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  #111  
Old 15th October 2008, 07:07 AM
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Philip Argy Philip Argy is offline
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Quote:
Originally Posted by Ash W View Post
It is not easy to test a piece of equipment or software for every possible permutation. .... Sure some people got hurt by what appears to be a first for this type, but the plane and it's passengers still made it to the ground in one piece.
I don't share your design philosophy I'm afraid, Ash. Safety critical systems require a special approach. The outcome in this case obviously could have been much worse but that doesn't make it an acceptable outcome.

My point remains that the logic flaw that exists is one that should have been obvious to test for - I don't rate it as outside the realm of conditions that could be foreseen. The auto pilot disengagement routine logic was sound. It should be pretty obvious that the same reason that required the autopilot to be disengaged should have caused the flight computers to ignore any further input from ADIRU-1 once it had been diagnosed as faulty. In fact I'd be astonished if that logic isn't present, so the task is more to uncover why it didn't trigger, which is probably related to the Flight Control Primary Computer pitch fault.
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  #112  
Old 15th October 2008, 07:33 AM
NickN NickN is offline
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This is just a hypothetical question but it could just have easily been an outcome of this incident I suppose......

What would have happened if this incident was magnified 10x and say the aircraft pitched up and down so heavily it was pushed outside its operational envelope and broke apart mid-air?

As I said it's a hypothetical question but what would have prevented that outcome from happening?
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  #113  
Old 15th October 2008, 11:33 AM
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Mike W Mike W is offline
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Article today in "The Australian"

http://www.theaustralian.news.com.au...-23349,00.html

Quote:
Global alert after Qantas dive

Steve Creedy and Mark Dodd | October 15, 2008
EUROPEAN plane-maker Airbus has warned A330 operators around the world to guard against potential computer problems after last week's roller-coaster ride by a Qantas jet.

The global alert comes after investigators found that a faulty unit that provides information about the plane's movement and position resulted in the autopilot disconnecting and prompted flight control computers to pitch the plane's nose downward.

More than 70 people were injured, 14 seriously, when they were thrown around the cabin as the plane pitched down violently near Learmonth, in Western Australia northwest, while en route from Singapore to Perth.

The jet diverted to Learmonth and the worst injured were airlifted to Perth by the Royal Flying Doctor Service.

Investigators said last night the false information from an air data inertial reference unit (ADIRU) fed "very high, random and incorrect values".

The ADIRU supplies information such as air speed, altitude and position.

The fault led to the flight control computers pitching the aircraft's nose down by about 8.5 degrees and led to a fault in the flight control primary computer
.... goes on
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  #114  
Old 15th October 2008, 01:47 PM
Radi K Radi K is offline
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Is QPA back in SYD?
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  #115  
Old 15th October 2008, 02:33 PM
Nigel C Nigel C is offline
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Yep, I saw it over at the Jet Base this morning. It's parked north of Hangar 96.
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  #116  
Old 15th October 2008, 03:27 PM
Marty H Marty H is offline
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Would imagine its going to take some time to get the interior repaired.
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  #117  
Old 15th October 2008, 04:46 PM
damien b damien b is offline
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Quote:
Originally Posted by Philip Argy View Post
I don't share your design philosophy I'm afraid, Ash. Safety critical systems require a special approach. The outcome in this case obviously could have been much worse but that doesn't make it an acceptable outcome.

My point remains that the logic flaw that exists is one that should have been obvious to test for - I don't rate it as outside the realm of conditions that could be foreseen. The auto pilot disengagement routine logic was sound. It should be pretty obvious that the same reason that required the autopilot to be disengaged should have caused the flight computers to ignore any further input from ADIRU-1 once it had been diagnosed as faulty. In fact I'd be astonished if that logic isn't present, so the task is more to uncover why it didn't trigger, which is probably related to the Flight Control Primary Computer pitch fault.
Software is software unfortunately and designers along with engineers and test pilots can test the aircraft its sytems and the software for many varied faults. What has probably occured here is a failure of a component downward of either the ADIRU or FCC which has contributed to the ADIRU not being taken off line when it failed. Now that may be something like a relay or even a digital component which has failed or a slight glitch in the digital code.

To design a system for every possible failure and to cover everything that may occur, especially a low probability failure is not going to happen. It takes too long, costs to much and there comes a point in the design where the 'what if' scenerio's get to long and complex. I can not speak for Airbus but i saw the design philosophy behind the software and fault redundancy on the C-130J which was built to civil standards and the number of what ifs covered is huge yet faults will still occur that have not been thought of were or considered unlikely and thus not taken into consideration.

Its easy to say everything should be covered for safety but in reality it doesn't happen - its too costly, takes too long and for a thing that may only fail once in several million hours of flying its not something considered as critical to certification.
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  #118  
Old 15th October 2008, 04:49 PM
Ash W Ash W is offline
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Quote:
Originally Posted by Philip Argy View Post
I don't share your design philosophy I'm afraid, Ash. Safety critical systems require a special approach. The outcome in this case obviously could have been much worse but that doesn't make it an acceptable outcome.

...
It isn't a philosophy it is reality and I daresay safety critical items do get special attention, but as I said the reality is you cannot test for everything. We can sit here and say they should of tested this and that but that is with hindsite.
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  #119  
Old 16th October 2008, 03:05 AM
Robert S Robert S is offline
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Apologies if this photo gallery has been posted before, but I didn't see it:

http://www.news.com.au/perthnow/larg...013959,00.html

Also there's been some media reports that are drawing comparisons to this incident:

http://www.atsb.gov.au/publications/...200503722.aspx
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  #120  
Old 10th November 2008, 02:19 PM
Tom PER Tom PER is offline
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Sorry to dig up an old thread.

What's the latest on -QPA's current status? Did it end up going back to Airbus or HAECO for repairs? A source reckons their was 2 QF A333's parked at the hangars a couple of week back in HKG.

Last I heard it was parked near the QF hangars in SYD but someone on Airliners.net reckons it's back in service.

Haven't seen it pop up on any of the ACARS sites.
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