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-   -   Wing down during final approach. (https://www.pprune.org/private-flying/532972-wing-down-during-final-approach.html)

Chuck Ellsworth 29th Jan 2014 21:43

Wing down during final approach.
 
There are a lot of pilots who use the wing down sideslip method to keep their airplane tracking the runway center line on the final approach to landing.

Do they fly their cross country tracks using the wing down side slip method to maintain the desired track?

3 Point 29th Jan 2014 22:22

I shouldn't have thought so; what's your point???

Piper.Classique 29th Jan 2014 22:22

What is an appropriate technique for one phase of flight is not necessarily so for another.
In answer to your question as far as I am concerned, I sideslip on final in a crosswind. When flying crosscountry I fly the heading that will enable me to maintain my desired track. Or follow the motorway. Whatever.

Lord Spandex Masher 29th Jan 2014 22:38

I'd have thought that landing sideways (past a point anyway) is less desirable than flying sideways.

Chuck Ellsworth 29th Jan 2014 22:43


I shouldn't have thought so; what's your point???
My point is really quite simple.

I am trying to understand why anyone would cross control an airplane on final approach to correct for drift when you can fly wings level correcting for drift down to the landing flare.

In another thread I asked how many times you have been a passenger in a big jet and had to suffer through a wing down sideslip during the final approach?

These flying forums can be a great method to discuss how we are taught to fly airplanes, and side slipping down the final approach is one of the issues that I could never understand why it is taught.

Over the past sixty years I have never flown an airplane that could not be comfortably flown to the flare pointed into wind in a wings level attitude.....so why would I side slip down final approach...I just find that to be unorthodox.

Remember ... I am merely expressing my own opinion on this and trying to understand why so many other pilots choose to do it the hard way.

riverrock83 29th Jan 2014 23:01

How many times has this been asked on this forum?

Simple answer, is because wing down is easier to maintain stability right down to touching the ground.

Alternative is having to use a boot full of rudder at the last moment, then sudden use of aileron to stop the wind blowing you side ways when you straighten up.

Larger aircraft have more momentum, meaning they are less prone to being pushed sideways in the wind once you straighten. Also some large aircraft (737?) have twisting main wheels, so you don't have to straighten till you touch the ground.

jecuk 29th Jan 2014 23:30

What a strange question. Both ways work. Why does it matter which method is employed?

Chuck Ellsworth 30th Jan 2014 00:15


Simple answer, is because wing down is easier to maintain stability right down to touching the ground.
Objectively I find it to be more difficult to sideslip down final than fly controls neutral pointed into wind.....but of course you may find your method easier.


Alternative is having to use a boot full of rudder at the last moment, then sudden use of aileron to stop the wind blowing you side ways when you straighten up.
I have literally flown tens of thousands of approaches and never ever had any difficulty using rudder to align the airplane with the runway with co-ordinated into wind aileron as needed to land.


Larger aircraft have more momentum, meaning they are less prone to being pushed sideways in the wind once you straighten. Also some large aircraft (737?) have twisting main wheels, so you don't have to straighten till you touch the ground.
Yes, heavier aircraft have more inertia....light aircraft are designed so their flight controls will react in direct peroration to the airspeed they are deflected at to maintain control of all three axises.

And once again I have never ever flown any airplane that could not be landed using the crab/flare/ yaw the nose method for landing.

Speaking of twisting main wheels......

They are called X/ wind landing gear.

I clearly remember one approach and landing I did in a DC3 with X/wind gear on a narrow strip by Hudson Bay, the X/wind was really strong and I was crabbing about thirty degrees to the left to fly the center line and the X/wind gear worked so well I was able to touch down and roll out with the nose still pointed thirty degrees into wind....it was weird having to look so far to the right to see the runway to flare touch down and roll out..


What a strange question. Both ways work. Why does it matter which method is employed?
Why is my question strange?

Of course both ways work, in fact you could fly final approach inverted and roll upright just prior to the flare.....but any passenger would not feel comfortable......

glendalegoon 30th Jan 2014 00:49

really everyone, just try the crab and then straighten out just over the runway.

very few planes won't do this well.

Chuck Ellsworth 30th Jan 2014 00:59


really everyone, just try the crab and then straighten out just over the runway.
Eureka!!... Finally someone agrees with me. :O:O


very few planes won't do this well.
Exactly, there may be some back yard home built that may not have sufficient rudder effectiveness ( Authority for you younger uns. :E ) to yaw the airplane enough to align with the runway, but I have never seen a certified aircraft that did not have sufficient rudder effectiveness to use the crab/flare method for any crosswind landings that can be performed using the side slip method.

IFMU 30th Jan 2014 01:03

Chuck,
I learned to fly in a PA12. My instructor taught me to slip on final in a crosswind. As a student it was helpful for getting my head in the game. As a PPL I continued that technique, but I got lazier as I went. Lazy for me meant to crab rather than slip. I used to tow gliders, so I did a lot of landings. I never quite kicked it out at the last minute, used to do it 5' above the runway. But I find that as I am flying less lately that I will be in the slip sooner. It probably has something to do with comfort level. I have a good 34 years less than you and I am sure many thousands of hours less. Maybe my view would be the same if I had similar experience. I am not sure how you make the leap from slip on final to slip on cross country though.
Bryan

glendalegoon 30th Jan 2014 01:07

Yes CHUCK, I do agree with you .

Though I don't know you at all.

I've flown small planes and big planes and they all work just fine. CRAB, near the runway kick the rudder and put the other wing down.

I could spend hundreds of words explaining it in detail. But I won't.

One plane I flew, it seemed better to crab, put the wing down and THEN kick rudder. But it was sort of odd.

I use the word: KICK as a slang term for proper pressure on the rudder pedal.

Try it folks, it works, its how the big boys do it.

But you must learn your ways, the plane you are flying's ways and learn when to do it.

One poor guy was my copilot about 29 years ago. It was a regional turboprop. He had just come off B52s (which has crosswind gear). He used the wing low method from about a three mile final.

I let him do it.

He was exhausted by the time we got to the runway.

I spoke to him kindly and showed him the next day how the crab and straighten out method worked.

He thanked me. No one at the little airline had shown him. YET HE HAD BEEN FLYING ONE OF THE BIGGEST PLANES OUT THERE . He could have taught me how to fly the B52.

Hang in there Chuck. Let me know if I can be of any help.

TO the pilot who asked when you make the transition, I made the big leap of faith sometime around 150 hours. Well over 30 years ago.

You have to have faith in your ability to straighten out near the end. I just made up my mind one day to get her done. Just believe for one moment you can handle a plane like robert a bob hoover. and you can!

Chuck Ellsworth 30th Jan 2014 01:17


I am not sure how you make the leap from slip on final to slip on cross country though.
I was being facetious. :E

The PA12 was Pipers finest moment....just loved the thing.



Hang in there Chuck. Let me know if I can be of any help.
Thanks glendalegoon I appreciate your offer.......however I have been around Pprune for a long time and I have a skin thicker than a Florida Everglades alligator. :O

Also before I get myself into these back and forth discussions I am fairly certain that I can explain whatever position I take on the subject of airplane handling skills because that was how I earned my living in aviation.

And we don't want the forum to get boring.

Big Pistons Forever 30th Jan 2014 01:26

Both methods work, however I have found most pilots find it easier to side slip particularly for the high wing Cessna's. For the PPL I teach students to crab down to about 300 feet AGL and then transition to a wing down sideslip. This gives them enough time to get things stabilized prior to the flare.

As they gain experience they can delay the transition to lower altitudes until they can carry the crab right into the flare rolling the into wind wing down while simultaneously using the rudder to align the aircraft with the runway. Done well this provides a very graceful smooth touchdown.

foxmoth 30th Jan 2014 01:40


really everyone, just try the crab and then straighten out just over the runway.

very few planes won't do this well.
I could just as easily say "really everyone, just try the wing down, no need to worry about getting your timing wrong, you just keep it aligned with the runway:rolleyes:" and to me that is the best thing, at ALL times the aircraft is pointing straight down the runway. I can do both, but certainly on a Tailwheel prefer wing down - though for comfort or nervous pax may just transfer from crab to wing down in the flare as per BPFs post.

I note also that this is ACTUALLY what you are doing yourself

and put the other wing down
:cool: rather than a true crab approach where you just kick straight and keep wings level hoping you have timed it right, but even this to me is not as good for a newish pilot as setting up the wing down at say 300', because you are then making a lot of changes at very low level.

India Four Two 30th Jan 2014 01:47


in fact you could fly final approach inverted and roll upright just prior to the flare
It can be done, but you need to be quick-thinking and very skilled!

Zlin wing Structural Failure Report - Neil Williams

Extract from the report which is a must read:

A slow inverted flare was made and the aircraft was levelled as near to the ground as possible.
Low, low rollout
As the speed fell to 87 m.p.h., 140 k.p.h. a full aileron rollout was made to the right, and just a trace of negative G was maintained in order to hold the left wing in place. The aircraft responded well to the controls at this stage, but as it approached level flight the left wing started to fold up again. The nose was already down as a result of the slight negative G, and subsequent examination of the impact marks showed that the left wing tip touched the ground during the roll, although this could not be felt inside the aircraft. As the wing folded the aircraft hit the ground hard in a slight nose down, left bank attitude. I released the controls and concentrated on trying to roll into a ball, knees and feet pulled up and in, and head down protected by arms. I had a blurred impression of the world going past the windscreen sideways and then with a final jolt, everything stopped.
http://www.pcbdesign007.com/articlefiles/69913-zlin.gif

Desert185 30th Jan 2014 04:52

One more vote for crab on final. Never liked the slip method in a light aircraft, and it just isn't done on a large aircraft...at least none that I have flown.

If making a coupled approach, the autopilot will crab, not slip (and glideslope is pitch, not power). Why manually fly it differently? To each his own, I guess, but slipping isn't what I teach or practice.

Andy_P 30th Jan 2014 05:20

I am just learning to fly crosswind, we crab pretty much until just before the flare (or during flare), then side slip.

EDIT. Sometimes side slip earlier to lose speed though, but thats only when I cock up my final!

Cows getting bigger 30th Jan 2014 05:43

Some aircraft lend themselves to the slip (Pitts springs to mind).

I also find that some students have difficulty getting everything straight in the latter stages of the flare with the crab method.

Personally I don't mind other than the fact that the wing down can feel a little uncomfortable for passengers.

kharmael 30th Jan 2014 07:40

Why not just fly the cocked off down the slope, then at 2-300' adopt the wing down technique to land with the wheels and aircraft straight? You don't have to be wing down from the top of drop!? It provides more stability and control when landing on narrow strips in larger aircraft.

OP: With "tens of thousands of landings" I am sure that your sentence asking whether one flies x-country in the wing-down technique is facetious, at least I hope it is. :8


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