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.
A Matter of Millimeters: The story of Qantas flight 32
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Re: A Matter of Millimeters: The story of Qantas flight 32
#32And 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.
> 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.
Re: A Matter of Millimeters: The story of Qantas flight 32
#33there 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 >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…
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.
Re: A Matter of Millimeters: The story of Qantas flight 32
#3430 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.
Re: A Matter of Millimeters: The story of Qantas flight 32
#35My 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.
Re: A Matter of Millimeters: The story of Qantas flight 32
#36I 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.
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.
Re: A Matter of Millimeters: The story of Qantas flight 32
#37And 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.
> 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.
Also, let's not completely discount remote pilots
Re: A Matter of Millimeters: The story of Qantas flight 32
#38Earlier quoted context omitted.
> 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.
Also, let's not completely discount remote pilots
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.
Re: A Matter of Millimeters: The story of Qantas flight 32
#39I'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?
Re: A Matter of Millimeters: The story of Qantas flight 32
#40I 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.