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

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

#51

Post by CydeWeys »

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 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 to fly six hours away from the nearest landing strip -- that's how far they can coast on the single remaining engine if necessary!

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

#52

Post by CydeWeys »

myth_buster wrote: post #32

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

There's thousands of other more dangerous things you should worry about in your daily life. Like lightning or shark attacks.

Now on the other hand, you could be taken out by an entire airplane crashing, e.g. https://en.wikipedia.org/wiki/American_Airlines_Flight_587

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

#53

Post by inamberclad »

CydeWeys wrote: post #51
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 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…

It's not really coasting. A transport category aircraft is required to have enough power to continue climbing if it loses an engine, so it must also have enough power to maintain level flight indefinitely (barring fuel consumption, oil leaks, or mechanical damage from an engine failure)

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

#54

Post by CydeWeys »

inamberclad wrote: post #53
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…

It's not really coasting. A transport category aircraft is required to have enough power to continue climbing if it loses an engine, so it must also have enough power to maintain level flight indefinitely (barring fuel consumption, oil leaks, or mechanical damage from an engine failure)

I meant to say "cruise", if that makes more sense.

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

#55

Post by timb07 »

CydeWeys wrote: post #51
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 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…

Actually, adding engines increases resilience, or the ability to tolerate failure.

The extra complexity of extra engines actually reduces reliability, since there are more components that can fail.

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

#56

Post by timb07 »

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.

It's rare that the funny response is actually more likely to be the accurate response.

One possibility is that the fan shaft failed, and since the fan was no longer attached to the plane that it had been pulling through the sky, it went happily ahead by itself (perhaps still in one piece), taking the cowling with it.

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

#57

Post by ajarmst »

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 stage. If I had to guess, failure of the low-pressure shaft.

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

#58

Post by ajarmst »

timb07 wrote: post #56
userbinator wrote: post #36

Earlier quoted context omitted.

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

It's rare that the funny response is actually more likely to be the accurate response. One possibility is that the fan shaft failed, and since the fan was no longer attached to the plane that it had been pulling through the sky, it went happily ahead by itself (perhaps still in one piece), taking the cowling with it.

That was my initial guess. It could also have been a contained failure that damaged the cowl, which later separated from aerodynamic stress. But the missing fan (and maybe a compressor stage) does seem to imply a shaft failure. The main question is whether that was the beginning of the event, or a later result from a different failure.

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

#59

Post by anyfoo »

Judgmentality wrote: post #48
noobermin wrote: post #37

Earlier quoted context omitted.

I know we're not supposed to upvote or acknowledge jokes on HN, but this was in such good taste I couldn't resist.

https://news.ycombinator.com/newsguidelines.html It doesn't say anything about jokes.

I think the unspoken agreement is that nobody wants HN discussions to turn into reddit with its overabundant pun threads and "funny" one liners. But this one was on point.

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

#60

Post by WalterBright »

CydeWeys wrote: post #51
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 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.

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