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As an example, was the 447 computer so deprived of sensory inputs that it couldn't protect the aircraft from nonsensical control inputs - or is there no such software? It seems incredible that systems wouldn't know inputs were illogical. I'm attempting to make a clear distinction between inputs and net flightpath. |
Originally Posted by Loose rivets
(Post 10737548)
As an example, was the 447 computer so deprived of sensory inputs that it couldn't protect the aircraft from nonsensical control inputs - or is there no such software? It seems incredible that systems wouldn't know inputs were illogical. I'm attempting to make a clear distinction between inputs and net flightpath. |
Originally Posted by Loose rivets
(Post 10737548)
As an example, was the 447 computer so deprived of sensory inputs that it couldn't protect the aircraft from nonsensical control inputs - or is there no such software? It seems incredible that systems wouldn't know inputs were illogical. I'm attempting to make a clear distinction between inputs and net flightpath.
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As I see it, the Airbus arithmetical addition of inputs allows an instant, instinctive rescue input to be made even if one does not press the take-over button - to flare the aircraft for example. This is the equivalent of feeling the yoke being pulled back by PM, or having the clutch and brake applied by your driving instructor in a dual control car.
Once when first taxiing an A330, I went off the line at a confusing and poorly lit intersection, at night in an unfamiliar US airport. The TRE slammed on the brakes, which was very dramatic, and it shook up the passengers and crew. Had he simply used his tiller to pull the aircraft back on line, and said to me "I have control" or "no, over here", that would have been that, and no drama, (but the 'Dual input' call might have sounded). The Airbus 'dual input' callout should not be feared, but is a cue for subsequent discussion. |
Originally Posted by Uplinker
(Post 10738015)
As I see it, the Airbus arithmetical addition of inputs allows an instant, instinctive rescue input to be made even if one does not press the take-over button - to flare the aircraft for example. This is the equivalent of feeling the yoke being pulled back by PM, or having the clutch and brake applied by your driving instructor in a dual control car.
Once when first taxiing an A330, I went off the line at a confusing and poorly lit intersection, at night in an unfamiliar US airport. The TRE slammed on the brakes, which was very dramatic, and it shook up the passengers and crew. Had he simply used his tiller to pull the aircraft back on line, and said to me "I have control" or "no, over here", that would have been that, and no drama, (but the 'Dual input' call might have sounded). The Airbus 'dual input' callout should not be feared, but is a cue for subsequent discussion. |
I feel you Uplinker. Was a bit of overreaction. By the way there is no “dual input” auto call out in case of both tiller deflection at the same time. At least not on the A320 family.
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Had he simply used his tiller to pull the aircraft back on line, and said to me "I have control" or "no, over here", that would have been that, and no drama, (but the 'Dual input' call might have sounded). |
Actually, no I don't think there is for steering. Apologies.
Originally Posted by sonicbum
(Post 10738134)
The "dual input" is a big no-no and must not be used, in any circumstance. In Your scenario, if your trainer added his input to yours on the NWS on an A330 in a poorly lit taxiway, that would have been the perfect recipe for wheels on the grass.
My point is that by fearing "Dual Input" even for a second, more drastic intervention is the only course of action left. |
Originally Posted by Uplinker
(Post 10739126)
Actually, no I don't think there is for steering. Apologies.
But in my case the TRE would have steered back towards the correct centreline, arithmetically neutralising my input and taking us away from the wrong line or the grass - while simultaneously saying "I have control", |
Originally Posted by Check Airman
(Post 10578365)
This represents the biggest design flaw of this airplane in my opinion. Not sure why the regulators allowed this to be certified, and (especially after AF447) continue to let it go unchecked. From the AAIB, in a rare moment of clarity (https://assets.publishing.service.go...JZ_12-08.pdf): Simulator assessment The AAIB investigator carried out an assessment exercise in a full flight A320 simulator taking the role of a ‘trainee’ pilot, together with an experienced A320 Type Rating Examiner (Aircraft) (TRE(A)). The TRE(A) was current in both line and base training of pilots of all levels of experience. Having briefed the TRE(A) that he should act as he would during normal operations, the ‘trainee’ flew normal approaches and landings, interspersed with approaches and landings during which deliberate handling errors were made. No prior warning was given to the TRE (A) of these errors. In the first of these ‘unusual’ approaches, a manual approach was flown with autothrust, but the ‘trainee’ ceased to make sidestick inputs at 50 ft RA. The TRE(A) was unable to intervene in time and the aircraft struck the runway without a flare. In other ‘unusual’ approaches, the TRE(A) was again unable to intervene, or intervened too late, to prevent a hard landing. In a fly-by-wire aircraft fitted with sidesticks, the instructor also monitors the approach by assessing the aircraft’s performance, but does not have an option of sensing control inputs made by the trainee. By the time it is apparent that no flare, or an incorrect flare, has been made, it may be too late for the instructor to intervene and the aircraft to respond before a possible heavy touchdown occurs The priority takeover pushbutton is mounted on the top of each sidestick. Whilst control of the aircraft through manipulation of the sidestick is highly instinctive, operation of the priority takeover button is a highly cognitive action. |
Hi sonicbum, trust me, he slammed those suckers on! :)
Originally Posted by Kit Sanbumps KG
(Post 10740663)
..........That sidestick has blood on its hands...
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Originally Posted by Kit Sanbumps KG
(Post 10740663)
Yes.
From the AAIB, in a rare moment of clarity (https://assets.publishing.service.go...JZ_12-08.pdf): and and some proper HF from them: That sidestick has blood on its hands... What a shame manufacturer B has sunk to similar depths and no longer provides a credible alternative. |
Despite over 21000 posts AF447 refuses to die. AF447 and QZ8501 pilots at controls at that time were simply not competent to do what was required and they were not not going to discover it by accident. No pun intended. In 447 TOGA and high pitch and 8501 again pull back on stick. This is not what you do in alternate law. So it is a past time that may be AoA display, oh no! the feedback to the other stick perhaps. It has not happened and not going to happen. We are discussing dual input. These laments are not contributing anything. They should be shifted to 447 thread.
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vilas i think the people talking about AF447 are pointing to the fatal flaw in the system. I think the FBW system is great, but it should never have been designed with uncoupled sidesticks. The extra weight and complexity may have saved the lives of the AF447 pax and crew.
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@vilas while mine opinion differs significantly from C/A's, I do not find your otherwise correct point applicable to this thread.
Yes, the controlling pilots for both AF and QZ made hard to explain inputs after losing spatial awareness. The question why was this not over-ruled by PIC was never answered sufficiently. Reading the QZ report in this respect is heart-stopping. The take-over button only works when you use it, again your note on incompentece are true. Yet the intuitiveness is galaxies apart if you need to correct. Airbus pilots (LHS+) are trained to cope but are they proficient in using the button? What means are there to achieve and maintain such skill? Is it understood that teaching the "I have controls" call and press the button (per FCOM/FCTM) is negative training? |
Originally Posted by Check Airman
(Post 10741682)
vilas i think the people talking about AF447 are pointing to the fatal flaw in the system. I think the FBW system is great, but it should never have been designed with uncoupled sidesticks. The extra weight and complexity may have saved the lives of the AF447 pax and crew.
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Originally Posted by FlightDetent
(Post 10741968)
@vilas while mine opinion differs significantly from C/A's, I do not find your otherwise correct point applicable to this thread.
Yes, the controlling pilots for both AF and QZ made hard to explain inputs after losing spatial awareness. The question why was this not over-ruled by PIC was never answered sufficiently. Reading the QZ report in this respect is heart-stopping. The take-over button only works when you use it, again your note on incompentece are true. Yet the intuitiveness is galaxies apart if you need to correct. Airbus pilots (LHS+) are trained to cope but are they proficient in using the button? What means are there to achieve and maintain such skill? Is it understood that teaching the "I have controls" call and press the button (per FCOM/FCTM) is negative training? It is up to ATOs and Operators to establish training policies and procedures in such a way that pilots are and remain proficient with the proper takeover technique. It is important to clear bad habits and insist on the usage of the proper technique which can be practiced during simulator sessions with the instructor occupying the other pilot seat. In my company the flight safety team has a very pragmatic and common-sensed based approach on event management but "dual inputs" are highly not tolerated (like an unstable below 500ft), including during training flights, because it can lead to very serious events. |
Originally Posted by sonicbum
(Post 10742551)
The "uncoupled" sidesticks has nothing to do with the AF447 accident and I personally believe that there was not at the time and still there is not any need for such a thing as there is zero evidence from past accidents that it could have changed the course of action.
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Originally Posted by Report PK-AXC
38. Since 2317:29 UTC, both left and right side stick input were continuously active until the end of the recording. The inputs were different where the right sidestick was pulled for most of this segment, the nose down (forward) pitching commands of the left sidestick became ineffective because of the summing function of the system, resulting in ineffective control the aircraft.
Although there were at least 3 other things that could have helped avoid the outcome. All mandatory for airline pilot competence and none of them demonstrated by the crew. That is also true. |
Originally Posted by FlightDetent
(Post 10742661)
If there was a dotted line below: "...there is zero evidence from past accidents ... (interconnected side-sticks) ... could have changed the course of action" I would not sign. :(
Although there were at least 3 other things that could have helped avoid the outcome. All mandatory for airline pilot competence and none of them demonstrated by the crew. That is also true. |
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