Reports of A400 Crash, Saville, Spain
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"Power frozen" meaning that the 3 engines remained at take off power when they were throttled down shortly after TO whilst engine 4 reduced as planned???
All 4 throttles then reduced to idle which they all responded to and when power reapplied, 3 engines stayed at idle whilst engine 4 responded as expected?
All 4 throttles then reduced to idle which they all responded to and when power reapplied, 3 engines stayed at idle whilst engine 4 responded as expected?
Do the reports / discussions relate to a software version (separate program loads) or the (re)configuration of a single ‘standard’ software?
A comparison with ‘older’ conventional aircraft, the production pre first flight testing could include installing specific testing devices such as control rod loading and angle measurements in the aircraft. These were not flight-worthy and thus had to be clearly identifiable and/or have ‘interference’ links preventing flight use. Similarly, failure conditions could be tested with system pin-outs or interference links (grnd/flt switches) which created abnormal situations which could not or would not be advisable to test in flight. The devices would again be clearly identified – big red flag, etc; which of course did not prevent the rare ‘surprise’ during first flights if some aspect was overlooked.
Are we to assume that similar activities with software loads/configurations are conducted during ground testing; i.e. not flight worthy programs / configurations. If so then the problem is perhaps more with software control/configuration opposed to the design/operation of the power-plant control system, but the latter should never be discounted.
I recall one ‘conventional’ design weakness which was not discovered during ground testing and resulted in all engines going sub idle at touchdown after first flight – ‘wt on wheels’/engine control logic, and a minor unrelated system failure. This could have happened in flight but fortunately the specific trigger circumstances were not encountered.
A comparison with ‘older’ conventional aircraft, the production pre first flight testing could include installing specific testing devices such as control rod loading and angle measurements in the aircraft. These were not flight-worthy and thus had to be clearly identifiable and/or have ‘interference’ links preventing flight use. Similarly, failure conditions could be tested with system pin-outs or interference links (grnd/flt switches) which created abnormal situations which could not or would not be advisable to test in flight. The devices would again be clearly identified – big red flag, etc; which of course did not prevent the rare ‘surprise’ during first flights if some aspect was overlooked.
Are we to assume that similar activities with software loads/configurations are conducted during ground testing; i.e. not flight worthy programs / configurations. If so then the problem is perhaps more with software control/configuration opposed to the design/operation of the power-plant control system, but the latter should never be discounted.
I recall one ‘conventional’ design weakness which was not discovered during ground testing and resulted in all engines going sub idle at touchdown after first flight – ‘wt on wheels’/engine control logic, and a minor unrelated system failure. This could have happened in flight but fortunately the specific trigger circumstances were not encountered.
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If so then the problem is perhaps more with software control/configuration opposed to the design/operation of the power-plant control system
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Wing bending relief
KenV-'There are four wing tanks on the C-17. And they feed fuel to their associated engines equally. The outer tanks are not kept full for wing bending relief.'
I beg to differ Ken, the outboard tanks on the C-17 are kept full until the inboards reach the same level then they all come down together.
I beg to differ Ken, the outboard tanks on the C-17 are kept full until the inboards reach the same level then they all come down together.
Are we to assume that similar activities with software loads/configurations are conducted during ground testing; i.e. not flight worthy programs / configurations. If so then the problem is perhaps more with software control/configuration opposed to the design/operation of the power-plant control system, but the latter should never be discounted.
We had an incident in service a while back where a newly installed engine was squawked on the next flight for T/O thrust shortfall and excessive throttle stagger. The engine in question was a brand new spare received from the engine manufacture. It turned out that the engine manufacture used software trims in the engine test cell in order to perform some of the normal production acceptance testing on a new engine - and somehow this engine had gotten shipped with those s/w trims still installed in the FADEC
. Very embarrassing for the engine company, but fortunately there was a happy outcome, and new procedures were implemented to prevent a repeat.Sorry for the speculation, but it rather sounds like some sort of s/w trim had been installed in the engine s/w (either by the engine manufacture, or by Airbus as part of their pre-flight functional testing) and not "removed prior to flight" on the three engines.
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KenV-'There are four wing tanks on the C-17. And they feed fuel to their associated engines equally. The outer tanks are not kept full for wing bending relief.'
I beg to differ Ken, the outboard tanks on the C-17 are kept full until the inboards reach the same level then they all come down together.
I beg to differ Ken, the outboard tanks on the C-17 are kept full until the inboards reach the same level then they all come down together.
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Originally Posted by tdracer
We had an incident in service a while back where a newly installed engine was squawked on the next flight for T/O thrust shortfall and excessive throttle stagger. The engine in question was a brand new spare received from the engine manufacture. It turned out that the engine manufacture used software trims in the engine test cell in order to perform some of the normal production acceptance testing on a new engine - and somehow this engine had gotten shipped with those s/w trims still installed in the FADEC . Very embarrassing for the engine company, but fortunately there was a happy outcome, and new procedures were implemented to prevent a repeat.
Sorry for the speculation, but it rather sounds like some sort of s/w trim had been installed in the engine s/w (either by the engine manufacture, or by Airbus as part of their pre-flight functional testing) and not "removed prior to flight" on the three engines.
Sorry for the speculation, but it rather sounds like some sort of s/w trim had been installed in the engine s/w (either by the engine manufacture, or by Airbus as part of their pre-flight functional testing) and not "removed prior to flight" on the three engines.
Last edited by roulishollandais; 5th Jun 2015 at 08:25. Reason: spelling
Arrived back at Bordeaux-Merinac on Wednesday 0845 local and there was a A400 on the stand. Could only see the fin, but had not realised how big the aircraft is. Also an RAF Airtanker there both 27 May and 3 June.
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It seems so easy to modify a software without all the tests with the test data are done.
In the spacecraft world, launch vehicles and devices to be launched are subect to a hardware freeze and a software freeze both in development and manufacture, and these pre-determined freezes are written in stone: nothing can be changed after that date. Oh, except in France, of course.
In the spacecraft world, launch vehicles and devices to be launched are subect to a hardware freeze and a software freeze both in development and manufacture, and these pre-determined freezes are written in stone: nothing can be changed after that date. Oh, except in France, of course.
Well I muss confess the whole narrative is perplexing.
I have admittedly no experience with this specific power plant but I really fail to see how it's engine control software can be erroneously installed, be functional to the point of passing all static tests yet fail in such an extreme way to crash the aircraft.
I can understand that it was mis-configured, was getting erroneous inputs from sensors or - most likely - was simply buggy - all explanations apparently not applying here. An installation error that goes undetected until flight time ? On 3 out of 4 engines ? Wow...
I have admittedly no experience with this specific power plant but I really fail to see how it's engine control software can be erroneously installed, be functional to the point of passing all static tests yet fail in such an extreme way to crash the aircraft.
I can understand that it was mis-configured, was getting erroneous inputs from sensors or - most likely - was simply buggy - all explanations apparently not applying here. An installation error that goes undetected until flight time ? On 3 out of 4 engines ? Wow...
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O/T
I think when they said a quality failing you have to take a metaphorical step back and look at the "whole" picture.
A software install can be 100% correctly completed and still be "wrong" ie the installers have been issued a wrong version of the correct software; configuration control, process control-it may well be not the fault of the techs doing the actual upload if the information they were supplied with was wrong in the first place...
A software install can be 100% correctly completed and still be "wrong" ie the installers have been issued a wrong version of the correct software; configuration control, process control-it may well be not the fault of the techs doing the actual upload if the information they were supplied with was wrong in the first place...
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Roulis,
Have a good look at DAL. It's not a case of rewrite the code, upload, off you go. Safety critical software has to demonstrate an appropriate level of verification and assurance in manufacture and testing before it goes anywhere near an aircraft.
Something went wrong, speculation over such a complex failure will not solve anything.cwe will get the investigation findings in due course.
Have a good look at DAL. It's not a case of rewrite the code, upload, off you go. Safety critical software has to demonstrate an appropriate level of verification and assurance in manufacture and testing before it goes anywhere near an aircraft.
Something went wrong, speculation over such a complex failure will not solve anything.cwe will get the investigation findings in due course.
Safety critical software has to demonstrate an appropriate level of verification and assurance in manufacture and testing before it goes anywhere near an aircraft.
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Modification
Why don't Airbus introduce a suitable series of levers and rods from the thrust levers on the flight deck directly to the fuel control units on the engines.
Then they could have a third chap sit on the flight deck to help manage these levers and when not doing that could carry out walk rounds, a bit of down route engineering and seek out "interesting" places to take the crew too for refreshments...
Ditch FADEC and software and bring back flight engineers?
Then they could have a third chap sit on the flight deck to help manage these levers and when not doing that could carry out walk rounds, a bit of down route engineering and seek out "interesting" places to take the crew too for refreshments...
Ditch FADEC and software and bring back flight engineers?
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Bigpants wrote:
Yes, if you want to turn the clock back about 30 years. But at least that would mean the presence of a moose-trapper amongst the aircrew....
"You haven't seen ugly until you've seen something rejected by an air engineer!"
Ditch FADEC and software and bring back flight engineers?
"You haven't seen ugly until you've seen something rejected by an air engineer!"