A dangerous habit i have noticed creep into my landings!
 

HI guys just posting this to see if anyone can offer any good tips or advice! I am a recent PPL obtainee pilot with just under 80 hours! The reason i am writing this is because i brought two of my friends up today on a local pleasure flight for their enjoyment and just for an all round spin! the problem is the whole flight went perfectly and everything was good and all but i bounced on two of my landings and hit slightly hard on the last full stop! my other two friends who have no knowledge of flying felt they were normal and didnt question at all but that little voice crept inside and said man you could have done way better than that!! I suppose i would be the type of pilot always reaching for perfectionism and things like that really annoy me for ages afterwards coz secretly your trying to impress i suppose! The aircraft is a c172 which i recently started flying again after a long period flying 152 for nearly 4 months weekly! I used to always get great satisfaction out of landing that! i shall set the scene and condition of todays flight! was landing westerly rwy 29 and the wind was 270@13 approach speed was acceptable i thought for conditions 60-65knots with 20degrees flap. normal approaches actually quite low on slope due to higher rpm we have to use on finals against flap drag to run in the new engine, anyway i approached round out height as usual and closed the throttle and allowed the plane to settle but heres where the fun starts float float float!! i then slightly lower the nose and allow it to bleed off as the plane lowers more and slows my natural tendency is to pull back on the stick and increase the angle just before i notice it touches but then it feels like time has stood still until the dreaded bounce just one small one though,i have noticed however that i lose sight of the end of the rwy:bored: during this last flare before touchdown and im guessing thats a problem i must eradicate! why does it land hard if at the slowest and lowest height prior to the wheels actually touching the tarmac and i apply a fair bit of increased angle of attack! at least the stall warners went off on all the landings plus the last one was a bit hard but she landed on the mains first before i lowered the nose anyhow but i am desperate need of a greaser sometime soon!! Advice please!! thanks everyone!:ok:

Are you fairly short? I ask because unless the nose up angle is extreme, you shouldn't be losing sight of the end of the runway in the flare.
Also, this doesn't make much sense to me.
While a new engine might be a little tight, it won't be noticeable to the pilot.
Why not fly at the normal approach angle that you've been taught to use? At the flap setting you would normally use?
The 172's flaps are rather effective. Especially the last setting if you are in an older 172, which gives a very draggy 40 degrees. Once you flare with full flap, (if the speed is in the range you've indicated) it won't float for long.
You should really be asking your instructor for tips. And maybe practicing the landings. Once you've got them "nailed", you can start introducing variations, like a different approach angle, different flap settings/speeds etc.
Personally, in light winds, I've found 61 on short final, 55 (or less) over the fence, full flap, and just a hint of power - about 1500 - until the flare, works quite well.
[edit]
PS regarding the thread title, this isn't really dangerous, unless you are flying a very shallow approach slope. (A shallow slope will be (a) closer to the ground than necessary, and (b) might not afford a good option if the engine quits on final.)
Don't be too alarmed. It's probably just ongoing practice needed.

Your quoted approach speed sounds OK but on the other hand extended float followed by bounces suggests excess speed. On most light singles 10 knots above the bottom of the white arc usually works as a "last look" speed before touch down.

Whatever, don't get paranoid about it. Some days just nothing goes right for no apparent reason....next time will be just fine ;)

I almost never land a C-172 with 20 flap. As you have seen, any extra speed and it will float.

How long were you up with your friends? If you've burned off 2-3 hours of gas, your weight is down and a few kt. less approach speed is called for.

When I was checked out in the C-172 some decades ago, I was advised 50 kt. over the fence. That was with 20 flap.

A good practice (first few times with an instructor please) is simulated engine failure on the downwind, keep a tight circuit and increase flaps to 40 once the runway is made. In this case 50 kt over the fence is not a good idea -- 60-65 will give you what you need to round out. With 40 flaps, the extra knots go away quite quickly in the flare.

In the flare, I use peripheral vision to see exactly how high I am over the runway. Pavement or grass texture is a good clue. In many types you can see where the mainwheels are.

Hi,

grab an instructor familiar with the aircraft type and spend enough time in the circuit until you are both happy.

Money well spent.

Rgds.

EIJ,

It's been a while since I flew a 172 with anyone in the back, but I am wondering if the fact that the CG was further aft, causing reduced stability, might have had anything to do with your problems.

I also agree with the comments about speed. Try slowing down. In light winds, I use 55kt on final and 50kt over the fence.

Don't agonize too much about it - just keep practicing.

Landing tip
 

echoindiajuliet,

Hi! Don't worry too much, this is a common problem.

Here is your answer:

The book says: 55 over the numbers with 30 degrees of flap (50 for short field and 40 degrees of flap - older models)

Good thinking on your part about adding a speed increment for wind. The rule of thumb for light aircraft is this:

For any headwind component above 10 knots, add one quarter of the headwind component plus all of the gust up to a maximum additional 20 knots. For example in your case; the headwind component is about 12, so a 1/4 of that is 3. 55+3 = 58 knots over the numbers target speed (63 knots approach speed ( 58+5).

Therefore your choice of approach speed (without any form of calculation) was bang on for the conditions, you simply needed more flap.

Lets say on another day the wind is gusting, then what? Amending your example 270/13G19. The headwind component of the gust value is about 5. So your new over the numbers target speed becomes 63 knots. (1/4 of 12 = 3 + all of the gust (5) = 8.

55 + 8 = 63.

This wind increment rule of thumb works for all light aircraft.


I hope that is of some use.


Cheers.

L

I was advised simply to add half the gust factor. What's the reasoning behind making an allowance for the headwind component?

?!?!?
 

I think you'll find it's the transition between the two that's the problem: The 150 is more sensitive in pitch, and has shorter legs - I suspect your flare judgement is a smidge off, you'll get it dialled.

Have to confess it's never occurred to me to land with less than full flap though - I'm a little puzzled as to what the purpose in that is.

Lembrado,

Do I understand you correctly that the head wind correction you apply refers to the approach speed, and meant to be bled off when on short final?

In that case, I can see it making sense; the wind typically increasing with altitude, means the headwind component will likely reduce on final, resulting in a reduction of airspeed for a constant ground speed. Without the head wind correction, you'd need to speed up (ground speed wise) on short final to prevent air speed from dropping. With the correction, airspeed will bleed itself off as the headwind reduces.

(C.f. GS MINI on the Airbii...) :8

Perhaps worth recalling though that there are many different C172 variants out there... The "proper" (by the book) speed before wind corrections could be as high as 69 kts for a flaps up landing in a heavy C172S... Might not wanna try that at 50 kts! :ok:

PompeyPaul, had a good night out? :}

In my view, based on some bitter experience, if ever you feel the need to lower the nose after beginning the flare, recognise that it has gone wrong and have an escape plan. This plan will probably include the application of some power, to cushion the impact, or to go around.

Soay

Adding an arbitrary half the gust value for any direction of wind is meaningless. I only have a basic understanding of aerodynamics, but any factor has to be in relation to what the wing experiences. In this case a headwind component, so that is the value one must consider.



bjornhall

The increment value is to the 'over the numbers' speed. The rest of your explanation fits - the whole reason for an increment is the loss of performance sheer close to the ground.

(I read somewhere that on the airbus the auto throttle goes into a very neat ground speed mode - way beyond me!) Anyway, off topic.


The point of this formula is ease of use in the air and an interesting discussion on the ground.

Cheers.

L

I meant half the headwind component of the gust, just as you did. bjornhall's explanation of the reason for your 1.25 factor on the steady headwind component makes sense, so I'll try that out.

echoindiajuliet

You are 80 hours TT, still on the steep part of the learning curve, nothing to worry about - even 20,000 hour pilots have occasional landings they don't like, in fact credit yourself with good airmanship for being unhappy with a landing that didn't meet your own standards :ok:

Best thing to do is get an instructor for an hour and do some circuits; the extra, trained, pair of eyes will give you any feedback you need.

Mark 1234

In the UK, many schools teach intermediate flap settings for landing, e.g. I was taught 20 deg on the 150 and 25 on the PA28.

I don't agree with it, as I think pilot needs to be able to judge when to use full flap and when not to, e.g. some types in a tricky crosswind.

I agree with this. I was always told to imagine the control column was on a ratchet ...... once you start bringing it back approaching the flare ... don't be tempted to push it forward .... there-in lies nosewheel collapses and wheelbarrowing. If it's not working, use a little power as the man says, or go around.

Are you used to flying alone or with 2 fat mates in the back ? ;) ie. were you any heavier than usual, or perhaps with more weight aft?

I normally use 30 deg of flap and go for the steeper approach angle, unless it's gusty and then I'll use 20deg or less, but the perspective is a lot flatter.

Sometimes even use 40deg (but don't try sideslipping with 40deg flap) - at 40deg you come down like a brick (especially with floats ;) ).

Why not go up with an instructor and practice steep approaches and getting the flare right.

PS was your seat position raised or lowered or any different to normal?

PPS Good on you for starting the debate ... just be ready for 1001 opinions

Excess speed results in a float if you hold the airplane off until it stalls. Otherwise, excess speed means that you touch down at a higher speed.

Try to be configured for landing early, with your power set, and on-speed. A stable approach makes a good landing easier, whereas an unstable approach to landing increases your workload and causes variations for which you must account...it makes every landing different (and thus hard to be consistent).

Don't get caught in the habit of adding excess speeds for a few knots of wind. If you're talking strong gusts with windshear type conditions, then yes, add some speed. If you have a crosswind of several knots or a headwind of a few knots, leave it alone and simply fly the speed to which you're accustomed. Don't make your job any harder.

Try to hold a fairly constant power setting on approach, with only small, minor corrections as needed. Same for your approach angle.

You should be able to land with any flap setting and be comfortable. The greater the flap setting, however, the slower your approach speed can be, which makes your job easier.

Don't get in the mindset of not being able to relax back pressure, not being able to "push forward" or not being able to increase the rate at which you apply back pressure, as you land. Of course you'll need to do these things.

Personally, I prefer to trim up so I'm holding either neutral or a little forward pressure; all I need to do is relax as I land. A good rule of thumb as you make your final approach is to stop trimming as you reach your approach speed; trim until then, but stop once you're on speed. I prefer to trim a little more, so I have uptrim; it's an old habit from flying ag (crop dusting) which has the safety effect of causing the airplane to climb if I relax pressure on the stick or yoke.

The downside to having up-trim as you approach to land is that during a go-around (balked landing, missed approach, etc), then you're going to require substantial forward pressure on the controls. Some people don't like that. I do; I'd rather be holding forward pressure most of the time, than neutral or back pressure. That said, if you're on speed and trimmed up, you may need slight forward or back pressure during the landing, or you may simply elect to freeze the controls and wait for a ballooning effect to go away. Don't be in the mindset of not being able to relax back pressure, or even apply forward pressure on the controls; they're available for you to do whatever you need to do to make the airplane land. Just remember to apply just enough, and not too much control force, and to generally make small corrections, and make them early.

Remember, if you've got a big error, then a bigger correction, and a small error, a smaller correction. Always be prepared to go around. As the saying goes, "go-arounds are free."

I had similar issues on the C172 after a long hiatus in my flying (I flew mostly 152s for my PPL issue).

Anywho, with every landing I seem to get three or four for the price of one, hop skip and a jump everytime with varying degrees of severity - nothing dangerous but a bit embarassing with friends and I didn't enjoy the flying as much since the prospect of landing was always on my mind. The strangest thing was that I also flew a PA28 and Alarus at the same time, with absolutely no landing problems. I looked at everything - speed spot on etc and even got some friends flying with me to video the landing.

To cut a long story short, the problem was not my lack of skill it was in perception. When I retrained the instructor was all about the specific phases of "round out" and "flare", these work fine in the low wing aircraft since I find that these are specific phases, punctuated with a long old float in between. This didn't work for me in the 172 since I had trouble figuring out where the mystical line was between "round out" and "flare", so I would either land with too little nose up attitude or drop in from a few feet. My flare was pretty much what echoindiajuliet describes as a last desperate yank on the yoke as you feel the dreaded drop towards tarmac.

For me the solution came from recalling my initial training when I was just a young 'un: Don't think in these specific phases, make a smooth transition from descent at about the height of a double decker bus and try and fly level about 30cm off the surface of the runway. Look down the runway like you would driving down a motorway and if the nose gets in the way look off to the side. For me that's it - just fly 30cm above the runway and manipulate the controls (smoothly!) to maintain this. Since I've changed my mental picture, my landings has been hop-skip-jumpless, consistent and satifactory, plus I've got to enjoy the flight beforehand!

I can only say this works for me, but I hope this helps!

Cheers,

Gareth.

Many people (including me!) believe that the 152 is a lot more tolerant than the 172 of being landed too fast. Could be as simple as that.

I agree with SNS3Guppy that one should fly a consistent approach. I was taught to land flapless if in gusty wind conditions but seldom do. Some of my most gentle landings have been with a strong headwind - makes sense as the groundspeed is slower. Often a pleasant surprise after battling with turbulence on the approach.