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Old 12th Oct 2012, 08:50
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Dan Winterland
 
Join Date: Jun 2001
Location: Fragrant Harbour
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I seem to recall we use to used about 5 degrees wheel movement per 10 knots cross wind on the 747 (waiting to be corrected). As spoilers deployed after 10 degrees, there would be spoliers deployed on the take off roll with more than 20 knots of cross wind. Mr Boeing said this was OK and that the take off run performance wasn't compromised - I was never totally convinvced myself.

Airbus roll control is very different. Sidestick movement demands a roll rate. If you get airborne with the stick deflected, you have roll demanded and the aircraft will start rolling as soon as it's off the ground. But with no sidestick applied you will get airborne with wings level and no correction is required regardless of cross wind. (OK Airbus guys , I know that you effectively take off in direct law and that normal law is blended in gradually up to 50' RA - but this is the official Airbus technique and it seems to work when I try it).
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