Airbus sideslip crosswind

[mi68guel]

https://cimg1.ibsrv.net/gimg/pprune.org-vbulletin/2000x1124/crosswind_landing_330_7043ad4b70cccf854d0bd0952be553384af8af f7.jpg
What about the rudder pedals? Wind from the right and right rudder applied?? That doesn't look good to me. What do you think? This is A330 official type rating training

[Vessbot]

Yes, wind from right needs left rudder. I don't think the pictures are all supposed to tell a consistent story. It' just "topic of the day is sideslips! So here's a picture of some rudder pedals, here's a picture of a crosswind..." (Or if they are supposed to be consistent, there were bigger fish to fry than thorough quality control on this slide, and it's a simple mistake.)

[mi68guel]

A320 strong crosswind from the right-hand side. Decrab applying left rudder...if the side stick is in the neutral position, the airplane automatically applies some upwind bank angle (rolls to the right) to zero the roll rate induced by the yaw correction. Am I right?

[vilas]

A320 strong crosswind from the right-hand side. Decrab applying left rudder...if the side stick is in the neutral position, the airplane automatically applies some upwind bank angle (rolls to the right) to zero the roll rate induced by the yaw correction. Am I right? Not by applying bank angle but by applying some ailron and may be spoilers it will prevent the roll from the yaw. Also the axis is ahead of C of G so the aircraft swings towards the wind.
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[mi68guel]

https://cimg0.ibsrv.net/gimg/pprune.org-vbulletin/2000x1361/captura_de_pantalla_2020_09_18_a_las_16_26_26_c899a0eef1a3a3 a0da08d115cbc614ca52967cdd.png
This is the correct picture. Sidestick neutral, when the right rudder is applied to align with the RWY the aircraft AUTOMATICALLY lowers the upwind wing (left one).

[KingAir1978]

The only thing in this picture that's not necessarily correct it the A/C trajectory.

[mi68guel]

After de crabbing the acft trajectory is aligned with the fuselage and the runway track so it looks good to me.

[Tail-take-off]

https://cimg0.ibsrv.net/gimg/pprune.org-vbulletin/2000x1361/captura_de_pantalla_2020_09_18_a_las_16_26_26_c899a0eef1a3a3 a0da08d115cbc614ca52967cdd.png
This is the correct picture. Sidestick neutral, when the right rudder is applied to align with the RWY the aircraft AUTOMATICALLY lowers the upwind wing (left one).

The answer is in the text at the bottom of your picture: “the lateral controls attempt to zero the roll rate” which means that they try to maintain the current angle of bank. If you want to lower the upwind wing you’ll have to do it yourself. The lateral controls will then attempt to maintain that.

[mi68guel]

The text says "sideslip is automatically performed" so with sidestick neutral and rudder applied the sideslip is done automatically by the aircraft applying bank angle opposite to the rudder deflection. Why don´t you try it the next time you go to the SIM?

[fantom]

Applying steady rudder for a huge crosswind is a dead easy way to land the 320. I used it whenever necessary.

[vilas]

The text says "sideslip is automatically performed" so with sidestick neutral and rudder applied the sideslip is done automatically by the aircraft applying bank angle opposite to the rudder deflection. Why don´t you try it the next time you go to the SIM?
With side stick neutral the flight control laws maintain zero rate of roll. It will not bank but prevent the yaw from causing roll. FCTM below:
The recommended de-crab technique is to use all of the following:
‐ The rudder to align the aircraft with the runway heading during the flare
‐ The roll control, if needed, to maintain the aircraft on the runway centerline. Any tendency to drift downwind should be counteracted by an appropriate lateral (roll) input on the sidestick.
In the case of strong crosswind, in the de-crab phase, the PF should be prepared to add small bank angle into the wind in order to maintain the aircraft on the runway centerline. The aircraft may be landed with a partial de-crab (residual crab angle up to about 5 °) to prevent an excessive bank. This technique prevents wingtip/sharklet (or engine nacelle) strike caused by an excessive bank angle.
As a consequence, this may result in touching down with some bank angle into the wind (hence
with the upwind landing gear first).

[sonicbum]

Just to add to all the wisdom already published a quick read by Airbus. (https://skybrary.aero/bookshelf/books/179.pdf)

Truth is no matter how knowledgeable you are, certain manoeuvres require a lot of practice to be mastered and need to be practiced regularly to avoid loosing the “grip”. Those Covid times possibly flying 1 - 2 times a month surely do not help.

[Tail-take-off]

The text says "sideslip is automatically performed" so with sidestick neutral and rudder applied the sideslip is done automatically by the aircraft applying bank angle opposite to the rudder deflection. Why don´t you try it the next time you go to the SIM?
Correct, with rudder applied but wings level the aircraft will be sideslipping. I teach the FCTM method in the sim as quoted by Vilas in his reply above.

[vilas]

The text says "sideslip is automatically performed" so with sidestick neutral and rudder applied the sideslip is done automatically by the aircraft applying bank angle opposite to the rudder deflection. Why don´t you try it the next time you go to the SIM?
Try in the sim autoland with 20kts crosswind. Keep the Flt Ctl page open and it will show you what it does.

[mi68guel]

With side stick neutral the flight control laws maintain zero rate of roll. It will not bank but prevent the yaw from causing roll. FCTM below:
The recommended de-crab technique is to use all of the following:
‐ The rudder to align the aircraft with the runway heading during the flare
‐ The roll control, if needed, to maintain the aircraft on the runway centerline. Any tendency to drift downwind should be counteracted by an appropriate lateral (roll) input on the sidestick.
In the case of strong crosswind, in the de-crab phase, the PF should be prepared to add small bank angle into the wind in order to maintain the aircraft on the runway centerline. The aircraft may be landed with a partial de-crab (residual crab angle up to about 5 °) to prevent an excessive bank. This technique prevents wingtip/sharklet (or engine nacelle) strike caused by an excessive bank angle.
As a consequence, this may result in touching down with some bank angle into the wind (hence
with the upwind landing gear first).

I´ve got an FCTM too and I read it carefully!!

[mi68guel]

Try manual flight, crosswind and press the rudder and tell me were the bank angle goes (sidestick neutral)....

[vilas]

Try manual flight, crosswind and press the rudder and tell me were the bank angle goes (sidestick neutral)....
With stick neutral for rudder application there is supposed to be no bank. The exercise in sim I mentioned is mentioned in Miami airbus Instructors meeting. When OEI demo is given with hands off it only banks 7° to 9° for same reason. It can't keep zero bank because yaw damper doesn't have that much authority.

[mi68guel]

With stick neutral for rudder application there is supposed to be no bank. The exercise in sim I mentioned is mentioned in Miami airbus Instructors meeting. When OEI demo is given with hands off it only banks 7° to 9° for same reason. It can't keep zero bank because yaw damper doesn't have that much authority.
If you are a SIM instructor, can you try it there. With all the information I have, I disagree with you, sorry!!

[mi68guel]

The answer is in the text at the bottom of your picture: “the lateral controls attempt to zero the roll rate” which means that they try to maintain the current angle of bank. If you want to lower the upwind wing you’ll have to do it yourself. The lateral controls will then attempt to maintain that.

I don´t understand the picture as you do! The only way to finish this topic is by trying it in the SIM or empty flight. Sidestick neutral , apply rudder and see where the bank angle goes. I say oppositte to the rudder deflection (sidesliping automatically).

[mi68guel]

Correct, with rudder applied but wings level the aircraft will be sideslipping. I teach the FCTM method in the sim as quoted by Vilas in his reply above.

You are mentioning a condition "but wings level" ...This is not the case I´m talking about. What I´m saying is: fly wings level, A/P off, apply rudder, and see what happens (bank angle YES/NO which side??). I say R rudder bank angle to the left, L rudder bank angle to the right....

[Banana Joe]

I am not rated but the way I understand it is that the F/CTL computers will attempt to mantain present bank angle. Even if you were to cross the threshold with a 10° bank angle and then apply rudder without any sidestick input, the F/CTL computers will apply ailerons and spoilers to attempt to mantain 10° bank angle.
If you're level (0° bank angle), than the wings will be kept level as much as possible: the bank angle goes nowhere. It's 0.

This is coming from someone that was about to change to Airbus and lurked in the books in his free time...

[Vessbot]

I say R rudder bank angle to the left, L rudder bank angle to the right....

Both the pictures you've posted say that "the lateral controls attempt to zero the roll rate," and nowhere in that does it say that it banks opposite. That is not zero roll rate. Yes it would be revealing to see what happens in the sim, and in all the decades and the countless people that have flown Airbus sims, someone would have probably noticed if it banks opposite.

You're reading too much into the part of the quote that "a sideslip is automatically performed," which is poorly worded and doesn't mean anything. Forget about that. Aerodynamically, sideslip is any time the the relative wind is misaligned from the axis of the airplane when looking from above, aka beta angle is not zero. (Much like thinking about AOA, or alpha angle, when looking from the side). This is only a part of the sideslip (or forwardslip) maneuvers flown in small planes where the plane is cross-controlled so as to create an aerodynamic sideslip while preventing heading change.

[mi68guel]

and nowhere in that does it say that it banks opposite.

It doesn´t say it because there´s a picture of an airplane sideslipping with stick in neutral
You're reading too much into the part of the quote that "a sideslip is automatically performed," which is poorly worded and doesn't mean anything.
I´m not a native English speaker but it looks clear to me. sideslip is an intentional cross control manoeuver in which the pilot has made an aileron input in one direction with a simultaneous rudder input in the opposite direction. In this case, is not the pilot who does. It´s written that a sideslip is AUTOMATICALLY performed by the plane
I´m gonna stop answering. Can anybody please try it in the SIM and record it? Thanks

[vilas]

performed by the plane
I´m gonna stop answering. Can anybody please try it in the SIM and record it? Thanks
A320 doesn't do it. If you try Auto land with crosswind as I mentioned it just keeps wings level by raising aileron and spoilers.

[vilas]

Read Airbus Safety First issue #15

[Vessbot]

It doesn´t say it because there´s a picture of an airplane sideslipping with stick in neutral


The picture doesn't mean anything, you're reading too much into that too. It's just a picture of a crosswind landing since the topic of the slide is crosswind landings in general. It doesn't mean that the specific FBW output of the specific control input discussed in the text is what the picture is.


I´m not a native English speaker but it looks clear to me. sideslip is an intentional cross control manoeuver in which the pilot has made an aileron input in one direction with a simultaneous rudder input in the opposite direction. In this case, is not the pilot who does. It´s written that a sideslip is AUTOMATICALLY performed by the plane
I´m gonna stop answering. Can anybody please try it in the SIM and record it? Thanks

Words sometimes have multiple meanings, and this is one of those times. One meaning of "sideslip" is what you said, but as I tried to explain in my last post, there are also others. The meaning referred to in the training slide, is not the one you said.

[Tail-take-off]

Mi68uel
You keep telling everyone to try it in the simulator. Why don’t you do the same? We’re all eagerly awaiting your report on the results!

[neilki]

Mi68uel
You keep telling everyone to try it in the simulator. Why don’t you do the same? We’re all eagerly awaiting your report on the results!
I for one would love a deep dive technical volume on how Fifi actually works. The current publications are targeted at line pilots; and often those converting from a conventional jet.

The Airbus does use G & Roll Rate, but it also takes into account G Rate. -From memory, CLB modes command different delta G depending on the change in Altitude selected -thats in the FCOM.
Consider a similar situation to the Crosswind discussion; an Engine Failure at 50' in SRS with the AP engaged. The Flight Control Computers are perhaps taken by more of a surprise than the Pilot on a PC (!!) but Fifi gets upset and struggles to correct the roll and yaw for a good couple of seconds. Look at the FLT CTRL page. It's like the LED display on a 90's boombox.
Under manual flight in VMC the maneuver can be performed more smoothly.

The bottom line for crosswinds, just like Airbus says; is the jet is designed to land just like a Boeing. Thats why the ELACs introduce a pitch snapshot then command nose down.
In a strong crosswind, rudder will introduce roll; given a couple of seconds the roll will be corrected; but in the flare at ten feet; we don't have a couple of seconds and the pilot actually has to fly the jet. Bank angle to correct drift et al..
PS. The Airbus does not have a yaw damper. It has a FAC that contains yaw damping functionality, but the FAC sends commands to the Rudder Hydraulics based on what it understands is going on..

[vilas]

[QUOTE] [PS. The Airbus does not have a yaw damper. It has a FAC that contains yaw damping functionality, but the FAC sends commands to the Rudder Hydraulics based on what it understands is going on../QUOTE] Not true at all. Airbus definitely has yaw dampers which work on G and Y hydraulics. If you loose G+Y you have FAC but loose yaw damping. Check FCOM Flt Ctl reconfiguration.

[FlightDetent]

If you're level (0° bank angle), than the wings will be kept level as much as possible: the bank angle goes nowhere. It's 0.

This is coming from someone that was about to change to Airbus and lurked in the books in his free time...Clearly. A qualified instructor would explain on the very beginning that's not what the FBW is capable of. The general heading is there, but zooming from the big picture into real life detail, much livelier attitude is revealed. De-crabbing is a dynamic manoeuvre, mostly in ground effect and flare mode, the usual characteristics of swept wing apply. Pertinently discussed by other contributors.