LH A320 Rough Landing @ Hamburg

[Chris Scott]

Quote from Rumet [Mar05/09:55, currently post#278]:
Since direct law kicks in 5 secs after touchdown, can someone please explain what the correct use of the sidestick is to keep wings level during decrabbing ?
I see it clearly after those 5 seconds, but before that how is commanding a roll rate with both main landing gears on the ground made equivalent to applying a required aileron deflection ?
[Unquote]

My previous have not covered this 5-second period (which I confess was news to me, but makes sense if you consider the case of a bounced landing, with or without go-around). I've argued that, as soon as the second main gear is firmly on the ground, you can use into-wind AILERON to hold the wings level.

This is obviously not strictly correct; with into-wind stick you are actually commanding a roll-rate during those 5 seconds after touchdown. In practice, though, a moderate amount of stick - very much like you would use on a conventional aeroplane - is not enough to lift the downwind gear off the runway, but will counteract the tendency of the upwind wing to lift.

Quote from CABUS [above]:
I personally feel this is an advert for a cross control approach setting off the drift early on allowing the PF to assess the x wing comp before 20feet. This probably would of ended in an earlier GA or a more controlled touch down and would be much more comfortable for the pax and crew in the back.
[Unquote]

The problem with the FULL sideslip technique, for the A320, has already been covered by me and others. The sideslip angle required in a limiting crosswind would probably lead to winglet-scrape.


By the way, I have had to EDIT my post earlier today, in respect of an error I made in the take-off case. [Nobody spotted it...]