"Crabbing"

when landing with a crosswind, when do you apply rudder? Just before or just after touchdown?

Both.
Just before and after the main gear touchdown.

Rudder is used on approach but is slowly taken out just before touchdown to align the plane with the centerline. After touchdown the rudder is used to move the front wheel to keep the plane on track.

Just before you touchdown. Watch out through, the secondary effect of rudder is roll, so just make sure that you counteract the roll that is going to happen as you add the rudder.

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Cool. Something I’ve never quite gotten the hang of. Thanks folks.

Depends on the airplane, Airbus and Boeing use different techniques, and on the crosswind. Its a practice and learn thingy.

As @ArcticPolaris sais you will get a secondary effect called “Roll”, on Boeing you have to counteract for this, on the Airbus not.

I’m always unsure about this, I tend to “crab” for most of the approach, keeping the small circle in the HUD pointed at the runway, even though the nose is pointing somewhere different. I would use the rudder a mile or two out from touchdown to get the aircraft exactly parallel with the runway, so it’s not landing sideways on.
Thre only problem is that the rudder also controls the nosewheel so if you’re still using it when the nosewheel makes contact with the runway, the plane will veer off dangerously ! I find the trick is to release the rudder after the main landing gear has hit the tarmac, but just before those front wheels touch down, easier said than done !

I’ve no idea if that’s how it works in the real world, I’m sure someone more knowledgeable than me will inform…

You would typically point the nose to the left or the right of the rwy during the whole approach, and decrab with the rudder past the threshold whilst flaring - countering the roll effect if there is one. If you merely point the nose to the centerline during the whole approach you will be slightly off course at touchdown.

I actually didn’t know that Airbus auto-compensates (Not really sure what else to call it) for that roll. Thanks for that! Learn something new everyday :)

This is what happens if you use the Boeing technique on the Airbus:

http://www.avherald.com/h?article=4400bee5&opt=0

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Must be really odd to not touch the ailerons during the landing phase! That auto wings leveling system sounds pretty interesting…