Unbelievable A380 landing
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Question for 380 pilots out there. Does the yaw damper operate more through the lower rudder than upper? It seems the lower is countering the yaw created by gusts and the upper only really comes into play when the final decrab takes place. The gusts looked to be playing merry hell with him at times creating significant heading changes.
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Rudder inputs were way behind what the aeroplane was doing. A taildragger would have rolled itself into a fiery ball for such gross mis-use of the rudder. Give him some Auster time - that'll get his lazy feet sorted out!
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Shaggy if you use the rudder on a big swept wing jet like you do on an Auster you would be dead.
Why post when you have no knowledge of the techniques & handling of big jets, it just makes you look stupid.
Why post when you have no knowledge of the techniques & handling of big jets, it just makes you look stupid.
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As someone with just offering a drivers license and therefore without any deeper knowledge about flying or planes I would like to ask a question regarding the behaviour of the lower and upper part of the rudder of that A380.
Look at the video.
Through approach the pilot or the autopilot manages to slip down smoothly and hold the course and so on with almost just using the lower part of the rudder. A split second before touch down the upper part of the rudder kicks in too and then the brutal force of that giant rudder working as a whole lets the plane swing heavily to the left.
Why is that? It seems that this kicking in of the upper rudder and its influence on the plane`s direction comes surprisingly to the pilot. Also when he tries to countermanage the direction it seems that he is not overreacting but does not know or expect that both upper and lower rudder work together. Therefore that PIO.
Thanks in advance.
Look at the video.
Through approach the pilot or the autopilot manages to slip down smoothly and hold the course and so on with almost just using the lower part of the rudder. A split second before touch down the upper part of the rudder kicks in too and then the brutal force of that giant rudder working as a whole lets the plane swing heavily to the left.
Why is that? It seems that this kicking in of the upper rudder and its influence on the plane`s direction comes surprisingly to the pilot. Also when he tries to countermanage the direction it seems that he is not overreacting but does not know or expect that both upper and lower rudder work together. Therefore that PIO.
Thanks in advance.
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I'm not an Airbus pilot (just 747), but there are 2 possibilities that come to me immediately:
1) He may have had the autopilot coupled, and decided to go manual at the last moment.
2) He may have tried to "kick out" the crab angle just prior to touchdown, and grossly overdid it, setting up the PIO.
With such a variable, gusty wind, I prefer to fly the airplane manually most of the way down the glideslope, so I can get a better feel for the excursions. Also, the 747 autothrottle will not keep up with significant gusts. I prefer to keep a relatively constant throttle position and allow the airspeed to fluctuate around the bug speed somewhat.
Also, I don't attempt to "kick out" a crab angle, but smoothly add rudder and aileron in the last 50-100' of altitude. The 747 will land in a crab, so there is no overriding reason to try to eliminate all crab and risk the overcontrol.
1) He may have had the autopilot coupled, and decided to go manual at the last moment.
2) He may have tried to "kick out" the crab angle just prior to touchdown, and grossly overdid it, setting up the PIO.
With such a variable, gusty wind, I prefer to fly the airplane manually most of the way down the glideslope, so I can get a better feel for the excursions. Also, the 747 autothrottle will not keep up with significant gusts. I prefer to keep a relatively constant throttle position and allow the airspeed to fluctuate around the bug speed somewhat.
Also, I don't attempt to "kick out" a crab angle, but smoothly add rudder and aileron in the last 50-100' of altitude. The 747 will land in a crab, so there is no overriding reason to try to eliminate all crab and risk the overcontrol.
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The rudder inputs in flight are the FWB system. It's detecting the crosswind gusts as sideslip, and using the rudder to get rid of it. If you turn the flight control page on during an approach in a gusty crosswind, you can see that there is constant rudder activity.
The rudder inputs after the impact with the runway, are all pilot induced!
The rudder inputs after the impact with the runway, are all pilot induced!
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Yeas, but the NTSB tested the materials and found they were still exceeding design strength. The National Transportation Safety Board determines that the probable cause of this accident was the in-flight separation of the vertical stabilizer as a result of the loads beyond ultimate design that were created by the first officer’s unnecessary and excessive rudder pedal inputs. --- NASA-Langley’s and Airbus’ FEA models showed that the stress and strain profiles of the right rear lug at the time of vertical stabilizer separation were equivalent to those of the full-scale certification test at failure, and NASA’s PFA results showed that the failure load, failure mode, and location of failure initiation for the accident condition were equivalent to those of the full-scale certification test. --- The stresses developed exceeded the strength values for the CFRP material used in the manufacturing of the lugs; thus, the accident lug and the tested lugs fractured because of a tensile static overload. The accident reports has the full details on that in sections 1.16.3 and 1.16.4.
Going on memory here but I remember that the rudder travel limiter ended up being a big contributor to that accident and another close call event in AA903. In the A300 system at higher speeds, the breakout force for the rudder is high enough so that once achieved it is extremely difficult to pull back before full travel is commanded.
NTSB Recommendation re Airbus Rudder Travel Limits [Archive] - PPRuNe Forums
Of course Airbus went no no.... don't look at the man behind the curtain, look at the awful training and that FO with suspect history, and unfortunately the NTSB bought it for the final report.
I do wonder if the A380 is like the A300 in which the FDR is not recording the actual pilot inputs but the actual rudder travel.
In the AA587 data, it leaves permanent doubt since we will never really know what the FO's rudder inputs were.
Of course, even if the PF wasn't totally at fault for that goofy landing, like if the flight control system put him in a place that needed correction, I doubt that defense will mean much to EK. Just going popular opinion around here... even if he wasn't at fault at all it still wouldn't matter as it's all about public perception. I do wonder about if punitive action will be taken against the PNF as well...
Last edited by Sorry Dog; 15th Oct 2017 at 14:40.
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As someone with just offering a drivers license and therefore without any deeper knowledge about flying or planes I would like to ask a question regarding the behaviour of the lower and upper part of the rudder of that A380.
Look at the video.
Through approach the pilot or the autopilot manages to slip down smoothly and hold the course and so on with almost just using the lower part of the rudder. A split second before touch down the upper part of the rudder kicks in too and then the brutal force of that giant rudder working as a whole lets the plane swing heavily to the left.
Why is that? It seems that this kicking in of the upper rudder and its influence on the plane`s direction comes surprisingly to the pilot. Also when he tries to countermanage the direction it seems that he is not overreacting but does not know or expect that both upper and lower rudder work together. Therefore that PIO.
Thanks in advance.
Look at the video.
Through approach the pilot or the autopilot manages to slip down smoothly and hold the course and so on with almost just using the lower part of the rudder. A split second before touch down the upper part of the rudder kicks in too and then the brutal force of that giant rudder working as a whole lets the plane swing heavily to the left.
Why is that? It seems that this kicking in of the upper rudder and its influence on the plane`s direction comes surprisingly to the pilot. Also when he tries to countermanage the direction it seems that he is not overreacting but does not know or expect that both upper and lower rudder work together. Therefore that PIO.
Thanks in advance.
I agree. During the approach the upper rudder is not moving in sequence with the lower rudder until a split second prior to touchdown when the upper rudder can then be seen to deflect to the left and therefore increasing the yaw rate. This must surely have been a most unwelcome surprise to the handling pilot who, under the circumstances, handled the situation as best he could. During the landing roll, both rudders are operating together until the final phase of rollout when the upper rudder can then be seen to misalign with the lower one (again). Might it conceivably be that there might be a fault within the speed sensing system (rudder limiter) which caused this upset. In any event, don't castigate the pilot until such time as it can be proven that there wasn't a problem with the rudder system.
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A deep understanding of how airbus control laws operate is required before wondering what the control surfaces are doing. For sure their movement is not necessarily conventional. No criticism here as I have sat in many a class room watching instructors correcting miss-understandings by current airbus pilots.
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The real issue is he's not even crabbing...he's making a rudder displacements that look like crabbing
Not having ever flown an Airbus but knowledgeable on C* vs C*U stability.
With both systems a crab is just a shallow turn and a level off once the runway stops sliding sideways away from you
Not having ever flown an Airbus but knowledgeable on C* vs C*U stability.
With both systems a crab is just a shallow turn and a level off once the runway stops sliding sideways away from you
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and to be fair, we all have these days with bad landings. my decrabbings aren't perfect all the time and sometimes i get a ballooning. were not perfect.
sure it was no good work they did, but we all should recap if we've always landed perfectly in the aiming zone or if we've had long landings, not on centerlines and dropped from 10ft landings...
sure it was no good work they did, but we all should recap if we've always landed perfectly in the aiming zone or if we've had long landings, not on centerlines and dropped from 10ft landings...