Crosswind Take-Off
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Crosswind Take-Off
Hi,
In case of CrossWind Take-off, what is your procedures for Ailerons usage? Do you use ailerons during the take-off run?
for which aircraft?
In case of CrossWind Take-off, what is your procedures for Ailerons usage? Do you use ailerons during the take-off run?
for which aircraft?
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On the Airbus, no, you don't, you can very easily get spoiler deployment which is undesirable.
EDIT: this is what Airbus have to say on the matter.
EDIT: this is what Airbus have to say on the matter.
Originally Posted by Airbus
For crosswind takeoffs, routine use of into wind aileron is not necessary. In strong crosswind conditions, small lateral stick input may be used to maintain wings level, if deemed necessary due to into wind wing reaction, but avoid using large deflections, resulting in excessive spoiler deployment which increase the aircraft tendency to turn into the wind (due to high weight on wheels on the spoiler extended side), reduces lift and increases drag. Spoiler deflection becomes significant with more than a third sidestick deflection.
As the aircraft lifts off, any lateral stick input applied will result in a roll rate demand, making aircraft lateral control more difficult. Wings must be level.
As the aircraft lifts off, any lateral stick input applied will result in a roll rate demand, making aircraft lateral control more difficult. Wings must be level.
Last edited by 99jolegg; 20th Sep 2013 at 16:23.
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Once again, FLY THE AIRPLANE!
If ailerons are needed to keep the wings level, use them! At low speed they are ineffective, so there is little reason to use them. However, it may be useful to use a couple degrees of aileron input as a reminder that you will likely need it later in the takeoff run. Little if any spoiler will be extended unless significant yoke input is applied.
If ailerons are needed to keep the wings level, use them! At low speed they are ineffective, so there is little reason to use them. However, it may be useful to use a couple degrees of aileron input as a reminder that you will likely need it later in the takeoff run. Little if any spoiler will be extended unless significant yoke input is applied.
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Correct.
Ideally, during and after lift-off, the into wind wing, needs to be "lowered" until the aircraft is on the required track, after t/o.
Even in a "normal" aircraft, ie ailerons only, even into wind aileron deflection does create a lot of drag. This needs to be considered if the t/o run is marginal for the conditions. So much so, if runway/strip conditions allow, delay and use just enough into wind aileron to keep the wings "level" at lift-off.
Ideally, during and after lift-off, the into wind wing, needs to be "lowered" until the aircraft is on the required track, after t/o.
Even in a "normal" aircraft, ie ailerons only, even into wind aileron deflection does create a lot of drag. This needs to be considered if the t/o run is marginal for the conditions. So much so, if runway/strip conditions allow, delay and use just enough into wind aileron to keep the wings "level" at lift-off.
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Crosswind Take-Off
On the Mighty Dash, (this fleet at least of Q400) we will apply some small amount of into-wind aileron. Amount depends on the strength and angle off the nose!
It's also fun to get a wing right down on a strong crosswind landing
you can't do that with a 73!
It's also fun to get a wing right down on a strong crosswind landing
you can't do that with a 73!
It depends on the aircraft type. Airbus have their good reasons for not using aileron, and they built it so they should know.
Boeing 737 technique is usually to use a small amount, consistent with not too much spoiler deployment on take-off, or scraping a pod on landing.
But some aircraft need a fistful, particularly those with narrow main gear e.g. ATR 42/72, MU 2 and Bae-146 and nearly all taildraggers (for those of you who know what they are). The old F27's nose-wheel steering authority is fairly useless at the best of times, so that won't save you once you get a bit sideways. The DC3 is another benign animal that becomes a beast in a 15+ knot crosswind.
All these types are normally easy to land, and this lulls pilots into a false sense of security until a crosswind has them heading for the runway edge lights due to poor use of primary flight controls.
On these types, once the crosswind is up near the limit you have to be quite aggressive with use of aileron, particularly landing on narrow or slippery runways. Pilots should be prepared to apply an equally aggressive amount of opposite rudder and may need some asymmetric braking as the speed decreases.
Where one is published, let the FCTM be your guide. Where not, ask those who have some serious time on type how best to handle that particular type.
Boeing 737 technique is usually to use a small amount, consistent with not too much spoiler deployment on take-off, or scraping a pod on landing.
But some aircraft need a fistful, particularly those with narrow main gear e.g. ATR 42/72, MU 2 and Bae-146 and nearly all taildraggers (for those of you who know what they are). The old F27's nose-wheel steering authority is fairly useless at the best of times, so that won't save you once you get a bit sideways. The DC3 is another benign animal that becomes a beast in a 15+ knot crosswind.
All these types are normally easy to land, and this lulls pilots into a false sense of security until a crosswind has them heading for the runway edge lights due to poor use of primary flight controls.
On these types, once the crosswind is up near the limit you have to be quite aggressive with use of aileron, particularly landing on narrow or slippery runways. Pilots should be prepared to apply an equally aggressive amount of opposite rudder and may need some asymmetric braking as the speed decreases.
Where one is published, let the FCTM be your guide. Where not, ask those who have some serious time on type how best to handle that particular type.
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Originally Posted by 99jo
EDIT: this is what Airbus have to say on the matter.
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BOAC,
No, the aircraft is entirely conventional on the ground. Side stick movement is proportional to control surface deflection and there is no auto-trim. It doesn't do anything more for you than a 737 would do. The aircraft never moves the ailerons of its own accord without autopilot. Presuming no Load Alleviation Function (LAF) is installed.
In the air (above 50ft, when the aircraft transitions from ground mode to flight mode and auto trim becomes available) the side stick is proportional to load factor. Hands off, it'll retain its trajectory but won't apply control surface input in doing so.
Spoiler deployment is only a possibility by using more than a third side stick deflection. This presents itself as a tiny deflection on the PFD; literally moving the cross to the edge of the dot...about half a centimetres movement on the PFD. Once you get the spoiler deployment, you get the bits and pieces going on described by Airbus in the FCTM that I posted before.
No, the aircraft is entirely conventional on the ground. Side stick movement is proportional to control surface deflection and there is no auto-trim. It doesn't do anything more for you than a 737 would do. The aircraft never moves the ailerons of its own accord without autopilot. Presuming no Load Alleviation Function (LAF) is installed.
In the air (above 50ft, when the aircraft transitions from ground mode to flight mode and auto trim becomes available) the side stick is proportional to load factor. Hands off, it'll retain its trajectory but won't apply control surface input in doing so.
Spoiler deployment is only a possibility by using more than a third side stick deflection. This presents itself as a tiny deflection on the PFD; literally moving the cross to the edge of the dot...about half a centimetres movement on the PFD. Once you get the spoiler deployment, you get the bits and pieces going on described by Airbus in the FCTM that I posted before.
On the DH8-400, while it is not disallowed to apply a tiny amount of aileron into the wind if one prefers, it is mostly unneeded. The main wheel base is rather wide and a crosswind will not noticeably lift the upwind wing during the ground run. Other types, e. g. the F-70/100 with their much narrower wheel base, have shown much less benign characteristics - on the Fokker, a moderate aileron input is rather helpful during a cross-wind takeoff and also the landing run.
So as usual - it depends. The type flown, the strength of the crosswind, and also to some amount the personal preference of the pilot flying will decide. As Mach E. Avelli has rightfully stated, what the book says usually works fine.
So as usual - it depends. The type flown, the strength of the crosswind, and also to some amount the personal preference of the pilot flying will decide. As Mach E. Avelli has rightfully stated, what the book says usually works fine.
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[In the air (above 50ft, when the aircraft transitions from ground mode to flight mode and auto trim becomes available) the side stick is proportional to load factor. Hands off, it'll retain its trajectory but won't apply control surface input in doing so.]
Yes it will! 'Hands off' means a demand for the aircraft to 'retain its trajectory' but it must use the flight control surfaces to do this, for example in disturbances such as turbulence...
Yes it will! 'Hands off' means a demand for the aircraft to 'retain its trajectory' but it must use the flight control surfaces to do this, for example in disturbances such as turbulence...
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Pendant in the room!
Roll control goes to 'normal law' half a second after lift off and pitch>8degrees - Not 50 ft!
So if you use lateral stick (I do..Small amounts just for the rotation) you need to release it pretty much as you lift off as normal law will take over!
Roll control goes to 'normal law' half a second after lift off and pitch>8degrees - Not 50 ft!
So if you use lateral stick (I do..Small amounts just for the rotation) you need to release it pretty much as you lift off as normal law will take over!
However, it may be useful to use a couple degrees of aileron input as a reminder that you will likely need it later in the takeoff run
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What sort of airman are you if you need a gimmick like that to "remind" you to apply aileron if needed to keep wings level?
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Tester78,
Are you talking about control surface movement in pitch i.e. trimmable horizontal stabiliser (THS) in which case, yes I agree. Since we are talking about crosswinds, I was talking more about roll to which I don't think the constant trajectory applies? Certainly in my experience a wing coming up in a gust or thermal doesn't stay in the position the gust put it and doesn't go back to where it was either!
Cough,
Thanks - hadn't realised that.
Are you talking about control surface movement in pitch i.e. trimmable horizontal stabiliser (THS) in which case, yes I agree. Since we are talking about crosswinds, I was talking more about roll to which I don't think the constant trajectory applies? Certainly in my experience a wing coming up in a gust or thermal doesn't stay in the position the gust put it and doesn't go back to where it was either!
Cough,
Thanks - hadn't realised that.
