Atlas Air Boeing 747-8 cargo plane - possible uncontained engine failure 4

[EnzoAus]

ABC (Australia) is reporting an engine fire on an Atlas Air Boeing 747 cargo plane. The link includes the article and a video of the plane on fire. Apparently a tennis ball-sized hole was found above the engine after it landed safely. The Atlas Boeing 747-8 is eight years old according to the FAA, and is powered by four General Electric GEnx engines. CNN also has an article on the event.

https://www.abc.net.au/news/2024-01...as-air-fire-emergency-landing-miami/103371366

https://edition.cnn.com/2024/01/19/us/miami-boeing-plane-emergency-landing/index.html

 

[3DDave]

The plane was not on fire. The brightness on the image is boosted. The image below is the true color.

 

[EnzoAus]

Thanks - I did wonder about the video image.

 

[Murph 9000]

Juan Browne / blancolirio has a video covering the incident.

Atlas 747-8 Spectacular GEnx Engine Failure Miami 18 Jan 2024

 

[thebard3]

Of course, all of the news outlets have to include in their story references to the 737 door plug incident like the two are somehow in any way related.

Brad Waybright

The more you know, the more you know you don't know.

 

[hokie66]

They are both aircraft.

 

[zeusfaber]

Both involved a hole in a bit of an aeroplane where there didn't ought to be one.

 

[3DDave]

One was built by Boeing; this engine wasn't.

 

[EnzoAus]

Not my area of experience but aren't these engines designed to contain any dislodged material and isn't there a fire suppression system which would normally extinguish an engine fire?
If so, then it appears that the originating incident might have pierced two levels of safeguards.

 

[zeusfaber]

aren't these engines designed to contain any dislodged material

The usual approach (given the weight of Chobham armour) is to design the engine to contain smaller items that might let go, and then aggressively manage fatigue lives for the things that are too big to contain to make their probability of failure tolerably small.

If a failure is big enough to become uncontained, you need to assume that lots of safeguards are liable to be compromised (for a good example, read Alistair's link in the JAL thread to the AAIB report on the British Airtours fire) - whether that's engine fire suppression, fuel tank integrity or even the structural integrity of the airframe. Provided the underlying event is sufficiently unlikely, the loss of those safeguards becomes tolerable.

A.

 

[SWComposites]

There is usually a fan case around the large bypass air fan up front that is designed to contain those blades. If part of the high temp turbine farther aft lets go, not much is going to stop that from departing the aircraft. Yes the is a fire suppression system. And a fuel flow shut off system. But some turbine failures are just impractical to design for. The aircraft is designed to fly with a shut down engine.

 

[TugboatEng]

With a pod mounted engine it's not such a big problem for it to be on fire provided the fire doesn't propagate into the wing structure. Maybe wait until the aircraft is stopped on the ground and the fire is under the wing instead of behind it before deploying the fire suppression system.

 

[3DDave]

The fan blades are to be contained as they are susceptible to damage by bird strikes or large hailstone ingestion.

Anything farther back has both a large amount of energy and a high strength and the frequent result of loss of a compressor or turbine blade is enough imbalance that sheds more blades or causes the disk they are attached to to leave.

Fire suppression works outside the engine casing, but this fire appears to be belching out from the engine core, which is designed to contain fire and isn't normally reachable by fire suppression. There may have been no fire indication if the fire remained in the engine core.

The reported size of the hole is about what a compressor or turbine blade would make. The imbalance can shake into contact parts that should not contact. That may be what was causing the showers of sparks.

 

[EdStainless]

It is a composite (Kevlar usually) jacket that is used for fan/LP compressor containment.
The metallic engine case is designed to contain typical blade-out situation for HP compressor and all turbine stages.
Remember that these engines are tested for bird strike (they have to make a certain amount of power for a set time).
During development they do deliberately cause larger blade-out failures.
This engine family had issues when it was first introduced (shaft failure at front of turbine).
It is possible that the fix isn't as good as they thought.

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P.E. Metallurgy, consulting work welcomed

 

[Alistair_Heaton]

It's called surging. It's due to compressor stall. Huge amounts of fuel get chucked out the front and back.

The plane isn't actually on fire

 

[TugboatEng]

This video shows the containment in action at 1m20s. Yes, the fan stage has Kevlar belts to help contain the blades.

https://youtu.be/iBqWS1hil18?si=HZsaWEKVmUr9Ahni

As a bonus, the control handles at 3m20s are Mathers CH5 handles formerly used on tugboats (pneumatic controls are becoming obsolete).

 

[dik]

Juan Browne video explains the reason...

-----*****-----
So strange to see the singularity approaching while the entire planet is rapidly turning into a hellscape. -John Coates

-Dik

 

[TugboatEng]

Only a few years ago Southwest flight 1380 had an uncontained failure of a single fan blade. The blade broke a window on the 737 resulting in the death of a passenger.

At around the same time there was another flight that ruptured the fan disk. It blew the nacelle off the engine. That plane was able to land safely.

 

[EdStainless]

Yes, TBE there have been a few bypass fan failures that have resulted in pieces being ejected out the front of the engine.
These have then destroyed the front of the nacelle and caused blade-out types of damage.
This mode of failure was not designed for.
A number of engine families in service will be getting updated nacelles fitted to them.
This work is being done rather quietly.

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P.E. Metallurgy, consulting work welcomed

 

[Alistair_Heaton]

Our engines it's the wing anti ice which causes issues...


Gear engines the fan is 1/4 of the rotation velocity of a previous gen engine