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Manual Crosswind Landing Tutorial with Screenshots (Read 13939 times)
Oct 18th, 2005 at 9:54am

Nav   Offline
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My previous tutorial (‘ILS Landing Tutorial with Screenshots’') -

http://205.252.250.26/cgi-bin/yabb2/YaBB.pl?num=1111322151

- (or see ‘Flight Simulator 2004 FAQs’ above, Item 11) - seemed to help people starting out with FS9, so I thought I’d try doing another one to cover the next stage – coping with wind. Once you master manual crosswind landings you can make full use of ‘real weather’ and land anywhere, whether or not ILS is available.

There are two methods of dealing with a crosswind. The first is'crabbing'; 'aiming off', pointing the nose a suitable amount upwind of the runway - which is your only available method if you are using an ordinary two-axis joystick. The second, more realistic, method - available only if you have a twist or force-feedback stick (or actual rudder pedals) giving rudder control – is to use a combination of banking and opposite rudder to stay on the runway line. The first is all you really need in FS9 - but I’ve covered both methods.

Rather than use a default aeroplane this time, I indulged myself and used my current favourite, John Sanderson’s beautiful Battle of Britain Hurricane Mk. IIA (available from Simviation). Partly because, with her wide-spaced undercarriage, she behaves like a real lady when landing (so did the real thing, I believe) and partly because it was fun being able to switch the reflector gunsight on to show you where the nose is pointing at any given time. Smiley (You can get a similar effect by hitting ’Views/View Options/Axis Indicator/Small V’ on the top menu).

APPROACH.

The airport I chose is Nantucket, Massachusetts (Runway 24).  I set up a crosswind at right angles to the runway, and started the approach about 5 miles out at 1,750 feet.

One of the foibles of the Hurricane is that the gear and flaps won’t go down (or stay down) until airspeed is below 120 knots. So the first thing I’ve had to do is throttle the huge Merlin engine back and hold the nose up until the speed drops off. While waiting, I’ve pressed ’Shift-Z’ , and the picture shows the red legend at the top of the screen telling me (among other things) that there is an eight-knot wind blowing at right-angles to the runway (from the right as you look at the picture).

...
Now I’ve got gear and flaps down, mixture full rich, propeller pitch fully-fine, speed around 110 knots, rate of descent about 600 feet/minute, and the aeroplane trimmed. I’m settling in to the approach, and allowing for the wind by pointing the nose well to the right.

...
The thing to emphasise at this point is, DON’T look at where the nose is pointing, look at the runway and keep it in line. In the picture above, even though the nose of the aeroplane looks as if it’s pointing towards New York City rather than Nantucket, as long as the runway view stays straight, our flight-path is correct.  That’s what I meant by ‘aiming off’. Amazing how much crabbing it takes just to counter an eight-knot crosswind, isn’t it?

However, you don’t have to worry too much about the perfect line at this early stage. Spare some time to get power, pitch, and trim exactly right, so that the aeroplane is stable in the descent. And relax as much as you can, save your energies for when you get closer in.

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That’ll teach me! I got a little careless here, as the picture shows. While fiddling with the power and trim, I reduced the crab angle slightly, and I’m a fraction downwind of the proper line. I’m in the act of banking slightly to the right to correct that. It’s best to err on the side of pointing too far upwind, rather than the other way. The wind will always ‘oblige’ by drifting you back on line if need be – but if you once get too far downwind of the runway line, especially as you get close in, it can be a hard slog to get back to where you should be.

I’ll end this post now, and describe the actual landing in the next one.
« Last Edit: Oct 26th, 2010 at 9:17am by Nav »  
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Reply #1 - Oct 18th, 2005 at 9:59am

Nav   Offline
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THE LANDING.

Back on the runway line, and close in now.

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I’ve got my hand on the throttle lever ready to cut the power. But you’ll notice that the nose is STILL pointing upwind of the runway. This is the stage where it is easy to blow the whole thing. This is because at flaring speed (you’ll note that I’m already down to 100 knots), with gear and full flap down and the power off, you’re at your most vulnerable. You could say that it’s the moment the wind has been waiting for! So resist the temptation to straighten out too early; if you do, the wind is quite capable of drifting you right across to the wrong side of the runway while you’re busy flaring and floating along waiting for touchdown.

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Flare as late as you can, then concentrate on keeping the wings level, and the rate of descent 'moderate,' until she settles. Don't worry about a small amount of drift - in real flying you are taught to use the rudder to counteract this, but of course that option is not open to you if you only have a two-axis stick.

As you see, the wind nearly got me in the end, I’m to the left of the centreline as I flare. My excuse is that I was busy taking screenshots! Anyway, in a crosswind situation, it doesn’t pay to worry too much about being exactly on the centreline, or ‘landing on the numbers’. You’ll find that ‘near enough is good enough’, especially at first.

At this point I’ll move on to the final post, in which I’ll ‘backtrack’ a bit and show you how, if you have twist/force-feedback or rudder pedals, you can control your arrival so that you stay on the centreline through the approach and landing.
« Last Edit: Oct 31st, 2010 at 8:44am by Nav »  
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Reply #2 - Oct 18th, 2005 at 10:05am

Nav   Offline
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USING THE RUDDER – ‘CROSSING THE CONTROLS’.

The other way of countering a crosswind, rather than ‘aiming off’, is to drop a wing into the wind. But, of course, banking to the right (as in this case, with the wind coming from the right) causes the aeroplane to turn right. The trick, if you have rudder control, is to ‘cross the controls’ - apply a touch of opposite (left) rudder. Thus the bank, telling the aeroplane to turn right, is counteracted by the rudder telling it to turn left; and, if you get the balance right, it goes straight on – as in the picture below.  That way, you can stay directly in line with the runway. The best way to stay relaxed is to use crabbing early in the approach, to keep the aeroplane roughly in line, and then bring the rudder into play closer in, to line up exactly.

This picture shows me back on the approach – but using right banking and a touch of left rudder this time. By the way, I DO mean a 'touch' - you'll be surprised how little is required to counteract the bank.

Make sure, though, that you keep checking the speed and rate of descent, in case more power is required to overcome the extra drag caused by the bank-and-rudder combination. Technically the aeroplane is actually in a slight sideslip, not flying 'straight and level'; this makes no difference to the approach path 'as you see it' (especially in just two dimensions on the computer screen), but (because the wings aren't exactly level and the nose isn't completely in line with the runway) it DOES mean slightly less lift, a touch more drag.....

...
The snag is, twist or force-feedback joysticks have their limitations. As you twist them to actuate the rudder, your grip tends to tighten – which makes it difficult to handle the stick with enough sensitivity to keep it doing its main job of controlling the ailerons and elevators.  I find that it helps if, instead of just twisting the stick, you change your grip so that your fingers hold it in a slight turn while your wrist remains straight. That’s not a perfect solution, though – it takes a lot of practice to get it right every time.

Twist-control of the rudder remains one aspect of FS9 which is more difficult than real-life flying, where your feet control the rudderbar. I don’t have rudder pedals for the Sim – my guess is that if you DO have them, it makes use of the rudder a whole lot easier. But if you persevere and practise with the twist-grip, you will eventually get the hang of it. The advantage once you’ve mastered it, of course, is that, even in a crosswind, you can fly a straight approach, flare normally, and touch down right on the centre-line – most of the time, anyway  Smiley

...
Anyway, here’s the Hurricane finally touching down  - almost a three-pointer, and on the centreline - pleased with that one….

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As before, I’d advise setting up a practice flight and then saving it. You can substitute any aeroplane you want to practise with – and by going into ‘Weather’ and selecting ‘User-Defined Weather’, you can put in any wind direction and strength, or any other testing weather conditions you like. One other idea is to fly your practice flight using ILS at first - that will give you a good 'mental picture' of how the approach should look, before you fly it for yourself. And don't hesitate to make use of the Visual Flight Path too, early on.

Any questions, anything that isn’t clear, let me know. Hope it’s been useful, anyway.
« Last Edit: Oct 26th, 2010 at 9:37am by Nav »  
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Reply #3 - Oct 18th, 2005 at 3:47pm

wealthysoup   Offline
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Goes nicely with your ILS approach tutorial  8)
But for a wing down approach if your really good you won't need rudder to keep you straight.
Also if your flying with crossed controls it's a good idea to watch your airspeed because on low powered planes it makes it very easy to stall because of the extra drag.  Cheesy
 

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Reply #4 - Oct 18th, 2005 at 5:39pm

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Another super tute Nav. 8) Very well done and it was a great read. Plus I learnt a number of things too. Cheesy
 

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Reply #5 - Oct 18th, 2005 at 10:07pm

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I do great slips in real life, I find them next to impossible in FS.  Then again, I have a twist handle, which would explain that.

Once again Nav, great tute.  You may just want to add a note about landing in a crosswind AND using ILS Wink
 
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Reply #6 - Oct 19th, 2005 at 12:28am

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I have found ONE plane that did slips good in FS...Aeroworx B200. I can hold that sucker cross controlled from FAF to the 'keys with my eyes shut (well, figure of speech  Grin )
The rest is just....a mess really. Timing is way off and the ground handling is laughable in FS.  Sad
 
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Reply #7 - Oct 19th, 2005 at 1:53am

FrodoFraggins   Offline
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I can land with my eyes shut, in the 30knots cross wind
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In the PMDG 737 that is, LOL....

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Reply #8 - Oct 19th, 2005 at 3:59am
RollerBall   Ex Member

 
Hmmm....not so sure about your 'wing down' method nav.

Your 'crabbing' technique is fine. IRL you yank it bank with rudder just before you touch down so you don't but side stress on the gear and wear out your tyres.

However, with the 'wing down' method, you don't apply opposite rudder. The slight bank would usually cause you to turn and that is counteracted by the cross-wind alone. You only put enough bank on for that to happen so the end result is the same as with crabbing.

As previous posters have mentioned, banking with opposite rudder leads to side slipping which is not the point of the exercise at all. The reason is that when you side slip you also have to lower the nose to avoid a stall and you're considerably increasing the workload and the degree of pilot control necessary to maintain a steady approach speed and a constant rate of controlled descent. Certainly I was never taught to apply opposite rudder and I've used the method many many times.

Side slipping is a very useful technique mainly if for whatever reason you need to lose height quickly. Then you cross the controls and usually shove the nose down as well while watching your speed. My old CFI always said to do it in good time otherwise you lose height, fine, but end up with too much airspeed to land without floating right down the runway. Disastrous and the cause of many accidents if it isn't a long one.

All of the above work fine in the sim including side slipping but I personally fel that the amount of acceleration you get when you cross the controls and shove the nose down is less than you experience IRL. That's maybe why you're getting away with it in your cross wind landings.
 
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Reply #9 - Oct 19th, 2005 at 7:52am

Brett_Henderson   Offline
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Quote:
Hmmm....not so sure about your 'wing down' method nav.


I (many moons ago) had the "kick the tail out at flare" technique down pat and could handle a 20knot direct cross-wind easily.. I actually prefered cross-wind landings, as it gives you something to work with. No wind landings are like trying to hit a knuckle ball.

Anyway.. my instructor would not sign me off for a checkride, he wouldn't even let me solo in low-wing planes until I got the hang of wing down landing.  We did Dutch-Rolls to the point that I dreaded flying  Wink

If you rely soley on straightening out during round out and flare... it's just a matter of time before a gusty crosswind forces you either off the runway or into a tricky go-around. PLUS.. unwitting pax don't like flying sideways near the ground..  it scares them.

Quote:
However, with the 'wing down' method, you don't apply opposite rudder. The slight bank would usually cause you to turn and that is counteracted by the cross-wind alone. You only put enough bank on for that to happen so the end result is the same as with crabbing.


I dont wanna nitpick.. but there's some dangerous mis-information here.  If you bank enough to turn into the wind.. then take the bank out.. you're indeed flying a crab. If you keep the bank in without opposite rudder, you'll just keep turning MORE into the wind. If you keep banking/not-banking to stay lined up.. you're working even harder than if you just set the slip early.

Cross-control crosswind landings ARE the proper technique.. ESPECIALLY in a gusty crosswind. Slipping on final is no different.  Airspeed and altitude are controlled the same way as a normal landing... pitch and power..
 
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Reply #10 - Oct 19th, 2005 at 8:47am

Nav   Offline
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Thanks for the constructive comments, guys.

wealthysoup, good point about the extra drag - I'll work that point in, it's important.

beefhole, ILS approaches ('crosswinds made easy' Smiley) are more or less covered in the earlier tute - but I'll suggest that beginners fly their practice crosswind approach on ILS first, to get a 'mind-picture' of how everything should look.

Rollerball, have to (cordially) disagree. I think you're forgetting the 'triangle of forces'. It's as much 'up-rudder' as 'cross-rudder', and it's essential at times in a crosswind approach; you simply can't maintain adequate directional control just by varying the bank angle, you have to balance the controls. But you made me realise that I didn't emphasise 'a touch of rudder' often enough - obviously people shouldn't just bung on full opposite rudder and leave it at that! I'll see about some amendments to clarify things.
 
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Reply #11 - Jun 16th, 2006 at 3:12pm

Lysander77   Offline
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Excellent information, clearly stated, well illustrated, and withal most helpful!
Many thanks...
           Lysander77
 

...
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Reply #12 - Jun 16th, 2006 at 5:16pm
RollerBall   Ex Member

 
Quote:
Rollerball, have to (cordially) disagree. I think you're forgetting the 'triangle of forces'


hmmm..just saw this again. Didn't see these comments about 'dangerous misinformation' and all.

What happens if you shove the stick to the right and leave it there. Answer - you keep rolling. How do you stop it rolling - you centre the stick. You then apply left rudder to induce the desired opposite yaw.

I don't call that 'crossed' controls - the stick is centred. I'd call that woolly thinking.

Tongue
 
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Reply #13 - Jun 17th, 2006 at 12:47am

Nav   Offline
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Thanks for the kind comment, Lysander77, cheers!  Smiley
 
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Reply #14 - Jun 17th, 2006 at 10:02am

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A couple things I'd like to add:

I agree with Brett that crabbing is generally more useful, but of course at some point you have to cross up the controls (slip) to get the plane rolling on the ground aligned with the runway.
The slip used in a "wing low" approach is a forward slip (downwind or forward wing down, nose pointed into wind); a side slip is when you lower the upwind wing and use just enough opposite rudder to keep the nose aligned with the runway.

Crabbing works better initially because you have greater stability and if the wind gusts, any thrust available will be aligned with the direction of wind, counteracting that more efficiently.

You don't want to touch down crabbed, so you'll have to slip at some point, but  watch out- in the landing configuration, you're down in the bottom corner of the performance envelope,close to the normal stall speed, and if you stall the wing while the controls are crossed-up, you could have a little problem.This is the main reason one doesn't want to slip all the way down final... which is not to say that it cannot be done safely.

For what it's worth, in real life and the sim, I generally feel it out: at the top of final, I'll sideslip slightly to get aligned and see what happens, then let the nose veer into the wind a little to find a decent crab angle that allows me to descend on the centerline at the desired vertical speed. If I'm high coming over the fence (due to error or to clear obstacles close to the runway), I might lower that wing on the downwind side a hair to lose altitude while holding the nose into the wind (forward slip),  but as I flare, I have to establich a side slip (wing low, or at least "down" aileron, on the side the wind is coming from, with opposite rudder to keep the nose on the centerline).
All of these techniques are usually quite subtle, but extreme cases can be seen where conditions and airplane design allow.
 

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