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United B777 engine failure

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United B777 engine failure

Old 21st Feb 2021, 12:29
  #61 (permalink)  
 
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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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Old 21st Feb 2021, 12:36
  #62 (permalink)  
 
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It is not a structural part, and as such is a very lightweight honeycomb structure and has a large surface area. So yes, rather parachute-y.
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Old 21st Feb 2021, 12:39
  #63 (permalink)  
 
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blancolirio channel said that the fire continued on the ground. Assuming all shutoff valves worked, all fuel in the engine should have burned off by the time and/or been flushed out, so I think it may have been an oil fire.

The imbalance of a fan-blade-off event will be violent enough to shake the cowling to pieces. Combustion chambers are not known to explode; they are designed to contain an extremely fierce fire, and are open on both ends.
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Old 21st Feb 2021, 12:49
  #64 (permalink)  
 
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Why do ATC always ask stupid questions about fuel and souls on board..?

Look, ATC paper-shufflers, the aircraft has only just taken off, so it has enough fuel to hang around for ages.
And the number of souls is on the loadsheet. Why the ... do you think we leave a copy of the loadsheet behind?
Oh - and by the way: I am dealing with a ***** emergency here, and my hands (and brain) are full....

In addition, dear ATC - please stop thinking of Sully landings, will you?
Contrary to what the FAA were promoting on the Hudson, we are not supposed to do a split-arrse ‘turn-n-return’ back onto the same runway. We are supposed to take up the hold and secure the engine, before calmly returning in a composed and ordered manner. That is the approved SOP. And from experience, the pattern this aircraft took is the absolute minumum flight time to get everything done.

As you can see from the video, the engine was happily smouldering away to itself, and not endagering the aircraft. That is why podded engines were invented. Podded engines with the N1 and compressors well in front of the leading edge, so that an N1 failure will not disrupt the wing systems or fuel tanks.

It all worked as designed and planned, and there was no need for a panic-return. So please stop offering immediate returns to land - unless specifically requested. (If a turn-n-retrn had. een executed, I can just imagine the request for fuel-load and souls onboard on 1/2 mile finals....)

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Old 21st Feb 2021, 13:04
  #65 (permalink)  
 
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bsieker

Here is a Bae146 engine with an exploded combustion chamber, that also took out the cowlings.

The vibration we can see on the B777 failure may be aerodynamic, as the slipstream runs around the decidedly non-aerodynamic N1 fan. Those fat cowlings are not there for normal flight - they are designed to allow smooth airflow around the engine after it fails (and the airflow spills out around the front of the engine). Take the cowling away, and the resulting turbulence is bound to make it shake, rattle, and roll...

Bae146 combustion chamber failure:
https://news.aviation-safety.net/201...engine-repairs

The ALF507 was not the best of engines, and had a variety of N1, compressor, combustion-chamber, and turbine-section failures. Which is why the aircraft was unfairly known as the Bring Another Engine 146. Or the Cockroach, for short.

Last edited by silverstrata; 21st Feb 2021 at 13:34.
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Old 21st Feb 2021, 13:05
  #66 (permalink)  
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Originally Posted by WingNut60 View Post
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?

Think it converted the Ram roof to low rider..

As far as terminal velocity goes, would be interesting to see if it was rotating around its radius like a Flettner lifting surface.
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Old 21st Feb 2021, 13:06
  #67 (permalink)  
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silverstrata

One of the happy snaps on CNN shows at least one fan blade is a shorty.
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Old 21st Feb 2021, 13:07
  #68 (permalink)  
 
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unmanned_droid

"This does not appear to be an FBO event so the peak design loads were likely not reached."

How do you account for the gap where you would expect a fan blade to be, in the photos ?
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Old 21st Feb 2021, 13:11
  #69 (permalink)  
 
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Lockhart

You're presuming that the pilots' actions actually caused the SOVs to close, they may not have. QANTAS A380 2010 could not shut down No 1 engine (undamaged). It ran for about 3 hours after the landing, until fuel exhaustion. EK A340 on the ground in Toulouse, engines ran for about 9 hours (?) until fuel exhaustion, but that was very different reasons. i.e. lack of access to flight deck.
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Old 21st Feb 2021, 13:36
  #70 (permalink)  
 
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Silver, ATC probably ask for the POB because they are required to.

As for the rest, ATC's reaction was prompted by the chaotic radio calls and lack of information provided by the crew. The crew would have done this in the sim every 6 months for years. To blurt out a panicked "we need to turn" without giving a direction is mind-boggling. No wonder ATC thought the situation was dire and that they might need an immediate reland. What about "Mayday Mayday Mayday, UAXXXX, engine fire, tracking direct Zimmr until advised, standby for further information".

As for the fire bell still ringing during the radio calls...
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Old 21st Feb 2021, 13:39
  #71 (permalink)  
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Why do ATC always ask stupid questions about fuel and souls on board..?
They're asking on behalf of the crash/fire/rescue, who think that information is smart to know. ATC should not guess, and do not have time to go find the paper elsewhere at the airport of departure.
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Old 21st Feb 2021, 13:40
  #72 (permalink)  
 
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fdr

Link?
Image?
The N1 fan appears to be intact, as does the containment-ring.
So which blades can you see, other than the N1?
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Old 21st Feb 2021, 13:42
  #73 (permalink)  
 
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Capn Bloggs

Yeah - we know that.
But every aircraft has left a loadsheet behind, for the last 80 years.
And with modern comms, it is not difficult to get that information from the handling agent or airline.
(Who are not dealing with an engine fire...)

As for the ‘we need to turn’ call, it is natural to ask ATC for a turn, because only ATC know where all the other traffic is. The number of times a commercial pilot will tell ATC they are turning, can be counted on one hand in an entire career. Perhaps with a storm-cell ahead, or the like.

The request for an ATC-determined turn was natural and logical, and for ATC to then overload the pilots with a “which way” request was stupid in the extreme. The crew may not even instantly know where the airport is (it being behind them), nor where any prohibited areas, terrain restrictions, or conflicting traffic may be.

ATC should have kept things simple, and just given a normal traffic pattern back to the departure runway: “this will be a left-hand circuit for rwy 26”. And perhaps for reassurance added: “other options available, if you require”.

(Remember, the crew need to know the runway to set up the ILS - they don’t need a guessing-game for which approach, while dealing with an engine fire.)

Last edited by silverstrata; 21st Feb 2021 at 14:17.
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Old 21st Feb 2021, 13:58
  #74 (permalink)  
 
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silverstrata

"The N1 fan appears to be intact"

Really?



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Old 21st Feb 2021, 14:01
  #75 (permalink)  
 
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DaveReidUK

If you has posted the pic, we would know.
This is not a guessing-game.

P.S. The reason the containment-ring appears intact, is the blade-tips often fly off forwards, hitting the front cowl rather than the ring. The blades are under extreme forwards pressure, especially during the low-airspeed high-rpm climb.

I am presuming the different colour of the broken blades is due to reflections from sunlight, with the Sun being behind the camera position.

Last edited by silverstrata; 21st Feb 2021 at 14:16.
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Old 21st Feb 2021, 15:02
  #76 (permalink)  
 
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Bits of the rotating group or engine casing as opposed to cowl, inlet lipskin etc.
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Old 21st Feb 2021, 15:10
  #77 (permalink)  
 
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correct on the blade tips going forward. but it isn't the aereo loads which might only move the tip about a few mils in the time before it is laying down against the casings. Also you forgot to mention the much heavier inner blade portion which is pumped aft and imbed itself in the Kevlar belt. The rest of the engine response eats up the engine innards and that's where most of the interest will point
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Old 21st Feb 2021, 15:12
  #78 (permalink)  
 
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Originally Posted by silverstrata View Post
P.S. The reason the containment-ring appears intact, is the blade-tips often fly off forwards, hitting the front cowl rather than the ring. The blades are under extreme forwards pressure, especially during the low-airspeed high-rpm climb.
Really ?

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Old 21st Feb 2021, 15:16
  #79 (permalink)  
 
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You're presuming that the pilots' actions actually caused the SOVs to close, they may not have. QANTAS A380 2010 could not shut down No 1 engine (undamaged). It ran for about 3 hours after the landing, until fuel exhaustion. EK A340 on the ground in Toulouse, engines ran for about 9 hours (?) until fuel exhaustion, but that was very different reasons. i.e. lack of access to flight deck.
In the Qantas incident the wing was penetrated multiple times by debris; this severed wiring and made shut off impossible. This is a totally different scenario, as the wing is intact.
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Old 21st Feb 2021, 15:51
  #80 (permalink)  
 
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ATC always train not to turn in to dead engine if possible although that’s not so important with modern jet aircraft direction of turn is still a reasonable question (although I’d welcome any other views on this, particularly about non jet types).

SOB - Aircraft was probably 8/10 mins from touchdown so why ask someone else to try and get through to an ops department to find someone that will give the upmost priority to a request for souls on board?
If the fire service need that info best to get it from the flight deck.

I’d also want to know which engine was out to pass that to fire service too.

Good to hear UAL say “Mayday” I realise US procedures are different but nothing catches the attention quite like the M word.

While overall I thought it was really well handled on both sides the ATC didn’t know if the fire was still burning (endangering wing/control surfaces/falling out of the sky) or fire was out and a ‘normal’ return.
On that basis, any criticism about circuit or questioning seems pretty harsh in my view.
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