floaty landings

[GeorgeC]

I'm a pre-solo student pilot with a dozen hours or so in the 172. For the last little while, I've been practicing right-handed patterns on a runway with no VASI. To further complicate things, it's been breezy of late, up to 14 gusting 20.

My C172 POH says that landings are okay with any flap setting. I have typically used 30° on normal approaches, but have subsequently tried 20°, 10°, and no flaps in windy conditions. The lower flap settings seem to make the plane a little more controllable and less prone to wallowing.

Things are getting easier every time I go up, but I am still prone to flaring prematurely (happens to everyone...), hesitating when it comes to chopping the throttle after I cross the runway threshold, and underestimating the power of ground effect.

That said, I'm still finding myself floating down the runway or ballooning out of ground effect. Are there other confounding factors I should be looking for, or is the wind just messing with me?

 

[Henning]

Nope, use full flaps and slow down your approach.

 

[ScottM]

Nope, use full flaps and slow down your approach.

What Henning said.

There really is no reason for a normal approach to not use full flaps. From what you describe it sound as though you are a little fast on the your final speed. With a 172 under 65 knots in a no wind situation will work well. Yes the plane handles a little different at slower speeds. If that is causing you some problem I suggest that it would be beneficial to work on some slow speed flight at altitude to get a better feel for the airplane.

It just takes practice.

 

[Ken Ibold]

Excessive float means you're going into the flare with excessive kinetic energy. Remember that kinetic energy is a function of the *square* of the speed.

 

[dmccormack]

"Float" = excess speed.

You have to lose that airspeed so that the airplane will continue to sink as you level off and increase back pressure.

Gusty winds in the 20s may require you to plant it on. If you're still learning the basics of lanidng you may want to schedule lessons early in the AM before the wind picks up.

 

[GeorgeC]

Under ordinary circumstances, 65 knots and 30° flaps work great. With the gusty winds this morning, though, I was coming in at 70 and clean.

 

[Ken Ibold]

Under ordinary circumstances, 65 knots and 30° flaps work great. With the gusty winds this morning, though, I was coming in at 70 and clean.

At what point are you beginning to decelerate from 70? You indicate chopping the power at the threshold. Are you keeping 70 to the threshold?

 

[ScottM]

Under ordinary circumstances, 65 knots and 30° flaps work great. With the gusty winds this morning, though, I was coming in at 70 and clean.

Why not 70 knots and 30 degrees flaps?

When thinking of your answer try to recall what flaps actually do. There are a couple of things, one of which is something that can help a lot of you are going a little too fast.

 

[azure]

A question (okay, 2 questions) for the OP: what is 1.3*Vso in a 172? And what is your gross weight when you're up with your instructor?

 

[Richard]

I'm a pre-solo student pilot with a dozen hours or so...

That said, I'm still finding myself floating down the runway or ballooning out of ground effect.

You shoulda been on the SWA flight I took PHX-SNA. That dude coulda logged 3 landings. I had to bite my tongue not to rub it in.

It's all about speed control.

 

[Richard]

Under ordinary circumstances, 65 knots and 30° flaps work great. With the gusty winds this morning, though, I was coming in at 70 and clean.

Lemme see if I get your thinking. You carried some speed for the gust factor and didn't use landing flaps because the POH advises not to in gusts?

As a private on my long cross country I made that mistake. I used about 4,000 feet to land a PA-38 Tomahawk. Winds were something like 22G35 with a 20 degree crosswind component. Live and learn.

 

[Henning]

You shoulda been on the SWA flight I took PHX-SNA. That dude coulda logged 3 landings. I had to bite my tongue not to rub it in.

It's all about speed control.

I just laugh, point and shake my head as I exit the plane... SWA stews are pretty good about vocalizing commentary on bad landings.

 

[GeorgeC]

A question (okay, 2 questions) for the OP: what is 1.3*Vso in a 172? And what is your gross weight when you're up with your instructor?

1.3 * Vso = 43 kts
1.3 * Vs = 57 kts

Gross weight would be around 2000 lbs with me, my instructor, and full tanks.

Lemme see if I get your thinking. You carried some speed for the gust factor and didn't use landing flaps because the POH advises not to in gusts?

Yes.

 

[tonycondon]

in my experience even 65 kts is too fast with full flaps in a 172 at typical training weights.

 

[Ted]

You're coming in too fast. Slow down. If it's 14G20, your gust component is only 6 kts, which isn't much. Carrying extra speed in isn't necessary, unless it happens to be a headwind and you're sick of watching the cars pass you on the highway.

 

[dmccormack]

I fly a Chief and it won't land until I'm under 35 MPH.

That's really, really slow, but what you learn is that excess speed is no help when you're trying to land.

I'll relay a thought from an experienced CFI: "Land with just enough energy to control the airplane. Anymore is excess and useless."

 

[whifferdill]

in my experience even 65 kts is too fast with full flaps in a 172 at typical training weights.

Yep, try the actual 1.3Vso mentioned...57kts with full flaps. That is plenty sufficient for a 172. You'll float even less if you fly a power-off approach, which also reduces your workload as you're rounding out. 172s are good gliders and have very little power-off descent rate, so don't be apprehensive about it. I know your CFI probably considers power-off approaches to be an "emergency" procedure, but that's a whole 'nuther subject and has been beaten to death plenty.

 

[Henning]

1.3 * Vso = 43 kts
1.3 * Vs = 57 kts

Gross weight would be around 2000 lbs with me, my instructor, and full tanks.



Yes.

So if 1.3Vs, which should be your speed on final from 200' on down, is 57kts at max gross (still not sure why you're staying clean, makes no sense), and you were a couple hundred pounds light which reduces the speed even more, what were you doing at 70? That's 15kts of excess speed you're carrying, and kinetic energy increases by the square of speed. Couple all that excess energy with a clean wing and yeah, you're gonna float for 1000'. If you had full flaps in you can reduce your energy by yet another 15 kts and be able to slow down a lot quicker in the flare.

Another issue, you say "chop the throttle over the runway" You should be able to chop the throttle 1/4 mile out. If you can't that means you are too low on final and you are flying too big of a pattern, and that is your instructors fault. When on downwind, the runway should be down off the side at a 45* angle. When you are abeam the threshold youshould start your descent. When the threshold gets 45* behind your shoulder is when you should be turning base. That means if you have a pattern altitude of 800', you shouldn't be offset from the runway more than 800' or 1000' for 1000'. You'll find you won't have to be carrying any power at all except to adjust for the wind. Toss in 10* of flaps when you start your descent, 20* when you roll out on base and 30 when you roll out on final. By the time you are at 200' you should have your speed stabilized at 45 kts and the threshold should be at a stable height about 2/3rds the way up your windshield. As soon as you notice the threshold moving up, add a bit of power. If you see it moving down, add a bit of slip.

There is absolutely no need to fly a 747 pattern in a 172, it's bad form. You're in a light small airplane, fly it like a light small airplane. If your instructor wants you to fly huge drag in patterns, find a different instructor. If tower asks you to extend downwind, then that's what you do, but default should always be a tight pattern.
Also remember Trim Trim Triim. every time you change anything, you're going to need to trim, all the way to the ground even. Use the trim to set your attitude, you only use the yoke to make momentary adjustments then you trim to neutral.

 

[GeorgeC]

My simulated engine outs have tended to be better than my power-on landings. One less thing to worry about, I suppose.

It looks like the wind will continue into this weekend, so I'll have ample opportunity to try to slow things down. On the upside, hopefully practicing in wind will make landing in calm conditions that much easier.

 

[Sticky1]

OH........land "floaties" not water "Floaties.....I don't know then....

 

[Henning]

My simulated engine outs have tended to be better than my power-on landings. One less thing to worry about, I suppose.

It looks like the wind will continue into this weekend, so I'll have ample opportunity to try to slow things down. On the upside, hopefully practicing in wind will make landing in calm conditions that much easier.

Wind makes things easier, it gives you something to work against and slows your ground speed.

 

[The Old Man]

On the upside, hopefully practicing in wind will make landing in calm conditions that much easier.

Not necessarily so.

You need to work in light winds with small gust factors until the sight picture is "burned" into your mind and muscle memory. Then when wind soes something weird to that picture, tour reaction is simply to correct the picture.

Edit: Note that I fly a Beech A23. The breed is terribly (notoruiously) unforgiving of sloppy speed control.

 

[whifferdill]

My simulated engine outs have tended to be better than my power-on landings.

Then stop thinking of them as "simulated engine outs"....and more like standard practice.

 

[GeorgeC]

So if 1.3Vs, which should be your speed on final from 200' on down, is 57kts at max gross (still not sure why you're staying clean, makes no sense), and you were a couple hundred pounds light which reduces the speed even more, what were you doing at 70?

65 kts is our normal approach speed (which, in retrospect, may be padded to keep us students from stalling) plus another 5 for gust factor. Clean because the AFH recommended it for gusty conditions. Perhaps I am being overly cautious, or I've spent more hours reading about flying than I've actually spent flying...

Another issue, you say "chop the throttle over the runway" You should be able to chop the throttle 1/4 mile out. If you can't that means you are too low on final and you are flying too big of a pattern

I'm guilty there. My instructor's patterns have been much tighter than mine. I'm getting more comfortable with making mine tighter and not being as low on final, but that will take more practice.

edit:

By the time you are at 200' you should have your speed stabilized at 45 kts and the threshold should be at a stable height about 2/3rds the way up your windshield. As soon as you notice the threshold moving up, add a bit of power. If you see it moving down, add a bit of slip.

Hadn't heard that 2/3 rule of thumb before, thanks. My sight picture looks like this:

www.youtube.com/watch?v=ZJzOr7dS9Zg

 

[Henning]

I'm guilty there. My instructor's patterns have been much tighter than mine. I'm getting more comfortable with making mine tighter and not being as low on final, but that will take more practice.

No, it will take more discipline. Technique takes practice, Form takes discipline. The issue you are having is a form issue, not technique. You have to pay attention and set it up right. Then the handling of it is simple. Once you have the basic down, then you can manipulate form.

 

[Henning]

Hadn't heard that 2/3 rule of thumb before, thanks. My sight picture looks like this:

www.youtube.com/watch?v=ZJzOr7dS9Zg

Not bad, but yeah way down the runway.

Here's a video a buddy shot when I took him on his first flight, and it's in a 172. It's a bit long, but I promise there's a landing there lol. It's not a great example because it's a big long pattern because of traffic so it's flat, plus it's a pretty good little crosswind, but what I want you to pay attention to is the stall horn and where it comes on, notice it comes on twice since I'm holding the downwind wheel off until it won't any more. This is in gusty winds 12-18kts with about a 45* crosswind and I'm landing with 40* of flaps.

http://www.youtube.com/watch?v=lFR0BKqTs6U

 

[GeorgeC]

Thanks. FWIW, those were with flaps 30, in calm wind. My pattern procedures are as you described earlier, except I'm at 85 kias on downwind, 75 on base, and 65 on final. My stall warning horn has rarely, if ever, sounded during flare.

Not bad, but yeah way down the runway.

 

[Henning]

Thanks. FWIW, those were with flaps 30, in calm wind. My pattern procedures are as you described earlier, except I'm at 85 kias on downwind, 75 on base, and 65 on final. My stall warning horn has rarely, if ever, sounded during flare.

You notice mine is chirping all the way on short final even before the flare? The stall hornstarts going off between 5-7 knots before stall, plenty of margin. The nice thing about a 172 stall horn is that it is an actual air powered reed horn so the note changes intensity the closer you get to stall. Just because it's chirping doesn't mean you have to panic. If it's chirping and the threshold is moving up in the window and you don't think you'll make the threshold, just add a touch of throttle. If you are on short final, the last 20'or so and it's not chirping, you're going too fast on a long dragged in approach like this. You only need that energy to arrest your descent. You only have to arrest your descent if you are descending. If you're dragging in, you have no descent rate to speak of so carrying the extra energy willmean you're going to float further. 1.3Vso is for a normal landing on final, not short final, and 1.2 Vso is for a short field. if 1.3 Vso is 43 knots, then what does that make 65, 1.9? Nearly twice your stall speed. How do you expect the plane to land at nearly twice the stall speed, plus you are trying to burn off that speed in Ground Effect where your drag is reduced. That's why you're ending up past the 1000' markers before touching down. SLOW WAY DOWN. I don't know who came up with 65 kts on final for a light 172 but it's wrong, 65 was a speed to use in the old 172s that were marked in Miles per hour which equates to 56 knots, and you only use that speed with a heavy plane. Also note, this was with a 12-18kt gusty cross wind and full flaps, 40* flaps at that. There was no issue with uncontrollably of the aircraft. The whole "Carry extra speed and don't use flaps" is all poppycock. The extra speed you carry is 1/2 the GUST value. 18-12=6 knot gust /2= 3 kts. If the stall horn is chirping in the lull, I'm perfect.

 

[Dan Thomas]

65 is too fast for a 172, and many folks will hold their speed until they flare three feet off the surface. Guaranteed to float. You should have the power coming off at 25 feet or so and lifting the nose to bleed off the speed before you get into ground effect, and a good flare will have the stall warning sounding shortly before touchdown. The horn is calibrated to sound 5 to 10 knots above the stall, and the stall is even lower in ground effect. Never hearing the horn means you're probably putting all three wheels on the surface at once, which risks a wheelbarrowing accident.

Many more airplanes get busted with excessive approach speed than with too little and stalling on final. Too much speed can cause wheelbarrowing (loss of directional control with the nosewheel on and the mains off), porpoising (broken nosegear and prop), ballooning (and stalling after ballooning well off the runway), and running off the runway end. Excessive speed is no guarantee of safety.

Dan

 

[GeorgeC]

The 172N POH says 55-65 kias flaps down approach speed; I don't understand the discrepancy between this figure and 1.3 Vso. Incidentally, Vso is 33 on my checklist, but is 41 in my POH.

 

[Jim Logajan]

The 172N POH says 55-65 kias flaps down approach speed; I don't understand the discrepancy between this figure and 1.3 Vso. Incidentally, Vso is 33 on my checklist, but is 41 in my POH.

33 is probably KIAS and 41 probably KCAS.

I tend to remember and use KIAS since that's what I'm dealing with in the cockpit - but I'm still a student myself so my advice has no depth of experience behind it.

 

[nosehair]

Here's a technique from the old days:

Go up and actually stall the airplane in power-off landing configuration(Vso), note the actual airspeed reading at the moment of stall on that day at at that weight, multiply the number by 1.3, and try a few approaches at the actual airspeed your airplane indicates best.

 

[Jim Logajan]

The 172N POH says 55-65 kias flaps down approach speed; I don't understand the discrepancy between this figure and 1.3 Vso. Incidentally, Vso is 33 on my checklist, but is 41 in my POH.

One other point - I would suggest you go with what the manufacturer's POH says for normal landing speed in KIAS - not 1.3 Vso in KIAS, KCAS, or Warp Time-Dilation calibrated speed. The latter is, I believe, a RULE OF THUMB ABSENT POH GUIDANCE.

Caveat again: I am just a student too. I expect I'll get beat up now by those who have advised 1.3 Vso!

 

[dmccormack]

One other point - I would suggest you go with what the manufacturer's POH says for normal landing speed in KIAS - not 1.3 Vso in KIAS, KCAS, or Warp Time-Dilation calibrated speed. The latter is, I believe, a RULE OF THUMB ABSENT POH GUIDANCE.

Caveat again: I am just a student too. I expect I'll get beat up now by those who have advised 1.3 Vso!

Where do you think the POH numbers come from?



Yeah -- 1.3 Vso at Max gross Weight, maybe?

 

[Henning]

One other point - I would suggest you go with what the manufacturer's POH says for normal landing speed in KIAS - not 1.3 Vso in KIAS, KCAS, or Warp Time-Dilation calibrated speed. The latter is, I believe, a RULE OF THUMB ABSENT POH GUIDANCE.

Caveat again: I am just a student too. I expect I'll get beat up now by those who have advised 1.3 Vso!

You have that backwards. POH doesn't adjust for weight except to give you a 10 knot range. In reality, after a while, you don't need to look at airspeed because you'll be able to feel it in the elevator resistance.

"If knowledge fails you, refer to the manual"

 

[Jim Logajan]

You have that backwards. POH doesn't adjust for weight except to give you a 10 knot range. In reality, after a while, you don't need to look at airspeed because you'll be able to feel it in the elevator resistance.

"If knowledge fails you, refer to the manual"

So I shouldn't trim out that elevator resistance so I don't become a slave of the POH? :wink2:

 

[dmccormack]

So I shouldn't trim out that elevator resistance so I don't become a slave of the POH? :wink2:

Why not? The airplane is designed with certain things in mind.

 

[Henning]

So I shouldn't trim out that elevator resistance so I don't become a slave of the POH? :wink2:

??? Try to make sense and not confuse other students...

 

[azure]

Something to keep in mind is, Vso is given in the book for max gross weight. You said you're about 2000 lbs with instructor, what is max gross? IIRC it's something like 2300. To account for the difference in weight, you need to adjust your target airspeed by the factor sqrt(2000/2300).

Actually by the book, 1.3*Vso adjusted for your weight comes in at about 53 KCAS. Now I don't know anyone who flies quite that slow on final in a 172, but I know that I didn't land the 172 I trained in very well until I slowed down to about 55-57 KIAS on final. (Flying the 150 I started in solo, I did my best landings ever coming in around 50 mph.) As lots of others have said, 65 kts in a 172 is too fast on short final unless you've got a whale of a gust factor.

 

[Henning]

Something to keep in mind is, Vso is given in the book for max gross weight. You said you're about 2000 lbs with instructor, what is max gross? IIRC it's something like 2300. To account for the difference in weight, you need to adjust your target airspeed by the factor sqrt(2000/2300).

Actually by the book, 1.3*Vso adjusted for your weight comes in at about 53 KCAS. Now I don't know anyone who flies quite that slow on final in a 172, but I know that I didn't land the 172 I trained in very well until I slowed down to about 55-57 KIAS on final. (Flying the 150 I started in solo, I did my best landings ever coming in around 50 mph.) As lots of others have said, 65 kts in a 172 is too fast on short final unless you've got a whale of a gust factor.

I do. When I did my checkout in the 172 I used in that video, on my first landing/lap I started my turn for the threshold abeam the numbers dumped in all the flaps and trimmed it to what turned out to be +/- 40KIAS all the way down and still had plenty of energy for the flare and I made the first turn off on 08 at Ft Lauderdale Exec. The instructor/owner who was checking me out said "screw this, I've got work to do, take me back to the hangar, you know how to fly."

Once you start flying the airplane instead of the numbers, your landings get much better. These aren't swept wing jets...