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AN-124 Uncontained Engine Failure

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AN-124 Uncontained Engine Failure

Old 14th Nov 2020, 23:11
  #41 (permalink)  
 
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tdracer

I can think of one.
Uncontained Engine Failure and Subsequent Fire American Airlines Flight 383 Boeing 767-323, N345AN Chicago, Illinois October 28, 2016
CF6-80C2B6 turbofan engines, with one engine mounted under each wing.
https://reports.aviation-safety.net/...763_N345AN.pdf
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Old 14th Nov 2020, 23:48
  #42 (permalink)  
 
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lomapaseo, bear in mind they didn't state anything to the tower as they had lost contact.

morton, granted he was low, but other than that there were no other visual clues and the landing itself was perfectly normal.
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Old 15th Nov 2020, 03:18
  #43 (permalink)  
 
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Morton, I agree. Jets like that don't do low-level immediate returns just because the radio has failed.
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Old 15th Nov 2020, 09:16
  #44 (permalink)  
 
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Bloggs / Morton, et al,

e.g. BAe146 immediate return with total electrical failure at dusk, low cloud, and snow. (Total as in 'total', nil, zip, nothing.)

Also, related to this thread was the 146 which suffered a failure of an engine rear bearing, shaft shear, and uncontained turbine disc - maintenance misunderstanding.
The crew successfully managed the engine failure, adjacent engine failure / fire, with indications that a third engine had failed - no instruments / electrics. The consequential loss of all hydraulics, flaps, spoiler, airbrake, and no pitch trim. And, from extensive shrapnel damage, the loss of cabin pressure, two small fires in the cabin (no injuries), holes in the flaps, fuel tank, and main spar !
Landing on a long military runway which fortunately had a shallow lead-in taxiway providing a paved overrun area. (Mexico)

Celebrate - and learn from the successes.
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Old 15th Nov 2020, 09:17
  #45 (permalink)  
 
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How would a pre-programmed air vehicle, autonomous drone or remotely piloted aircraft have dealt with an electric failure and non normal handling like this?
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Old 15th Nov 2020, 09:23
  #46 (permalink)  
 
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Most likely very badly.
But there is the argument that it would have saved many other situations where the pilots have crashed perfectly flyable airframes.
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Old 15th Nov 2020, 13:11
  #47 (permalink)  
 
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Let's take an example: CFIT, 1995, American Airlines 965, Colombia. That was a "perfectly flyable airframe" - although stated by this SLF/attorney that's not incorrect or controversial. So, the "argument" is that today's algorithm techniques and related processes could have conducted that flight operation without a CFIT accident with many fatalities. But not at that time - the capacity assumed by the "argument" didn't exist yet in 1995. Logically the "argument" addresses most (maybe nearly all) of the accidents involving perfectly flyable airframes via a counter-factual.

What about today, when the capacity is said by some to be at the brink of adequacy? Let's assume it is ready. But what about the other side of the equation advanced by the "argument"? Is it not correct that aviator training, safety management systems, and a variety of related processes have reduced the likelihood of a similar CFIT event to very low levels? Okay, so in some regions or countries, this level of fidelity to training requirements and methods may be less, or woefully less. What makes it true that in a place where a flight crew conducts a flight operation such as the one that resulted in the recent accident in Karachi, that the care and feeding of an autonomous/algorithmic system won't also be inadequate to the task? So the comparison advanced by the "argument" isn't actually valid.

Not least, there certainly still are lots of arguments (no sarcastic quotes this time) about whether the performance and reliability of autonomous/algorithmic systems have or have not reached a sufficient level, in the judgment of professional people with the requisite high level of knowledge and authoritativeness. Or, the jury is still out -- in fact, the court has not even given the jury its instructions yet. (The recent issuance of a position paper by IFALPA on these issues says a lot more than an SLF/atty should try to articulate . . . a thread started on it was moved over to Ground & Other Ops (Safety, CRM etc.)).

It's not just electrical failures. I'm waiting for the algorithmic whiz kids to provide an algorithm that would fly American 191 out of Chicago O'Hare on 25 May 1979, safely. Oh, that's a lousy example, because the faulty engineering of the hydraulic lines, and the maintenance issue with the engine removal and replacement, were unknowns at the time of the flight operation? Right then, and we can therefore be assured that the algorithms and their related processes won't have any errors in their derivation and iteration, or in the upkeep of the overall autonomous system either, I see?
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Old 15th Nov 2020, 13:49
  #48 (permalink)  
 
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American 191 was actually a perfectly flyable airframe, after the engine came off they de-accelerated from 165kn to the stipulated engine out speed of 153kn where upon the left wing stalled, had they not de-accelerated a safe circuit would have been possible. The crew were blameless, they followed the book. Work colleague was on board.

Less Hair, I'd assume a smoking hole rather than the highly successful handling by the crew.
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Old 15th Nov 2020, 14:38
  #49 (permalink)  
 
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Originally Posted by Less Hair View Post
How would a pre-programmed air vehicle, autonomous drone or remotely piloted aircraft have dealt with an electric failure and non normal handling like this?
Pick a flat spot
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Old 15th Nov 2020, 15:27
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With regard to 25 May 1979, Chicago, I stand corrected.
Full understanding of discussion of the aircraft systems performance in the NTSB report (middle of p. 51 - 55) is beyond my reach. It nevertheless can be seen that the Board did find the airframe was flyable. I regret the posted error (and meant, positively, no aspersion upon the crew, none whatsoever).
https://www.ntsb.gov/investigations/...ts/AAR7917.pdf
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Old 16th Nov 2020, 09:08
  #51 (permalink)  
 
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Originally Posted by Pistonprop View Post
morton, all ATC knew was that they had lost radio contact. You don't call out the emergency vehicles for comm failure. Could they see any damage on the a/c? I doubt it.
An AN 124 had a compressor stall on departure from Farnborough once having spent about 10 min on the runway; nothing was said to ATC (I was the tower controller so I should know) and we didn't see or hear anything untoward from the tower (I'm told there was a flash of flame and a bang but it was on the far side of the fuselage from us) but it required an engine change.
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Old 16th Nov 2020, 09:26
  #52 (permalink)  
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Originally Posted by Less Hair View Post
How would a pre-programmed air vehicle, autonomous drone or remotely piloted aircraft have dealt with an electric failure and non normal handling like this?
A total electrical failure on a UAV means the drone is falling off the sky. Happened a few times already .
morton : So, he takes off, doesn’t get very high and circles back to the Airfield – all in Radio silence. Those in the tower have a terrific view of him coming round, landing and running into the overshoot.
Am I missing something or have they photo-shopped out all the emergency services chasing after this Aircraft during a very non-standard approach and landing?
For ATC , it was a comm failure , nothing else. Happens also sometimes. No big deal in VMC in daylight. . . They did a good job making sure no-one was in the runway and probably send green light signals, and from the APP and the landing touchdown nothing indicated they would overrun in the end. I can see the button pushed only when they saw the snow clouds in the end...
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Old 16th Nov 2020, 12:29
  #53 (permalink)  
 
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The problem is to predict combinations of complex failure scenarios and to have a system ready to cope with it. I see this incident as proof how long we have to go until automated safe commercial flight is possible.
Reality turns out to be different than clean room test scenarios - every time again.
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Old 16th Nov 2020, 23:54
  #54 (permalink)  
 
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This is getting silly. If you have a 100% complete electrical on "pre-programmed air vehicle, autonomous drone or remotely piloted aircraft", it's going to crash. Period - end of story.
So, you design the system so that you'll never have a 100% complete electrical failure.
No different than the FBW systems on most new aircraft - if you have a 100% complete electrical failure in your FBW, you're going to have a very bad day because FBW isn't going to work without electrical power of some sort. So you design numerous backups so that it doesn't happen (for certification purposes, that means a probability of occurrence less than once in 10-9 flight hours).
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Old 17th Nov 2020, 00:38
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Finally, someone who knows how to use their brain . . .

Aircraft control systems which are designed around humans USE the human as part of the safety mitigation strategy . . . in the example here lots of stuff fails and the human can still control the aircraft, albeit with reduced performance. This is not a miracle, it's one of the key reasons the human is there is the first place and why the aircraft is designed in the way it is, it's a system, the human is part of it. Increasingly large parts of the non human part of the system are there to stop the human from screwing up . . . in reality . . .

Only a neanderthal would design an automated flight control system without an equally effective mitigation strategy, again possibly with reduced performance. A neanderthal solution would never be permitted to fly and kill people.

Automated control systems are perfectly possible, or very close to it, in the real world, today, The question is . . . is it cheaper to use a human despite their repeated and ongoing failures ?, after all they are cheap, readily available and reasonably good at the job and their failings are relatively well understoof. Are the benefits of fully automated systems justifiable given their likely cost ? Inevitably that cost will reduce, and inevitably the benefits will swing to the side of the machines.

Whether the justification is increased safety or reduced costs (it'll always be the latter despite people claiming it's the former), that change will happen.
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Old 17th Nov 2020, 02:33
  #56 (permalink)  
 
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This 10-9 stuff doesn't apply to the thread subject event albeit it does apply to some of the preceding expanded subject what-if discussions
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Old 17th Nov 2020, 19:23
  #57 (permalink)  
 
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In a sense it still does - uncontained engine failures are considered to be a 10-7 to 10-8 event. Current airframer guidance for uncontained engine failures is to do what is known as a "one in twenty" analysis - basically showing that the probability that an uncontained failure will do catastrophic aircraft damage is no greater than 1 in 20 or 5%. So that takes an uncontained failure causing catastrophic airframe damage into the 10-9 range.
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Old 17th Nov 2020, 22:11
  #58 (permalink)  
 
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I believe your 10-7-10-8 is off by a factor of 10.There is no certified standard for anywhere near10-9 as it's impracticable on transport aircraft . As you stated though if you satisfy the regulators idea of good-enough that's then OK..
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Old 18th Nov 2020, 20:26
  #59 (permalink)  
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Antonov built that to compete with 1,000 brick ***** houses and it would win. One cannot say that carbon fibre would have swallowed that amount of damage and still be able to make a normal touch down. The overrun due to other equipment failures. Remarkable.
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Old 19th Nov 2020, 07:46
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Fun fact:
Turbine discs always shatter into three 120 degree pie cuts due to geometric/material constrains. So basically, you can calculate statistic probability of one of those piercing trough the something important (and pierce it will, there is a lot of kinetic energy involved). The trick is to move important stuff apart so nothing critical goes offline when severed. DC10 had some issues in that regard.
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