Question : Why did I bounce my landings today ?

[schmoo]

Since the more experienced flyers seem to love the chance to show off their prowess, I have a question about my landings today.

Let me begin by telling you I am a low time PPL ( around 95 hours ). Although I rarely grease my landings, I have never had the pleasure of bouncing along the runway 3 or 4 times until today. My first landing attempt caught me off guard when the plane bounced a second time. Judging that it would be better to go around than nurse it down with some power, I did the go-around.

The second landing attempt was successful.....barely. Again the plane bounced twice, but after the second time I was ready for it and nursed it down with some power. But it was fugly as hell.

Since I am a newbie pilot, my pride is not hurt. But, I am a little perplexed that it never happened to me before this, especially when I have flown in much windier conditions than today. On my second attempt, I was determined to nail my approach speed and angle, and I feel like I did so. It felt like I would have bounced that plane all day.

I would expect that the factors leading to a bouncy landing are multiple, but here is some info to help focus your suggestions. I'm sure some of this info is unnecessary, but I'll include it all anyway:

- The plane I flew was a 172P, when I usually fly an R or S model. This was my first P model in almost a year.
- My first landing of the day was at an airport 1/2 hour away and it was fine. A bit on the hard side, but acceptable.
- The 172P trim wheel indicated that the plane needed a lot of nose down trim. Did not confirm whether the trim wheel was just over-indicating or whether that much extra trim was actually needed.
- On my return, I was told that the P model I was flying was actually an old float plane and had 180 hp engine, rather than 160 hp.
- One tire on the main gear was quite new while the other one had several flat spots
- winds were light and variable...might even say non-existent

I appreciate any and all suggestions.

[navajo_jay]

Hi schmoo,

Even after 4000hrs, I still get some crappy landings. So it's normal, don't worry about it. You will get some periods in your career where you nail all of your landing, and suddenly, it feels like you forgot how to land Maybe to much on the down time hehe!

Anyways, I think you bounce because when you think it's time to touch down, it's too early still. Try to hold your flare a little longer and look far ahead. Don't forget to chop the power when you are about to flare and keep the attitude towards the runway to keep your speed. When it's time to flare, remember slow flight. Same thing above the runway. You are the man and don't let the plane fly for you. Use that yoke and hold the attitude as long as you can and l'affaire est Ketchup!

Good luck!

[Rudy]

How was the weather? This time of year you're going to get a lot of thermal lift off of the runway surface from the intense sunlight. The lack of wind would support this theory.

[oldtimer]

Urban legend has it where an airline pilot made a rough landing. Standing in the doorway, a passenger remarked about the hard landing.
Captains reply "The Company allows 2 hard landings per year, this was my first".

[Big Pistons Forever]

If the airplane bounces you are almost certainly going too fast. One up anymore then 60 kts on final is excessive. I must say I am concerned that you don't know what engine is in the airplane you are flying. The engine mod will almost certainly have STC specific restrictions and special procedures, like for instance the use of the auxiliary fuel pump which is a common requirement for the 180 mod. In addition the 180 hp engine is heavier then the stock engine and many of these converted airplanes will be out of the forward C of G limit without some weight in the back. A too forward C of G will reduce elevator effectiveness in the flare and increase the posiability of a nose wheel first touch down and subsequent bounce. This is something that must be avoided as it is the precursor to a potential landing accident

[Cat Driver]

Schmoo, not actually being in the airplane with you and witnessing what caused the bounces it is difficult to advice you what you did wrong.

However one thing I can comment on, looking at the far end of the runway is not going to solve your problems.

Find someone like the Colonel in your local area and he/ she will be able to better advise you what you are doing wrong.


. E.

[lilflyboy262]

Too fast or flared too high!

I just blame it on my first officer

[bezerker]

I know its risky to comment without researching it to death behorehand. Yet here is a case where the bouys are all showing the lake surface wind is starting to go opposite to the 9AM landing direction. Headwind expected ... so its valuable information to expose invisible 10kt difference in smooth approach.


I don't care who you are, that there is funny.

[teacher]

Hold the nose at the attitude that you originally touched down at and let the aircraft settle back down on the runway. Fight the urge to lower the nose unless it's a really bad bounce or balloon, it just makes it worse and could lead to pilot induced oscillations. If it's a really bad bounce or balloon you can lower the nose slightly to prevent a continued climb but only enough to stop the climb, than repeat the flare when you begin to decend again. Add a little power if the decent rate becomes excessive. If you're about to stall after ballooning or bouncing execute a go around or stall recovery.

I used to tell my students to "reset your flare" by returning to the point just before you flared after you bounce or balloon than flare again. In most cases holding your attitude will bleed off any excess airspeed and let you settle back down on the runway. Again, it's hard to actually help without being next to you in the plane. The above worked for my students and still works for me now to prevent bouncing or ballooning.

[JDW]

maybe someone got a little overzealous in pumping up the tires. especially if you have flown underinflated recently, the extra springiness can take you by surprise

[Mach1]

This is just a guess as I was not there but, it is possible you were not flairing enough. You may have been touching down with the nose wheel first, causing a bounce. The various models of 172 all have slightly different seat positions/height relative to the glare shield. This would mean a different picture out the window than you might be used to seeing.

A suggestion that worked for me a long time ago... I stopped trying to land the airplane. I changed my thought pattern from worrying about the landing to flying the airplane as close to the ground as possible, as slow as possible without power. Eventually you run out of lift and because my thoughts were on flying rather than landing... the landing just happened. It is one of those old sayings about flying the airplane to the shutdown. Hence the crosswind controls while taxiing. In reality, you won't do anything different than you normally do, it is just a change in what you are focusing on as you fly the airplane. Note of caution: Don't run out of runway... go around if you have to.

[Duncan Idaho]

Some combination of too fast, too much power and looking at the runway in front of you instead of the runway at the end. All three will lead to hard landings/bounces/porpoising. Porpoising can definitely total the airplane so if you bounce just try to land again. Think to yourself, new landing. Some people don't think the first one is over yet and instead, let the airplane rock and roll doing it's own thing.. that's when you need new parts and sheet metal technicians!

[Rowdy Burns]

However one thing I can comment on, looking at the far end of the runway is not going to solve your problems.

Although at least it's looking outside, I taught this way [incorrectly] many times. I find now that looking to the point where apparent motion ceases works best and for a variety of aircraft.

[Colonel Sanders]

It's hard to know for sure without being there, but ...

As BPF pointed out, likely it's excessive speed on final,
and as someone else pointed out, lift from the hot sun
on the pavement can make it worse.

Also, note that true airspeed increases with density altitude.
Not sure that's really your problem, but as altitude and
temperature increase, you will be going faster with the
same indicated airspeed. Something to remember.

One thing that can help with consistency of landings in
the 172 is to always use the same amout of flap, if at
all possible. If on one approach you are using no flap,
and the next approach you are using 40 flap, you're
going to have wildly different power settings on the glidepath
and very different flares, and that makes it really hard
on low-time pilots. Strive for a consistent approach
which should lead to a consistent flare which should
lead to a consistent touchdown and rollout.

I would suggest using at least 10 degrees of flap on the
172. You don't have to, but it gives you the majority of
your stall speed reduction, which allows you to touch down
at the slowest speed. Beyond 15 degrees or so, all you're
getting from flap is drag on approach which is necessary
over a steep obstacle to keep the speed down without
sideslipping.

Another issue I have with FTU airplanes is that the idle is
set too high on them! I have flown FTU 172's with the
idle set at almost 1000 RPM, which is insane. You wouldn't
believe the difference a couple hundred RPM makes in terms
of how long you float in the flare. AME's

What you want to do, is rapidly decelerate after you flare.

To do this, ensure that the power is all the way off. People
often make the mistake and leave the throttle a bit in. Even
a 1/4 inch makes a big difference.

Another thing you need to work on: NO FISHING FOR A GREASER!

I don't want to see you sawing back and forth on the control
column in the flare. Pilots love to try to induce oscillations into
airplanes with the flight controls, especially in pitch and yaw.

You do not land the airplane. You establish the aircraft in the
landing attitude - slightly nose high, NEVER TOUCH DOWN FIRST
ON THE NOSEWHEEL - at 6 inches to one foot with the power
off, and try to stop the aircraft from landing with progressively
more back yoke as the aircraft slows down. Keep the nose tire
one inch in the air. Touch down mains first.

What I tell students is to FREEZE THE CONTROLS when they get
the aircraft in the landing attitude at 6 inches. The less you do,
the better a landing you will get.

You think you have it bad ... watch this!

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

[Colonel Sanders]

The problem you have in a nosewheel trainer - floating
and bouncing along in the flare, not really flying, not
really landed - is a problem we have in spades with
tailwheel aircraft and training.

As a rough rule of thumb, 0 to 20 mph is taxiing.
Somewhere over 40 mph (type dependent obviously)
you can probably go flying IN GROUND EFFECT only.
So if you have a problem at 38 mph it is easily solved
with full throttle. As soon as you have an inch of daylight
between your tires and the pavement a tailwheel aircraft
is much, much easier to operate!

Between 20 and 40 mph is thusly what I refer to
as "the expensive speed" where things can go horribly
wrong in a tailwheel aircaft.

A landing in a tailwheel aircraft is not judged objectively
by how soft the touchdown is, your grandmother's
hemorrhoids notwithstanding.

The quality of a tailwheel aircraft landing is objectively
measured by the number of degrees of yaw angle
experienced after the tires touch the pavement. Ideally
it is zero - you touch down perfectly aligned with the
runway - and your direction of travel - and no wobbles
in yaw. Yeah, right.

The longer you spend in the "expensive speed" range
(20 to 40 mph) the more likely things are to go wrong.

I am a very lazy person. I like to give myself the easiest
possible problem to solve. The faster I can de-celerate
from 40 mph to 20 mph during the landing, the less time
there is for me to screw up. The same applies to your
porpoising in pitch in the 172.

It's important to remember that aircraft are truly horrible
ground vehicles. Their center of gravity is too high, gear
are too close together, tires are stolen from shopping carts, etc.

If I could put a drag chute on a light aircraft (think century
series fighter, or NHRA dragster) I would, but the paperwork
would be daunting, and the repacking would be boring.

The USN doesn't f__k around - they use four arresting cables
on their carriers with beefy hydraulic tailhooks on their airplanes.
Another nice idea, but not likely to happen at your local FTU,
and it leads to hideously politically incorrect parties in Vegas.

I will share you with a small secret that allows you to de-celerate
from 40 to 20 mph as fast as possible ...

First, set the idle speed low, and make sure you get the throttle
off all the way. As I said above, this makes an incredible difference
to how long you float.

Also, constant speed props have MUCH more drag than fixed pitch
props, because they go fine. This is especially true of 3-blade props.

If you combine the two ideas, sooner or later a crafty idea comes
to mind. Set the idle speed on your constant speed prop so low that
when you pull the throttle back all the way on the ground the engine
quits.

AME's are now honking and screeching and heading for the exits
with their hands over their ears.

But it works really well! I actually know of a fellow in Quebec that
used this trick on a 3-blade biplane he was operating on a very very
short strip. Unfortunately that same biplane, later doing aerobatics
over the water off Key West, had the prop stop during a hammerhead
which caused many bad words to be said in the cockpit. They got it
restarted, but I wanted to point out that there are problems with
this trick - it is NOT suitable for FTU's where AME's set the idle to
1000 RPM.

[cgzro]

Dont try to land ..try to stall at a few inches.
That way bounce is limited to what the gear tires can generate and not the wing.

[Colonel Sanders]

Dont try to land ..try to stall at a few inches

Good technique Peter, but technically I doubt many people
actually do a "full stall" landing. As they slow down in the
landing attitude, lift decreases and the aircraft descends.

Someone with an AOA could easily verify this. Just because
the stall warning horn goes off, doesn't mean you're actually
at or past the critical AOA - just getting close to it.

[CFR]

The technical points have been covered, how about some physiological ones.

Landing is a very intense few minutes requiring good concentration and hand, eye, feet coordination.

Bad night's sleep, were you tired? End of a long flight or a long work day? How did you feel, was your head in the game?

Did you take any stimulants (coffee, tea, cafinated soft drink, Red Bull [tm]). Big meal, no-meal. Any over the counter meds that might take the edge off.

What about environmental ones

Sun low in the sky or directly overhead (shadows)? Haze, smoke, cloud cover (affects the available light)? Dirty windshield, dirty glasses/sunglasses glare?

It seems my personal cause for a bounced landing is using the runway that can be seen from the school. The more likely it is that some one can see the landing, the worse it gets!

[schmoo]

The pyschological possiblities sound interesting, and could very well have played a factor. The thing is, although I was tired, I have been more tired. ALthough it was a warm day, I have flown in warmer. Coffee ? Oh yeah. Just came from breakfast at Hanover.

As I walked in from the ramp, I spoke with the next person who was renting the plane. I mentioned that I had a little trouble getting it down today. He countered by saying that he hated that particular plane. He had flown it a few days before and found it hard to control. He was another low time pilot however.

I appreciate all the replies.

[Colonel Sanders]

he hated that particular plane ... found it hard to control

Not sure I understand that. Some airplanes are heavier than
others (and rigged poorly) and fly slower, which is annoying.

Some airplanes have sloppy flight controls. Others have
bent landing gear with improper geometry. Some might
have empty dampers which allow for nosewheel shimmy.

All of the above is easily diagnosed and can be repaired
for varying amounts of cash.

But I have never met an individual aircraft which was for
holistic reasons, harder to control than others of the type.

Just came from breakfast at Hanover

There's your problem. Extremely bad karma. A place I
will never, ever visit ever again. Seriously. Too much
generational damage.

[black hole]

TOO much coffee !!!!

[Beefitarian]

Comment : Some mention too much speed.

Question : Why were you considering, "nursing it in with power."?

I'm thinking the two options are,
Go around.
or
Ease the throttle closed and bring the nose up to get rid of the excess speed.

[schmoo]

Comment : Some mention too much speed.

Question : Why were you considering, "nursing it in with power."?

I'm thinking the two options are,
Go around.
or
Ease the throttle closed and bring the nose up to get rid of the excess speed.

By the second bounce, I don't think speed was an issue as much as the vertical descent causing me to keep dropping onto the runway. I had the nose up so I figured my options were go-around or a bit of throttle to flatten it out and try to settle it down again. I swear that's what I have been told by every instructor who has signed me out.

[luzzbightyear]

I once had a (certain canadian carrier) captain tell us after his hard landing is was the asphalts' fault. Of course they made a little joke outta that one. Even in the majors they have bad landings and don't care to admit it.

[Pratt X 3]

Heard on Southwest Airlines just after a very hard landing in Salt Lake City: The flight attendant came on the intercom and said, "That was quite a bump and I know what ya'll are thinking. I'm here to tell you it wasn't the airline's fault, it wasn't the pilot's fault, it wasn't the flight attendants' fault.....it was the asphalt!"