Live data from Hacker News

A Matter of Millimeters: The story of Qantas flight 32

admiralcloudberg.medium.com

171–180 of 307 posts

Re: A Matter of Millimeters: The story of Qantas flight 32

#171
post #6

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 o…

And that's how software should be written too..

Re: A Matter of Millimeters: The story of Qantas flight 32

#172

Earlier quoted context omitted.

As a former Boeing engineer, other industries can learn a great deal from how airplanes are designed. The Fukushima and Deepwater Horizon disasters were both "zipper" failures that showed little thought was given to "when X fails, then what?" Note I wrote when X fails, not if X fails. It's a different way of thinking.

I agree in principle, but I don't think industries should be looking at current-day Boeing's engineering practices except for an example of how a proud company's culture can rot from the inside out with fatal consequences.

Reminder that this article was about an aircraft built by Airbus.

(Airbus is not Boeing.)

Re: A Matter of Millimeters: The story of Qantas flight 32

#173

Earlier quoted context omitted.

They didn't, which is why they shut it down.

I've read the ruptured engine was still operating for 3 hours after the plane landed.

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.

Re: A Matter of Millimeters: The story of Qantas flight 32

#175

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 thing…

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.

Re: A Matter of Millimeters: The story of Qantas flight 32

#176
post #160

Earlier quoted context omitted.

I wouldn't say it's simply cost-benefit analysis. It's also scale of accidents. A whole lot more people die from car accidents, yet there are few reports on national news on accidents. So fewer people care. Meanwhile each time there is an aviation disaster, 100s of people die and it's all over the news for weeks. Similarly with train accidents and nuclear accidents. There where only 2 very large ones but they still h…

> I wouldn't say it's simply cost-benefit analysis. It's also scale of accidents. But that is cost/benefit analysis. When any accident can kill hundreds and do millions to billions in damage besides (to say nothing of the image damage to both the sector and the specific brand), the benefit of trying to prevent every accident is significant, so acceptable costs are commensurate.

I think it goes beyond what you'd expect just from the increased scale putting more lives at risk. Compare our regulatory system for buses and cars, two transportation options that are probably as close as possible to differing only in scale. Buses are ~65x less deadly than cars, and yet we still respond to the occasional shocking bus accident by trying to make them safer.

Which is actually counterproductive! This makes it harder to compete as a bus service, bus lines shut down, and more people drive. I wrote more about this at https://www.jefftk.com/p/make-buses-dangerous and https://www.jefftk.com/p/in-light-of-crashes-we-should-not-m...

Re: A Matter of Millimeters: The story of Qantas flight 32

#177

Earlier quoted context omitted.

They didn't, which is why they shut it down.

I've read the ruptured engine was still operating for 3 hours after the plane landed.

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.

Re: A Matter of Millimeters: The story of Qantas flight 32

#178

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 w…

I had a small experience with RR as a company through a contract. Including some time spent in Derby. The things I saw left me question how any innovation could happen at all in there or why we did not have a much higher rate of fuck-you-shima per year or how the hell plane engines are not exploding daily. IIRC the B777 engine controllers are still m68k. Discontinued in 1995.

> IIRC the B777 engine controllers are still m68k. Discontinued in 1995.

That seems sensible? You’d need a really compelling reason to rewrite the entire control software and recertify the engine to match. Especially for an engine which has seen no order in 15 years.

Re: A Matter of Millimeters: The story of Qantas flight 32

#179

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 thing…

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.

Re: A Matter of Millimeters: The story of Qantas flight 32

#180

Earlier quoted context omitted.

Because its dead simple to machine a center and the designer did not factor in machinist/engineer/qa/facility incompetence.

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…

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.
Post reply on HN