Crosswind Question

[Front.]

One question that i've had is this. During a cross wind landing you can either crab of side slip. I do both as both are good routines. The question i have though applies to crabbing style more than side slipping.

When you're on a rather big cross wind when looking at what the plane is able to handle, let's say 15 knots xc for a PA28-161, when you're crabbing, how do you prevent the plane from not skidding off the runway prior to stepping on the rudder and aligning your self for the runway.

The way i always did crabs was like this. Maintain crab angle till approximately 10-20 feet. Get into a side slip, and touch down. I notice that even in a side slip, the plane has a intertia to move away from the centerline as the wind's hitting it.

So to visualize this. Landing runway 26L. Winds are 230/15G25. If you're landing, and get from a crab into a side slip, the inertia of continuing to drift along on the touch down has happened to be several times and i didn't know how to correct it.

The question i have is how do you put a stop towards skidding on the runway, cause if the plane still has inertia to drift after the touch down, i've always had "side-skids" if you want to call it that way, but was able to recover from it quickly.

Wanted to get some inside notes on how you guys do it and if i am doing something wrong perhaps.

[Pugster]

The way i always did crabs was like this. Maintain crab angle till approximately 10-20 feet. Get into a side slip, and touch down. I notice that even in a side slip, the plane has a intertia to move away from the centerline as the wind's hitting it.

Maybe you're just not slipping "enough"? Try increasing the amount of control input you're using and it may cure up the problems...

[EBDUB]

I agree with pugster, but to go into more detail it sounds like you are not using enough aileron to counteract the drift.

as the a/c slows down in the flare you need to add increasing amounts of both aileron and rudder. if this is done right you should land on the upwind main first holding the downwind wheel off the ground with the ailerons. in some situations you might have to roll on the one wheel for some distance to stop the aircraft from drifting. a good way to help with this is remebering that the goal is once the a/c has slowed to taxi speed you are supposed to have full aileron deflection into the wind, so throughout the flare and landing roll the ailerons will gradually be moving from neutral in the crab to full deflection at taxi speeds.

I know there is a huge difference between reading this and actually being able to carry this out smoothly but that just comes with practice. hope this helps have fun and keep the shiny side up!

P.S. just a question front are you still training, or licenced?

[Front.]

The way i always did crabs was like this. Maintain crab angle till approximately 10-20 feet. Get into a side slip, and touch down. I notice that even in a side slip, the plane has a intertia to move away from the centerline as the wind's hitting it.

Maybe you're just not slipping "enough"? Try increasing the amount of control input you're using and it may cure up the problems...

Got another insight regarding that and i think that might do the trick. I am a bit too shy to use almost full opposite aileron to controll the directional movement.

Thanks for the help

[Justwannafly]

just be careful....the bomber landing maneouver is hard to do...especialy for someone working on their private
..though it sure looks nice;)

[RatherBeFlying]

After flying gliders for the Summer, I found myself crabbing all the way down in the Citabria: fly down with crab to about five feet: then straighten up, flare and wing into wind all at once.

For a lower time pilot, setting up a sideslip in the approach leaves you with just the flare to do rather than three control inputs all at once.

The difference between gliders and high wing power a/c is that the shorter wing allows more wing down and that being higher up (6+' compared to knee high) the crosswind component is stronger; so needs more wing down.

[Front.]

just be careful....the bomber landing maneouver is hard to do...especialy for someone working on their private
..though it sure looks nice;)

the advice i got from somebody flying left seat 757's was to practice the crab manoevers by getting from a crab into a side slip 200 feet above the ground, and once i get comfortable with that, then do it at lower altitudes.

I am obviously not going to do it 5 feet above the ground on day one because i tried that and ended up skidding off the runway lol...


I don't know how this being related to private has any relevance though. It's a practice many don't get to try out untill after their private.The only time i have a hard time doing this is on a wet runway when the friction is less to keep you on the runway. If it's dry i do it perfectly around 10 feet above the ground. I am supposing that since the friction would be higher on a dry runway, even if i wasn't 100% algined on the runway track, i would be held on the runway enough to not skidd off.

Have to start working on this crab -> side slip thing during wet conditions.

Thanks for the inputs everyone.

[RatherBeFlying]

Here's the deal -- the higher up you convert from a crab to a sideslip, the longer the crosswind has to blow you off.

Also the higher up you are, the stronger the crosswind component and the more sideslip you need to begin with.

This all adds up to more work holding and adjusting the sideslip when you initiate it higher up.

The requirement for delaying the sideslip is that you have to be familiar enough with your a/c's control response that you can perform the correct control inputs before contacting the ground in a crab.

So until you're more familiar with the a/c, you do need to initiate the sideslip at sufficient height for you to sort out how much bank and rudder is needed to hold the centreline.

You can start the sideslip a little bit upwind of the centreline and maybe put in a bit more correction than you think you need. It's easier to allow the x-wind to blow you back to the centre line than to crank on a bunch more bank and rudder to get back.

If I had the luck to be flying a '67, I'd be decrabbing considerably higher than 5 ' -- 200' sounds about right.

[Front.]

If I had the luck to be flying a '67, I'd be decrabbing considerably higher than 5 ' -- 200' sounds about right.

Yes i didn't mean that the airliners crab 5 feet above the ground lol. It's 50' normally.

[square]

Are you sure it's the inertia? I was warned that some runway incursions have actually happened in crosswinds not because of INERTIA but because of WEATHERVANING. Just because you've touched down, it's not like aerodynamics no longer apply to you. The wind tries to straighten out you vertical stab/fuselage parallel to the wind, so there's a force there trying to yaw you into the wind. Could that be it? If you notice the nose moving (it would yaw left a little in the example..) it probably is. But if you totally maintain your direction then I guess not.

Even still, it can't be inertia. If you're doing a proper slip, your flight path should be parallel the centerline; that means your inertia relative to the ground is completely forward, you have no lateral inertia because of the wind.. it would be because your either slipping too much (if you skid into the wind) or not enough (if you skid away from it.)

Or it could just be that the lateral force of the wind is simply pushing you off centerline, you'd start feeling that on touch down. If you're skidding away from the wind it's a maybe.

My advice:

Start the slip a little earlier than flare-height so you can confirm that you're actually tracking centerline.

Once you touch down, quickly put in full crosswind inputs as per your POH.


Really interesting question though man, let us know how it turns out

[mellow_pilot]

Ya, it's clearly not inertia since that would tend to carry you down the center line (assuming you were lined up during your 'crab phase').

It's just poor (that really means lack of practice) sideslip technique. It's really hard to set up a proper sideslip in just a few feet. Keep at it, it'll come... just try not to touchdown if you're still drifting, you'll do repetative damage to the airplane.

I assume this it during training, so if you're drifting, carry power until you have it stabalized, go around if need be. There's no reason to land if the apporach is bad and you're just training. Giv'er another go in the circuit...

Good luck.

[RatherBeFlying]

Before the first mainwheel touches, you want to have the a/c pointed straight down the runway with zero drift (see above for several ways to get there) and then touch down in that condition at a good low speed for the a/c and conditions.

Once on the runway, your airspeed begins decreasing and your control power decreases with the square of the airspeed; so, you have to apply increasing amounts of aileron and rudder and you may come to the stops. During this time the nose- or tailwheel will come to the ground which may along with differential braking help you in maintaining directional control.

Some a/c can handle more x-wind on the ground than others.

[glorifiedtaxidriver]

Enter your sideslip further up. Try approaching from 2 or 300' in the sideslip. Watch to see how much control input you need to maintain centreline. As you get close to the ground and flare, you will generally need less control input than at alititude so if you can hold it straight at 200' you'll be ok in the flare. When you touch down, stay on the upwind wheel until you can see and feel with opposite rudder that you're maintaining runway heading and then ease the downwind wing down till your downwind wheel makes contact. As you slow down you are going to need more and more rudder as there is less air flowing over it.

Also, be very careful when approaching with full, or close to full control inputs in a strong crosswind. If you need full left aileron to correct for drift you will have little to no room for correction if caught in an unexpected gust. In this situation while still inexperienced, it shows better decisionmaking to chose a more into wind runway if available.


You can also try landing with less flap. You'll approach faster, but with less flap hanging out grabbing wind you'll find it easier to maintain heading. And the plane won't weathercock as much while slowing down.

good luck.

[RatherBeFlying]

Keep an eye out on where you're landing. I was coming into an airstrip with a humongous xwind that suddenly disappeared when I got below the trees and had to very quickly undo my sideslip.

[Carl]

I dont reccomend the crab to slip transition to anyone in ab initio flight training environment. it's very hard to judge and control the amount of input to use during and after the transition has been completed. If you are going to transition, I like the idea of practicing at altitude until you have good control of your hands and feet, then gradually take it lower to the ground. I've seen many people playing with this during landings, and from what I see it aint somthing that youa re going to master with very few hours. Besides you wont find that maneuver in the flight training manual. Now go.......

" Get er Done "