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Posted by gumby 10 hours ago

Qantas Airbus A380 engine failure in 2010 (2023)(admiralcloudberg.medium.com)
103 points | 60 comments
paulmooreparks 3 hours ago|
I flew on this exact same plane, VH-OQA, on November 4, 2019, from Singapore to Melbourne.

While I was sitting at the gate, I remembered that line from Rain Main about "Qantas never crashed," and since that flight would be my first time flying on an A380, I wondered if any had crashed or had any other incidents. I looked up "a380 crash" on my phone, and what do you know? The first hit was a Wikipedia article about a Qantas A380 uncontained engine failure, which had occurred four minutes after takeoff... from Changi! Even wilder was the fact that it had happened 9 years earlier. When I looked up the plane's registration number on Flightradar24, I realized that was the same plane I was flying to Melbourne on.

gregjw 2 hours ago|
yikes, im sure that didnt freak you out at all.
Insanity 46 minutes ago||
I'd be insanely stressed about this. While at the same time realizing that logically it has flown for _years_ without incident afterwards.
emtel 13 minutes ago||
Can anyone explain why on earth you would counter bore a pipe at all, let alone after installation? I read the article but couldn’t understand the explanation. It seems like a totally ludicrous way to make a pipe.
u1hcw9nx 9 hours ago||
Turbine disk failure is one thing that can down a plane, and you can only reduce the probability so much.

Fan blades and turbine blades can be contained by containment cases if they break off, but turbine disks can't. When a disk breaks, it's an uncontained engine failure. A 20 kg disk fragment flying at Mach 1 goes through everything.

Airframes are have a 30-degree fragment spread cone around every disk stage. Airframes are designed so that no single fragment can destroy all redundant systems at once in this zone (flight controls, fuel lines, and hydraulic systems). Jet fuel cannot be stored in the wings in this zone.

chasil 8 hours ago||
I admit that I glossed over the section on the machining of the oil pipe, but the facility appears to bear most of the blame.

These were pulled and scrapped from the whole A380 fleet.

"Investigators also criticized the culture within the Hucknall facility that manufactured the HP/IP bearing hubs, identifying signs of complacency and widespread procedural non-compliance. A paperwork review showed that the required signatures were missing from 131 out of 138 retrospective concessions issued between 2009 and 2011, and a large number of minor non-conformances had not been properly handled through the normal chain of command."

jacquesm 7 hours ago||
That's an oversight failure as much as a failure of that plant.
NetMageSCW 5 hours ago||
The oversight was at the plant.
jacquesm 3 hours ago||
Yes, but there are levels of oversight and this kind of thing should not be possible to hide. Someone on the official side of this messed up as well.
mcapodici 4 hours ago|||
It is worse than even that:

> Within the space of four seconds, the energy from the annulus gas flow accelerated the IP turbine past its critical speed, until centrifugal forces exceeded the ultimate strength of the nickel alloy disk. The red-hot, wildly spinning disk instantly fractured into several sections, which rocketed outward in multiple directions at incomprehensible speed.

mr_toad 1 hour 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, even if the plane later landed safely.”

They got lucky.

usefulcat 7 hours ago|||
> Jet fuel cannot be stored in the wings in this zone.

TFA describes a fuel leak resulting from a piece of the turbine disk passing through a fuel tank located within the wing:

"When the fragments of the IP turbine disk passed through the wing and belly of the A380, they caused considerable secondary damage along the way, not only to the №2 engine but also to the left wing fuel tank, which sprang a leak"

It also includes a photo of the inside of the damaged wing tank.

Was the requirement you describe added after this incident?

ahartmetz 7 hours ago||
Seems close to impossible for existing designs. The wings are commonly almost entirely full of fuel at max fuel, and I doubt that taking the capacity hit is an option even in newly designed planes.
amelius 7 hours ago|||
But it seems to me that the whole failure could have been prevented with a bunch of temperature sensors spread throughout the engine, and a good anomaly detection system.
Farmadupe 3 hours ago||
Don't know why you're getting faded out, because having worked on exactly this engine, software mitigations were put in place. That's exactly your `anomaly detection system`

It was a belt-and-braces fix, because the primary fix was of course to manufacture the engines correctly in the first place.

The "lots of temperature sensors" thing is actually easier said than done; jet engines already have lots of temperature sensors, and they will turn the engine off if a huge overtemperature is detected, but it's not a free win to add more of them. It increases the risk of a faulty sensor shutting down a perfectly good engine in flight, which from a safety-critical perspective is a borderline disaster condition all by itself.

(technically you usually cross-correlate temperature sensor readings with pressure sensor readings to prevent sensor faults turning engines off, but still, extra sensors isn't always a free win.)

polishdude20 8 hours ago||
What's a turbine disc?
gumby 8 hours ago||
It’s explained in the article
CursedSilicon 9 hours ago||
One of my favourite memories of flying Qantas when I was younger was the inflight entertainment.

If memory serves, they were celebrating some sort of milestone like "60 years without a fatal accident" or similar. Quite an impressive feat!

I'm unclear if it was directly related. But the Qantas inflight entertainment system on our flight from Sydney to Los Angeles meanwhile contained about 12 seasons of the National Geographic series "Air Crash Investigation" (Mayday: Air Disasters for Americans)

I will admit that show made an 18 hour slog of a flight significantly more enjoyable

Insanity 43 minutes ago||
Lol, I quite like the show and considered watching it. But then thought other passengers on the plane might see it and become a bit unsettled by it.

So last few times I opted for "To Catch A Smuggler". Still flight related but hopefully less unsettling.

AdamJacobMuller 4 hours ago|||
Watching Mayday on flights is one of my favorite things to do for some odd reason.
annzabelle 48 minutes ago||
There's a podcast (that's been on "hiatus" for 6 years) that I used to listen to that would do an air crash segment. The show was called Hello Internet, and I would always try to queue up the air crash episodes for any flights I was on.

One of the hosts recently started a new podcast called Runway 23 that's mostly about air crashes, and his cohost is actually a Qantas pilot.

alex1138 3 hours ago||
That's hilarious. They don't think about "hey, maybe not show this, we might have nervous passengers"?
dostick 4 hours ago||
The whole incident was because of 0.2mm offset in a machined part! And the company that made the part ignored the quality compliance process was not fired. I wonder why - did Airbus think it’s their failure not to verify that the subcontractor adhered to procedures?
quink 2 hours ago|
This feels more like engine manufacturer QC rather than anything Airbus.

Because also, from Wikipedia: On 22 June 2011, Qantas announced that it had agreed to a compensation of AUD$95 million (£62 million/US$100 million) from Rolls-Royce. - skipping Airbus entirely.

libraryofbabel 7 hours ago||
I once heard someone describe Admiral Cloudberg's air crash investigation blog as "the best thing on the Internet" and I still think that might be true. She is a great researcher and a superb writer, which stands out all the more these days in these fallen times of load-bearing AI slop. Her blog is beloved of both aviation geeks and, for obvious reasons, SREs (and other engineers).

She recently posted what's basically her magnum opus, on the Potomac river midair collision.[0] It's the length of a short book. I'm working my way through it; I'm taking a flight today, and I'll probably read it on the plane tonight.

This article, on how an A380 with 469 souls aboard almost crashed, but didn't, is one of her best. I like it because it's a happy ending, and a story of the combined effects of good engineering design (the astonishing degree of redundancy built into the A380 proved just enough to prevent catastrophe), and human troubleshooting under pressure in the cockpit by some smart people with vast experience who remained calm throughout. (Another favorite article of her, on the Air France 447 crash, tells the exact opposite story: poor systems design combined with pilots basically losing the most basic ability to aviate in the heat of the moment. That one is a much darker read.[1])

[0] https://admiralcloudberg.medium.com/reaping-the-whirlwind-in... [1] https://admiralcloudberg.medium.com/the-long-way-down-the-cr...

exceptione 7 hours ago||

  > The detailed software allowed them to enter various parameters including the weather, runway condition, and any systems failures, and then calculate whether it was possible to land. But when everything had been entered, the program spit out an unhelpful answer: “no result.”

 > When calculating the landing distance, the software applied a generic “operational coefficient” to account conservatively for variations in pilot techniques that could result in less efficient deceleration. The problem, as investigators would later discover, was that the software applied the coefficient again whenever another system failure was added. With so many system failures on the aircraft, the coefficient was applied a total of 9 times, resulting in a calculated landing distance considerably greater than the length of the available runway. However, Check Captain Evans was able to fix the problem by manually entering their actual landing weight, overriding the program’s assumption of a maximum landing weight. By specifying a 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.
This reeks so much of if-then-else programming as opposed to making a well-typed conceptual model computable.
ShinyLeftPad 1 hour ago||
disc fragments didn't kill anyone just by accident. Have they not considered not seating anyone in the plane of the discs...
seemaze 8 hours ago||
This remarkable event, along with the an accessible history of the evolution of precision manufacturing is covered in Simon Winchester's excellent book The Perfectionists[0]. The audiobook is narrated by the author, which is quite enjoyable as well.

[0]https://www.harpercollins.com/products/the-perfectionists-si...

NetMageSCW 5 hours ago|
Retroactive, but one thing that struck me since they were overweight for landing and their fuel dump was inoperative, why not turn on the leveling pump and pump fuel out the hole in the left tank anyway? It would have lowered weight and improved balance.
vient 5 hours ago|
I got an impression from the text that pilots were not sure the fuel levelling line does not have a leak itself. Maybe they were afraid the line can leak fuel into fuselage somehow?
sleepy_keita 3 hours ago||
They got a warning that the fuel transfer system was damaged, so they decided not to use it, I think.
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