pangolin

Failure to hold the crosswind correction after touchdown.

Adlerdriver

Pangolin,
Apparently at least one person here thinks that's the accepted procedure.
I know it was posted two years ago, but I'm surprised it never raised any questions.

Never done a cross-wind landing like that. That dang cross-wind doesn't disappear as soon as my nose is down.

pangolin

Depending on the extremity of the crosswind you may touch down in a slight crab. You have to still hold rudder and aileron correction after touchdown.

1wife2airlines

You don't center the nosewheel as it touches and then resume using the rudder and nosewheel steering by rudder for directional control aided by forward stick pressure for nosewheel steering effectiveness?

Adlerdriver

No. Crosswind controls in during the landing are maintained during the nosewheel touchdown and throughout landing roll as appropriate. If you center the rudder as the nose wheel comes down, you're going to lose directional control, assuming the crosswind you landed in is still a factor.

1wife2airlines

If you do that your nosewheel is going to try to take you off centerline when steering takes effect with rudder in. I agree the aero inputs remain but when the nosewheel touches it gives you an added control of your ground track and starts to become primary which is why most guidance requires down stick input, while keeping aileron into the wind, to increase nosewheel steering capability.

Adlerdriver

Aerodynamic forces at initial touchdown far exceed those of the nosewheel steering. How could you possibly maintain runway centerline and align the aircraft with the runway upon touchdown if you center the rudder?

How do you takeoff in a crosswind? Every transport category aircraft I've ever flown requires upwind aileron and opposite rudder to be applied as airspeed increases during takeoff roll and rotation. Once airborne, those control inputs are smoothly removed. Why would it be any different during landing? Tracking centerline upon touchdown would be impossible without proper crosswind controls applied throughout landing roll until control surfaces are no longer effective.


Here are excerpts from flight manuals at my company


757/767:

On dry runways, upon touchdown the airplane tracks toward the upwind edge of the runway while de-crabbing to align with the runway.Immediate upwind aileron is needed to ensure the wings remain level while rudder is needed to track the runway centerline.

On very slippery runways, landing the airplane using crab only reduces drift toward the downwind side at touchdown,permits rapid operation of spoilers and autobrakes because all main gears touchdown simultaneously, and may reduce pilot workload since the airplane does not have to be de-crabbed before touchdown. However, proper rudder and upwind aileron must be applied after touchdown to ensure directional control is maintained.


777

However, proper rudder and upwind aileron must be applied after touchdown to ensure directional control is maintained.

Bottom line is you're giving way too much credit to the nosewheel steering available with simple rudder inputs at touchdown speed. In almost 30 years of flying, I've never heard anyone tell me they're going to center the rudder at touchdown in a crosswind. If you need the rudder to track the centerline at 150 knots a foot off the runway, you still need it 5 seconds later when you touchdown.

1wife2airlines

I wouldn't tell you I'm going to do that. I just use the proper rudder to maintain centerline. That might involve an input to bring a the nose back to centerline when the nosewheel steering has an effect and most times I anticipate a need to straighten the nosewheel as it compresses. I have never lost directional control of a DC9, 727, F100, 767, 757 doing what I described nor had any minor deviations other than my first crosswind landing on my LOE in CDG. As nose compressed there was a slight 2-3 foot swerve because I had rudder in which I then smoothly corrected for back to centerline.

Adlerdriver

Great. That makes a lot more sense than this comment you made two years ago which prompted me to respond.

firefighterplt

I don’t have any experience in transport aircraft, but I would assume that NWS doesn’t engage until nose gear WOW—and I’d imagine there is some blending logic to keep the jet from instantaneously snapping in the commanded NWS angle on touchdown?

Or am I giving the engineers too much credit?