Comments

**Notebook** · #1

Quote:

An Air France flight from Paris to Los Angeles was forced to make a sudden diversion when it lost part of an engine over the Atlantic.
One of the four engines on the Airbus 380 flight AF66 failed west of Greenland on Saturday.

http://www.bbc.co.uk/news/world-europe-41454712

MaverickSawyer · 09-30-2017, 10:11 PM

Wow. Uncontained fan failures like that are rare for a reason.

Some unlucky mechanic is going to their license over this.

RisingFury · 09-30-2017, 11:08 PM

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...

ADSWNJ · 10-01-2017, 04:35 PM

Quote:

Originally Posted by RisingFury

The A380 is a safe aircraft, but this is the second serious engine failure...

(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** · 10-01-2017, 04:45 PM

Quote:

Originally Posted by ADSWNJ

It's a testament to the strength of the airframe that in both cases there were no casualties.

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 · 10-01-2017, 04:45 PM

Quote:

Originally Posted by ADSWNJ

(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.

More likely it's just luck that flying debris didn't hit the right spot.

Linguofreak · 10-01-2017, 06:19 PM

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 ----------

Quote:

Originally Posted by RisingFury

The A380 is a safe aircraft, but this is the second serious engine failure...

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.

Evil_Onyx · 10-01-2017, 08:19 PM

I think its more of a indication of how close to the limit those engines actually operate.

ADSWNJ · 10-01-2017, 09:36 PM

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).

**Notebook** · 10-02-2017, 07:14 AM

I know the A380 has a camera in the tail. hopefully they will get some useful material from that.

N.

boogabooga · 10-02-2017, 02:48 PM

Quote:

Originally Posted by ADSWNJ

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).

You can check Youtube for fan failure testing high-speed camera footage.

ADSWNJ · 10-03-2017, 12:34 AM

Quote:

Originally Posted by boogabooga

You can check Youtube for fan failure testing high-speed camera footage.

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 · 10-03-2017, 06:20 PM

Yeah, they seem to be all single disk failure tests.

Linguofreak · 10-03-2017, 07:38 PM

Quote:

Originally Posted by ADSWNJ

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.

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 · 10-06-2017, 01:26 AM

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.

Quick Links	Need Help?
About Us Register to Participate Orbiter Website Orbiter Download Projects Recommended Addons Orbit Hangar Mods Photo Gallery Social Groups External Links	Did you forget your password? Rules & Guidelines Frequently Asked Questions Orbiter F.A.Q. Orbiter Tutorials Orbiter IRC Chat Search Forum Site Map Contact Us Mark Forums Read

09-30-2017, 10:11 PM	#2
MaverickSawyer Acolyte of the Probe	Wow. Uncontained fan failures like that are rare for a reason. Some unlucky mechanic is going to their license over this.

09-30-2017, 11:08 PM	#3
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...

10-01-2017, 04:35 PM	#4
ADSWNJ Scientist	Quote: Originally Posted by RisingFury The A380 is a safe aircraft, but this is the second serious engine failure... (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.

10-01-2017, 04:45 PM	#5
Artlav Aperiodic traveller	Quote: Originally Posted by ADSWNJ It's a testament to the strength of the airframe that in both cases there were no casualties. 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.

10-01-2017, 04:45 PM	#6
Andy44 owner: Oil Creek Astronautix	Quote: Originally Posted by ADSWNJ (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. More likely it's just luck that flying debris didn't hit the right spot.

10-01-2017, 06:19 PM	#7
Linguofreak Orbinaut	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 ---------- Quote: Originally Posted by RisingFury The A380 is a safe aircraft, but this is the second serious engine failure... 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.

10-01-2017, 08:19 PM	#8
Evil_Onyx Orbinaut	I think its more of a indication of how close to the limit those engines actually operate.

10-01-2017, 09:36 PM	#9
ADSWNJ Scientist	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).

10-02-2017, 07:14 AM	#10
Notebook Donator	I know the A380 has a camera in the tail. hopefully they will get some useful material from that. N.

10-02-2017, 02:48 PM	#11
boogabooga Bug Crusher	Quote: Originally Posted by ADSWNJ 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). You can check Youtube for fan failure testing high-speed camera footage.

10-03-2017, 12:34 AM	#12
ADSWNJ Scientist	Quote: Originally Posted by boogabooga You can check Youtube for fan failure testing high-speed camera footage. 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.

10-03-2017, 06:20 PM	#13
boogabooga Bug Crusher	Yeah, they seem to be all single disk failure tests.

10-03-2017, 07:38 PM	#14
Linguofreak Orbinaut	Quote: Originally Posted by ADSWNJ 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. 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.

10-06-2017, 01:26 AM	#15
ADSWNJ Scientist	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.