Scary Landing / Confidence Takes It

[Tracey]

Going around in most certified airplanes with full flaps is a non issue in most conditions else it wouldn't be a certified airplane. See FAR Part 23 for all the rules (lots of our airplanes were certified under CAR3 but its pretty close).

If they didn't intend on you being able to use full flaps for landing they wouldn't have put them there.

Always best off to land with the least amount of energy, and the most drag, which means full flaps. We're flying -- not driving a race car.

Thanks for all of this. This is helpful, I'm learning a lot (and hijacking someone's thread-- sorry!).

 

[Henning]

I can only provide my thoughts on the subject-

• Less flaps-> stall speed higher, so the wings stop producing lift at a higher speed
• Because the wings stall at a higher speed, the wings stop producing lift so you won't 'float' down the runway.
• You're landing into the wind, so if the wind is strong, your ground speed isn't that high. I find very few direct crosswinds, probably because they design airports around weather patterns.
• Until you are on the ground, the control surfaces are more effective due to the greater air-flow.
• Landing a C-150 with 30° flaps in a 25 knot wind down the runway makes for a long final approach with a lot of throttle. Or your final looks something like a that of Harrier jet from the ground- as much vertical as horizontal movement. It's hard to see over the nose.

Here is the fallacy, in order to land at that speed, you will carry an even higher level of energy on final since you still need excess energy to give up to stop your descent. Since your kinetic energy (inertia) has increased at the square with your increase in speed you will need to carry geometrically more energy to give up which need is multiplied again by the lower lift of the wing clean. Now we're carrying geometrically more energy into the flare relative to what would be required with full flaps, and we carry that excess energy kinetically rather than producing our excess energy mechanically (which we can remove instantly with the throttle). To get rid of kinetic energy we use drag. Since you are clean and in ground effect now, your drag profile is extremely low you don't want to balloon or force the plane down, there are only 2 possibilities, you either float down the runway or put it into a quick extra slip to add drag. Most people consider that an added hazard, YMMV. So, now that we're done slipping or floating off that extra kinetic energy and the mains finally tag, we are still ABOVE the speed we touched down with full flaps and we have less ability to slow the plane than if we had full flaps down.

 

[Cap'n Jack]

A 172, it goes to 30 degrees of flaps, we dont' land with full flaps.

Please forgive me if I missed it, but why not? I'm pretty sure that under normal conditions, and not practicing for a flap failure or high winds, we pretty much would agree to use all the flaps.

 

[Tracey]

Tracey, I'm being very careful not to use the word "stupid". I don't like to criticize other's teaching until I understand the reasons for it.

It's not the way I was taught, or the way I was taught to teach it, but I'm not gonna call it dumb until I've walked a mile in your CFI's moccasins.

Maybe they want to keep us away from a higher stall speed?

 

[Tracey]

Please forgive me if I missed it, but why not? I'm pretty sure that under normal conditions, and not practicing for a flap failure or high winds, we pretty much would agree to use all the flaps.

I will ask my instructor. My guess is that they want us at a lower, not higher, stall speed? I'm not sure- but this is what my school teaches.

 

[Tracey]

there are only 2 possibilities, you either float down the runway or put it into a quick extra slip to add drag. Most people consider that an added hazard, YMMV. So, now that we're done slipping or floating off that extra kinetic energy and the mains finally tag, we are still ABOVE the speed we touched down with full flaps and we have less ability to slow the plane than if we had full flaps down.

Ok, THIS I get. And it makes sense.

Sorry for calling you Mr. Duct Tape.

 

[TMetzinger]

Maybe they want to keep us away from a higher stall speed?

No, more flaps equals LOWER stall speed. More flaps does mean somewhat "mushier" feeling in the controls at the few seconds before touchdown, and can mean a higher nose-up attitude on landing.

You might just ask "How come we short-field at 30 and normal at 20? Why don't we do every landing like a short-field landing?" And see what they say.

Regardless of what you hear here, you should fly the airplane the way your CFI and your DPE want it flown.

 

[Tracey]

No, more flaps equals LOWER stall speed. More flaps does mean somewhat "mushier" feeling in the controls at the few seconds before touchdown, and can mean a higher nose-up attitude on landing.

I probably shouldn't be posting when I'm tired. It's not pretty. Thanks Tim.

 

[wabower]

I am much more comfortable with your method.

Less flaps means more energy at touchdown - that's simple physics. More energy means higher brake and tire wear. More energy can also mean significantly greater energy in the event of an accident - the kinetic energy varies as the square of the speed.

Because of this, the airplane flying handbook recommends landing with full flaps at the lowest energy possible.

Now, I'm not saying your school is "WRONG" to teach normal landings with 20 degrees of flaps. That might be their starting point for students while they're getting comfortable with the airplane in the last foot of the approach. And since they teach you full flaps for a short field, they obviously do teach full flap landings.

I'd be interested in why they choose 20 degrees for a normal landing.

For comparison, we teach all landings with full flaps, and the difference between a "normal" and "short" landing is typically that the final approach leg is at 1.3 Vs0 for a normal landing and 1.2 Vs0 for a short-field landing.

 

[Cap'n Jack]

Here is the fallacy, in order to land at that speed, you will carry an even higher level of energy on final since you still need excess energy to give up to stop your descent. Since your kinetic energy (inertia) has increased has squared with your increase in speed you will need to carry geometrically more energy to give up which need is multiplied again by the lower lift of the wing clean. Now we're carrying geometrically more energy into the flare relative relative to what would be required with full flaps, and we carry that excess energy kinetically rather than producing our excess energy mechanically (which we can remove instantly with the throttle). To get rid of kinetic energy we use drag. Since you are clean and in ground effect now, your drag profile is extremely low you don't want to balloon or force the plane down, there are only 2 possibilities, you either float down the runway or put it into a quick extra slip to add drag. Most people consider that an added hazard, YMMV. So, now that we're done slipping or floating off that extra kinetic energy and the mains finally tag, we are still ABOVE the speed we touched down with full flaps and we have less ability to slow the plane than if we had full flaps down.

I don't recall having to do any of the stuff I've bolded. I'm not floating because the wing has stalled. Just because the wing is clean doesn't mean I'm landing at cruise speed! On a C172 or C150, the wings do exhibit ground effect but probably not to the extent as a low-wing plane.

 

[Everskyward]

Regardless of what you hear here, you should fly the airplane the way your CFI and your DPE want it flown.

Right, and after the checkride she can decide on her own or experiment with both techniques. In any case, pilots should be able to land with flaps varying from 0 to full before they get their private even if that's not what they normally use.

 

[wabower]

There's no rhyme nor reason to the methods, theories, superstitions and OWT's used by various schools, flight departments, CFI's, sages, soothsayers and sycophants. Nor is there much anybody else can do about it other than shrug their shoulders with palms extended upwards.

I will ask my instructor. My guess is that they want us at a lower, not higher, stall speed? I'm not sure- but this is what my school teaches.

 

[zaitcev]

Since your kinetic energy (inertia) has increased at the square with your increase in speed

Kinetic energy depends on ground speed. If you fly an ultralight head-on into 30 knot wind at 30 knots airspeed, it has zero kinetic energy. So if someone reduces the flaps and the corresponding increase in the stall speed is less than the wind (or wind increase over the wind in which he would be comfortable using full flaps), he still has less energy to dissipate in roundout and rollout.

 

[Henning]

All well and good; but see my comment re skill set above. Students bounce airplanes a lot harder and higher than old hands. Students are not quick on the power, they tend to "set it and forget it". It is a good idea for students to limit themselves to less than full flaps in a strong crosswind until their skills come up to where they are not behind the airplane.

In general my thoughts to any CFI that would post/say something like that (the people who know me will confirm I'd say it to their face as well lol) would go like: "Yeah?!? WHO'S FAULT!!!
This ticks me off. Teaching crap technique because you can't teach proper technique. Incompetence is not an excuse for not doing your job right; square up your act or quit. I don't care if it's risky, scary, hard or what, if you can't cut it with so many of your students that you just start them off on poor crutches, you need to quit the business because you are ripping people off and are damaging GA by running off good people. You are the problem with aviation, the lazy mediocre CFI."

 

[Henning]

A 172, it goes to 30 degrees of flaps, we dont' land with full flaps.

YHGTBSM!!!! HOLY F- The chief instructor goes for this?

 

[Cap'n Jack]

Here is the fallacy, in order to land at that speed, you will carry an even higher level of energy on final since you still need excess energy to give up to stop your descent. Since your kinetic energy (inertia) has increased at the square with your increase in speed you will need to carry geometrically more energy to give up which need is multiplied again by the lower lift of the wing clean. Now we're carrying geometrically more energy into the flare relative to what would be required with full flaps, and we carry that excess energy kinetically rather than producing our excess energy mechanically (which we can remove instantly with the throttle). To get rid of kinetic energy we use drag. Since you are clean and in ground effect now, your drag profile is extremely low you don't want to balloon or force the plane down, there are only 2 possibilities, you either float down the runway or put it into a quick extra slip to add drag. Most people consider that an added hazard, YMMV. So, now that we're done slipping or floating off that extra kinetic energy and the mains finally tag, we are still ABOVE the speed we touched down with full flaps and we have less ability to slow the plane than if we had full flaps down.

I find that the earth does a good job of stopping my descent. The wing is generating the same lift as with the flaps down- enough to keep the plane in the air. There is no multiplication.

We're only talking 8 or 10 knots here- enough to noticably get better control but not that much faster then full-flaps landings. As this makes sense to do only in stronger winds (20 knots or higher), I'm still going to get stopped pretty quickly.

 

[Tracey]

YHGTBSM!!!! HOLY F- The chief instructor goes for this?

Apparently. I will ask them what their thinking is behind this.

Not sure what YHGTBSM stands for, but I can sort of guess.

 

[Henning]

Kinetic energy depends on ground speed. If you fly an ultralight head-on into 30 knot wind at 30 knots airspeed, it has zero kinetic energy. So if someone reduces the flaps and the corresponding increase in the stall speed is less than the wind (or wind increase over the wind in which he would be comfortable using full flaps), he still has less energy to dissipate in roundout and rollout.

Correct, now apply the equation to a 152+. How many students are flying in winds (headwind component only mind you) higher than their stall speed?

 

[TMetzinger]

YHGTBSM!!!! HOLY F- The chief instructor goes for this?

Again, what we know is that they are teaching a student to use 20 degrees of flaps for normal landings AT THIS POINT in her training. No need to go ballistic because it's different than you or I might do it.

Let's wait and see what (if anything) changes as her training progresses.

 

[Tracey]

Let's wait and see what (if anything) changes as her training progresses.

My guess-- and I could be wrong-- is that not much will change since I've begun the xc phase. I will ask though, and report back.

 

[Henning]

Again, what we know is that they are teaching a student to use 20 degrees of flaps for normal landings AT THIS POINT in her training. No need to go ballistic because it's different than you or I might do it.

Let's wait and see what (if anything) changes as her training progresses.

Do you think this has nothing to do with the ratio of training hours to certificate? WTF happenned to the FOI, doesn't it say something about "The Law of Primacy?" She should have never been introduced to the idea that flaps 20 is normal because she is being taught incorrectly as per the AFM and FAA guidance. They are teaching dangerous technique flaunting all instructions from the FAA to teach them the technique listed in the AFM.

This is Bull****.

 

[denverpilot]

Yes. on bigger airplanes like the 182, you can get even more aggressive pitch-ups, but you just need to be ready for it. Trim is your friend.

+1

 

[Captain]

When it comes to gusty winds less flaps has a place.

Less flaps mean more airflow over the control surfaces and that means more control. It MIGHT mean a higher touch down speed, but not always. Remember, the reason we're coming in with partial flaps is because the 'winds a'blowin' right? Well I'd like to think we're landing with a head wind...so that extra 10 or 15 knots might well be negated by the wind resulting in the same ground speed upon touch down.

Many POH's and AFM's recommend less than full flaps for high winds or high gust factors. I've never heard of a 'normal partial flap' landing technique however.

 

[Captain]

You're missing a few things and making the situation more dangerous than it has to be. You can still fly the higher speed if you desire with full flaps in by just adding some throttle, and when you do that, you'll find that the increased prop wash across the tail Not always, a T tail for example negates this.will give you even greater control authority increase (and more stability as well) at a lower speed than you were landing at with O-10 flaps in. Next is slowing down. With flaps 10 and the extra speed you've got way more lift going on with little increase in drag which means you you are light on your wheels longer which reduces your braking effectiveness and increases your susceptibility to being blown off the runway and at a greater speed. I disagree, having velocity means you have the means to counter being 'blown off the runway'. The wings always stop flying first. With flaps up that is even more true. Having the excess speed of a partial flap landing means the ailerons, elevator and rudder are in play that much loner.You are also risking floating, ballooning, porpoising and all those other fun bouncy things that in a strong crosswind puts planes on their backs in the grass. Since kinetic energy (the stuff that causes damage and death) increases with the square of speed, any thing that goes wrong will have a much larger portion of damage that comes with it.Nothing wrong here. I say, "don't do ANY of that.

With full flaps you can add throttle using mechanical energy is that a term?to maintain your control and then pull it as soon as your mains touch and you will stop flying and with full flaps, the drag added is greater than the lift added so it's helping you slow down from high speed rather than hindering you like 10* flaps does.

You use flaps to regulate lift, you use flaps to regulate drag, you DO NOT use flaps to regulate speed, you use pitch and power for that.

Sure, you don't use flaps to 'regulate speed'..but flaps DO set a baseline for speed. Flap setting determines stall speed and that determines ref. A higher ref speed means more air over the control surfaces (ailerons, elevator and rudder) and that means more control. When the winds tossing you around more control is better.

As far as the full flaps giving more drag than lift...that is true. However that is a true statement IN THE AIR. Once your on the ground you can FAR exceed the drag of the flaps by using the drag of the wings by using aerodynamic braking coupled with brake braking.

 

[Cap'n Jack]

My guess-- and I could be wrong-- is that not much will change since I've begun the xc phase. I will ask though, and report back.

Please ask.

Back to the partial flaps topic, it depends on the plane too. My Piper handbook shows maybe a 4 knot differential in stall speed between flaps up and down (just looking at the difference in starting point on their graphs). That means much less difference between the behavior of the aircraft with flaps up or down- better to land full flaps in these.

A C-150, C-152, or C-172 shows a much greater difference in stall speed (8 knots) between flaps up and down.

 

[jesse]

Again, what we know is that they are teaching a student to use 20 degrees of flaps for normal landings AT THIS POINT in her training. No need to go ballistic because it's different than you or I might do it.

Let's wait and see what (if anything) changes as her training progresses.

It makes no sense to teach someone incorrectly to start with. I expect my presolo students to land as well as the guy I just did a flight review for before they solo. I teach them the right way to start - much easier for them to comprehend.

 

[cowtowner]

Boy, I guess I shouldn't mention a flight school here in town that teaches their primary students to land with no flaps, and doesn't introduce their use until short/soft field landings.

 

[Threefingeredjack]

Sure, you don't use flaps to 'regulate speed'..but flaps DO set a baseline for speed. Flap setting determines stall speed and that determines ref. A higher ref speed means more air over the control surfaces (ailerons, elevator and rudder) and that means more control. When the winds tossing you around more control is better.

As far as the full flaps giving more drag than lift...that is true. However that is a true statement IN THE AIR. Once your on the ground you can FAR exceed the drag of the flaps by using the drag of the wings by using aerodynamic braking coupled with brake braking.

And the speed difference between full and no flaps on GA A/C isn't noticeable to most folks. It certainly isn't high enough to be "dangerous"

 

[Cap'n Jack]

And the speed difference between full and no flaps on GA A/C isn't noticeable to most folks. It certainly isn't high enough to be "dangerous"

Depends on the plane- the small Cessnas have an 8-10 knot difference and I feel that on the controls. The Piper Cherokee has a much smaller difference and less noticable. I agree that the speed difference isn't that dangerous.

 

[wabower]

Well, you can take comfort in the knowledge that it was taught that way in 1958. Flaps were only used when you screwed up and found yourself too high on final. But they were also teaching the use of hand-signals to indicate intention to turn in cars as well.

Boy, I guess I shouldn't mention a flight school here in town that teaches their primary students to land with no flaps, and doesn't introduce their use until short/soft field landings.

 

[azure]

If the plane is still airworthy, obstacles are not a factor, vis and ceiling are workable, and you have enough fuel for at least one more circuit, it's not too late. In other words, 99% of the time, it's not too late to go around. Even after you've touched down, it's not too late.

This is all true -- but you still have to make the decision before it's the 1% of the time that it really IS too late. I came within a few feet of doing that today at a field with just over 1700 feet of usable runway on 36, with a gusty crosswind that at a nearby field was reported as 290 at 15.

What happened is that even with airspeed control on short final that I was pretty proud of, the winds were crazy enough at the threshold that I floated for a bit. At that field I should have gone around right then. When the squirreliness subsided I thought I still had a chance, touched down and prepared to hit the brakes to get stopped. But I ended up skipping down the runway, and then the wind kicked up and I was airborne, with not enough distance to try to salvage the landing again. I fixated on trying to get the bounces under control. Big mistake, the dumbest thing I've done in a long time! And I had ALMOST backed myself into the corner of not having enough room and airspeed to clear the trees on the departure end of 36 when I went full throttle. Actually, it was too close for comfort and at one point on the climbout I saw that even with full power, I was headed into the branches. I pushed like crazy to gain airspeed (was briefly down to around 50 KIAS, well below Vx), but I think it was a lucky gust of wind or a thermal that gave me enough lift to clear the trees. That's the closest I've ever come to not clearing an obstacle on climbout, and it was quite a lesson in how important it is to stick to the planned abort point. No BS, no "I think this will work out". On that runway, passing the fuel pump at midfield, if not firmly down, it's go around, no exceptions.

 

[danhagan]

During the flare, I start getting blown off the the right as I guess I don't have my left wing down enough. Keep getting blown and then get the scared ****less feeling that this isn't going to end well. It hit the ground moving somewhat sideways and the tires screech.

On the way back, I had pretty much decided that I was done with flying.

Needless to say, my confidence took a real hit today.

Your brain knows what to do, it takes breaks occasionally under 100 hr mark. Keep working the controls to keep that nose on centerline, if you flare and sit waiting for touchdown, things are going to get ugly ... adjust ....adjust ... adjust.

It was a 172, Probably bit off a little more than I could chew. Lesson learned.

I think you bit off just the right amount ...

That point didn't come until very late, and I was only inches off the ground. I do remember the idea of doing a go around did flash through my mind, but I just felt like it was too late, if there is such a thing. I have done a go around in a similar situation before, but I was higher when the go around decision was made that time.

Switch to the 152 and a fat instructor. You can probably only take 11-14 gallons a fuel, but make sure you are at MTOW. Go in the pattern for 10-15 TNG's and have them tell YOU when they want the go around simulation. My instructor loved to call it after the mains were on and the nose was ready to settle on a hot day, and would hear him say," It's OK to settle back down to the runway for another touch during the go-around in an underpowered plane, just make sure your alignment is straight." Those anemic 100 ft/min climbs and super late go around calls helped a TON ... now I fly a Tiger and feel like I can bug out even easier whenever necessary.

I'm curious what the experts 'round here have to say about this... this is something that I can see myself doing as well (feeling like it's "too late" to do a go around when you're only inches above the ground).

Has anyone done a go-around when they were only inches above the ground? Is it recommended/not recommended?

See above, but do it with your CFI first.

Thanks for the comments folks. To make matters worse, there was a plane at the hold short line to takeoff after I landed, so I provided him some entertainment.

Nobody ever see the good ones ...

No, for a short field landing it's full flaps.

You've done a go-around with 40 degrees of flaps? I'm guessing that you hold it in a fairly level attitude until airspeed is high enough and you begin to show a positive rate of climb, and then begin to raise the flaps?

I've only forgotten flaps ONCE. 172 that could do 40* during an IR lesson post PPL on the missed (toggle control no detente) with foggles - learned to change my scan during the missed to include a little more than the 6 pack. Still climbed great with 40*, couldn't get airspeed above Vx though (wake up doofus Dan)

 

[david0tey]

I took a spur of the moment flight a couple of days ago just to get some pattern work in and the winds had a similar affect on me that morning. When I woke up, I checked the TAF and it was calling for 10 knot winds (not perfect for a newbie, but definitely something I can handle). When I got to the airport and checked the metar, it was saying 8knots for the wind. It looked like it was turning out to be a good day. Started up, tuned in the ATIS, and the winds were "010@11 gusting 14. This made me a little uneasy but I still knew I had been in worse conditions so I taxied on out. The ground controller then gives me an update as I am taxiing, "wind 360 @13 gusting 16"...I suppose this is where I should have called it a day but I didn't. Another problem was that runway 2/20 was closed and therefore I was going to be using runway 7 with a wind from 360 degrees. Took off, a little squirly but nothing I hadn't seen before. Then on downwind, the controller says to me, "runway 7 cleared for the option, wind 360 @ 16 gusting 22. What!? How did a forecasted wind of 10 knots turn into 22 knot gusts? I did 2 landings and said screw it, didnt feel comfortable at all. Has anyone had a TAF be so far off that it almost seemed dangerous? It makes me think there is something wrong with the way I am briefing my weather. Am i missing something or is this just one of those things?

 

[DutchessFlier]

Sorry to be late to all this....based on a reading of the OP first post, what happened to GO AROUND, GO AROUND, GO AROUND the moment you did not feel totally comfortable with how you were lined up on the initial approach?

Take a deep breath, you got back into the plane and flew home, that was great! You learned alot about yourself and the airplane as well. Get hold of a good instructor who can take you up in some 'relatively' gusty crosswinds and spend an hour or so in the pattern.

BTW we've ALL been where you have been.

 

[Funkeruski]

I actually went up with my CFI on Monday to the same airport. Winds were from 090 at 15 or so, for runway 14. Did better this time. Just got to concentrate on keep that upwind wing down with plenty of opposite rudder to keep the nose heading down the runway. Looking forward to more cross wind practice.

 

[N801BH]

I actually went up with my CFI on Monday to the same airport. Winds were from 090 at 15 or so, for runway 14. Did better this time. Just got to concentrate on keep that upwind wing down with plenty of opposite rudder to keep the nose heading down the runway. Looking forward to more cross wind practice.

That's the attitude..

 

[david0tey]

That's the attitude..

pun intended?

 

[N801BH]

pun intended?

No pun at all sir.... Funkeruski had a fear, and went out and addressed them with a CFI.... That is the sign of a great pilot..

 

[denverpilot]

Has anyone had a TAF be so far off that it almost seemed dangerous? It makes me think there is something wrong with the way I am briefing my weather. Am i missing something or is this just one of those things?

Nope. TAFs are an educated weather-guesser's best guess. Every weather-guesser has a bad day or three.

Try this sometime. Most local news is really just regurgitated NWS forecasts. Track for two weeks how many times they absolutely NAIL the forecast, including wind speed. Or just track it via a cheap NOAA All-Hazards radio.

The failure rate is close to 70% around here. If I had a failure rate that high in my day job, I'd be fired.

Granted, they have more variables to track...

Watch and see what they get wrong. It's often a few common things that they get lazy about and miss that was actually fairly predictable.

Forecasts are often totally wrong. AccuWeather predicted high winds here on Sunday. They arrived Monday and cranked up multiple wildfires. A full day off.

 

[wabower]

WX people often say they are pretty accurate at predicting what's going to happen, but they're never sure when.

Nope. TAFs are an educated weather-guesser's best guess. Every weather-guesser has a bad day or three.

Try this sometime. Most local news is really just regurgitated NWS forecasts. Track for two weeks how many times they absolutely NAIL the forecast, including wind speed. Or just track it via a cheap NOAA All-Hazards radio.

The failure rate is close to 70% around here. If I had a failure rate that high in my day job, I'd be fired.

Granted, they have more variables to track...

Watch and see what they get wrong. It's often a few common things that they get lazy about and miss that was actually fairly predictable.

Forecasts are often totally wrong. AccuWeather predicted high winds here on Sunday. They arrived Monday and cranked up multiple wildfires. A full day off.