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QANTAS A380 Uncontained failure.

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QANTAS A380 Uncontained failure.

Old 27th Jun 2013, 22:52
  #741 (permalink)  
 
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Whoof! Took me three times longer to read the report than it did for the crew to handle all those ECAM items.

All that from a ~1mm machining error.
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Old 28th Jun 2013, 22:24
  #742 (permalink)  
 
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All that from a ~1mm machining error.
That was only the first domino to fall.

In the basic architecture of the turbine section, the IPT system could not tolerate a shaft separation; It was virtually guaranteed to overspeed until the disc burst. That is a basic design issue; the manufacturing fault in the oil tube was merely the straw that broke the camel's back.
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Old 29th Jun 2013, 00:33
  #743 (permalink)  
 
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That was only the first domino to fall.

In the basic architecture of the turbine section, the IPT system could not tolerate a shaft separation; It was virtually guaranteed to overspeed until the disc burst. That is a basic design issue; the manufacturing fault in the oil tube was merely the straw that broke the camel's back.
Of course they have addressed that little detail by changing the architect of the FADEC

I hope their FMEA analysis shows that good engines will not be shutdown erroneously with this doomsday code
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Old 21st Oct 2015, 12:57
  #744 (permalink)  
 
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Qantas, Rolls Royce, Airbus who knew prior to 4 Nov 2010

Re Qantas, Rolls Royce, Airbus
Who knew prior to 4 Nov 2010
that there was a high risk in the occurance of a QF32 failure and where there was no informed consent in advance of departure?

Cybercy
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Old 21st Oct 2015, 21:33
  #745 (permalink)  
 
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In fact there were two warning signals earlier in 2010:

I give you QF74, 744, RB211 on 30 Aug 2010 (SFO local date): Qantas QF74 Uncontained Engine Failure - Video & Pics
IPT came disconnected from its shaft and drifted aft due to pneumatic forces in the engine. In this case, the IPT blades DID clash (i.e. first made contact) with LPT stator vanes, thus very rapidly destroying the driving torque to the loose IPT disc. Blade shrapnel penetrated the case and cowl, but the pieces were relatively small so the damage to the airframe was limited.
The above happened within a few weeks of a RR test bench failure of another Trent (787 version). Little detail is publicly available, but I believe I heard someone mention IPT.

Contrast this with the QF32, A380, 04 Nov 2010 SIN: T972 suffers IPT disc rupture after shaft disconnect. No rotor/stator airfoil clash, instead the disc became axially restrained against relatively hard/smooth/low friction internal surfaces. Disc continued to accelerate, driven by relatively intact airfoils, until burst speed was reached.
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Old 21st Oct 2015, 23:31
  #746 (permalink)  
 
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In fact there were two warning signals earlier in 2010:
Warning signals consist of two parts...... cause and effect.

I doubt that anyone foresaw that the combinations that occurred in QF32 were likely.

Afterwards it's easy to look at all combinations ever having occurred in the total data base of the industry and then say, not surprised given etc. etc.
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Old 22nd Oct 2015, 13:01
  #747 (permalink)  
 
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I'm not saying they were in any way identical - only that IP shaft separations occurred and these should have sparked a "what if..." in some engineer's mind. QF32 should not have been a complete surprise.
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