of “layers of safety” overlapping, it's a story of “layers of randomness” overlapping. What would be really interesting is a distribution of outcomes for all possible trajectories of debris, i. e., how (un)lucky they actually were. I guess corporations don't release models like those to the public. Also, that special chamber for oil filter requiring precise drilling of a perfectly fine pipe seems “ewww” to me. It is not serviceable anyway without reinstalling everything from scratch, as far as I understand, why not make it a single piece?

Neil44 3y ago
I guess it's a glass half full type situation. There's a lot of universes where that plane did not make it back and a lot of decisions aligned to ensure that it did.
Game_Ender 3y ago
The author is positive because of all the safety layers that existed and staid intact, despite how flawed humans and companies are. The culture of looking at previous accidents like the UA232, where they lost ann engine and ALL controls with it, meant the A380 control system was engineered to take even more damage and it worked. I do agree though it did not spend enough effort focusing on the areas to improve: - A computer controlled engine that runs for 60 seconds while on fire, and lets a dangerous part spin too fast. It seems like something that should of been covered ahead of time. - An engine manufacturing process that is so complex it’s almost impossible to validate. - A fault management system that only shows you 1 or 2 at a time when you have 40.

class3shock 3y ago

Just throwing this out there, if anyone reading this knows of other writers/blogs/books/etc. similarly looking into aviation engineering/failures I would love some recommendations.

throwaway290 3y ago
https://avherald.com/ https://avherald.com/
dezgeg 3y ago
https://fearoflanding.com/ https://fearoflanding.com/

mrlonglong 3y ago

I applaud this article for being so thorough and informative on this subject. I hope Airbus changes their mind about building new ones. We like them even if airlines don't like the operating costs.

jdietrich 3y ago

To a half-competent machinist or manufacturing metrologist, half a millimetre of concentricity error on a part of that size might as well be half a mile. It's a huge, grievous error that can be seen with the naked eye. You don't get an error of that scale through normal variation, it's a clear sign of a serious problem with your setup. This part of the article really leapt out at me: The tolerance for this bore was supposed to be Ø 0.05 mm according to the design drawings, but was changed to Ø 0.5 mm in the manufacturing drawings without explanation. Even so, the non-conformance on the accident hub was between Ø 0.90 and Ø 0.98 (an offset of 0.45–0.49 mm), which should have been flagged by the machine. The CMM records from the accident hub were not retained, so it was not possible for investigators to confirm that the error was actually registered. The meaning might not be obvious if you've never worked in a machine shop, but it's crystal clear if you have. Many people at that plant knew that they were delivering out-of-spec parts. Everyone who handled that part could have told you at a glance that the counterbore was badly off-centre. Rather than going back to remake the parts, rather than figuring out why the parts were bad, they just went through the motions of QC, shipped them anyway, falsified documentation and discarded evidence. For all the complexity of the analysis, the root cause is blindingly simple - flagrant negligence, concealed by flagrant deceit.

ambyra 3y ago
The article said it wasn’t visible because that stub was machined after it was placed in the hub. Which begs the question “why would you weld a tube in place and then finish machining it after?” Maybe it was easier/faster to machine it while it was on a hub. Also, wasn’t there an oil filter that had to go in there? Wouldn’t the oil filter experience interference if the counterbore was offset? Closing comment: damn I thought people paid more attention when building turbines.
- spacecadet 3y ago
  Yes, but what the poster meant is that it would be and that is confirmed in the images.

ardel95 3y ago

The story of what happened in the cockpit during the failure is just as interesting! The captain made a number of right decisions in a very challenging situation that allowed the plane to safely land. Mentour Pilot did a video on that: https://youtu.be/JSMe1wAdMdg?si=YSgbqFpR_EBe-FvX https://youtu.be/JSMe1wAdMdg?si=YSgbqFpR_EBe-FvX

YeGoblynQueenne 3y ago

>> The story of Qantas flight 32, as told herein, is therefore not only the tale of a dramatic emergency, but a testament to the safety of aviation today — a story that should make every reader feel a little less fearful of flight. I'm not afraid of flight. I'm afraid of fall. (Sounds much better in Greek: δεν φοβάμαι την πτήση, φοβάμαι την πτώση).

matheusmoreira 3y ago

> It goes without saying that if any of the turbine fragments had entered the passenger cabin, there would have been injuries, if not fatalities Understatement of the century. Somehow those spinning discs completely missed those passengers!! They were in such a state that when they disintegrated they went up and through the wing, towards the ground and one nearly missed the plane itself, striking its ventral section instead of passenger cabins. That near miss took out a huge number of aircraft systems so how catastrophic would the damage have been if they had gone through the plane?? I read the entire article and my conclusion is their luck was immeasurable from the very beginning. They were blessed with such tremendous luck even before the flight crew got the chance to demonstrate their badassery and heroism. One of those discs destroyed part of a building.

smdyc1 3y ago

Had to chuckle at this: "If you have made it this far, I first of all commend your patience, and/or your nerdiness." A thoroughly enjoyable write-up this was.

contingencies 3y ago

Many things failed, at least: (1) failure to identify safety-critical parts for review (2) failure in design drawings made without regard for fabrication (3) failure to make reference to original design goals when altering part designs (4) bad machining plan altering work-holding during the machining (5) failure to inspect finished parts

contingencies 3y ago
(5) was particularly bad: an off center hole should have been visible to the naked eye of any trained machinist, and at least one person should have inspected all safety critical parts. This would have been the final fail-safe to catch the combination of all prior errors. It was not made. There's actually another failure - (6) - which is the failure to perform visual inspection of the assembling mechanic which should have generated a query or note at the very least. While at this point the mechanic is probably given specific points to check, and an aggressive timeline for assembly, and has little motivation to extend critical thinking beyond the assembly task as they cannot possibly intuit all of the design intent for every part and subassembly, a better run assembly process with a culture of observation would have had this flagged for verification with designers.

Log_out_ 3y ago

The part out of tolerance could have been caught by comparing it to a master part within tolerance? Laserscan it or capacitor probe measure it and encounters the lack of material. In car part companies there is usually a qm-lab drawing samples from production. Does airplane turbine production not have this step?

xony 3y ago

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