Airbus crash/training flight
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night_flight99 -
Everything you write has merit. Of course, there would be no need for a stall 'test' in a case where one airline is returning an aircraft back to its owner I don't think. Again, it's because of a sytem on board this and similar aircraft that led to this accident, even if it turns out to be 'pilot error' in the end.
Everything you write has merit. Of course, there would be no need for a stall 'test' in a case where one airline is returning an aircraft back to its owner I don't think. Again, it's because of a sytem on board this and similar aircraft that led to this accident, even if it turns out to be 'pilot error' in the end.
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DC-ATE
You just don't get it do you 
There was NO requirement to do this test. It is the exact equivalent of a stall shaker test - and it is just as likely to be tested unnecessarily and at the wrong altitude as Alpha Max... Whether or not a stall shaker test is a "handover" requirement, an Alpha Max check is not required.
You really seem hell bent on blaming FBW for this when it is totally irrelevant as to the conduct of the test
NoD
Of course, there would be no need for a stall 'test' in a case where one airline is returning an aircraft back to its owner I don't think. Again, it's because of a sytem on board this and similar aircraft that led to this accident, even if it turns out to be 'pilot error' in the end.
There was NO requirement to do this test. It is the exact equivalent of a stall shaker test - and it is just as likely to be tested unnecessarily and at the wrong altitude as Alpha Max... Whether or not a stall shaker test is a "handover" requirement, an Alpha Max check is not required.You really seem hell bent on blaming FBW for this when it is totally irrelevant as to the conduct of the test
NoD
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You really seem hell bent on blaming FBW for this when it is totally irrelevant as to the conduct of the test
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Well, if that little "toy" wasn't there, they couldn't test or play with it could they?
NoD
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I'm not all that fond of stick shakers either. And I've never flown anything with a stick pusher. I'm all for "recognition" and not relying on something 'automatic' at this most critical stage of flight. As I said in my post about stalling a 737, the stick shaker can come AFTER a stall recognition. So, in my mind a stick shaker and/or pusher is a "toy" as well.
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The importance of AoA probes... and FAC's.
The FAC computes a/c gross weight, and displays limit speeds on the PFD - below 14,500 ft. the FAC uses AoA information as opposed to a "memorized" value of GW. Hence the need to do this test at FL 140 max - for up-to-date values of Vls etc. - to FL 100 as a minimum safe altitude for the test.
In Normal Law the FAC displays Vls, α prot, α max on the PFD speed scale. In the case of this a/c with erroneous fixed AoA values who knows what value of gross weight the FAC's computed? The fact that the crew slowed down to less than 107 kt (the calculated Vmin elsewhere in the report) indicates to me that perhaps the computed minimum speeds were less than the true values - but I don't know for sure. Another clue is the fact that the A/THR mode never went to αFloor.
If true, a further complication would be that Autotrim did not stop as the speed reduced through the true Vls.
Once in Direct Law with TOGA thrust, THS further nose-up than normal, lots of trim wheel movement would be necessary to gain a decent amount of nose-down elevator authority.
The FAC computes a/c gross weight, and displays limit speeds on the PFD - below 14,500 ft. the FAC uses AoA information as opposed to a "memorized" value of GW. Hence the need to do this test at FL 140 max - for up-to-date values of Vls etc. - to FL 100 as a minimum safe altitude for the test.
In Normal Law the FAC displays Vls, α prot, α max on the PFD speed scale. In the case of this a/c with erroneous fixed AoA values who knows what value of gross weight the FAC's computed? The fact that the crew slowed down to less than 107 kt (the calculated Vmin elsewhere in the report) indicates to me that perhaps the computed minimum speeds were less than the true values - but I don't know for sure. Another clue is the fact that the A/THR mode never went to αFloor.
If true, a further complication would be that Autotrim did not stop as the speed reduced through the true Vls.
Once in Direct Law with TOGA thrust, THS further nose-up than normal, lots of trim wheel movement would be necessary to gain a decent amount of nose-down elevator authority.
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"Again, it's because of a sytem on board this and similar aircraft that led to this accident, even if it turns out to be 'pilot error' in the end."
DC-ATE, in this instance it was a system of a fbw aircraft. If they had done a test on a conventional aircraft it would have been a stall protection system. The point is surely that it shouldn't have been done at that part of the envelope at all! FBW is a very effective concept of aircraft design but even it can't stop the human error chain and its ability to over ride protections, regrettably sometimes inappropriately.
Given a choice between a low energy state in a product of Airbus or McDonnell Douglas and I will take the airbus product every time!!
DC-ATE, in this instance it was a system of a fbw aircraft. If they had done a test on a conventional aircraft it would have been a stall protection system. The point is surely that it shouldn't have been done at that part of the envelope at all! FBW is a very effective concept of aircraft design but even it can't stop the human error chain and its ability to over ride protections, regrettably sometimes inappropriately.
Given a choice between a low energy state in a product of Airbus or McDonnell Douglas and I will take the airbus product every time!!
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night_flight99 -
As I stated earlier, I'm not sure a test of the stick shaker is required in a transfer situation. But, nevertheless, they would not have done it at low altitude...hopefully.
And.....FBW might very well be an "effective concept" of aircraft design. But's let remember WHY we have it. FMCs and EFIS and all the other acronyms that would take a whole page to list, are just bringing the head of the pilot inside the airplane, when it should be either outside or watching FLIGHT instruments. Computers telling a pilot when do start down, when to do this and that are doing nothing to enhance the ability to FLY the airplane or make it safer.
As to being in a "low energy state"; not sure I follow that. You shouldn't ever be in that state. Pilots are getting into those conditions because they're paying too much attention to things other than flight instruments. And you should never be in a position to have some computer tell you what to do.
OK.....enough.
DC-ATE, in this instance it was a system of a fbw aircraft. If they had done a test on a conventional aircraft it would have been a stall protection system. The point is surely that it shouldn't have been done at that part of the envelope at all! FBW is a very effective concept of aircraft design but even it can't stop the human error chain and its ability to over ride protections, regrettably sometimes inappropriately.
Given a choice between a low energy state in a product of Airbus or McDonnell Douglas and I will take the airbus product every time!!
Given a choice between a low energy state in a product of Airbus or McDonnell Douglas and I will take the airbus product every time!!
And.....FBW might very well be an "effective concept" of aircraft design. But's let remember WHY we have it. FMCs and EFIS and all the other acronyms that would take a whole page to list, are just bringing the head of the pilot inside the airplane, when it should be either outside or watching FLIGHT instruments. Computers telling a pilot when do start down, when to do this and that are doing nothing to enhance the ability to FLY the airplane or make it safer.
As to being in a "low energy state"; not sure I follow that. You shouldn't ever be in that state. Pilots are getting into those conditions because they're paying too much attention to things other than flight instruments. And you should never be in a position to have some computer tell you what to do.
OK.....enough.
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But what happened from 15:45:21? At this point speed had increased, wings were approx level, pitch was reasonable, full power had been on for some time, full fwd stick (but full aft stabiliser), ailerons were neutral...
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grumpyoldgeek -
If that is so, there are those on here who will not like my response to your Q. Do you suppose that has anything to do with any on board computer??
If I'm reading the graphs in the back of the report correctly, the pilot had the stick fully forward at 15:45:15 and, ignoring some little flicks, kept it there until 15:45:40. Despite that, the aircraft continued to increase in pitch during that time. I can't figure out how the numbers work for the stabilizer and elevator. Is there anyone that can shed some light on that?
If that is so, there are those on here who will not like my response to your Q. Do you suppose that has anything to do with any on board computer??
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What happens if you let go of the stick with full power and 11.2deg negative stabiliser?
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The fact that the crew slowed down to less than 107 kt (the calculated Vmin elsewhere in the report) indicates to me that perhaps the computed minimum speeds were less than the true values
The "Stall" Warning seems to be issued by the ADIRUs (3 of), in turn from the AoA probes (3 of). The "Stall" warning should not be heard in Normal Law, but that does not mean it is inhibited... just it should never get there (?) The fact that a "Stall" warning did go off can only mean (?) an AoA probe (presume the one not on the FDR trace) was working and got to the Stall limit AoA?
What happens if you let go of the stick with full power and 11.2deg negative stabiliser?
However, as posted above, essentially full fwd stick was held, and full down elevator achieved and held.Lots more to run on this one...
NoD
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The stabiliser was nose up not down. That's why the full down elevator was not effective in reducing the pitch attitude - for more gen read my post back one page.
NoD
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NoD
Two things may account for it..
The sidestick goes to neutral briefly then back to full nose down at 15:45:21, and both engines are producing Max EPR by 15:45:15. Plus a small increase in CAS - that's three.
TP
Two things may account for it..
The sidestick goes to neutral briefly then back to full nose down at 15:45:21, and both engines are producing Max EPR by 15:45:15. Plus a small increase in CAS - that's three.
TP
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TP... Reckon you might be right - there are a lot of things happening right there, and even if we have all the info (we don't) I am sure the actual dynamics would take some understanding.
It seems to reinforce the UP drill of nose up needing some power off
NoD
It seems to reinforce the UP drill of nose up needing some power off
NoD
framer
I find the use of the word "gratifying" somewhat offensive and comparing fiscal loss with the loss of human life doesn't deserve comment.
Whatever.
It doesn't, however, reduce the relevance of the parallels in the processes.
Risk management during normal operations in commercial aviation isn't left to the operating crew. It's integral to aircraft specification and defined in operating procedures.
I'd submit that - in performing tests only permitted between FL100 and FL140 at FL30 - the crew ventured into an area where (despite their 30k hours of flight experience) they weren't able to adequately assess the risk level of their actions.
Here's another one for you:
Software develoment has a "frozen zone" - a period in which product stability has been achieved and is not subjected to ANY change/risk.
Where's the parallel in your world? Approach phase, perhaps.
No thanks, it may be gratifying for you to liken it to your particular area of expertise but it is not really relavent (sic).
Whatever.
It doesn't, however, reduce the relevance of the parallels in the processes.
Do you think perhaps that with 30,000 odd hours of flight experience on the flight deck that day, that the concept of risk management wasn't completely new to them?
I'd submit that - in performing tests only permitted between FL100 and FL140 at FL30 - the crew ventured into an area where (despite their 30k hours of flight experience) they weren't able to adequately assess the risk level of their actions.
Here's another one for you:
Software develoment has a "frozen zone" - a period in which product stability has been achieved and is not subjected to ANY change/risk.
Where's the parallel in your world? Approach phase, perhaps.
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Narval, what the heck do you fly; anyone that flies Airbus FBW knows that during DIRECT LAW you will loose AUTO TRIM and there is a big anouncement in amber right in front of you to remaind you. Regular airplanes do not have auto trim !!!
My apologies, Guiones, I only flew the thing for a few thousand hours...must have missed it altogether! I never once saw alternate or direct law except in the books, probably that's why I'm writing here in good health. And as I flew many test flights after overhauls on conventional machines, I learnt that a bit of modesty and briefings on things that are "evident" never did any harm...
My apologies, Guiones, I only flew the thing for a few thousand hours...must have missed it altogether! I never once saw alternate or direct law except in the books, probably that's why I'm writing here in good health. And as I flew many test flights after overhauls on conventional machines, I learnt that a bit of modesty and briefings on things that are "evident" never did any harm...
DIRECT LAW flies just like a regular airplane, no protections.
...since the accident appears to have little applicability to Line Ops.
We won't know if there is any applicability to Line Ops until we know exactly why they weren't able to fly it like a "regular" airplane.
True the crew did something at an altitude far below where they should have been, but did the airplane respond the way it should have following their corrective actions? We don't yet know. They got lots of power out of the engines and a climbing attitude, but the plane departed anyway. Would they have been able to prevent the accident it they had started at FL140? Again, we don't know yet, but we'd better not give up until we find out.
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Unfortunately, we might never know without input from the crew. Sadly, this happens all too often in aircraft accidents and the investigators can come up with a suitable scenerio blaming the crew who can't defend themselves.
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Abnormal Attitude Law
I have been puzzling over the lack of THS movement from fully nose-up. I can't explain the lack of THS movement while in Direct law.
But at 15:45:40 the Pitch Law reverts from Direct to Alternate - this coincides as near as I can judge with a pitch attitude of 50° NU, increasing to 60°. This would put the a/c in Abnormal Attitude Law,which is:
Pitch Alternate, No Protections except Load Factor, and No Autotrim. The Trim Wheel would still control the THS.
Roll Direct
Yaw Mechanical.
These control laws would apply until the pitch reduces below 50° and the speed is above 60 kt. Then the pitch Law reverts to Alternate without protections, but with Autotrim enabled. So from 15:45:55 the Autotrim was enabled, but no THS movement is recorded.
To complete the picture I would like to see the Normal Load Factor and Flap/Slat position read-outs - I am puzzled why the crew retracted the Flaps to Zero.... anyone got any idea?
TP
But at 15:45:40 the Pitch Law reverts from Direct to Alternate - this coincides as near as I can judge with a pitch attitude of 50° NU, increasing to 60°. This would put the a/c in Abnormal Attitude Law,which is:
Pitch Alternate, No Protections except Load Factor, and No Autotrim. The Trim Wheel would still control the THS.
Roll Direct
Yaw Mechanical.
These control laws would apply until the pitch reduces below 50° and the speed is above 60 kt. Then the pitch Law reverts to Alternate without protections, but with Autotrim enabled. So from 15:45:55 the Autotrim was enabled, but no THS movement is recorded.
To complete the picture I would like to see the Normal Load Factor and Flap/Slat position read-outs - I am puzzled why the crew retracted the Flaps to Zero.... anyone got any idea?
TP