De-crabbing at the flare to land without drift.
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You have said it all I think! To further think on the fact that a good wave-off is better than a botched decrabbing (wind becoming unmanageable...) may I recall a beautiful and terrifying video on the subject?
Dailymotion - A320 atterrissage vent travers hambourg - une vidéo Webcam & Vlogs
I remember, long ago, when I passed a test to become an instructor in the french air force, the officer testing me offered his cap with pieces of paper. I should choose one, on which was the lesson for the test. I took one: "cross-wind landings". And first at the blackboard, I explained the technique...then for fifty minutes in the little jet (FougMagister) I taught him. Weather cavok. Wind calm. The most difficult lesson I ever taught, since he was stubborn enough to ask me to go through with it.
Dailymotion - A320 atterrissage vent travers hambourg - une vidéo Webcam & Vlogs
I remember, long ago, when I passed a test to become an instructor in the french air force, the officer testing me offered his cap with pieces of paper. I should choose one, on which was the lesson for the test. I took one: "cross-wind landings". And first at the blackboard, I explained the technique...then for fifty minutes in the little jet (FougMagister) I taught him. Weather cavok. Wind calm. The most difficult lesson I ever taught, since he was stubborn enough to ask me to go through with it.
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That video is why most of us, in a strong gusty crosswind, will prefer to set up a slipping final approach coming up to or over the boundary fence rather than in the flare - makes the flare cognitive feedback loop much easier by removing a bunch of inputs from consideration.
If the pilot had fed in some slip (the other way) during the yaw it would have been a fine landing ... a bit of cognitive overload one thinks ?
If the pilot had fed in some slip (the other way) during the yaw it would have been a fine landing ... a bit of cognitive overload one thinks ?
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may I recall a beautiful and terrifying video on the subject?
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NARVAL:
That video reminds me of the video one sees of aircraft landing at the completion of the old Kai Tak, IGS13 approach. Some demonstrate effortless proficiency and others demonstrate a distinct lack of knowledge and capability, regardless of the aircraft flown...although mostly done with the easiest of XW airplanes I have ever flown...the B-747.
I would like to know the rest of the story and see previous and succeeding aircraft make that attempt before making a judgment call on that singular film clip.
That video reminds me of the video one sees of aircraft landing at the completion of the old Kai Tak, IGS13 approach. Some demonstrate effortless proficiency and others demonstrate a distinct lack of knowledge and capability, regardless of the aircraft flown...although mostly done with the easiest of XW airplanes I have ever flown...the B-747.
I would like to know the rest of the story and see previous and succeeding aircraft make that attempt before making a judgment call on that singular film clip.
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I'm not an Airbus man. But as far as understood from that incident, the cause was an "software feature" in the airbus that limits the trow of the ailerons after touchdown.
Unfortunately they had a gust and touched down with the downwind main gear, where after it was impossible to bring the wing down with the limited trow.
I believe Airbus reprogrammed the software after that incident. Correct me if I am wrong.
Unfortunately they had a gust and touched down with the downwind main gear, where after it was impossible to bring the wing down with the limited trow.
I believe Airbus reprogrammed the software after that incident. Correct me if I am wrong.
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I'm not an Airbus man. But as far as understood from that incident, the cause was an "software feature" in the airbus that limits the trow of the ailerons after touchdown.
Unfortunately they had a gust and touched down with the downwind main gear, where after it was impossible to bring the wing down with the limited trow.
I believe Airbus reprogrammed the software after that incident. Correct me if I am wrong.
Unfortunately they had a gust and touched down with the downwind main gear, where after it was impossible to bring the wing down with the limited trow.
I believe Airbus reprogrammed the software after that incident. Correct me if I am wrong.
The cause was part overcontrol by the HP and then a dual inputs (both ways) to correct which caused excessive roll one way then the other causing the contact of the wingtips. Airbus did change the roll authority of ELACs around that time but it was to dampen roll in Flap 3.
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I know this discussion deals with jet aircraft, but this video of the F50 i think shows a nice view of a typical crosswind landing and subsequent rollout. Notice how the sideslip increases at the end of the rollout.
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LnS
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@busTRE, he wasn't all that much wrong. Read the safety recommendations of the BFU derived from that incident. Two deal with landing mode and reduced aileron trow after a single main gear touch down and a wrong description about that in the standard issue airbus FCOM, probably since corrected. Airbus changed the description of the recommended crosswind landing technique on its own even before the report was published though.
The following systematic causes led to this serious incident:
• The terminology maximum crosswind demonstrated for landing was not defined in the Operating Manual (OM/A) and in the Flight Crew Operating Manual (FCOM), Vol. 3, and the description given was misleading.
• The recommended crosswind landing technique was not clearly described in the aircraft standard documentation.
• The limited effect of lateral control was unknown.
• The terminology maximum crosswind demonstrated for landing was not defined in the Operating Manual (OM/A) and in the Flight Crew Operating Manual (FCOM), Vol. 3, and the description given was misleading.
• The recommended crosswind landing technique was not clearly described in the aircraft standard documentation.
• The limited effect of lateral control was unknown.
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Ah, the Fokker 50. Landed one unaware that x-wind has reached 42kts (uncontrolled airport). Some rudder trim here, some aileron trim there - didn't even notice the wind until landing roll, when our fin was fluttering like crazy. Sorry if off-topic, that video just had me reminiscing 
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Concerning that Lufthansa A320: Grab the report here:
http://www.bfu-web.de/cln_030/nn_226...indlanding.pdf
As Denti said the whole thing was completely unnecessary since the commander insisted on using the ILS on runway 23 with full crosswind (up to 47 knots as reported by the tower, beyond all limitations) instead of landing on runway 30 and shooting a LOC.
Handlingwise it seems like the thing caught a gust just as the PF straightened the airplane (maybe with not enough opposite aileron)... Nasty nasty nasty.
http://www.bfu-web.de/cln_030/nn_226...indlanding.pdf
As Denti said the whole thing was completely unnecessary since the commander insisted on using the ILS on runway 23 with full crosswind (up to 47 knots as reported by the tower, beyond all limitations) instead of landing on runway 30 and shooting a LOC.
Handlingwise it seems like the thing caught a gust just as the PF straightened the airplane (maybe with not enough opposite aileron)... Nasty nasty nasty.
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Hi STBYRUD,
They both had full opposite aileron - but even that wasn't enough because:
From page 46:
The aircraft touched down shortly after the 1,000 ft marker in the touchdown zone, about 2 m left of the runway centreline lights with the left wing 4° down and the fuselage pointed 2° to the right of runway allignment, whereupon the rudder pedals were returned to the neutral position.
The aircraft yawed towards the left, thereby increasing the lift from the right wing and decreasing that from the left wing. In spite of the co-pilot's right sidestick correction, this resulted in unintended contact between the downwind main landing gear and the runway. The objective had been to land with wings level. This was confirmed by the correct application of right sidestick prior to touchdown, which was intuitively supported by the Captain's sidestick (dual input).
After touchdown the aircraft yawed a further 5° to the left. The left main landing gear lost contact with the runway. At no time did the right main landing gear make contact with the runway. Lift dumpers (partial spoiler extension) remained inactive, because the necessary prerequisites were absent.
During the next few seconds the aircraft rolled to a 23° left wing down attitude in spite of the full right deflection of both sidesticks and application of right rudder. The switch to Ground Law limited the effect of roll control corrections. The left main landing gear again made contact with the runway. At about the same instant, the left wingtip made contact with the runway.
maybe with not enough opposite aileron
From page 46:
The aircraft touched down shortly after the 1,000 ft marker in the touchdown zone, about 2 m left of the runway centreline lights with the left wing 4° down and the fuselage pointed 2° to the right of runway allignment, whereupon the rudder pedals were returned to the neutral position.
The aircraft yawed towards the left, thereby increasing the lift from the right wing and decreasing that from the left wing. In spite of the co-pilot's right sidestick correction, this resulted in unintended contact between the downwind main landing gear and the runway. The objective had been to land with wings level. This was confirmed by the correct application of right sidestick prior to touchdown, which was intuitively supported by the Captain's sidestick (dual input).
After touchdown the aircraft yawed a further 5° to the left. The left main landing gear lost contact with the runway. At no time did the right main landing gear make contact with the runway. Lift dumpers (partial spoiler extension) remained inactive, because the necessary prerequisites were absent.
During the next few seconds the aircraft rolled to a 23° left wing down attitude in spite of the full right deflection of both sidesticks and application of right rudder. The switch to Ground Law limited the effect of roll control corrections. The left main landing gear again made contact with the runway. At about the same instant, the left wingtip made contact with the runway.
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Ground Law? Crikey, I'm not an Airbus hater, but at least I know whats happening to the surfaces on my Boeing... I don't think my brain's big enough to cope with all that stuff.
