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News Air France plane engine fails over Atlantic
- Thread starter Notebook
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MaverickSawyer
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Wow. Uncontained fan failures like that are rare for a reason.
Some unlucky mechanic is going to their license over this.
Some unlucky mechanic is going to their license over this.
RisingFury
OBSP developer
This is the reason why for the longest time, the FAA would not allow two engine aircraft to fly over the ocean. Engines are more reliable these days, leading to the ETOPS rating. Today is just a reminder that failures like these do happen...
ETOPS = Engines Turn Or Passengers Swim
The A380 is a safe aircraft, but this is the second serious engine failure...
ETOPS = Engines Turn Or Passengers Swim
The A380 is a safe aircraft, but this is the second serious engine failure...
ADSWNJ
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(Qantas 32 being the first.)
That makes one major engine issue for RR and now one for GE. It's a testament to the strength of the airframe that in both cases there were no casualties.
Artlav
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Well, uncontained fan disk failure is the worst case scenario the engines and airframes are designed for.
If you want a testament, you'll have to see what would happen after a turbine disk ruptures. Fortunately that never happened since the 50s or so.
Andy44
owner: Oil Creek Astronautix
More likely it's just luck that flying debris didn't hit the right spot.
Linguofreak
Well-known member
Nice how the BBC interviewed the right passenger (and that a mechanic was on board for them to interview). I've seen far too many cases where the media just, e.g, interviewed random passengers after a cabin pressure loss and came out with a story to the effect of "passengers screamed in terror as the plane plummeted towards the ground" (i.e, there was a rather frightening falling sensation as the crew began a rapid descent towards breathable air).
---------- Post added at 18:19 ---------- Previous post was at 17:48 ----------
I'll note that, according to Wikipedia, the aircraft in the Qantas incident was using Trent engines, whereas this one had EA engines, so it's more freak coincidence than an indication that a specific engine model is Perrine to uncontained failures.
---------- Post added at 18:19 ---------- Previous post was at 17:48 ----------
I'll note that, according to Wikipedia, the aircraft in the Qantas incident was using Trent engines, whereas this one had EA engines, so it's more freak coincidence than an indication that a specific engine model is Perrine to uncontained failures.
ADSWNJ
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I'd love to understand the failure modes and fluid dynamics for a main fan fail in cruise like this. Wild speculation on my part ... I could imagine driveshaft failure (with the fan rocketing forwards and then over the wing), or cascading failure of bearings or blades on the fan leading to enough asymmetry that the fan literally is shaken off (then forwards and up over the wing as well).
boogabooga
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You can check Youtube for fan failure testing high-speed camera footage.
ADSWNJ
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I've seen individual fan blade fail tests, and FOD tests, but never a whole fan disk failure. You got any links to one of those? If this was done in a static rig, I assume the fan disk would rocket forward with crazy velocity.
boogabooga
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Yeah, they seem to be all single disk failure tests.
Linguofreak
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Well, from what I recall of the last blade fail video I saw, a single blade failure knocks all the other blades loose in a rotation or two (not to mention throwing the fan out of balance) and quickly becomes a whole-disk failure. I think what you're really asking about is a shaft failure between the fan and compressor. Assuming a clean, straight-across break that developed in much less time than a single rotation of the fan, the fan might just shoot straight forward out of the engine, but I've never heard of such a failure occurring. If it did occur I'd expect a crack to develop asymmetrically from one side of the shaft to the other over the lifetime of the engine, until that side of the shaft could move forward enough to cause significant vibration as the fan rotated.at that point I'd expect the shaft forward of the crack to break loose in fairly short order, but it would probably throw all the fan blades off before it separated.
In other words, I expect all failures involving the mechanical failure of a rotating part to look pretty much identical from the perspective of the engine casing: a large number of blades break free and are thrown centrifugally into the casing, which, hopefully, does its job and catches them, whereafter they are caught by the airstream and pass out of the engine through the tailpipe (possibly causing similar blade-throws in the disks located aft of the initial failure point as they hit components downstream), or, if the casing doesn't catch them, they become shrapnel flying out perpendicular to the axis of the engine.
ADSWNJ
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Latest from Avherald.com: First observation of the engine suggests, the fan - the first rotating element - detached in flight dragging the air inlet with it. The damage appears to be limited to engine #4 and its immediate environment.
Seems like we may have a fairly unique failure here.
Seems like we may have a fairly unique failure here.
boogabooga
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:blink:
Andy44
owner: Oil Creek Astronautix
That's astonishing, I was thinking that would be needle-in-a-haystack hard to do. They should get that same team to go find MH370...
Mm.. not really.. the flight path of the plane was known 100%. And it was known exactly when and where the engine failed. All they had to do fly the same path at low altitude and go get the parts.
Lucky that it was on an ice-shelf and not sunk in the sea.
Lucky that it was on an ice-shelf and not sunk in the sea.
Linguofreak
Well-known member
Nah. You have the black box, the plane has GPS, you know from examining the remaining parts of the engine and the FADEC data from the black box an approximate failure mode, from which you can guess at the velocity with which the pieces left the aircraft, and maybe how big they were (which from which you can guess at the effects of air resistance). If the fan indeed left the aircraft intact, you can probably model fairly straighforwardly how it would fall (mass and shape, minus any damage, are known). So knowing how the debris will fall, you just plug in the GPS coordinates at the time of the event as a starting point, and probably calculate with fairly good accuracy where it will land. Given that the aircraft was over Greenland at the time, once you have that, the search probably isn't too hard. You're looking for the only thing that isn't snow colored. Now, if it had fallen onto something other than a featureless expanse of snow, it would be harder to find. If it had landed it water, good luck.
What surprises me is that ADSWNJ seems to have been right about the failure mode. I didn't think such a symmetrical failure was even possible. (My Dad, though, pointed out to me that the thrust produced by the fan will be taken up by a thrust bearing, not the shaft itself, and if that thrust bearing fails, the shaft will find itself under incredible tension and fail quite abruptly. He's the one with an actual aerospace engineering degree, so I'll take his word for it).
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