Southwest has an interesting engine failure

Hope the parts didn't hurt anyone on the ground...yikes.

Check out at the divot between the two windows...holy cow I sometimes sit in that row!

 

*makes note never to sit directly across from rotating props or other fast moving bits of metal*

 

From Faceplace on the interweb tubes
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It'll buff right out!

SV

 

Looks like a cowl failure as the fan is still intact. I would imagine that a good bit of trim had to be dialed in with all that drag induced by the missing cowl parts.

Also looks like a repair was made judging by the silver patch on the second photo is not zinc chromate green like the rest.

 

or slightly forward of them

 

Om not a 73 guy, but that looks like two red secure tabs in the 'fly away' mode. I also see an access port flapping in the wind.

With any sort of violent departure it prolly knocked them loose. But it sure would be a bummer if MX didnt secure things properly.

 

It's interesting in that the chunk that hit the fuselage didn't seem to come out of the engine, but if it was a fan blade or something thrown by the fan it had to go forward, out of the now broken off inlet and then slung out with enough force to hit the fuselage.

We once had a fan "stub" stage that lost a blade and it didn't go down the core of the engine. The blade broke off, went forward, around the splitter, and down the fan duct, and it nicked and afterburner spray ring on the way out.

You would think, that because this supercharing fan stage was down in the core path that it would have gone down the core, but it didn't, it went forward and then out.

High speed rotating airfoils have a lot of force on them, both aerodynamic and centrifugal, and it's hard sometimes to predict where they're going to go if they get liberated.

 

That's because you're speaking of compressor stages...when parts are liberated they may go to low pressure areas rather than being forced as air is through the subsequent stages of compression. That's a very interesting anecdote though. My opinion is that the ding in the fuselage and wing root are from the cowl parts "flying" outward as it came apart and not from any centripetal effect related to the motor itself.

 

The world today

A plane loses an engine and people immediately take selfies to post on Facebook.

"Here I am with my oxygen mask on! Wish us luck!"

 

And, there's always some ******* videoing himself narrating the events as they transpire.



Mark

 

I had a small convex mirror (mounted on the inboard side of one engine cowling so you can see the landing gear) 'depart' my aircraft in flight and I was amazed that it didn't appear to touch the wing but left a nice healthy ding on the side of the fuselage about 10 or 15 feet back from where it was mounted. I guess it just followed the airflow over the wing until it got to the trailing edge then it was free to smack into the airplane.

 

Apparently they did lose a fan blade, which impacted the fuselage, and the resulting vibration took the cowl off.

 

It makes you wonder if the cowling has failed due to a crack and broken off, as the 1st stage compressor blades appears to be intact from the limited view of the pic. I saw a demo of a rolls royce trent engine being tested on the tv, used a bird carcus and threw it in at full power. Bit of a mess but the containment ring stopped the bits hitting the plane body. Just shows how bullet proof they are.

 

Pucker factor.

 

Why slightly forward? Is that due to the "lift" being generated by a prop blade? If so, a fan blade doesn't create lift the same way, does it still move forward?

 

yes

 

ANA had an engine fire on takeoff a couple of weeks ago

https://youtu.be/urpr59HpEuY

The airplane was parked next to us yesterday.
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If they lost a fan blade it well could have come forward of the original plane of rotation and then would likely have exited the cowl. More modern engines have fan blade containment, but not sure if this one does.

Even so, if it got far enough forward of the containment band it would have gone right through the cowling as this is just thin sheet aluminum. As with the stub stage that we saw at P&W, the aero forces are pretty large and it could well have come forward some. before it exited the cowl.

Once it got out into the cowl structure it could well have damaged the structure and that, combined with the vibration could have resulted in the subsequent loss of the front of the cowl.

I have a hard time thinking that a piece of the cowl could have hit the fuselage and created the damage there, what came out of there had to have a big lateral component to get that far with the slipstream going by at over 125 mph...

Lastly, the loss of a fan blade creates an equal and opposite imbalance force that we used to consider (and probably is) instantaneous. That is, the imbalance force hits the shaft system with a force that is about the same as if you shot it with a fan blade moving near the speed of sound. Then we'd do a forced vibration analysis to make sure the shaft held together under that kind of loading.

 

How is it different?

 

They definitely lost a fan blade. I've seen pictures of the fan.