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BA 777 on fire in Las Vegas

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BA 777 on fire in Las Vegas

Old 11th Sep 2015, 04:54
  #361 (permalink)  
 
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Wasn't the Sioux City DC10 accident a result of uncontained failure of the LP compressor disc.
Sioux City was a fan disc, not a compressor disc. For purposes of rotor burst analysis, a 1/3 fan disc is assumed to have infinite energy - hence my earlier comment that it would go anywhere it wanted to. Nothing on the aircraft is going to stop it (or even slow it significantly).
While a compressor spool doesn't have the energy of a fan disc, a failed spool is effectively a burst rotor. As noted before, it's not going to be contained by the compressor case, at least not at high power. When we do uncontained burst analysis, there are certain assumptions that come into play. Blades and blade bits are considered 'low energy' - if they make it out of the engine case they won't penetrate 'protected' systems, however they can spread over a wider area (15 degree spread, vs. 5 degrees for high energy debris). Rotors and spools are considered 'high' energy, it's simply not practical to protect systems. Rather, systems are located to minimize (but not eliminate) the risk of catastrophic damage.

It really is an interesting question as to what would have happened had this failure occurred after V1 and they'd continued the takeoff. My gut feeling is it wouldn't have been catastrophic - assuming the fuel leak was from the engine fuel line (and not a wing penetration), most of the spilled fuel would have gone out the back. It would certainly have been exciting, and a return to land with a trans-Atlantic fuel load, but something a capable crew (which this one showed every sign of being) would have been able to handle.
Hopefully the final report will address those aspects of survivability had the failure occurred 30 seconds later.
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Old 11th Sep 2015, 05:33
  #362 (permalink)  
 
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While a compressor spool doesn't have the energy of a fan disc, a failed spool is effectively a burst rotor.
The HP compressor will be doing upwards of 10,000rpm, a whole lot faster than the fan which would be getting up to 2,500 rpm. The compressor has a smaller diameter, but has several stages on the same disk to save weight but increases the load on the disk, etc. Working it out is complicated.

Whatever it works out to be, I think one thing we can reasonably say right now is that the compressor disk in question is not strong enough; bits of it were on the tarmac which is exactly where they shouldn't be.

Another way of looking at it is that there's several tens of thousands of horsepower (tens of megawatts) going into the compressor. A good size power station turbine is only 500MW; these large turbofan engines are using the equivalent of a large fraction of your average power station just to run the compressor, never mind propelling the aircraft forwards.

When that goes significantly wrong there is going to be a one helluva bang. Of course the reason we're more used to the idea of turbine failures is that, whilst they're under a similar rotational load (same RPM), each turbine blade has a much, much higher aerodynamic load and runs very hot too.

Interestingly the RPM of these turbofans is far lower than the turbocharger on a car, which may get up to 100,000 RPM. Of the millions of those that have been made one or two must have broken up. They're a lot smaller and lighter, so keeping the bits inside is going to be much easier.
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Old 11th Sep 2015, 06:51
  #363 (permalink)  
 
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"Parts of the engine's high pressure compressor were found on the runway"


British Airways fire investigators: Engine failed, pieces found on runway - CNN.com

British Airways fire investigators: Engine failed, pieces found on runway

(CNN)The left engine of British Airlines Flight 2276, which burst into flames Tuesday at McCarran International Airport in Las Vegas, showed multiple breaches in the metal casing surrounding it and parts of the engine's high pressure compressor were found on the runway, according to an initial examination by aviation experts.
Investigators with the National Transportation Safety Board said they don't know yet what caused the engine failure during takeoff shortly after 4 p.m. (7 p.m. ET) Tuesday.
But CNN has learned that the Federal Aviation Administration issued an airworthiness directive in 2011 to airlines using this GE90-85B engine.
It warned of possible "uncontained engine failure," which means parts of the engine can break and fly out . The FAA mandated repetitive inspections of the high pressure compressor rotor spool for cracks.
The NTSB said it is too early to draw any conclusions, but the part of the plane's engine that was heavily damaged is the same part mentioned in the FAA's airworthiness directive.

A source close to the investigation said a physical inspection of the plane will be key in the case and may provide more clues than the black box, which can't tell investigators if a part of the engine broke off.

A thud, then an evacuation order

Jay Jennings was one of the 157 passengers, along with 13 crew members, on the London-bound jet when he heard a big thud as the flight was about to takeoff. He lifted his window shade and "just saw flames on the engine," he said.
For a few frenetic minutes, frightening plumes of black smoke engulfed the jetliner.

The plane stopped and sat for what felt like a minute, Jennings said. Then the captain came on the intercom and told the passengers there was an emergency and they needed to evacuate.
When one of the emergency doors opened, smoke poured in. "Not safe, not safe," someone said, Jennings recalled.

Last edited by meekmok; 11th Sep 2015 at 07:07.
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Old 11th Sep 2015, 07:52
  #364 (permalink)  
 
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From an engineers PoV, the compressor casing should have held. Many questions asked why so much fuel leaked and that's probably because the FMU was taken out in the process.
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Old 11th Sep 2015, 07:55
  #365 (permalink)  
 
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Whilst the result is a credit to all, the presence of the third pilot, allegedly being able to enter the cabin to assess the situation before reporting back to the Captain, the engines being invisible from the flight deck is interesting.

How many more seconds would have been taken if third pilot had not been present and able to do this?
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Old 11th Sep 2015, 08:52
  #366 (permalink)  
 
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Previous Incident at EGLL

I was involved in a very similar incident at EGLL back in 1998. B777 G-VIIH aborted take off with a uncontained engine failure. This happened at 71 kts !! pretty similar to the current incident. There was no fire in this one

Metal from the turbine was was strewn all over the runway and all in very small pices.
The No 1 engine was a GE90-85BG04, serial no. 900158,

There is a AAIB report here

https://assets.digital.cabinet-offic...pdf_500368.pdf
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Old 11th Sep 2015, 09:07
  #367 (permalink)  
 
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#362

I think the 13 different CL memory items is not just in reference to QRH/ECL NNC but includes the manoeuvres too. TCAS, EGPWS, Windshear etc.
Quite correct 320goat.
The checklists I revised after any time away from the flight deck were :
Aborted Engine Start; Dual Eng Fail/Stall; Eng Lim/Surge/Stall; Eng Svr Damage/Sep; Fire APU; Fire Engine Tailpipe; Fire Eng; Eng Autostart; Cabin Altitude; TCAS; Pull Up Go Around; Windshear Go Around & Passenger Evacuation as the other drills could be called from the Electronic Checklist.
Surprisingly, I don't recall any memory items for the various Smoke checklists.

And no airbubba, I don't have a simulator in the basement; my thrills since retirement are driving a team of horses, hence the monika "Whip".
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Old 11th Sep 2015, 09:21
  #368 (permalink)  
 
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On the face of it appears job well done by all crew.

Happy no serious injuries.

Now most importantly when could the crew get together for a private debrief over a few cold ones and some umbrella drinks for the girls.

I'm guessing after the authorities Drug and alcohol test and get a few basics out of the way, they may all be able to get poolside and calm the nerves.

Anyone know how long the crew would be tied up.
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Old 11th Sep 2015, 09:57
  #369 (permalink)  
 
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BA 777 (MML) just did full stop on landing at LHR and met by fire crews. Now moving off 09L slowly.
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Old 11th Sep 2015, 10:06
  #370 (permalink)  
 
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Originally Posted by flt001 View Post
BA 777 (MML) just did full stop on landing at LHR and met by fire crews. Now moving off 09L slowly.
Hydraulic loss/failure I believe. No biggy
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Old 11th Sep 2015, 13:24
  #371 (permalink)  
 
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NTSB confirms "uncontained engine failure"

BA jet engine failure uncontained, pieces hit runway: investigators | Reuters

"Initial examination of the left engine revealed multiple breaches of the engine case in the area around the high pressure compressor," the NTSB said in a statement."

Re-stresses the interesting case of Boeing and GE to oppose FAA on insisting on its "unsafe condition" definition in AD 2011-15-06 concerning GE90-85B engines as mentioned in post #188.

If specific failure addressed in this AD would indeed prove to be the origin of the uncontained failure in this case, and of course indeed assuming that BA complied with the inspections pertaining from this AD, then GE and Boeing would have quite some explaining to do, as they in their comments to the FAA at the time ascertained that "....by their analyses, cracks in the weld joint would not develop into an uncontained failure." The FAA disagreed with this at the time and pursued the AD.
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Old 11th Sep 2015, 13:33
  #372 (permalink)  
 
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#399 - previous incident at EGLL

Just to clarify, the AAIB bulletin for the 1998 incident (caused by the previous misassembly of the LPT module) noted that "there was no failure of the engine containment", although turbine debris was ejected out of the tailpipe onto the runway.
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Old 11th Sep 2015, 13:37
  #373 (permalink)  
 
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I have a feeling that this will go into the textbooks as to how to deal with catastrophic failure between 80kts and V1.
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Old 11th Sep 2015, 13:39
  #374 (permalink)  
 
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So it's not CAA mandated for G- operated airliners to have blinds up for landing even though in every flight I have been on they've insisted on it?
If it's not mandatory or company SOP I am a little surprised......
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Old 11th Sep 2015, 14:13
  #375 (permalink)  
 
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see previous ....

when people actually listen to the safety brief they will know not to try and get the trolley bags before evacuation.
Cabin crew will also go down the cabin to ensure that tables are stowed, seats are upright, belts are fastened, earplugs to iphones etc. are out, and blinds are open.

What people do after that is basically down to whether they respect the cabin crew and the advice they were given.

There are plenty of travellers who think they know better, and the cc cannot be expected to police them all, all of the time.
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Old 11th Sep 2015, 15:29
  #376 (permalink)  
 
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From what I've been told by one of our company pilots, blinds are open so that firecrew can see inside.
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Old 11th Sep 2015, 15:48
  #377 (permalink)  
 
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Strangly enough I was in the USA last week and the cabin crew on all 4 flights asked pax to close the blinds before landing in order to help keep the cabin cool during the turnaround.
I thought it was not the best of plans.
I would understand if they had requested this after landing before arrival at the gate.
Delta Airlines.
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Old 11th Sep 2015, 16:48
  #378 (permalink)  
 
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How many more seconds would have been taken if third pilot had not been present and able to do this?
Third pilots may not always be aboard, but FAs are. Wouldn't it make sense to brief them to eyeball obvious problems? It doesn't take a lot of stick time to report smoke and flames engulfing a wing. It might even be faster than waiting for a third pilot's report, when a third pilot was available.
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Old 11th Sep 2015, 16:56
  #379 (permalink)  
 
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Originally Posted by PersonFromPorlock View Post
Third pilots may not always be aboard, but FAs are. Wouldn't it make sense to brief them to eyeball obvious problems? It doesn't take a lot of stick time to report smoke and flames engulfing a wing. It might even be faster than waiting for a third pilot's report, when a third pilot was available.
Why do you imagine this isn't already done?

Evacuating an aircraft is a big deal. You expect serious injuries from an evacuation.

If you have a spare pilot, then it is wise to use him just to confirm it is really necessary.
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Old 11th Sep 2015, 16:57
  #380 (permalink)  
 
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Originally Posted by Teddy Robinson View Post
when people actually listen to the safety brief they will know not to try and get the trolley bags before evacuation.
Cabin crew will also go down the cabin to ensure that tables are stowed, seats are upright, belts are fastened, earplugs to iphones etc. are out, and blinds are open.

What people do after that is basically down to whether they respect the cabin crew and the advice they were given.

There are plenty of travellers who think they know better, and the cc cannot be expected to police them all, all of the time.
I have listened to the safety briefs on the airlines that I fly on (around 4 times a week or so) and they never mention bags being left on evacuation. That is on both in the talked through safety briefs from the FA and jokey video safety briefs on the IFE. Just like the blinds up/down for takeoff and landing it seems to be airline specific. Even the BA flight briefing it was a single short throw away line in the cartoon video which spent far more time showing a cartoon FA giving a dropped cuddly toy back to a cartoon child.

Safety briefs need to be far more specific: E.g. "In an evacuation you must not take bags with you. Any important papers should be in your pockets"
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