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-   -   United B777 engine failure (https://www.pprune.org/rumours-news/638797-united-b777-engine-failure.html)

clareprop 21st Feb 2021 07:01


I agree with the comments that the thread title seems inappropriate, as video evidence so far points to a brilliant example of a successful containment.
You can play with words as much as you all like - technically. Now tell these people it was a contained engine failure.

https://www.bbc.com/news/world-us-canada-56141673

rmiller4292 21st Feb 2021 07:02

At 1:10 in the VAS video above you can hear the fire warning aural annunciation in the background.

fox niner 21st Feb 2021 07:04

Is there anyone who can find out whether this engine or airframe has been in long term storage during the pandemic?

KingKoopa 21st Feb 2021 07:16

lomapaseo

I'm pretty sure they got a fire indication of some type when the failure occurred -- when you listen to the ATC audio, you can clearly hear the fire bell in the background. This would have been accompanied by FIRE ENG R on the EICAS and a master warning.

You're correct in saying that there's no fire detection installed where the fire is visible in the video, though.

daelight 21st Feb 2021 07:23

fox niner

From FR24 records, she's been flying pretty much 2 sectors a day, since ~1 month hiatus in Febuary 2020 -

https://cimg1.ibsrv.net/gimg/pprune....f06af5ec1d.png


WHBM 21st Feb 2021 08:22

ACMS

I'm aware of that, and in fact alluded to it. However it's the same engine design that was on the original certification. You haven't been able to get a P&W on a new 777 for many years now (which might be an interesting point to start reviewing things).

DaveReidUK 21st Feb 2021 08:27

flynerd

Freezing the video would suggest a fan blade and a half missing. Looks like a carbon copy of UA1175 three years ago.

Fursty Ferret 21st Feb 2021 08:27

Having listened to the ATC it highlights the clear problem in the USA of controllers handling multiple frequencies without band-boxing. It's almost impossible to make a radio call without stepping on someone because you can't tell if someone else is transmitting. My policy in the USA is that if I need to make an emergency turn I'll do it and wait for ATC to contact me. Not being able to get a call in clearly added significantly to the crew's workload in this instance which isn't ideal in a terrain heavy airport with the performance issues associated with being single-engine on departure at high elevations.

Fursty Ferret 21st Feb 2021 08:33

lomapaseo

In the ATC broadcast you can hear the fire warning. Not sure why people are saying that the fire detection is in the the engine core - there's no point having fire detection there, that bit of the engine is always on fire... You put fire detection around the core, not in it, the purpose being to detect a leak in the hot gas path.

B2N2 21st Feb 2021 09:28

tdracer

Well pardon my artistic liberties in explaining this. We said 90% the same, good enough for government work.

Less Hair 21st Feb 2021 10:00

Parts hit the house and fell right into the kitchen and living room.

rb14 21st Feb 2021 10:30

I was quite surprised how often ATC was communicating. Of course there were the initial exchanges but then we reached a "OK we're running some checklists". From that point it felt like some of the ATC comms might have been a little distracting?

fdr 21st Feb 2021 10:35

Mike_UEM

That took longer to arise as a comment than was expected.... :}

25.903(d)(1) Design precautions must be taken to minimize the hazards to the airplane in the event of an engine rotor failure or...

and that doesn't seem to fully answer the question, but, AC20.128A ?DESIGN CONSIDERATIONS FOR MINIMIZING HAZARDS CAUSED BY UNCONTAINED TURBINE ENGINE AND AUXILIARY POWER UNIT ROTOR FAILURE of 25 MArch 1997 states in para 6 (c) of definitions:

Uncontained Failure: For the purpose of airplane evaluations in accordance with this AC, uncontained failure of a turbine engine is any failure which results in the escape of rotor fragments from the engine or APU that could result in a hazard. Rotor failures which are of concern are those where released fragments have sufficient energy to create a hazard to the airplane.

That was put out by the Mangler of TAD-ACS out of Seattle, Mike Kaszycki... for "harmonization".

The inlet looks like it would make a great paddling pool while the engine was an excellent cigar lighter.




N707ZS 21st Feb 2021 10:36

If the parts land on your property are they still the property of the airline.

3Greens 21st Feb 2021 10:45

yes. If someone enters your house, you don’t then take ownership of their wristwatch and wallet etc...

unmanned_droid 21st Feb 2021 10:54

Big Pistons Forever

FBO and UERF loads should have been part of the load cases so will have been covered in the static analysis of the pylon attachments and wing structure (my experience is with stress analysis of A wings and this is true of the aircraft I have worked on so feel confident it would have been the case for B wings). In my experience we mix the engine failure loads in with the other groupings so the design is covered for some fairly nasty concurrent situations.

The FBO loads are likely to produce the peak engine failure loads as alluded to elsewhere in this thread simply because of the size of blades. This does not appear to be an FBO event so the peak design loads were likely not reached.

The amount of movement isn't cause for concern and the attachments can stand that kind of cycling for the time taken to get back to the ground. It doesn't look like there is any damage to the pylon structure in the video and the vibration to me looks to be consistent and well damped suggesting that all wing and engine attachments are still operating as normal. I would say the risk of losing the engine was minimal in this specific situation. The engine probably moves that much in strong winds anyway - but you don't notice it because it's an oscillation or 2 (for example there's a video of an A380 landing in Manchester with all 4 engines moving around and pointing in different directions during a winter storm/gales).

bsieker 21st Feb 2021 11:20

clareprop

Nobody argues that it was not a catastrophic failure, but "uncontained" vs. "contained" have specific technical meanings for a good reason. No matter what the press calls it, we should not muddle those terms.

silverstrata 21st Feb 2021 11:27

The flames are coming out of the thrust-reverser matrix.
Which might suggest a failure between the HP compressors and the turbine section.
Perhaps in the combustion chamber itself.
I imagine an exploding combustion chamber might be powerful enough to take out all the cowlings.

Maninthebar 21st Feb 2021 11:28

fdr's quote (above) would indicate that this event might well be classified as 'uncontained'
"Uncontained Failure: For the purpose of airplane evaluations in accordance with this AC, uncontained failure of a turbine engine is any failure which results in the escape of rotor fragments from the engine or APU that could result in a hazard. Rotor failures which are of concern are those where released fragments have sufficient energy to create a hazard to the airplane."

WingNut60 21st Feb 2021 11:29

I am somewhat surprised at the seemingly gentle landing of the inlet ring, a bit of bark off the tree branch seems to be about the limit of the damage.
Am I right in thinking that it may have descended parachute fashion?


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