Crosswind landing A320

[Speedwinner]

Good morning,

Airbus says we are allowed to do a max 5° crab angle on touchdown. So far so good. What im observing in training and outside in the real aircraft is that people land pretty often with a crab more than 5° with strong crosswinds( DUB, MAN, LIS). Same in the simulator. Many pilots are not familiar with the actual strong pressure you need to get out the crab to acceptable values.

My question is: did you observe the same? And where do you read the crab angle? ND? Sometimes this indication seems not fully reliable (visually aligned but the crab angle on the ND is above 5°) Would appreciate your help in this.

Happy Cwlandings guys!

SW

[sonicbum]

Good morning,

Airbus says we are allowed to do a max 5° crab angle on touchdown. So far so good. What im observing in training and outside in the real aircraft is that people land pretty often with a crab more than 5° with strong crosswinds( DUB, MAN, LIS). Same in the simulator. Many pilots are not familiar with the actual strong pressure you need to get out the crab to acceptable values.

My question is: did you observe the same? And where do you read the crab angle? ND? Sometimes this indication seems not fully reliable (visually aligned but the crab angle on the ND is above 5°) Would appreciate your help in this.

Happy Cwlandings guys!

SW

Hi SW,

Have a read at This Crosswind Landing Technique FOBN (https://skybrary.aero/sites/default/files/bookshelf/179.pdf)

Lots of valuable info to prepare yourself for your next crosswind landing.

With that being said, crosswind landings are like free kicks in football: you must practice loads of them with the proper technique to become proficient :)

[Speedwinner]

Thanks man, i have already read this article. My main point was: is the drift angle (Track to heading) representative for the max crab angle? For me i see often more than 5° but the AC is aligned from my point of view.

[sonicbum]

Thanks man, i have already read this article. My main point was: is the drift angle (Track to heading) representative for the max crab angle? For me i see often more than 5° but the AC is aligned from my point of view.

My bad, I have't read the question carefully.

I do share your opinions, especially when it comes to crosswind training in the SIM, the general tendency is to have a crew landing with more than 5° and it does indeed look almost parallel to the axis, and same in the aircraft.

At this stage during the flare the PM will be almost completely looking outside. I wrote almost because there is still the requirement to monitor that the landing pitch limit attitude is not exceeded. The remaining parameters will be monitored "on demand", i.e. the aircraft starts banking the PM will have a quick glance at the bank angle and announce "bank bank" if more than 7° (good luck with that :8).
There is no such thing as a "drift" call-out and no requirement to takeover in case of non application of the decrab maneuver. And this opens and has opened in the past a huge can of worms: yes but the LG could be damaged in case of touchdown with an excessive drift, yes but landing with more than 5° drift will trigger a flight data monitoring alert. On top of that it would be very difficult to takeover during the decrab with a 30+ kt crosswind and not risking more damages than good. The only viable option is a takeover to conduct a balked landing if your colleague is messing it up.

Given the above, many airlines restrict the maximum crosswind for landing (and sometimes for takeoff) to a certain value for FOs to anything between 15 and 25 kt. The rationale, at least where I work, is that at those crosswind an incorrect application of the decrab technique will not immediately affect the LG structure and the resulting behaviour of the aircraft on ground following the crabbed landing.

The above means that Captains will always then apply the correct decrab technique! :ok: Which is obviously not true because we all get skilled-rusty on things we don't practice very often even with thousand and thousand of hours under the belt.

[Speedwinner]

Thanks! So what means the not correct decrab technique will not stress the landing gear? I mean with a 35kt crosswind you have to kick off at least 10 degrees of crabangle plus fight the turbulence. I would say most of the pilot won’t make that.

[JABBARA]

Originally Posted by Speedwinner View Post (https://www.pprune.org/tech-log/652556-crosswind-landing-a320.html#post11428518)
Thanks man, i have already read this article. My main point was: is the drift angle (Track to heading) representative for the max crab angle? For me i see often more than 5° but the AC is aligned from my point of view.


Did I misunderstand something?
Please someone correct me if I am wrong
What I understand from word "drift" airplane track is aligned with Rwy centerline AND it is on the centerline, What I know during an approach, regardless what the crosswind is, drift should be zero, there is no other way, it is a "Must"
What I understand from word "crab" : To fly a zero drift approach and zero drift touch (which is a must) there are two ways
1 Crab approach and touch: Pilot flies the airplane into wind (upwind side) and TAS vector plus Wind vector gives a Ground Speed vector aligned with and on the centerline of runway extension, or on the the runway touch: It is a weird view from cockpit but easy
2 Sideslip approach and touch : From a crab position, pilot aligns heading with rwy with downwind side rudder but this starts a drift and this drift is stopped with a bank into wind A better view from cockpit but not that easy
If we agree with all above, maybe I have more things to say about decrabbing at touchdown

[dream747]

I am also wondering about the recommended crosswind landing techniques especially for a lot of the widebody aircraft out there. I'm only experienced on the A320, but from my own observations at work and from Youtube videos, bigger aeroplanes tend to not decrab so much, if any at all. Surely it causes stress on the landing gear like what. Sonicbum has explained.

To the OP, at my outfit everyone is trained to decrab in crosswinds before touching down. It's not easy to get it right all the time but no one deliberately tries to land without decrabbing before touch down unless we mess it up. Having said that, we have no way to establish how much is 5 degrees. We just try to put the nose straight as much as we possibly can.

[AerocatS2A]

To the OP, at my outfit everyone is trained to decrab in crosswinds before touching down. It's not easy to get it right all the time but no one deliberately tries to land without decrabbing before touch down unless we mess it up. Having said that, we have no way to establish how much is 5 degrees. We just try to put the nose straight as much as we possibly can.

This. In other words, don't over-think it. The manufacturer has given guidance about an acceptable crab angle but that doesn't mean either pilot should be staring at the ND to see how much off the runway heading you are. Landing is a visual manoeuvre, you can feel when you touch down nicely aligned with the runway (even a gentle touchdown feels somewhat harsh if you're a hair off runway alignment.)

[stilton]

Out of curiosity does the Airbus FBW allow crosswind correction with a side slip ?

[vilas]

Last hundred feet through flare and touchdown is purely visual. Whatever limitations of bank, crab, attitude are assessed visually. There's no way you can look at PFD or ND for that guidance. It's a judgement if one doesn't have then he has to develop over a period. Wind displayed on ND in A320 is not instantaneous so it's of no use anyway. If you shift your focus well down the runway where RW centre line markings appears a continuous line it gives a better judgement of crab the aircraft is flying. When you start removing the crab stop a little short of straight ahead. And if that starts a down wind drift put on a small bank. If it doesn't help go around. There's nothing else.
Airbus doesn't recommend sideslip because you don't bank in Airbus but give a rate of roll command.

[Speedwinner]

I agree with all the statements. Anyway, Airbus recommends max. 5° of crab angle during touchdown and we are supposed to eliminate the drift with our feeling for the airplane. Otherwise the gear may collapse ( this applies mainly on dry runway).

I also agree we shouldn’t check the drift on the nd, but when im PM, i see a lot of landings which have more than 5° drift on the only instrument we have in the cockpit: the ND.

[AerocatS2A]

I agree with all the statements. Anyway, Airbus recommends max. 5° of crab angle during touchdown and we are supposed to eliminate the drift with our feeling for the airplane. Otherwise the gear may collapse ( this applies mainly on dry runway).

I also agree we shouldn’t check the drift on the nd, but when im PM, i see a lot of landings which have more than 5° drift on the only instrument we have in the cockpit: the ND.
Don't worry about it. Do the best you can. The gear isn't going to collapse because you've landed with a 6º crab. If you have the position of a trainer then offer some advice to your students, if you're just a line pilot, lead by example and if anyone ever asks how you did such and such landing, tell them your technique.

[Boeingdriver999]

With an approach speed of ~140 knots over the ground and a max crosswind of ~40 knots the crab will be ~15 degrees.

Using words like “kick off” aren’t very helpful. It should be a smooth and steady input.

Anyway; if you watch the many YouTube videos showing off airline pilots ‘skills’ you will see that most crosswind techniques are appalling and bear no resemblance to what is taught.

[JABBARA]

Boeingdriver999

Using words like “kick off” aren’t very helpful. It should be a smooth and steady input.
That is the key point
Decrabbing at flare will cause a roll, named as "Yaw induced roll"
Therefore if rudder pedal input is too fast, controlling the caused roll may be too difficult. Whereas if it is smooth, there will be enough time to control roll by Sidestick This is what I strongly recommend at line

A good news, A 350 and 380 flight control law is designed so that a "Yaw induced roll" is prevented at flare, so no need to struggle to stop roll with sidestick while decrabbing
This is mentioned at Safety First Magazine.
I didn't check again today but if I am not wrong it was in FCOM as well

[Window heat]

With an approach speed of ~140 knots over the ground and a max crosswind of ~40 knots the crab will be ~15 degrees.

Using words like “kick off” aren’t very helpful. It should be a smooth and steady input.

Anyway; if you watch the many YouTube videos showing off airline pilots ‘skills’ you will see that most crosswind techniques are appalling and bear no resemblance to what is taught.

The videos I see on FB are embarrassing to the profession. In the 747, I would flare fully crabbed, push straight as the energy deteriorates and land wings level and straight. There may be a degree of drift but you're never perfect.

In the A330, I use identical technique but avoid the aileron application as a slow rudder application does not lead to a roll due to the FBW action.

I used the same yechnique in the A380 and the 737, except if my timing was off in the maggot id drop a wing to put the in to wind wheel on first, just like I do in lighties.

The 5° limit in the baby bus should only be needed when the xw is huge or you muck up the timing. If your timing is good, the A/C straightens as it touches, no drift and no crab.

[Boeingdriver999]

The videos I see on FB are embarrassing to the profession. In the 747, I would flare fully crabbed, push straight as the energy deteriorates and land wings level and straight. There may be a degree of drift but you're never perfect.

In the A330, I use identical technique but avoid the aileron application as a slow rudder application does not lead to a roll due to the FBW action.

I used the same yechnique in the A380 and the 737, except if my timing was off in the maggot id drop a wing to put the in to wind wheel on first, just like I do in lighties.

The 5° limit in the baby bus should only be needed when the xw is huge or you muck up the timing. If your timing is good, the A/C straightens as it touches, no drift and no crab.

This guy gets it :ok:

[mahogany bob]

My worst landing ever was on a gusty wet night in a Vulcan with about 15 - 20 kts X/W on a narrow R/W.

Overconfidently KICKED off the drift too early and got the wrong side of the wind . Heading towards the grass and too late to GO AROUND only option was to slam it on in a heap - luckily the Vulcan was very resilient and we walked away!

The AWACs ( Boeing 707 ) was a bitch to land in crosswinds -with CFM 56 engines scraping the concrete with more than about 3 deg bank applied (this happened a few times !)

Taught by my German instructor to at 50 ft gently arrest the rate of descent and at 20 ft slowly reduce power whilst very GENTLY pushing the rudder to straighten nose whilst applying FULL aileron into wind.Worked a treat!

The nose always straightened naturally during the flare with very little rudder input.

TOP TIP - make certain the ac is totally IN TRIM on finals , relax and keep breathing ! - GA early !

Sorry if if this is really old info and modern aircraft are obviously much more user friendly but I am sure that the same principles apply?

[Boeingdriver999]

Like I said; anyone who is using the word “kick” with regard to 3,000psi hydraulics is only demonstrating their own knowledge deficiency.

Here’s a fresh few examples of NIL crosswind landing technique in modern airliners including the A320. If you watch at 0.25 speed you can see zero rudder input until the 2nd/3rd(?) touchdown and then it’s momentary. At least the easyJet crew know the limitations of their training… :E

https://m.youtube.com/watch?v=Epi0zaFK99U

[stilton]

Certainly agree with pushing out the drift, there’s far too many references to ‘kicking it out’


One difference we had when we first started to operate the 757 was to land while maintaining the crab on wet runways, the rationale was to reduce downwind drift after touchdown


In a subsequent flight manual update this recommendation was removed, curious if anyone else has seen this

[vilas]

Certainly agree with pushing out the drift, there’s far too many references to ‘kicking it out’


One difference we had when we first started to operate the 757 was to land while maintaining the crab on wet runways, the rationale was to reduce downwind drift after touchdown


In a subsequent flight manual update this recommendation was removed, curious if anyone else has seen this
ON a wet runway even 747 was landed with crab. On wet runway on touchdown the aircraft skids in direction of flight path reducing side way stress. Then when it grips the surface it straightens automatically removing the crab.

[stilton]

ON a wet runway even 747 was landed with crab. On wet runway on touchdown the aircraft skids in direction of flight path reducing side way stress. Then when it grips the surface it straightens automatically removing the crab.


Yes, it all makes sense, just wondered if that’s still recommended procedure by an operators ?

[vilas]

Yes, it all makes sense, just wondered if that’s still recommended procedure by an operators ?
It was in training manual of 747 classic.

[JABBARA]

There wouldn't be any point to talk about if all were a B 52 design.
Looks like supermarket cart

https://www.youtube.com/watch?v=nhVD3E0-0Wc

[stilton]

It was in training manual of 747 classic.


Interesting, thanks for the information