Keeping it straight down the centre
 

Hi all

About time I invented a topic of conversation, so...

I fly PA28's - low wing if you've forgotten := and mostly I think I'm doing ok, BUT when it comes to landing I seem to drift across the runway. I've been taught predominantely the crab approach (I recall being shown a slip, I don't recall trying it myself, and would be a bit nervous in case a gust caused me to scrape a wing).

What do you do to keep going down the centre (assuming not too hectic a cross-wind)?

Also, is my fear of wing scraping justified?

Ta
Richy

Just have a look at the wingtip on your PA28 next time you fly. Stand by it. Look at the distance between underside of wingtip and the ground. Now imagine the aircraft banking whilst maintaining contact with, lets say the port undercarriage. Now imagine how steep a bank angle would be neeeded to scrape a wing.
There's not a chance! I even doubt there would be sufficient aileron / rudder authority to enter a 'slip' (not merely back) at the low approach / touch down speeds.

Re maintaining the centre line, practise, practise, practise. Try practising on a long runway with clear centre line markings, so you don't have to worry about correct touchdown point for time being. It will come....!

I assume you're talking about staying on the centre line before you touch the ground, rather than after? The two problems are quite different but obviously related.

Wing-down is, IMHO, much much easier, but you must practice it with an instructor until you are happy with it. I find it easiest to start off crabbed. Then, at some stage (early on during final approach is easiest, but you can leave it later and later as you get more practice), use rudder to straighten the nose, and enough aileron to ensure you stay on the centre line.

The next bit should all happen sub-conciously, although it doesn't harm to know what's going on. As you get closer to the ground, the wind will become lighter and its direction will change. The lighter wind will probably mean you'll need less wing-down, although the change in direction might mean you need more. Then, as you start to round out, you'll slow down. This means that the wind will have more effect on you, and the controls will loose their effectiveness, so you'll need to increase the amount of aileron and rudder in order to keep the nose straight and keep the aircraft on the centre-line. Like I said, though, you won't be aware of this - you will just make some small control corrections instinctively to keep everything where it needs to be until the wheels are firmly on the ground. Scraping a wing, as Dude rightly points out, really isn't an issue at all.

I don't know if you have any plans to move onto other aircraft. If you move to a lighter aircraft, you will find that wing-low approaches become more and more important. The problem with the crabbed approach is that, after removing the crab, there is a small amount of time for the wind to begin to move you sideways. The lighter the aircraft, the more of a problem this is, and the more appropriate the wing-low approach becomes, although this is probably seriously over-simplified and you will learn what's best for each aircraft as you get to know the type.

Find a good instructor and spend an hour or two in a nice strong cross-wind!

FFF
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I've never flown a Pa28 however the following was drilled into me years ago and works in everything, I've flown from Beech KingAirs to Cubs:

use the rudder to align aircraft centreline with runway centre line

use aileron to arrest drift

it is generally acknowledged that you need to lower the into wind wing

go figure....



Stik

Thanks for the replies guys.

FFF: yes, there are two problems, one while still in the air, and one on the ground. I understand the ground problem (centering the rudder/steering helps :O ).

I have a lesson planned for this weekend, circuits strangely enough, so I'll get the instructor to kill yet another bird with that one over-worked stone.

RR

Stik,It's not quite that simple. Try landing a monowheel Europa with a wing lowered and see how long the outriggers last.

Airliners tend not to lower a wing. I've heard lots of reasons for this, ranging from discomfort for passengers in a slip, through to possibility of scraping the engine cowlings on the ground, but until I get to do a 737 type rating I don't know which is true. I think a lot of flying schools tend to teach students to fly like this because it prepares them for airliners. But for light aircraft, I believe that wing-low is generally better (noting the exceptions like the Europa). Like most things, I guess it has a load of pros and cons.

FFF
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RichyRich

Fellow PA28 amateur here.

If you're losing the line it's probably because, having got it right once, the relative cross-wind changes as you descend. I find that you have to concentrate really, really hard every second - until you get used to it.

I think of it as ....

Ailerons to put the nose of the aircraft on the runway centreline and keep it there.

Rudder to twist the fuselage so it is aligned with the runway.

But for every second you delay as it starts to get away from you it takes longer to get sorted out again.

15kts crosswind at 90 degs when visiting a short grass field last month, and no dragging a wingtip. But my "first time" pax was a little unnerved.

Now I believe that the PA28, unlike the Cessna, actually turns the nosewheel in the air as you use the rudder. So after mainwheel touchdown centre the rudder, as otherwise you start heading off the runway on getting the nosewheel down.

Please excuse my ignorance, I'm a newbie to flying a real plane.

I've had a couple of lessons in a Pa28 and both times I was allowed to do the line up. The first time there was quite a cross wind and it seemed very natural to use the rudder to cancel out the drift to remain on the centre line (runway has lovely white lines down the middle).

What are the advantages of using a wing down stlye?

Cheers

A couple of extra pointers:
[list=1][*]Be at the right speed. Some people have a tendency to add a few knots extra "for luck" in a crosswind. A PA28 will float if the speed is too high, and it's not easy to keep floating over the centre line as your speed decreases.[*]Treat your PA28 as though you were landing a taildragger - don't relax until the end of the landing roll. After landing, focus on a point at the end of the runway, and use the rudder to make sure you don't let yourself deviate left or right. (Most people seem to end up on the left side of the runway.... )[/list=1]

Something that really helped me when I was learning was a long session of circuits with an instructor at an airfield with a very narrow runway. Wide runways had let me get away with poor technique.

Why is this? I know I tend to be on the left, and instructors I've flown with or spoken to have told me that most pilots do, but I've never found a reason.

Logic would suggest that, being seated on the left, you'd try to get your seat over the centre-line, which would result in the aircraft actually being to the right of the centre-line - the opposite of what happens in practice. And I don't know about anyone else, but I tend to be on the left in tandem aircraft, too, so I don't think it's related to seating position.

Anyone got any ideas?

FFF
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I've got no clue....

There must be some explanation though. When I was learning to fly on skis, I was taught to apply a little right rudder as I flared to stop the plane drifting to the left after touchdown.

I can't explain it, but it works.

Mark139: the wing-down style will keep the centre of the plane lined up with the centre of the runway. A crab needs a kick to align the plane just before the main wheels touch down.

Therein lies my problem. I seem to mistime the 'kick' - too early, trying to get it 'out of the way', get the thing lined up and continue floating: off to the left. Interesting that 'most others' drift off to the left too: I thought it was just me :suspect: Perhaps something to do with torque...

Aerobatic Flyer: I think you're right about the wide runways and getting away with murder. Another of my problems. One day I'll try taildraggers, but first the aim is to finish getting my licence. Originally planned for before the end of summer: I seem to have missed that goal, so now 'Before the winter really sets in'...

Rich,

I think the natural tendancy to land to the left, and the drift caused by getting your "kick" in too early, are completely unrelated.

If the cross-wind is from the left and you kick too early, you will tend to drift to the right.

On the other hand, with no cross-wind at all, or with the wing-down method where there is no need for a kick (and so no possibility to time it wrong), lots of pilots will tend to land to the left of the centre line for no apparent reason.

Mark,

You asked:The big advantage is the lack of the "kick" which Rich has talked about. You actually land the aircraft with the into-wind wing low, one main wheel first then the other. The problem with the kick is that it has to be timed pretty much perfectly. You certainly don't want to get it late, in any aircraft. If you do it early, the lighter the aircraft, the more of a problem this will be, because once you've removed the crab, the aircraft will tend to get blown sideways by the cross-wind.

Aerobatic Flyer,

That's interesting. Never heard of it before - but it obviously works for you. I think, for me at least, the problem with being on the left happens before I flare. If I'm aware of it (and I try to always be aware of it, but I'd be lying if I claimed that I was aware of it most of the time!) I can actually catch myself lining up on final to the left of the centre-line, and I can correct it well before I reach the numbers.

FFF
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I think it's probably a subconscious thing because in this country we drive on the left and a runway with a centre-line looks a bit like a road.

Perhaps some of our non-UK readers confirm whether everyone lands on the right in other countries?

I was never allowed to get away with it by my instructor -- he'd want my eye-line crack on the centre-line, take-off or landing.

Mark

That's what I thought before I moved to France. But they do the same here.

Perhaps they all subconsciously want to be British?! :)

Please, someone tell me I'm not the only one who's getting confused by having a Mark139 and a Mark147 both posting on the same thread. This is even worse than Stick&Rudder and Stiknruda!

FFF
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The answer is simple............

On final approach use the crab method initially. It's easy to adjust for gusty conditions etc and a quick side slip from this configuration is easy to administer.

To try and flare from the crab is tricky as it is easy to kick the rudder too early or too late. The first causes drift over the numbers and the second might just cause your tyres to fall off your wheel rims.

So, as you pass over the numbers, convert your "crab" configuration to a wing down configuration. This will eliminate drift and also keep you tracking straight down the runway.

Too many people think it is wrong to touch down on one main wheel when they land. They are wrong. A perfect X-wind landing is executed by a soft touchdown on one main wheel and then the other mainwheel will naturally follow. As long as the nose wheel is lowered gently it has been a successful landing.

Try it, it works!

Monock, your last para is spot on.

I was taught on C150s to use either crab or wing-down on final approach as required, but then to convert at a sensible height to wing down, touch down first on the into-wind wheel (keeping straight with opposite rudder), and then hold the aileron input which will continue to keep the into-wind wing down until, and after, the other mainwheel has touched. Then nosewheel down as normal, but continue to hold the aileron input for the rest of the landing roll.

Totally avoids the problem of timing an accurate kick from the crab at low level.

Slip

Monocock/slipslider

I agree totally but with a tailwheel - it's a case as the first wheel contacts; slowly, gently increase forward stick with same aileron until elevator authority is insufficient, where upon the the other main followed by the tailwheel.


Stik

edited to read true!

Landing on the Left
 

Cheers guys, this is a comfort to me (as a relative newcomer).

Landing on the left seems to be associated with closing the throttle as that's when my drift always starts, even in nil wind.

The prop is normally offset so that it balances the torque at cruise power, and usually requires right rudder on take-off and some left rudder in descent. Therefore (and it's probably done automatically), most pilots probably fly final approach with a tiny amount of left rudder which then catches you out when the throttle is closed in the flare.

Does that help anyone explain it?