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Qantas Airbus A380 engine failure in 2010 (2023)

admiralcloudberg.medium.com

91–100 of 122 posts

Re: Qantas Airbus A380 engine failure in 2010 (2023)

#91
post #62

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.

The counterbore accommodates a filter element. Maybe they were worried it could change the interference fit if they drilled them before installation, or wanted the swaging effect.

It's probably significantly easier to machine it this way. The pipe is curved, so work holding isn't straightforward. Once the blank is installed in its place in the bearing chamber face then you can just move that larger part around to machine all the features in it, including the counterbore.

Re: Qantas Airbus A380 engine failure in 2010 (2023)

#92
post #84

Earlier quoted context omitted.

It's not (purely) the sales and finance people, planes need to be able to get off the ground to be useful at all. I doubt even an A380 would still be able to lift off if you strap a dozen inches of armor plating to every part of the plane that could possibly be reached by shrapnel.

You'd put the containment armor directly around the engine. It wouldn't take dozens of inches. Whether you use Newton's rule of thumb (penetration ends when the mass of armor displaced equals the mass of the shell that hit it) or more modern rules - a failing turbine disk is neither a precision-engineered anti-armor weapon, nor a heavy battleship shell. I'd bet the plane would still be able to take off, if it made it…

Full containment is probably possible, but it would render the aircraft nearly useless, not just economically uncompetitive.

A 70kg chunk of nickel alloy is very dense, and at 800m/s , that’s 20 MJ. Thats about the same as 5kg of TNT, but focused on a small area.

For comparison, a modern 120mm artillery shell fired from a tank or similar field artillery has 10-20 MJ of kinetic energy.

A couple thousand kg of armour could likely contain that kind of energy, but it would also translate that energy to the engine mounts, wing, spar, and fuselage if it was not going to become a projectile itself. You could easily stop a fragment and critically damage a spar attachment, rupture a wing fuel tank, or end up with translational shock damage to any number of critical systems and structures. You’d probably have to double or triple your engineering margins of the entire aircraft, probably doubling the weight of the airframe.

So yeah, possible probably. But not on an aircraft designed to carry passengers or freight. It would be the biggest 6 seat aircraft ever built lol.

Interestingly, if you work backwards from that cargo capacity, you can arrive at a much smaller aircraft that could possibly feature full containment, because engine diameter and energy goes way down and containment starts to look much more practical. I would not be surprised if containment could be achieved in the small biz jet scale, with just significant sacrifices in cargo or range.

OTOH even the A10 warthog does not have full disk containment, and it’s probably the strongest candidate ever fielded for such a project… so, ymmv.

Re: Qantas Airbus A380 engine failure in 2010 (2023)

#93
post #27

Earlier quoted context omitted.

> That created the dangerous situation where they couldn't turn off the engine after landing. Which is vastly preferable compared to all of the dangerous situations just prior to that landing.

The vastly preferable situation was to have redundant wiring that properly complied with regulations, which was retrofitted in an airworthiness directive (safety recall) after the accident. They also required engine software that detected the sudden increase in speed associated with a shaft break and automatically cut fuel.

Sort of. Rolls Royce voluntarily developed this software modification in response to learning that their reasoning about it never being able to happen was incorrect and being unable to concretely account for how it happened. EASA, which was not even the relevant safety authority for this incident, upon learning of its existence, only then required it to be installed on all A380 Trent 900 engines.

Re: Qantas Airbus A380 engine failure in 2010 (2023)

#94
post #43
post #14

Catastrophic failure? Check Plane landed without casualties? Check Plane design so good it helped avoid casualties? Check Hum... Ah! Not an american Boeing but a french Airbus. Of course. The article mentions this story should make everyone a little less afraid of flying. Sure, as long as its not on a Boeing plane.

The plane was a significant factor but you really shouldn't look past the calibre of expertise in the cabin on this particular flight. > 5 pilots were in the cockpit of this flight. In addition to the normal crew of pilot-in-command and co-pilot, there was an experienced relief pilot and two additional check captains; one was being trained as a check captain (CC) and the supervising CC, who was training the CC. Capta…

It was probably helped by the fact that airbus didn’t try to pretend that the aircraft was just a slightly different version of some previous aircraft and therefore doesn’t require any additional training lol.

Re: Qantas Airbus A380 engine failure in 2010 (2023)

#95

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 basicall…

Going to plug her Patreon (https://www.patreon.com/Admiral_Cloudberg) here because her articles are extensively researched and consistently well-written, and I enjoy reading them, and hope to continue reading new ones in the future!

Re: Qantas Airbus A380 engine failure in 2010 (2023)

#96
post #3

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. Airfr…

As it sounds like you have some knowledge about these engines, from the article:

“These [combustion] gases spin the [turbine] disk, which is attached by a drive arm to its associated drive shaft. The shaft then transfers the turbine’s rotational energy forward to the corresponding compressor at the front of the engine.”

I'm probably misunderstanding, but it sounds like the disk is attached to the shaft by a single so-called “drive arm”, which could be imagined to span maybe 10° on the circumference. I would have thought there'd be at least 3 such arms at 120° intervals, if not a continuous full 360° connection, which then I wouldn't call an arm. Could you clarify this point?

Re: Qantas Airbus A380 engine failure in 2010 (2023)

#97

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 basicall…

This was a scary one to read:

https://admiralcloudberg.medium.com/years-of-salt-and-metal-...

It baffles me that that airlines can run so well on check lists and procedures instead of thinking and understanding. This is a case where just a tiny bit of understanding on the part of the mechanics would have avoided a crash and two deaths.

Re: Qantas Airbus A380 engine failure in 2010 (2023)

#98
post #55

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…

yikes, im sure that didnt freak you out at all.

I wouldn't, the A380 is designed to fly with just one operational engine.

Re: Qantas Airbus A380 engine failure in 2010 (2023)

#99

> 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 p…

reads like a glitch from Pokemon Red/Blue (Gen1). Even the simplest tests would have catched this issue.

Re: Qantas Airbus A380 engine failure in 2010 (2023)

#100
post #55

Earlier quoted context omitted.

yikes, im sure that didnt freak you out at all.

I wouldn't, the A380 is designed to fly with just one operational engine.

There is no way an a380 is maintaining level flight with only one engine.
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