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Air France A380 over Greenland on Sep 30th: Fan and engine inlet separated

avherald.com

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Re: Air France A380 over Greenland on Sep 30th: Fan and engine inlet separated

#61

Post by WalterBright »

ajarmst wrote: post #57
SmellTheGlove wrote: post #30

It's amazing to me that modern aircraft engineering is so good that an engine can lose its fan blade entirely at 35000 feet and the plane can still continue on for 2 hours and safely land. An uncontained failure like this is the worst kind, and I know it could have gone worse, but it didn't and that amazes me. I wonder if the cowling contained the initial disintegration but was removed in the process. I'm not an engi…

Agreed. When I saw the amount of damage, but little on the wing edge (there may be damage on the underside), I assumed the engine maintained confinement long enough to dissipate a lot of energy. If the cowl was damaged during this, then it may have then come off due to aerodymic stress. Either that or they were very lucky. From the photo I saw, it looks like they lost the forward cowl, fan and maybe a compressor stag…

> I assumed the engine maintained confinement long enough to dissipate a lot of energy.

Not unless the cowling was armored, which it wasn't at least back in the 80's. That thin sheet of aluminum won't even be noticed by the high strength fan spinning at tremendous speeds.

Re: Air France A380 over Greenland on Sep 30th: Fan and engine inlet separated

#62

Post by WalterBright »

anarazel wrote: post #13
revelation wrote: post #10

Earlier quoted context omitted.

I mean, primary and backup hydraulics are hopelessly intertwined on this systems diagram, certainly physically. Not sure how much that is going to help against parts flying into it. Which is of course what happened in that linked incident below: https://en.wikipedia.org/wiki/United_Airlines_Flight_232 The three hydraulic systems were separate, so that failure of any one of them would leave the crew with full control,…

IIRC there's valves to contain such failures at regular intervals. And the electrical backup system can then provide some power in the cutoff sections. I'd hope that airplane designers learned a thing or two since the DC-10 (and have some additional tools to play with).

They do learn from every accident. It's why every accident is thoroughly investigated and the causes determined as well as possible.

Re: Air France A380 over Greenland on Sep 30th: Fan and engine inlet separated

#63

Post by WalterBright »

myth_buster wrote: post #32

Are there any serious dangers of debris falling over settlements in scenarios like these?

Just don't live under the airport approach and departure corridors. (I live under the landing corridor, I enjoy watching the airliners float by overhead.)

Watch out for blue meteorites :-)

Re: Air France A380 over Greenland on Sep 30th: Fan and engine inlet separated

#65

Post by cialowicz »

WalterBright wrote: post #60
CydeWeys wrote: post #51

Earlier quoted context omitted.

The A380 has four engines in total, and can easily tolerate the loss of just one in normal flight. Adding more engines has been a basic way to increase reliability since the beginning of the field; it's not just modern aircraft engineering. There's no other part of the airplane behind the engines either, so nothing to be hit by debris. What amazes me more is that the newest twinjets are now considered reliable enough…

> There's no other part of the airplane behind the engines either, so nothing to be hit by debris. The fans spin very fast, and will fly out radially, not just fall back. They'll slice right through anything they contact. The Airbus flight was very, very lucky.

The engines are designed so that a detached fan blade stays contained within the cowling. Here's a video of a fan blade containment test on a Rolls Royce Trent 500: https://youtu.be/RIOWjhjC1jM

Re: Air France A380 over Greenland on Sep 30th: Fan and engine inlet separated

#66

Post by candiodari »

SmellTheGlove wrote: post #30

It's amazing to me that modern aircraft engineering is so good that an engine can lose its fan blade entirely at 35000 feet and the plane can still continue on for 2 hours and safely land. An uncontained failure like this is the worst kind, and I know it could have gone worse, but it didn't and that amazes me. I wonder if the cowling contained the initial disintegration but was removed in the process. I'm not an engi…

The thing about it is, that these sorts of things get designed because of evolution. Some engine fails in some way, and it gets redesigned. Planes fail, ditto.

And after >100 years of that, we have pretty safe planes.

What most amazes me is that despite the scientific knowledge we "have", we can't design a new engine from first principles directly. We do it through trial and error. Lots of hilarious/horrible error.

Re: Air France A380 over Greenland on Sep 30th: Fan and engine inlet separated

#67

Post by cm2187 »

userbinator wrote: post #36
nabla9 wrote: post #2

It's more than just fan blade failure. Engines are tested against fan blade failures. The surrounding cowling should contain it. In this case the whole fan disk is gone. Uncontained failure like this can down the plane depending on the where the parts fly.

Indeed, you could say that the front fell off. That's not very typical.

Can't help thinking of El Al flight 1862's weird "engine fell off" scenario:

https://youtu.be/QkWUIaEoUls?t=36m49s

Re: Air France A380 over Greenland on Sep 30th: Fan and engine inlet separated

#68

Post by userbinator »

magnat wrote: post #64

That's the most neutral-point-of-view flight incident news article I've seen for quite some time. The whole site is so refreshingly level-headed.

AVherald is run by a single person who just compiles reports of incidents as they're received, so there's absolutely no editorialising goes on.

Re: Air France A380 over Greenland on Sep 30th: Fan and engine inlet separated

#70

Post by InternetOfStuff »

WalterBright wrote: post #61
ajarmst wrote: post #57

Earlier quoted context omitted.

Agreed. When I saw the amount of damage, but little on the wing edge (there may be damage on the underside), I assumed the engine maintained confinement long enough to dissipate a lot of energy. If the cowl was damaged during this, then it may have then come off due to aerodymic stress. Either that or they were very lucky. From the photo I saw, it looks like they lost the forward cowl, fan and maybe a compressor stag…

> I assumed the engine maintained confinement long enough to dissipate a lot of energy. Not unless the cowling was armored, which it wasn't at least back in the 80's. That thin sheet of aluminum won't even be noticed by the high strength fan spinning at tremendous speeds.

> Not unless the cowling was armored, which it wasn't at least back in the 80's.

AFAIK part of engine qualification is proving that the nacelle will retain a fan blade breaking off at full throttle. There are remarkable youtube videos of these qualification tests.

The entire fan is another matter though. I assume the nacelle will offer some resistance, but not contain it entirely.

And the turbines as well, they don't even attempt to retain those.

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