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Unverified video taken on the ground after landing. https://www.airliners.net/forum/viewtopic.php?f=3&t=1420137#p21273103 https://www.airliners.net/forum/viewto

by cmurf 8y ago

Unverified video taken on the ground after landing. https://www.airliners.net/forum/viewtopic.php?f=3&t=1420137#p21273103 https://www.airliners.net/forum/viewtopic.php?f=3&t=1420137#... It looks similar to other photos, and if authentic yes it suggests a significant roll to the left. From the available information I can't assess whether the plane was on the ground or airborne, either are possible. Aileron is normally used for crosswind takeoffs, to lift the leeward wing sooner in order to "lean" the plane into the crosswind to keep the plane from drifting from runway centerline. Essentially the opposite happened in this case. The airplane must have both drifted to the left of the runway center line (not out of the ordinary, in particular if it's gusty) as well as left wing dipped. It's possible this was a suddenly gusty takeoff. I'm not sure to what degree A320 series can do auto takeoff or computer assisted takeoffs, and what crosswind limits they presumably have where a pilot has to do the takeoff manually instead. Maybe the pilot's suggestion of a computer problem is related to that, and they subsequently took manual control.

danaliv 8y ago
Aileron is normally used for crosswind takeoff Airbus crosswind takeoff recommendation is no lateral stick input. The sidestick is a rate controller, so a lateral deflection commands a roll, not a specific control surface position like on non-fly-by-wire aircraft. And you run the risk of deploying spoilers.
- cmurf 8y ago
  The original article article URL before the change to avherald contains a post that addresses this: https://www.pprune.org/showthread.php?p=10450572 https://www.pprune.org/showthread.php?p=10450572 Obviously we'll have to wait and see what the actual story is, whether this is really old bad tribal knowledge, and if the operating manual contradicts that, and whether pilots are getting the proper training and consistently applying it in practice. I'm an opinionated and biased pilot and former flight instructor, but not an aerodynamic engineer. Spoiler extension does not increase the effective angle of attack of the wing, whereas a dropping aileron does. And therefore off hand, and without benefit of an Airbus type rating, I don't really care if the actual control surface is a bit of right spoiler instead of left (down) aileron, all I care about is that the windward wing does NOT lift off first because that will foul up the ground track on takeoff, and that's simply not proper technique.
  - danaliv 8y ago
    I'm not typed either, for the record. Current flight instructor and my boss is a check airman at a major--that's about all I've got to offer. :) As I understand it there's a potentially dangerous pitch-up moment that occurs if the roll spoilers deploy on takeoff. (Don't ask me why!)
- chopin 8y ago
  I am not sure about this. Control has several laws and for landing it is afaik not a rate controller but direct input. It could be the same for take off.

by cmurf 8y ago

danaliv 8y ago

Aileron is normally used for crosswind takeoff Airbus crosswind takeoff recommendation is no lateral stick input. The sidestick is a rate controller, so a lateral deflection commands a roll, not a specific control surface position like on non-fly-by-wire aircraft. And you run the risk of deploying spoilers.

cmurf 8y ago
The original article article URL before the change to avherald contains a post that addresses this: https://www.pprune.org/showthread.php?p=10450572 https://www.pprune.org/showthread.php?p=10450572 Obviously we'll have to wait and see what the actual story is, whether this is really old bad tribal knowledge, and if the operating manual contradicts that, and whether pilots are getting the proper training and consistently applying it in practice. I'm an opinionated and biased pilot and former flight instructor, but not an aerodynamic engineer. Spoiler extension does not increase the effective angle of attack of the wing, whereas a dropping aileron does. And therefore off hand, and without benefit of an Airbus type rating, I don't really care if the actual control surface is a bit of right spoiler instead of left (down) aileron, all I care about is that the windward wing does NOT lift off first because that will foul up the ground track on takeoff, and that's simply not proper technique.
- danaliv 8y ago
  I'm not typed either, for the record. Current flight instructor and my boss is a check airman at a major--that's about all I've got to offer. :) As I understand it there's a potentially dangerous pitch-up moment that occurs if the roll spoilers deploy on takeoff. (Don't ask me why!)
chopin 8y ago
I am not sure about this. Control has several laws and for landing it is afaik not a rate controller but direct input. It could be the same for take off.