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-   -   Judging height above runway. (https://www.pprune.org/private-flying/422151-judging-height-above-runway.html)

Chuck Ellsworth 25th Jul 2010 20:03

Judging height above runway.
 
Seeing as there are so many discussions about how to land an airplane, especially wheel landings in tail wheel airplanes it would be interesting to discuss the height above the runway we are able to accurately and consistently determine.

I will start by saying between six inches and one foot depending on the size of the airplane.

How about the rest of you?

Fuji Abound 25th Jul 2010 20:13

Hmmm, why do I get this funny feeling this will turn into a pi**ing competition. :confused:

Chuck Ellsworth 25th Jul 2010 20:25

Since when does judging height need to turn into a pi**ing competition?

Unless one is able to judge their height above the runway during the landing phase of the flight how can they fly safely?

Lister Noble 25th Jul 2010 20:47

How the hell can you tell?
If you know please tell me.

I reckon I fly just above the grass,then sometimes land with a bump,but blame it on the molehills;)

Chuck Ellsworth 25th Jul 2010 21:00


How the hell can you tell?
You judge height by the picture you are seeing.

When driving a car how do you judge your distance from other cars and any object near the road?

If you know please tell me
I will try...but first you need to tell me how you are judging your height during the latter stages of the landing.

You can PM me if you wish.

gasax 25th Jul 2010 21:35

Boys, boys!

In my usual aircraft I reckon 2 foot all the time and on a good day half that. Which given its general good behaviour is more than good enough to get a smooth arrival.

Put me in something taller/bigger/smaller/heavier and it gets more difficult. Probably 3 feet or so - and the need for a bit of playng with the power to ensure a soft arrival.

Viola 25th Jul 2010 22:14

I was taught to flare in a light aircraft when the 'green' of a grass airfield turns into individual blades of grass.

It depends on how good your eyesight is though!

kevmusic 25th Jul 2010 22:28

When it looks about right, to me......depending on which it is of the two types I currently fly - Tiger Moth or C152. To be frank, I have no idea what my hold-off height is, at my small level of experience. I do know that I generally get a smooth arrival (in the 3-point attitude :}) so whatever the height the seems to be, minus the distance from tyres to eyeline, is my hold-off height in inches. Simples! :)

Bigglesthefrog 26th Jul 2010 01:11

When I wore glasses I would very often find that I was flaring too high and dropping her on. Since having Laser surgery and therefore dispensing with all but reading glasses, my landings have improved out of all proportion.
I believe that this is because I now have a much better peripheral view than I had with glasses. This fits in with my old ex RAF flying instructor's advice, to look to the end of the runway and wait for the ground to come up in your peripheral vision and then keep her flying at that point until she lands herself.
I've never seen anything on the forum about the benefits of Laser surgery particularly associated with landing the aircraft, so I would be interested to hear from other pilots who have also undergone this procedure.

BTW.. I haven't typo'd the @ in LASER. For some reason it just comes up that way even though all the other "a" in the post come up normally. Strange eh:confused:

englishal 26th Jul 2010 06:13

I just do it...I have no idea how high in feet I am above the runway but it seem to work ok.

Genghis the Engineer 26th Jul 2010 07:06

utterly unscientific, but I'd guess that I generally estimate my correct roundout and flare heights to plus or minus about a quarter.

G

Lister Noble 26th Jul 2010 07:13

Chuck,thanks ,most of my landings are OK,(L4 Cub)so I suppose I'm at the right height when she stops flying.
I don't have any trouble landing ,just could not give you exact heights just before landing.
It would be interesting to have someone video my landings,so might ask a pal to do that for me.
Lister:)

Fuji Abound 26th Jul 2010 07:35


Since when does judging height need to turn into a pi**ing competition?
Chuck

I think it was the way you asked the question. I cant imagine anyone on here actually knows how far they are form the runway. You may have an idea, but without video footage it is no more or less than that.

There was a lengthy thread recently to which you contributed. I think we all agreed that in order to make a good landing you need a good sense of how close to the runway you are.

So I dont disagee it is important but if I say I reckon I can run an aircraft down a runway 2 foot above the ground I have no way of proving it is two foot so I am not sure what point you are seeking to make.

Robin400 26th Jul 2010 13:10

Using peripheral vision, round out when the runway edge widens sufficiently to tickle the bottom of your ears.
At night use runway edge lights.:)

Lister Noble 26th Jul 2010 13:15

Ears etc
 
Does that work on all runway widths?:)

Robin400 26th Jul 2010 13:35

Runway width
 
It seems to, maybe the width is your peripheral vision in relation to the ground.

gasax 26th Jul 2010 13:46

Well I'll argue about the runway width. I mainly fly from 'compact' runways and seem to need a differing set of references on something big or rather wide.

It it finding the point at which the flare needs to be maintained that I find more difficult. The best way seems to be to land to one side of the centreline and use those markings as a reference for height and then transfer to the runway end.

JW411 26th Jul 2010 14:18

Runway width matters a lot. If you are used to flaring whatever aircraft you happen to be flying on a standard 150 ft (46 m) wide runway then a 200 ft or 300 ft wide runway might just find you flaring a bit in the high side.

Indeed, a 100 ft wide runway (like the old Sharjah) can come as something of a surprise.

The very worst landing that I ever did took place at Francistown, Botswana on 14th Oct 1966 whilst in command of XN849 (one of Mrs Windsor's HS Argosys). None of us (apart from the Loadmaster) had ever been there before). We were told before take-off that there would be no one there to talk to us on the radio so, "look at the windsock and land".

We knew the Lat and Long and elevation of the airfield and that the main runway was something like 5,200 ft long. That was it.

I can remember on short finals remarking to my F/O that the runway was probably a lot longer - perhaps 7,500 ft.

That's when we entered the ground at speed.

The runway was indeed 5,200 ft long but it was only 60 ft wide!

Runway width matters a lot.

bookworm 26th Jul 2010 14:28


That's when we entered the ground at speed.
I call it "the Shoreham shock", which is even less comfortable than "the Filton flare, float, fall".

Chuck Ellsworth 26th Jul 2010 14:37

It is seven thirty in the morning and my caffeine level is still to low to function on a level sufficient to explain why judging height during a landing is of paramount importance.

So I will just say hello to the tribe and when I get in shape to face another day I shall come back and fully and clearly outline my thoughts on this subject and explain exactly how I teach accurate height judgment. :ok:

JW411 26th Jul 2010 14:56

So let us talk about grass.

In my "spare" time in the RAF, I helped run an RAFGSA Gliding Club (from 1963 until 1979). I was an instructor for most of those years and ended up as the CFI.

We had a USAF exchange officer (not aircrew) at one point who was a first class chap and was well ready to go solo but he simply could not get the hang of landing.

His instructor asked me to fly with him. The first landing was not good. When we got on to finals for the second time, I asked him if he could see the winch (which was about a mile away at the other end of the airfield). He said that he could so I told him to ignore everything else around him and try to hit the winch driver!

He did the nicest daisy cutter you have ever seen. Obviously, he was looking "too close".

I sent him solo.

So, open grass is different (not grass runways) and, I suspect, so is water.

P.S. If Nic.Van.V ex-USAF is reading this, we remember you with fondness!

2hotwot 26th Jul 2010 18:32

I find one of those long folding white sticks held out of the DV panel works well :)

FREDAcheck 26th Jul 2010 20:20

Six inches to a foot? I get it spot-on every time. Never had any trouble judging height above the runway. When I feel the bump I know I'm exactly at ground level.

FREDAcheck 26th Jul 2010 20:22

Anybody hear about David Blunkett parachute jumping? When he was asked how he could tell when he was getting close the ground he said: "It's easy: the dog's lead goes slack."

mary meagher 26th Jul 2010 20:29

Ah yes. And then there is the glassy water landing.

Lister Noble 26th Jul 2010 20:52

Width
 
I'm quite interested in this discussion.
The strip I fly from is probably about twice the width of the Cub.
Part hedge and ditch down one side and a standing crop the other ,or ploughed field depending on time of year.
Not a lot of time to do the "ears" system:}

kevmusic 26th Jul 2010 22:18

When I was gliding with 617 VGS from the Northern Grass at Manston, the runway width was the width of the field! Four gliders abreast in different states of readiness to launch. Now if only we could've had four winches............

ooops!! - thread drift to'unlikely formation take-offs'! Sorry!

Chuck Ellsworth 26th Jul 2010 23:29

The width of the runway has virtually nothing to do with how to judge your height above the landing surface right to touch down. ( Except glassy water of course which requires a specific technique. )

If width were an important factor then landing on snow covered lakes on skis or on same lake on floats judging height would be very difficult.

My intent here was to point out that the ability to accurately judge height right to touch down makes for far more accurate and safe landings.

Another factor we need to consider is agricultural pilots have to maintain a very accurate height during application runs, with some chemicals and crops the wheels are almost in the plants......so how do they judge height so accurately?

There is a big difference between being a barely acceptable pilot skills wise and being very accurate in all airplane handling realms.

It is not black magic, it just understanding the subject and becoming proficient.

And that starts with top quality instruction.

mary meagher 27th Jul 2010 08:08

Practice, practice. And look well ahead, as previous poster said.

In the training glider, I recommend beginning the flare at the height of the average elephant, or the view from the top front seat in a London bus.
And then gently and progressively moving the stick back, wait, back, wait,
wait, wait, until it settles like a gentle leaf upon the greensward.

Do not try this with a 747 captain in the front seat: prior demonstrations are required.

It flies 27th Jul 2010 08:16


I shall come back and fully and clearly outline my thoughts on this subject and explain exactly how I teach accurate height judgment

so how do they judge height so accurately?
O.k. Chuck, can you elaborate on this and explain to someone like me (student pilot, learning to fly on an Aeronca Champ at a 1250m x 30m asphalt runway) how I can become better at judging height at the flare?

What I do is look ahead to maintain direction and out of the corner of my eye look at the hangars/other sizeable objects to help judge height. I also try to remember the nose attitude from when I was on the ground to help with the three point landing. I have never done a wheel landing.

The Fenland Flyer 27th Jul 2010 09:50

As a low hours pilot judging height is something I'm still struggling with. It's judging the height to flare at that gives me problems as I often flare too early. What helps me is to think of the change in perspective, and the change from looking down at the runway to looking along it.
When I look along the runway rather than down at it I can't help but flare. For me waiting for the end of the runway to disappear from view as I look down it before starting to flare is the most helpful as it seems to work on all runway widths, but I suppose It won't work for a sloping runway :(

Chuck Ellsworth 27th Jul 2010 15:01


O.k. Chuck, can you elaborate on this and explain to someone like me (student pilot, learning to fly on an Aeronca Champ at a 1250m x 30m asphalt runway) how I can become better at judging height at the flare?
First find an instructor who understands how to teach landings.

That instructor will explain that during the final stage of the approach ( From around two hundred feet above the ground. ) you look at the point on the runway where you plan to flare the airplane from the approach attitude to the level attitude.

During this stage of the approach the instructor counts down the height from fifty feet to the point at which the flare is started.

( Approximately twenty feet in most little bug smashers. )

( And using ten foot segments to thirty feet then five foot segments to five feet above the runway, and then in one foot segments. )

From the flare point until wheel contact you shift your sight line ahead of the airplane looking down the runway to the point at which apparent movement ceases, which is about five hundred feet, looking to far down the runway will degrade your ability to accurately " SEE " your height above the runway.

You will learn to identify the picture you need to be seeing and thus learn what to look for as you arrive at the flare height above the runway.

I also video tape these lessons and use the tape as a teaching tool to better show the student where they should be looking at any given time,( I freeze the picture to better describe what they should be looking at. ) and also to have the student tell me where they were looking at that moment.

Generally they were looking to far ahead, which is why they were not able to accurately judge their height at that moment.

24Carrot 28th Jul 2010 00:09

It also occurs to me that how high you are is of historic interest only. Looking 500 ft ahead gives you about 5 seconds to do something about what you see there.

SoundBarrier 28th Jul 2010 00:37

In the flare....holding off.......<stall warning>.......<BADUNK>......and there's the ground.



sorry! :(

GOLF_BRAVO_ZULU 28th Jul 2010 00:55


Originally Posted by mary meagher
I recommend beginning the flare at the height of the average elephant, or the view from the top front seat in a London bus. And then gently and progressively moving the stick back, wait, back, wait, wait, wait, until it settles like a gentle leaf upon the greensward.

When I was learning to fly powered jobs, I had to forget everything I'd learned from flying Sedburghs and Cadet 3s. One of my gliding instructors said that I'd make a good flyingboat pilot. That's because my ex gliding instructor dad had coached me to fly on, just above stall and, as soon as the ground was felt, ease the stick forward and let the skid wind the speed off. It aint going to tip.

Remembering the view on the deck in a light/microlight machine isn't, to me, overly useful. In the hold off, the nose attitude is "up" and not that helpful; unless you've flown level for the last foot or so with no excess speed. A glance sideways is a big help (I've twice landed directly into a setting sun and sideways was the only place to look). Also, once your intended flare point has stopped drifting up and down the window and you know you're in, the end of the runway is the only point to concentrate on. Looking at your intended flare point approaching the flare just invites over control and a porpoise arrival.

For what it's worth; I learn from every flight.

It flies 28th Jul 2010 05:45

Thanks Chuck for the insight in your training method. I can imagine that after repeating this a number of times accuracy will improve.

I did not ask this because I have a lot of trouble flaring the aeroplane, but I would like to progress from being a 'barely acceptable pilot skills wise' to 'being very accurate in all airplane handling realms' someday. I will experiment with exactly where to look during the flare.

Thinking about this makes me wonder if you have a similar method to teach how to land consistently at a given spot on the runway?

Chuck Ellsworth 28th Jul 2010 14:43

Good morning it flies, I am pleased you want to become a more proficient pilot and would be even more pleased to help you succeed.

I see you live in Holland and that makes it quite simple to point you in the right direction.

Here is a link to Wings over Holland.

You go to Lelystad and ask for Bert.

You tell Bert I sent you and you want to learn how to become a proficient pilot.

PBY Flight Training - Chuck Ellsworth / Wings Over Holland

After you talk to Bert you will never again wonder about accepting the advice I am giving you. :ok:


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