Cross wind landings

[thing]

Isn't long final the correct call for final at more than the three mile point though? As in a straight in. Never used it myself but isn't it a bit like 'short final' call on an instrument approach when the approach controller hands you over to tower, usually with about three nanoseconds to change frequency and get the call in?

[9 lives]

It's thread drift, but we seem to have beaten this round of crosswind talk to the end (again).

but to practice them as an abnormal or emergency procedure to enhance engine out judgement not as a standard approach.

I have learned to like the idea of a power off approach from a few hundred feet up, with a bit of power added if you need it. One of many reasons for this preference, is if you're flying a retractable wheel plane, you'll get the gear warning horn, if you forgot the gear. If you carry power to the flare, you just disabled that system. Maybe okay, if you're unable to err with the gear, but the system is there to warn you, and it won't if you don't pull the power off far enough back to make use of it...

To bring it back around to topic a little, you don't need power to maintain control in a crosswind, just fly the plane. I was demonstrating one wheel crosswind landings in the Super Cub to my charge today. Held on the upwind wheel, power off, until the full aileron would no longer hold it, then other main, while I held the tail off, until the tail settled on for lack of speed with full stick forward. Power was not required for this. All that power should be doing for you on your final approach, is allowing you to select where you will land, not how....

[Flyingmac]

Quote:
" If you can't keep the aircraft pointing straight down the runway with crossed controls, the crosswind is out of limits."

This isnt correct and is to my mind a misleading statement.


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[9 lives]

The conditions one might experience while maintaining (or attempting to) the runway centerline down final will be a strong indicator what might be experienced at landing. It if fair to say that if you cannot hold the centerline down final, landing will be a challenge, and an overshoot should be an option (which to me suggests at least not selecting full flaps).

Generally, the wind is less intense at the surface, so if you have maintained the centerline down approach, it's likely not worse over the runway, but there can be gusts or mechanical turbulence to upset things. One of my frequented runways has an unfortunate tall stand of trees on a small hill on the prevailing upwind side of the touchdown zone - which keeps life interesting.

The term "crossed controls" brings to mind a full slip, with one of the controls being held to the stop against the effect of the other. If a pilot is needing to fly a full slip in a crosswind, I suggest aborting that landing, it was poorly set up. A full slip will not be required to maintain control in landable crosswind conditions. Some "crossed" control input might be required for the wing down technique, though not a "slip" worth. Yes, you might get to full control input once on the runway, because the aircraft has slowed, and more control displacement is required for achieve the desired effect. In such case, go ahead, that's what the control is there for!

It is possible to touch down fully slipped in some aircraft, I have done it for practice, though if done on pavement there are horrible tire chirping sounds. That's why grass, and even better wet grass, are more desirable for crosswind landings.

[Pull what]

Generally, the wind is less intense at the surface, so if you have maintained the centerline down approach, it's likely not worse over the runway

More misleading statements. Whats an intense wind? One that blows seriously?

You dont need any rudder correction to crab down the approach but you do need rudder input it to de crab and once you hit the stops you have no more rudder left. Whatever your crosswind limit is just above the runway you can double that wind velocity and still fly down tbe approach by crabbing so in tbe same way it might be possible to fly down the appraoch maintaing the centreline but not have sufficent rudder deflection to decrab on landing making it far worse(to use your description).

and even better wet grass, are more desirable for crosswind landings.

That has to be one of the most ridiculous statements Ive ever heard!

[Crash one]

Quote:
Quote:
and even better wet grass, are more desirable for crosswind landings.
That has to be one of the most ridiculous statements Ive ever heard!

Doing most of my flying off grass I'm inclined to agree with Step turn.
A serious crosswind is no problem and even less problem on wet grass with a tailwheel, because it slides sideways until it lines up with the track. It has saved my ass a few times. Ridiculous it is not!
Ditch the textbook and fly the aircraft.

[Chuck Ellsworth]

Step turn said:

and even better wet grass, are more desirable for crosswind landings.

Pull what said:

That has to be one of the most ridiculous statements Ive ever heard!

The above is why these internet forums can be so confusing for people wishing to learn about flying.

Step turn is correct, I have no idea what Pull what is trying to do, but for sure it is not educate new pilots with the correct information.

[worrab]

Perhaps making the point than an ideal crosswind landing on any surface is fine.

I believe it's only when one lands a little crabwise that the lesser friction of wet grass comes into its own by allowing the tyres to slide sideways slightly at the moment of touchdown and hence relieving some of the strain on the airframe.

[Chuck Ellsworth]

I believe it's only when one lands a little crabwise that the lesser friction of wet grass comes into its own by allowing the tyres to slide sideways slightly at the moment of touchdown and hence relieving some of the strain on the airframe.

The less friction a surface has the less problem with the airplane not being lined up with the landing direction.

I had a very difficult landing scenario one night long ago flying in the high Arctic in a DC3.

The landing conditions changed dramatically just prior to our arrival at the destination airport Resolute Bay N.W.T. , the surface winds had been almost zero for a couple of days while we did a fuel cache contract about an hour and a half N.E. of Resolute Bay.

About sixty miles out of Resolute Bay the Air Radio operator at the airport called us and asked our position and I said sixty miles out and he said the wind was increasing rapidly and there was surface blowing snow starting to reduce visibility.

We could see the lights of Resoute and told him to keep us updated of the wind and surface vis.

Long story short....by the time we were a couple of miles final the radio operator informed us the wind was fifty knots and nintey degrees off the runway and the ground visibility was zero.

We confirmed we had the winds and the vis and had the approach lights and runway lights in sight.

We had good visual of the runway right down to about fifty feet and then we entered the blowing snow and visibility went to zero.

We held the heading that had kept us on the centre line during the approach and rounded out and the wheels contacted the runway as smooth as silk, I pushed forward on the controls to keep it pinned to the runway and we slid down the runway going sideways on the snow and ice covered runway just as slick as snot.

We came to a stop still on the runway and advised the radio operator we had landed successfully.....we took forever to find our way to the ramp in the blowing snow.

So there you go gang, a true story of using a slippery runway to your advantage.

[9 lives]

Referring back to the photo I posted on page two, of the wingtip of my 150 a few inches off the surface, that would be very hard to accomplish on a higher friction surface. You'd probably roll the plane over, or at least shred a tire. Allowing a plane to drift laterally on the runway can ease directional control, particularly in a taildragger. That's why the Ercoupe had mainwheels which swung a little to each side, as there was no rudder control with which to "kick it straight" for touchdown.

When I was first getting used to a rather unforgiving taildragger, I took it out on to the ice (on wheels) in a big wind. Indeed, it was "intense" relative the the plane's characteristics! I landed progressively more and more off the wind, satisfying myself I could maintain control with the increasing crosswind component. Eventually, I was landing in a 20 knot crosswind (demonstrated was 12 for this aircraft). I had no problem maintaining my intended "runway" heading, until the plane slowed below a speed where the rudder was effective. The tailwheel had no friction on the ice. Then the plane weather cocked. On the ice, no harm done, but the point was clear.

But, as I approached this weather cocking at lower ground speed, there was more and more "slide" as the wind blew me across. If the surface had the friction of a dry hard runway, the plane might have groundlooped out of control if the tailwheel friction were inadequate to steer.

While training my charge in the Super Cub the other day, the 10 knot direct crosswind was enough to have me take notice. I kept her on the grass runway, and no problems. When We had to fly to the pavement to get gas, I flew. Once back on the grass, I had fun with one wheel landings, though not with the wing as low as I had in the 150.

So, I like grass runways, and wet if possible, for crosswind flying. If not, like parallel parking into a tight spot, I'll deal with what the circumstances offer me....

[India Four Two]

jabba pilot (if you are still here after five pages),

I would like to make an observation which may help you.

By way of background, I should say that I was trained (in England) to make a crabbed approach and then "kick off the drift" after flaring. I never felt comfortable with it, but our cross wind limits were so low, that there was never really a problem.

When I came to Canada, I was introduced to transitioning from the crabbed approach to wing-down in the flare. It took me a while to get used to, but now I wouldn't do a crosswind landing any other way.

I feel very comfortable landing single-engined aircraft in cross-winds up to the demonstrated speed and for ones that I am very familiar with, in crosswinds in excess of that value.

So after that long-winded introduction, the observation I wanted to make is that you have to get comfortable with the idea that you are planning to land on one main wheel, rather than rushing to get both mains on the ground as soon as possible.

Step Turn's photo of his 150's wingtip just above the ice is an extreme case, but it clearly illustrates the fact that rolling along on one mainwheel is easily managed.

A related point is that doing a slipping approach can be very disconcerting or even scary for non-pilot passengers. Ask me how I know!

[Heston]

I'm not the originator of this thought - I may even have seen it on pprune!


Its worth realising that all this discussion about crabbed vs slipping approaches is simply about WHEN you make the transition from crab to wing down. Look at it this way - when in the cruise we fly with the wings level compensating for the cross wind drift. In other words, crabbing. On landing, whatever we've done down the approach, if there is a cross wind then a good landing will involve some wing down with the controls crossed.


So somewhere in there we have made the transition from crabbing to wing down with crossed controls. On base leg? On long final? Half way down the final approach? Just before round-out? After round-out? It doesn't matter - do what works for you and the aeroplane.

[worrab]

...just don't try one-wheel landings with certain motor-gliders that spring to mind. "Kicking it straight" is the only way with a long, low wing unless the crosswind is negligible.

I really don't like the "Kicking it straight" phrase. It conveys the thought of an uncontrolled boot on the downwind rudder rather than the purposeful/thoughtful and possibly large shove that's needed.

[darkroomsource]

First understand, I am not disagreeing that a wet grass runway makes cross wind landings easier, especially in a tailwheel.

What I do wonder is this...
Is wet grass actually slipperier than dry grass?
The reason I ask is that it does require more runway to take off, and less to land on. And if I kick a football on wet grass it doesn't go as far as it does on dry grass.

So I wonder if it's not a case of the grass actually being "stickier" when wet which makes landing on wet grass better.

I'm not a physicist, and I didn't stay in a Holiday Inn express. So I could be talking out my ears.

[9 lives]

Is wet grass actually slipperier than dry grass?

Yes, grass will be more slippery when wet. I was once asked to ferry a 172 up to a friend following some brake maintenance. As I taxiied out along the wet grass runway, it seemed to be dragging just a little to the left. I looked down to notice that the left wheel was not turning. I considered the implication of this to my flight, knowing that both runways I would use were wet grass that morning. I took off with no fuss, and landed at my destination, stopping just short of the paved apron. The left wheel never turned at all (bolted shut by poor maintenance). My friend asked why I did not park it - I winked, and told him he'd soon figure it out!

Where grass can be a lower friction surface than pavement, it can still be higher drag too, just because it may be long. One condition does not necessarily equate to the other directly.

Understanding the friction characteristics of the "runway" you propose to use is important sometimes, but more so, if there is a crosswind. Casual pilots sometimes open the throttle for takeoff, with little apparent consideration for a crosswind (aileron down). On pavement, this may result in a bit of lurch at lift off, and a skipped mainwheel. On a low friction surface, you may have been blown laterally off the runway early in the takeoff roll, if you don't "fly" into the wind on takeoff.

You;ll read the expression: "Fly it from chock to chock". This very true concept applies very certainly to the effects of the wind while the aircraft is moving on the surface. As soon as you are moving, and until you stop, consider the affect of the wind on the aircraft, and the tools you have to maintain control - directional in particular. If your surface is: Grass, wet grass, snow, ice, or water, you have less to no tool in surface friction to assist you in maintaining directional control - so fly the plane!

You'll be amazed at the great effect of flight controls in maintaining control - even on the surface!

[thing]

I really don't like the "Kicking it straight" phrase.

I do. It's sort of rugged and punchy, gives me a warm glow.

[riverrock83]

So on this thread we've had Chuck tell us he illegally landed a DC3 sideways in the Arctic (i don't think a DC3 has auto land) and Step Turn tell us he happily flew an aircraft from the maintenance facility that did dodgy brake maintenance to another location rather than have that facility fix it (what else could they have broken?).
Not good examples for a student!

The issue with "kicking it straight" / aligning with the runway in the flare without also lowering a wing is momentum.
If you have an aircraft with lots of momentum (a large heavy beast) then it will continue to fly down the runway so it wont matter that you don't have your wing down to stop it drifting side ways.
If you are in a microlight with little momentum, as soon as you align with the runway, you will be blown sideways. As such - the lighter the aircraft, the more important it is that you get that wing down. Of course - the faster your approach speed, the more effective wing down is.

I normally align with the runway and get the wing down just below around 100 feet. My instructors showed me both techniques. I found that the crab to the flare method before aligning meant that everything happened very near touch down and so as an early student it would be hit and miss. I'd normally end up doing two approaches - first to get a feel for how much rudder / wing down was required, second to apply it. Making all those adjustments at 20 feet means the approach is no longer stable. Setting up early becomes safer until you are more experienced and can lower the height.

Of course - some aircraft are designed with twisting / castoring landing gear - but that is the minority. Most landing gear is not designed to handle side loads, so you need to go straight along the runway.


On the question about powered approaches - engines don't like being shock cooled, so you need power on to keep the engine warm. An extended period at idle when continuing at flying speed will damage an engine - then you wont have power as a choice! There is also the risk of carb heat - as previously mentioned, higher as the engine operates on lower power. When doing PFLs / Glide approaches, I've always been taught to "warm" the engine at least once during the descent.

Another reason for power is for the best short field performance, as others have said. Adding power allows you to fly on the back of the drag curve, lowering airspeed and so energy required to get rid off when landing. You need power applied to give you the energy to flare. eg - in my bulldog, we do power off approaches at 75 (that is best glide but it also gives energy to flare), normal approaches at 65 (small amount of power, power off at flare), short field at 55 (power on till touch down).

[Chuck Ellsworth]

So on this thread we've had Chuck tell us he illegally landed a DC3 sideways in the Arctic (i don't think a DC3 has auto land) and Step Turn tell us he happily flew an aircraft from the maintenance facility that did dodgy brake maintenance to another location rather than have that facility fix it (what else could they have broken?).
Not good examples for a student!

How was what I did illegal?

With no where else to go to land what would you have done?

And Step turn is able to make a decision on a ferry flight for maintenance in my opinion.

So once again riverrock83 what would you have done in the circumstance I found myself in the High Arctic at night with an unforecast sudden change in the weather?

[Jan Olieslagers]

engines don't like being shock cooled, so you need power on to keep the engine warm

This is the first serious argument PRO a powered approach in all this thread (or I should have missed some, but "it is non-standard" is not a serious argument to me).

It only, or at least mostly, applies to air-cooled engines, though. Which might explain why, in circles I frequent, where everybody and their dog fly behind a mixed-cooling Rotax 4-cylinder, powered approaches are frowned down upon.

[worrab]

A lovely thing about flying is that it really isn't "one size fits all". I suspect that were one to attempt a one-wheeled landing on say a Chevron it could well end in tears, but equally if it were kicked straight 100ft up one could easily end up in another county before reaching the threshold. On the other hand C150s will happily take any combination of crosswind techniques.

Similarly, in one aircraft a glide approach from the downwind is normal, in another a glide approach from the downwind is difficult and results in some fairly interesting attitudes. Maybe a more frequent use of glide approaches would improve PFLs/forced landings?