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crosswind approaches

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Old 14th Aug 2010, 14:54
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crosswind approaches

I was supposed to be going solo yesterday - but the weather just didn't want to play ball - just like the last three proposed dates - this time due to too much of a crosswind.

still, it was well within the limits for the tomohawk (about 10kt vs the 16kt limit), so my instructor suggested we get a bit of practice in.

what a hoot! the lesson totally flew by. the first takeoff was a bit interesting, but once I'd gotten over the adjustments needed after rotation, I was fairly 'comfortable'. the most enjoyable bit was correcting the crab with rudder before the flare. it was totally absorbing.

the wind was fairly consistent - are there any time-tested techniques for dealing with a gust in the round-out that people would like to share?
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Old 14th Aug 2010, 15:36
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are there any time-tested techniques for dealing with a gust in the round-out that people would like to share?
Go-around. Works every time.

If you're doing crosswind landings by doing a crab approach and then kicking straight (there are other ways of doing it) then there are various risks, such as if you're a bit fast and float for a few seconds after kicking straight you can be blown sideways across the runway. There's not a vast amount you can do if this happens other than a go-around.
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Old 14th Aug 2010, 15:46
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Most folk convert from crab to wing down in the last 50 ft or so. Wing down is where you drop the into wind wing and keep the aircraft straight with rudder so the controls are crossed. This is better for gusty conditions if you are quick enough with aileron and rudder to keep to the centre line in the round out and flare.

Do it well and you land one wheel at a time!

By the way "Max demonstrated crosswind" isn't a limit, it is what was demonstrated on the approval flight. Most light aircraft can cope with more than that, the limit being rudder authority.
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Old 14th Aug 2010, 16:01
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Most folk convert from crab to wing down in the last 50 ft or so. Wing down is where you drop the into wind wing and keep the aircraft straight with rudder so the controls are crossed. This is better for gusty conditions if you are quick enough with aileron and rudder to keep to the centre line in the round out and flare.

Do it well and you land one wheel at a time!
I've seen this written in various ways, I think of it the other way round i.e. aligning the aircraft with the rudder then using aileron to keep from drifting with the cross-wind. I suppose aerodynamically it amounts to the same thing though i.e. a side-slip.
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Old 14th Aug 2010, 16:32
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Most folk convert from crab to wing down in the last 50 ft or so. Wing down is where you drop the into wind wing and keep the aircraft straight with rudder so the controls are crossed. This is better for gusty conditions if you are quick enough with aileron and rudder to keep to the centre line in the round out and flare.

Do it well and you land one wheel at a time!
I'll give that a go in the sim later - sounds entertaining. I'm sure if I was forced to do it for real... it'd be squeaky bum time
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Old 14th Aug 2010, 16:51
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Yes, use wing down as soon as you are comfortable - it is a much more effective technique.

Your job flying the approach and landing is in fact to avoid landing.

Your mindset is to assume the aircraft is not going to land. Eventually if everything goes according to plan, you will eventually run out of airspeed before you run out of runway and make the perfect greaser, but, if you dont, you a ready to keep on flying in the go around.

In other words it is a good rule to remember, you only land when everything looks right and is right, otherwise go around and have another go. If you land before you and the aircraft are ready and stable it will not be pretty, even if you can walk away from it.

This probably makes little sense now - but maybe you will recall this approach in time, and it will make sense. It did for me.
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Old 14th Aug 2010, 17:32
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I usually fly the initial approach crabbed and then establish sideslip (wing-down) to be fully stabilised in that condition at 100ft above threshold. Kicking the rudder with adding opposite aileron just before flare is in my opinion much more dangerous technique, and combined with low experience and narrow runway may result in skidding off the runway - not to mention abuse to tires when not done perfectly.

PS: I think the max. demonstrated crosswind component for "Terrorhawk" is 15 knots.
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Old 14th Aug 2010, 17:33
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I'll give that a go in the sim later - sounds entertaining.
It's rather harder work than "crab - kick straight - hope for the best" but it works with more wind conditions and gives you an alternative to the go-around if things don't look quite right ... except of course that the go-around is still the solution to anything you can't cope with otherwise.
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Old 14th Aug 2010, 18:35
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I'll give that a go in the sim later - sounds entertaining.
Actually I think you'll find that this is one of the few areas where MSFS (4 or X) isn't all that good in modeling the aerodynamic behaviour of an aircraft. And even if it were, you need a good set of hardware (yoke, pedals, multi-monitor setup) to properly understand and appreciate what's going on. I've heard better stories about the X-Plane aerodynamic model in this respect, but never tested that for real.

Anyway, I found landing with the wing-down method (sideslip) one of the harder things to learn in flying. All of a sudden you've got to go from essentially using two controls (pitch and roll) to a situation where you are using three controls (pitch, roll and yaw) independently of each other.

What I did as a simplification, to keep my brain from becoming overloaded with this, was to fly a crabbed, stabilized approach. At 10-30 feet or so I would apply rudder to align the centerline of the aircraft with the runway centerline, plus a little anti-rudder aileron to prevent the secondary effect of yaw (roll). I would then lock the rudder with my feet in this position and simply fly the aircraft to the runway using roll and pitch only. This lead to consistently decent crosswind landings.

I'm not saying that this is the technique that eventually works in all conditions. In fact, the shifting wind gradient at low altitudes will almost guarantee that the aircraft is misaligned with the runway by a few degrees by the time you actually land. So for more demanding conditions and in tailwheel aircraft you've got to learn how to control the aircraft in all three dimensions simultaneously and independent of each other. But for a low-time pilot, in not too difficult conditions and in a nosewheel aircraft, it works just fine in preventing brain overload.
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Old 14th Aug 2010, 19:17
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And even if it were, you need a good set of hardware (yoke, pedals, multi-monitor setup) to properly understand and appreciate what's going on.
I'm running a saitek pro yoke setup with throttle quadrant and rudder pedals - it's helped me make pretty rapid progress, and due to the lack of force feedback or sensory cues, i'm finding the sim 'harder' than the real thing

we covered a sideslip approach on the third lesson - foolishly I'd mentioned trying it on the sim the night before to my instructor; we came in at a rediculous angle and I had to fight every instinct in holding the slip to maintain the descent rate, before he talked me through how to 'clean things up' at the threshold. it was totally and utterly bonkers. the biggest problem I had was metering the elevator inputs during the slip - I'd be making pretty big inputs and not waiting for reactions; and then there was the complete difference in the picture of the runway I'd become used to during a normal approach.

I got out of the plane with the biggest sweat patch on my back, shaking like a leaf. and totally buzzing.

that night I tried it again on my pc - and ended up spinning into the ground
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Old 14th Aug 2010, 21:02
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FWIW: when I trained on a high-winged medium performance ultralight, I was never taught crab approaches. "stick into the wind" was the motto, on take-off as well as on landing. And as our 15/33 runway was very prone to crosswinds, with some tricky turbulence from buildings just before touchdown, it was made a matter of routine to me to land on one wheel and slow down until the other touched - never doubt it will! - , still keeping the nose wheel up for as long as possible, to spare its feeble construction.

As I understand, crab approaches are for the faster lower-winged machines, for lack of better options.

BTW @cjm: consider flying late in the day, wind tends to fall shortly before the sun does. Round here a surprising amount of first soloes occur in late afternoon. I think UK climate won't be that much different.
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Old 14th Aug 2010, 21:49
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I was taught crab approaches but found the wing down method much much easier, as Jan alluded to it's better suited to high wing, single engined aircraft. Better to land with some slight drift than dig a wing tip in.
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Old 14th Aug 2010, 22:13
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we came in at a rediculous angle and I had to fight every instinct in holding the slip to maintain the descent rate,
Two things you need to remember.

First, in a sideslip, the wind noise is very much increased and there's a lot more turbulent air hitting the control surfaces. This sounds and feels scary but is perfectly OK.

Second, don't trust your ASI. And depending on the installation, the ALT and VS too. Wind is blown into their ports sideways instead of as-designed, so their readings may be completely off.

Sideslipping is almost completely done using outside visual cues, particularly by keeping the nose well below the horizon. You will want to experiment with sideslipping at high altitude to know what it should look (and feel) like, before you try it for real at low altitudes.

than dig a wing tip in.
Actually even your average low-wing GA aircraft would need a very significant bank angle before the wings dig in. Unless it's a multi-engine or a glider (with centerline wheels only).

But in the average single engine GA aircraft, you probably will not be able to reach that bank angle by sideslipping - you'll run out of rudder authority well before.
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Old 15th Aug 2010, 07:30
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I much prefer Wing Down. It is pretty easy once you get the hang of it. Just remember:

Keep the nose parallel to the runway using rudder
Counter drift across the runway with aileron.

I normally crab in until short final, then get the nose parallel to the runway with the rudder and hold it, then adjust aileron to put me down in the middle of the runway. It makes for a nice stable approach and you just flare as normal and will touch down on the upwind wheel first. Be aware that as you approach the runway the wind direction / speed will probably fluctuate so you will need constant adjustments on both.
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Old 15th Aug 2010, 10:33
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Personally the wing down method is far superior to kicking off the drift at the end. It has already been mentioned that with this method you fly the aircraft all the way onto the runway leaving you better placed if a go around is necessary. There is also a big benefit IMHO, that is that the anemometer at some airfields can be as much as a 1000m or more from the threshold of the runway you are landing on which can mean that the wind information that you are given can be very different to that which you are about to experience. By using the wing down method (in a crosswind close to or above the demonstrated maximum) you already know (using wing down) if you can hold off the drift. If you run out of rudder when using wing down and you are drifting off the centerline then you know early on when a go around is easy. Of course I realise this statement does not cover wind speed and direction variation with the descent but if you are not holding the centerline at 100ft then you probably won't at touchdown.
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Old 15th Aug 2010, 19:35
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I never do crab & kick touch downs in a Jodel, but seem to do them by preference in a Pa28.
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Old 17th Aug 2010, 01:34
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I think the crab and kick it straight is a large airplane technique that has migrated down to small aircraft. Back when people trained in light tailwheel trainers pretty much everybody used the wing down method with 3 point or wheel landings in light winds and almost always a wheel landing in high or gusty crosswind landings. With the advent of the modern tricycle gear trainers the option of the crab technique started to creep into flying training. My personal experience is for every light aircraft I have flown, the wing down method works best.

Last edited by Big Pistons Forever; 17th Aug 2010 at 05:25.
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Old 17th Aug 2010, 02:47
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Lets assume you are in the final stage of the approach just prior to the flare and you decide to initiate a go around.

Would it be easier to go around from a crabbing approach, or from a slipping approach at the maximum deflection of aileron for the rudder authority available?
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Old 17th Aug 2010, 07:26
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The point about crabbing is that it keeps the aircraft in balance, out of balance flying is uncomfortable particularly for passengers. This is why it's good to crab until fairly low (200ft or less).

After achieving a stabilised wing down approach it may still fail and you then power on, centre the ball, loose the drag flap and climb away. To track the runway heading you'll now be back in the crab to aim off the drift.
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Old 17th Aug 2010, 08:25
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I gave the wing down approach a few goes on the sim last night. once I'd gotten my head around the feel from the elevator whilst banked with opposing rudder, it didn't feel too bad. I'm looking forward to trying it for real, obviously under supervision!
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