crosswind approaches

[cjm_2010]

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?

[Gertrude the Wombat]

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.

[Johnm]

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.

[MichaelJP59]

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.

[cjm_2010]

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 :}

[Fuji Abound]

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.

[FlyingStone]

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.

[Gertrude the Wombat]

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.

[BackPacker]

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.

[cjm_2010]

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 :confused:

we covered a sideslip approach on the third lesson :sad: - 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 :D

[Jan Olieslagers]

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.

[WaspJunior]

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.

[BackPacker]

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.

[englishal]

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.

[trex450]

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.

[Maoraigh1]

I never do crab & kick touch downs in a Jodel, but seem to do them by preference in a Pa28.

[Big Pistons Forever]

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.

[Chuck Ellsworth]

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?

[Johnm]

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.

[cjm_2010]

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!

[NazgulAir]

During my initial training slipping was the preferred method on the tailwheel trainers, but we were taught the crab method too, mostly to use it in the initial phase of getting lined up. Moving on to bigger and heavier singles I still prefer to slip, whether it's in a low wing or high wing airplane. I was stunned to discover that the man who did my chechout on the C177RG Cardinal didn't know the technique: WHAT THE HELL ARE YOU DOING?!! he screamed at me when I "established" wing-down on final in a brisk crosswind.
Slipping is still my preferred crosswind technique. I never thought of it as something that is more difficult to do than crabbing; in fact I find it easier and I think its advantages outweigh its disadvantages.
YMMV. What is important that you can land safely, regardless of technique.

Disadvantages:
- greater side loads on the aircraft and control surfaces that may have load limits, such as flaps, particularly in turbulent/gusty conditions.
- loss of lift due to yaw component, requiring a higher approach speed.
- increased stall speed, requiring a higher power setting.

Advantages:
- early alignment with the runway
- control all the way down without big changes at the last minute
- good "feel" of the wind all the way down
- reduced risk of traversing on touchdown and putting side loads on the gear.

A greater rate of descent can be a disadvantage as well as a great help. The limiting factor is the ability of the aircraft to bear side loads with effective control surfaces to keep the desired flight path. I was once told by an airline pilot that the best way to get down fast on loss of cabin pressure is a controlled sideslip. It works for small aircraft and at lesser altitudes too, but you have to keep inertia in mind -- it takes time for an airfraft to come out of its slip so the load must be eased off in time or else it can be a very hard landing!

[RatherBeFlying]

In gliders it's a crab until a couple feet off the ground, then you push rudder to line up.

Rudder is not kicked.

Gliders have the sneaky advantage that there's much less wind in the 3 feet just above the ground.

No such luck in taildraggers which are mostly high wing. It really helps to land the upwind main first with the a/c pointed straight down the runway, i.e in a sideslip.

One reason for using less flap in Cessna singles in a crosswind is to avoid landing nosewheel first which can do bad things to the firewall.

[Chuck Ellsworth]

When I find a pilot who has problems keeping the airplane straight down the runway on landings I have them fly down the runway at around ten feet for the complete length of the runway using both methods of keeping the airplane going down the center line.

When they can comfortably maintain the center line using both methods they generally have far less problems during the actual landings.

[24Carrot]

One reason for using less flap in Cessna singles in a crosswind is to avoid landing nosewheel first which can do bad things to the firewall. In the C172 I fly there is a placard saying:
Avoid slips with flaps extended

The POH goes into more detail:
When landing in a strong crosswind, use the minimum flap setting required for the field length, If flap settings greater than 20° are used in sideslips with full rudder deflection, some elevator oscillation may be felt, at normal approach speeds. However, this does not affect control of the airplane. ...

[JTN]

In the C172 I fly there is a placard saying:
Avoid slips with flaps extended


Mine too, but I think this refers to the kind of "adventurous" slipping that one would not undertake with full flaps on landing.

ie if the x-wind is bad enough that you have full opposite lock on rudder / ailerons, you wouldn't be using full flap for the landing.

FWIW when I asked about this I was told a) the reason for the placard is that under full flaps a slip can in certain circumstances reverse control input and b) the placard relates to full rather than partial flap. And by full flap I mean the 40-deg "barn doors" that many of the old C172's I fly have. I've never tried it :eek: so can't tell you if it's true or not!

[Mark1234]

There was a whole thread about that some months back, I recall the conclusion was that the placarding and wording wasn't consistent between models. There are plenty of tall stories, but again, I believe the conclusion is in the use of the word 'avoid', rather than prohibited - if control reversals occured, I think the wording might be rather stronger! As for nosewheels, if you're half competant to pilot the thing, landing on the mains isn't hard, even with 40degree barndoors.

In a glider you're also pushed towards a crab by long wings and low ground clearance - landing on a wingtip is not advised. Powered I usually fly a crab right into the flare, push straight with the rudder, and drop the windward wing as required to maintain the centreline. Not really rocket science. In either case you fly the aeroplane all the way, and you can judge the crosswind by how far off the runway heading you're pointing (reference to trex540) Stabilised approaches are for big jets :)

In the main, I'm inclined to think whole thing is rather more down to personal preference, perhaps coloured by your handling comfort, and in some cases dictated by the aeroplane (e.g. wheelers, gliders etc)

[trex450]

One reason for using less flap in Cessna singles in a crosswind is to avoid landing nosewheel first which can do bad things to the firewall.

of course flaring will prevent this!

[silverelise]

it didn't feel too bad. I'm looking forward to trying it for real, obviously under supervision!
IME, being shown wing down approach, especially when the wind is from the right, is quite hairy and uncomfortable (C152). It feels unnatural coupled with the fact you're trying not to "correct" the FI's inputs when you follow through on the controls, whilst trying to brace yourself so you don't slip off the side of your seat on to his lap. All a bit weird.

[Flyingmac]

The angle of bank requred into a x/wind at or below the demonstrated limit of most aircraft is not excessive. Certainly not enough to slide you out of your seat. I personally crab in then change to wing down for the landing. If I crabbed all the way to the flare and got some float and hence drift, this is what I'd be doing anyway.

As for the avoidance of flap in the slip in a 172. My considered opinion based on considerable experience is.... B...ocks!