PPPPP , on a more serious note, this is a major issue for AB and the photos of the paint issue are interesting to look at.

 

This made me smile ..
.

 

Great pic. I imagine that the Mustang would have been throttling up whilst the others would have had to throttle back in order to stay in formation

 

Headed (way) out of town tomorrow for this...

 

That will buff right out I'm sure...

 

It looks like a blade let go. What's curious is it looks like part of a blade is imbedded in the nose cowl at the 3 o'clock position which means something funky happened.

The incident occurs, then the blades start eating themselves, debris naturally went rearwards through the compressor causing a stall/surge blowing material forward out the past the IGV's into the cowling is about the best guess I can muster from one photo. Whatever happened it all looks concentrated around the 3 o'clock position.

Do you know what caused this ?

 

My first thought was a structural failure rather than an ingestion - or certainly not a dramatic ingestion. Whatever hit the first row appeared to already have some strong centrifugal force and shared the love hence an outer blade failure plus the debris looks to have stayed air intake side. Could it even be internal? Interested to hear the outcome. Is there some damage or debris release from the nacelle inlet as well?

 

No further information just yet, awaiting the work authorization. My initial thought was they FOD'd the thing with ice but it could just be a classic blade separation. I'll keep you guys posted when we get to the aircraft. Probably flying out tomorrow night or Sunday morning

 

@64Wing
Thanks for posting and looking forward to hearing your assessment. Correct me if I'm wrong but the hole in the intake at 3 o'clock looks almost as if something has punched it's way from outside in rather than from inside out. The hole looks to me like a flower or mini bomb burst, which is what I'd expect if it was an object entering the intake from outside in. Otherwise, maybe the separated fan blade is embedded in the intake, scrunched up looking like a flower?

 

Ouch! What engine is that; J85-GE-17A maybe?

 

The only thing usually in the airflow portion of the nacelle is a PT2 probe and they are secured with four screws and a dollop of silicone.

My gut is telling me its blade separation caused by metal fatigue or perhaps FOD with fatigue being the number 1 culprit in my opinion. This will bug the hell out of me now until I know the outcome so please keep us up to speed.

 

Thats what I am wondering, the IGVs tells me its either military or a very early pure jet (no bypass) engine.

 

I think you are right, I just googled a photo and the IGVs that I assumed were variable are actually fixed and badly damaged

 

It’s hard to tell from the damage photo but I guessed variable IGVs behind fixed struts. The IGV actuator is located approximately in the position of the “flower petal” hole so maybe it suffered a catastrophic failure first that then triggered the rest.

 

Somewhere along the line, a "bang" occurred where there should have been a "suck"...

Image courtesy of Avgeekery.com via Facebook.

 

My buddy just sent me this this morning haha

 

So, the thing suffered a compressor blade separation. Just did a lot more damage than usual. The boys are removing the engine as we speak. New one should be on for trim runs tomorrow.

Our newly acquired 421B flew great with a few minor issues. Looking forward to more trips in it. But when spring rolls around and we're super busy again I'll be stuck in the 310 every day. Not really a complaint; she's a doll

 

Trim runs are old world maintenance tasks brother, today you just bolt the donkey on and the digital everything regulates everything else. I remember trimming JT3D FCU's, if you had to trim down three turns you would always trim down five and up two in order to prevent hysteresis.

I am sorry your engine ate itself but at least there was no other fall out associated with it. I wonder if this is a common problem and if there are AD notes against the engine or repeat BSI/NDT tasks to be performed at reduced intervals.

 

I'm amazed that a compressor blade separation can do so much damage. The engine looks completely trashed. I would have thought that when the blade separates, it would just punch its way out of the engine due to the centrifugal force involved. However, I could be wrong and I'm happy to be educated.

 

The blades are sustaining immense aerodynamic compression load as well as centrifugal load, so if a blade simply "lets go" due to root fracture it may not depart in an expected text book trajectory.

As a pax, I've experienced one "what was that bang?" on a C130, but the pilot calmly told us we still had three turning so don't worry.