Help estimating altitude without altimeter?

[tstock]

Hi, as a beginner I am still a little rough at this. I've done 3
successful patterns with no altimeter, but today I failed one
miserably with my instructor. There were two issues which threw me
off. 1) we towed higher than the past attempts, and 2) instead of
entering the pattern at a familiar entry point, he had me circle
directly over the airport which made judging the angle a bit
difficult.

While we did eventually land safely, I failed miserably at setting up
the first pattern (way too high) and was forced to land on the
opposite runway (which left me way too low). A little scary but a
good learning experience... one I do not care to repeat anytime soon.

I know I should be looking for the landing strip to be about 30
degrees below the horizon. But how can I do this when circling
directly over the field looking down at it?

I made a second attempt and moved my circle so that the outermost edge
of the circle was where I would enter the downwind.. I succeeded this
time. Unfortunately we also only towed to 1500' AGL which left me
with a much smaller chance of messing things up... so I can't say I am
completely confident despite the success.

Are there any easy methods for estimating the angle from the horizon?
For example a fist at arms length is 10 degrees, but obviously I can't
hold my first at arms length through the canopy. The method I've
used is to wait until my aim point aligns with the outer most edge of
the air brakes. To measure 45 degrees I look directly over the top of
my shoulder... is there a better method?

Thanks
-tom

[Darryl Ramm]

On Oct 25, 8:51*pm, tstock > wrote:
> Hi, as a beginner I am still a little rough at this. *I've done 3
> successful patterns with no altimeter, but today I failed one
> miserably with my instructor. * There were two issues which threw me
> off. 1) *we towed higher than the past attempts, and 2) instead of
> entering the pattern at a familiar entry point, he had me circle
> directly over the airport which made judging the angle a bit
> difficult.
>
> While we did eventually land safely, I failed miserably at setting up
> the first pattern (way too high) and was forced to land on the
> opposite runway (which left me way too low). *A little scary but a
> good learning experience... one I do not care to repeat anytime soon.
>
> I know I should be looking for the landing strip to be about 30
> degrees below the horizon. *But how can I do this when circling
> directly over the field looking down at it?
>
> I made a second attempt and moved my circle so that the outermost edge
> of the circle was where I would enter the downwind.. I succeeded this
> time. *Unfortunately we also only towed to 1500' AGL which left me
> with a much smaller chance of messing things up... so I can't say I am
> completely confident despite the success.
>
> Are there any easy methods for estimating the angle from the horizon?
> For example a fist at arms length is 10 degrees, but obviously I can't
> hold my first at arms length through the canopy. * The method I've
> used is to wait until my aim point aligns with the outer most edge of
> the air brakes. *To measure 45 degrees I look directly over the top of
> my shoulder... *is there a better method?
>
> Thanks
> -tom

But but but...

You were flying with an instructor. Was this not addressed to your
satisfaction in the post-flight debrief? Its fresh in your mind then
and that's the time to get answers. Sorry but I cringe at these "where
was the instructor" questions on r.a.s.

If you are circling overhead you can use sized of common things (cars,
gliders, runway width (if known), runway markings, etc.) to judge
height. I think I saw some good slides on that once that Cindy
Brickner had.

But...You don't transition from just circling overhead to rolling out
on the runway. At some time you transition from that circle overhead
to picking up an the downwind or base or whatever leg and a relatively
steady state angle to the runway. Even if the whole approach is curved
your sight picture needs to transition from looking down to across at
that 30-45 degree picture. At that point if you look too high you
should be doing something about it, extend the leg, get on the
spoilers, slip, or all the above.

So you have at least two things to go over with the instructor.
Judging height from overhead and being on-top of altitude correction
in the pattern.

Darryl

[Darryl Ramm]

On Oct 25, 9:30*pm, Darryl Ramm > wrote:
> On Oct 25, 8:51*pm, tstock > wrote:
>
>
>
> > Hi, as a beginner I am still a little rough at this. *I've done 3
> > successful patterns with no altimeter, but today I failed one
> > miserably with my instructor. * There were two issues which threw me
> > off. 1) *we towed higher than the past attempts, and 2) instead of
> > entering the pattern at a familiar entry point, he had me circle
> > directly over the airport which made judging the angle a bit
> > difficult.
>
> > While we did eventually land safely, I failed miserably at setting up
> > the first pattern (way too high) and was forced to land on the
> > opposite runway (which left me way too low). *A little scary but a
> > good learning experience... one I do not care to repeat anytime soon.
>
> > I know I should be looking for the landing strip to be about 30
> > degrees below the horizon. *But how can I do this when circling
> > directly over the field looking down at it?
>
> > I made a second attempt and moved my circle so that the outermost edge
> > of the circle was where I would enter the downwind.. I succeeded this
> > time. *Unfortunately we also only towed to 1500' AGL which left me
> > with a much smaller chance of messing things up... so I can't say I am
> > completely confident despite the success.
>
> > Are there any easy methods for estimating the angle from the horizon?
> > For example a fist at arms length is 10 degrees, but obviously I can't
> > hold my first at arms length through the canopy. * The method I've
> > used is to wait until my aim point aligns with the outer most edge of
> > the air brakes. *To measure 45 degrees I look directly over the top of
> > my shoulder... *is there a better method?
>
> > Thanks
> > -tom
>
> But but but...
>
> You were flying with an instructor. Was this not addressed to your
> satisfaction in the post-flight debrief? Its fresh in your mind then
> and that's the time to get answers. Sorry but I cringe at these "where
> was the instructor" questions on r.a.s.
>
> If you are circling overhead you can use sized of common things (cars,
> gliders, runway width (if known), runway markings, etc.) to judge
> height. I think I saw some good slides on that once that Cindy
> Brickner had.
>
> But...You don't transition from just circling overhead to rolling out
> on the runway. At some time you transition from that circle overhead
> to picking up an the downwind or base or whatever leg and a relatively
> steady state angle to the runway. Even if the whole approach is curved
> your sight picture needs to transition from looking down to across at
> that 30-45 degree picture. At that point if you look too high you
> should be doing something about it, extend the leg, get on the
> spoilers, slip, or all the above.
>
> So you have at least two things to go over with the instructor.
> Judging height from overhead and being on-top of altitude correction
> in the pattern.
>
> Darryl

BTW you can't use the horizon. It is hard to know where the true
horizon often is. What if you are in mountainous areas. In smoke or
haze etc. (which will cause enough problems with depth/distance
perception as is). Same reason you don't want to set up behind the tow
plane based on where the horizon looks. Even if you knew the location
of the true horizon you would not be able to estimate your altitude
from that to anything like a useful accuracy.

Darryl

[Andy[_10_]]

On Oct 25, 10:00*pm, Darryl Ramm > wrote:
> On Oct 25, 9:30*pm, Darryl Ramm > wrote:
>
>
>
>
>
> > On Oct 25, 8:51*pm, tstock > wrote:
>
> > > Hi, as a beginner I am still a little rough at this. *I've done 3
> > > successful patterns with no altimeter, but today I failed one
> > > miserably with my instructor. * There were two issues which threw me
> > > off. 1) *we towed higher than the past attempts, and 2) instead of
> > > entering the pattern at a familiar entry point, he had me circle
> > > directly over the airport which made judging the angle a bit
> > > difficult.
>
> > > While we did eventually land safely, I failed miserably at setting up
> > > the first pattern (way too high) and was forced to land on the
> > > opposite runway (which left me way too low). *A little scary but a
> > > good learning experience... one I do not care to repeat anytime soon.
>
> > > I know I should be looking for the landing strip to be about 30
> > > degrees below the horizon. *But how can I do this when circling
> > > directly over the field looking down at it?
>
> > > I made a second attempt and moved my circle so that the outermost edge
> > > of the circle was where I would enter the downwind.. I succeeded this
> > > time. *Unfortunately we also only towed to 1500' AGL which left me
> > > with a much smaller chance of messing things up... so I can't say I am
> > > completely confident despite the success.
>
> > > Are there any easy methods for estimating the angle from the horizon?
> > > For example a fist at arms length is 10 degrees, but obviously I can't
> > > hold my first at arms length through the canopy. * The method I've
> > > used is to wait until my aim point aligns with the outer most edge of
> > > the air brakes. *To measure 45 degrees I look directly over the top of
> > > my shoulder... *is there a better method?
>
> > > Thanks
> > > -tom
>
> > But but but...
>
> > You were flying with an instructor. Was this not addressed to your
> > satisfaction in the post-flight debrief? Its fresh in your mind then
> > and that's the time to get answers. Sorry but I cringe at these "where
> > was the instructor" questions on r.a.s.
>
> > If you are circling overhead you can use sized of common things (cars,
> > gliders, runway width (if known), runway markings, etc.) to judge
> > height. I think I saw some good slides on that once that Cindy
> > Brickner had.
>
> > But...You don't transition from just circling overhead to rolling out
> > on the runway. At some time you transition from that circle overhead
> > to picking up an the downwind or base or whatever leg and a relatively
> > steady state angle to the runway. Even if the whole approach is curved
> > your sight picture needs to transition from looking down to across at
> > that 30-45 degree picture. At that point if you look too high you
> > should be doing something about it, extend the leg, get on the
> > spoilers, slip, or all the above.
>
> > So you have at least two things to go over with the instructor.
> > Judging height from overhead and being on-top of altitude correction
> > in the pattern.
>
> > Darryl
>
> BTW you can't use the horizon. It is hard to know where the true
> horizon often is. What if you are in mountainous areas. In smoke or
> haze etc. (which will cause enough problems with depth/distance
> perception as is). Same reason you don't want to set up behind the tow
> plane based on where the horizon looks. Even if you knew the location
> of the true horizon you would not be able to estimate your altitude
> from that to anything like a useful accuracy.
>
> Darryl

I agree with Darryl - angle below the horizon only tells you the angle
to the runway, not your height. You can be at the right height 2,000
feet laterally from the runway or 3x the right height a nautical mile
from the runway and the angles will be the same. You really need to
judge height by looking at the angle between two points a known
distance apart on the ground. This can be the wingspan of an airplane,
the distance between phone poles the width or length of a runway,
circular crop fields - whatever works. Try guessing your height 20
times over the course of a flight - especially when you are between
1,000 and 2,500 feet AGL. You will build a pretty good sense faster
than you think.

9B

[John Smith]

Andy wrote:
> angle below the horizon only tells you the angle
> to the runway, not your height. You can be at the right height 2,000
> feet laterally from the runway or 3x the right height a nautical mile
> from the runway and the angles will be the same.

The vertical angle is all you need to know. Gliders tend to glide at an
angle.

[Tom[_9_]]

You will find this information in the book, "Glider Basics From First
Flight To Solo," available at most gliderports or
www.eglider.org

Tom

[tstock]

Since using the horizon is not reliable, I suppose placing the airport
a certain position above my shoulder could be a good technique to
estimate the angle. My shoulder will always be in the same place
unless my head has been removed.

[bildan]

On Oct 26, 6:40*am, tstock > wrote:
> Since using the horizon is not reliable, I suppose placing the airport
> a certain position above my shoulder could be a good technique to
> estimate the angle. *My shoulder will always be in the same place
> unless my head has been removed.

I play a game with my students called "Guess our height" With the
student's altimeter covered, I ask them to guess our altitude and them
I tell them what the back seat altimeter says. (Of course, you must
HAVE a back seat altimeter.)

The first few guesses may be wildly wrong but they get better fast. A
few dozen repeats and they're pretty accurate. I'd never ask a
student to fly a no-altimeter pattern and landing until they were at
least passable in estimating altitude.

Bill D

[.[_2_]]

On Oct 26, 3:51*am, tstock > wrote:
> Hi, as a beginner I am still a little rough at this. *I've done 3
> successful patterns with no altimeter, but today I failed one
> miserably with my instructor. * There were two issues which threw me
> off. 1) *we towed higher than the past attempts, and 2) instead of
> entering the pattern at a familiar entry point, he had me circle
> directly over the airport which made judging the angle a bit
> difficult.
>
> While we did eventually land safely, I failed miserably at setting up
> the first pattern (way too high) and was forced to land on the
> opposite runway (which left me way too low). *A little scary but a
> good learning experience... one I do not care to repeat anytime soon.
>
> I know I should be looking for the landing strip to be about 30
> degrees below the horizon. *But how can I do this when circling
> directly over the field looking down at it?
>
> I made a second attempt and moved my circle so that the outermost edge
> of the circle was where I would enter the downwind.. I succeeded this
> time. *Unfortunately we also only towed to 1500' AGL which left me
> with a much smaller chance of messing things up... so I can't say I am
> completely confident despite the success.
>
> Are there any easy methods for estimating the angle from the horizon?
> For example a fist at arms length is 10 degrees, but obviously I can't
> hold my first at arms length through the canopy. * The method I've
> used is to wait until my aim point aligns with the outer most edge of
> the air brakes. *To measure 45 degrees I look directly over the top of
> my shoulder... *is there a better method?
>
> Thanks
> -tom

Don't get hung up on the ' 30 degree' rule. Its a rough guide for
beginners to get them into the right ball park. The actual perspective
will vary depending on the performance of your glider. From any given
height the angle by which you assess the pattern in a Ka8 will be
steeper than in an ASH25. You have to make the judgements no matter
what your orientation to the airstrip so peering at your shoulder or
airbrake won't work. You must be able to make the assessments, as it
were, out of the side of your eye whilst flying the plane and looking
out for traffic so focusing short and agonising about angles is
potentially dangerous.

In the UK we put far more emphasis on 'whether it looks right' which
entails practise from all sorts of positions and heights. In that
respect your comment "one I do not care to repeat anytime soon" is
against your interests for it's only by having another go soon will
you learn. You need to get some right to achieve the 'Ahaa!' and some
wrong to give your brain the database needed to make good judgements.
The job of the guy in the back is to engineer all that safely. His is
to 'take you to peer over the edge of the abyss without falling in' to
quote one of our most respected national coaches.

Of course you can't judge your pattern from over the airfield. Your
general height judgement, unaided by altimeters, needs to be
sufficient to tell you it's time to move away to the position from
where you will start the circuit and use different judgements of
perspective to effect it. Darryl says that in his post. If you always
fly from the same place and do the same circuits you are at risk of
getting habituated on secondary fixed references and not exercising
the necessary judgement skills to land out in a pasture. If possible
set yourself targets of landing within pre-set boundaries on
different parts of the airfield so you keep sharp.

Given the luxury of sufficient height (which is usually denied by the
pilot himself attempting to soar too long and not being disciplined
enough to enter circuit mode in good time) you should ensure you are
outside (and usually up-wind) of the intended pattern so that you can
see it all. As circuits are roughly rectangular the high key point
wants to be as far from the centre line of your final line as you
would like you base leg to be long. Choose a ground feature under the
high key and lurk by it, still outside the pattern until the
perspective looks right - then set off on downwind.
Learn to ignore the altimeter. Monitor the ASI assiduously and pay
attention to the vario. And lookout, lookout, lookout.

Peter

[Burt Compton - Marfa]

COWS. I recall it was Tom Knauff who wrote that you could begin to
see the legs of a cow at 1,000' (300 meters) AGL.
I also use seeing the tires on a car, tractor or glider trailer. It
takes practice.
Lacking cows or vehicles you can correlate the TLAR ("That Looks About
Right") method with your altimeter on every pattern you presently fly
in preparation for XC / off-airport landings.

Also practice estimating altitude at different airports / landing
fields, and in different lighting / visibility conditions. You might
use a motorglider or airplane to fly to nearby airports and learn to
estimate 1,000' AGL. Take along a current aero chart so you know
those airport elevations and for obstacle / terrain clearance.

Landing on a field or gliderport next to a ridge is interesting, such
as on Harris Hill at Elmira, NY. You need to get down relatively low
on the adjacent parallel hill on your left downwind pattern then make
a close-in base to final over another hill with trees. Good fun. All
eyeball / TLAR in relation to your touchdown spot. Altimeter is not
the primary tool here. Indeed, it is a fairly unreliable instrument.
Use it to verify what you see, but be suspicious of it. Pressure
changes and lag can make it indicate inaccurate altitude.

Then there is the ongoing debate as to setting of the altimeter before
takeoff. Zero or field elevation (or correctly, the reported
pressure.) Read CFR 91.121.
Setting an altimeter to Zero may make it easier to teach a student
pilot a rote pattern that is OK only for that airport, but not ideal,
and depending on your interpretation of "cruising flight" in CFR
91.121, probably not in compliance with the regulation.

So I teach pressure / field elevation for altimeter setting, and make
'em do the math to determine height Above Ground Level. Essential for
XC flyin' and anywhere topography is not flat.

We start our landing checklist at 6,000' MSL over the airport at
Marfa, west Texas (MRF field elevation is 4,850' MSL) near the Davis
Mountains (8,400' MSL).
Visiting pilots taught elsewhere to set altimeters to zero have a heck
of a time with this reality, so I do covered altimeter training and
checkouts. And we have a nice large herd of cows on the grassy
plateau around the airport. No oil beneath this part of Texas -- just
water.

Burt Compton CFI / DPE
Marfa, west Texas USA
www.flygliders.com

[Surfer!]

>On Oct 26, 3:51*am, tstock > wrote:
>> Hi, as a beginner I am still a little rough at this. *I've done 3
>> successful patterns with no altimeter, but today I failed one
>> miserably with my instructor. * There were two issues which threw me
>> off. 1) *we towed higher than the past attempts, and 2) instead of
>> entering the pattern at a familiar entry point, he had me circle
>> directly over the airport which made judging the angle a bit
>> difficult.
>>
>> While we did eventually land safely, I failed miserably at setting up
>> the first pattern (way too high) and was forced to land on the
>> opposite runway (which left me way too low). *A little scary but a
>> good learning experience... one I do not care to repeat anytime soon.
<Snip>

It's not easy at first, you will get the hang of it. It is a vital
skill though - flying circuits by landmarks is awful easy to get into
doing, but if you come to land out you must be able to fly a circuit
somewhere you've never, ever seen before.

--
Surfer!
Email to: ramwater at uk2 dot net

[mattm[_2_]]

On Oct 26, 2:11*pm, Surfer! > wrote:
> >On Oct 26, 3:51*am, tstock > wrote:
> >> Hi, as a beginner I am still a little rough at this. *I've done 3
> >> successful patterns with no altimeter, but today I failed one
> >> miserably with my instructor. * There were two issues which threw me
> >> off. 1) *we towed higher than the past attempts, and 2) instead of
> >> entering the pattern at a familiar entry point, he had me circle
> >> directly over the airport which made judging the angle a bit
> >> difficult.
>
> >> While we did eventually land safely, I failed miserably at setting up
> >> the first pattern (way too high) and was forced to land on the
> >> opposite runway (which left me way too low). *A little scary but a
> >> good learning experience... one I do not care to repeat anytime soon.
>
> <Snip>
>
> It's not easy at first, you will get the hang of it. *It is a vital
> skill though - flying circuits by landmarks is awful easy to get into
> doing, but if you come to land out you must be able to fly a circuit
> somewhere you've never, ever seen before.
>
> --
> Surfer!
> Email to: ramwater at uk2 dot net

Just yesterday I heard another instructor say he coaches his students
to look for the aimpoint a certain distance out the wing when they're
flying level. For his plane (K-21) it works if the aimpoint is about
a
third of the wing out.

Another method I suggest is to find telephone poles. In the US,
barring other circumstances (like having to go around curves) the
poles are spaced about 200 feet apart. When you cross a road
count how many telephone poles to a point 45 degrees below
level you see from your flight path. 5 poles is 1000 feet.

I'll also point out that you've gotten a good demonstration of how
hard it really is to measure distances with your eyes. You can
get a rough idea but ultimately you won't be that accurate.
However, by using the angles around the pattern you can
make a safe approach.

-- Matt

[Eric Greenwell]

bildan wrote:
>
> I play a game with my students called "Guess our height" With the
> student's altimeter covered, I ask them to guess our altitude and them
> I tell them what the back seat altimeter says. (Of course, you must
> HAVE a back seat altimeter.)
>
> The first few guesses may be wildly wrong but they get better fast. A
> few dozen repeats and they're pretty accurate. I'd never ask a
> student to fly a no-altimeter pattern and landing until they were at
> least passable in estimating altitude.

My strategy was to let the students decide when to end the lesson and
head back to the airport. I'd just keep telling them to do stuff, or
showing them stuff, until they said "we're going back", then I'd shut up
and let them do it.

Since we flew off two different runways in varying conditions, they had
a lot practice returning from different directions and altitudes. After
each landing, we'd discuss how it went, and alternate choices. I never
asked them to estimate altitude, and I'm not any good at it anyway. The
standard was to arrive on downwind with enough altitude to do a typical
pattern. Too high or too low might mean a longer discussion, if I
thought there was a problem and not just the normal variation.

They all were good enough at it by the time they went solo, it was never
an issue. By doing it every flight, as soon as they could guide the
glider in more or less in the intended direction, it wasn't anything
that had to be taught later, or something they feared; after all, they
did it every flight except the first 3 or 4. I think it's something you
really have to *do* to learn, and watching someone else make the
decisions isn't useful.

I should point out that, in addition to "as soon as they could guide the
glider in more or less in the intended direction", they'd also received
instruction on the ground and during the first few flights on basic
pattern planning: pick the stop point, pick the aim point, pick the base
direction, pick the downwind entry.

--
Eric Greenwell - Washington State, USA
* Change "netto" to "net" to email me directly

* "Transponders in Sailplanes" http://tinyurl.com/y739x4
* Sections on Mode S, TPAS, ADS-B, Flarm, more

* "A Guide to Self-launching Sailplane Operation" at www.motorglider.org

[Andy[_10_]]

On Oct 26, 2:04*am, John Smith > wrote:
>
> The vertical angle is all you need to know. Gliders tend to glide at an
> angle.

It helps when you are in the pattern, but the issue here is what to do
when you are away from the pattern. Also, I wouldn't necessarily
recommend that a student focus solely on the angle. I would not
consider it equally good piloting to enter the pattern at 3,000' AGL a
mile abeam of the runway as at 1,000' 1/3 mile abeam of the runway.

For the circling over the airport problem you can get some indication
of altitude by looking at the path the wingtip traces on the ground
from a known bank angle. Above a certain height the path will be
counter to the turning direction, below that height it will be in the
same direction. Do the math to convince yourself. (Note: This is one
cue that creates problems as it tends to make skidding turns down low
seem "normal". A pilot will over-rudder to make the wingtip move
backward -- don't do this). You also get altitude cues from the rate
that objects on the ground change angle in straight ahead flight at a
known airspeed. The least precise cue except at very low altitudes (or
for very big objects) is the included angle from one end of a ground
object to another. Use the length of the ramp, not the length of a
car.

Another big issue is gaining the experience to know when you need to
"head for home" from 10-20 miles away to hit a point that's 1,000' AGL
for pattern entry. The angle for most gliders is very flat but looks
flatter and flatter the farther away you get because the glide
terminates well above the ground. For instance, if your glider can go
7 miles for every 1,000' (L/D= 37) the angle will "look" roughly half
as steep from 20 miles as from 5 miles away. Fortunately this builds
in some conservatism in the pilot's judgement rather than the other
way around.

Try some of these techniques from different altitudes the next few
times you fly. Eventually it becomes (almost) second nature. Also read
Tom Knauff's fine text or one of the many others on the subject. They
are written by professionals.

9B

[Bruce Hoult]

On Oct 28, 3:13*am, Andy > wrote:
> For the circling over the airport problem you can get some indication
> of altitude by looking at the path the wingtip traces on the ground
> from a known bank angle. *Above a certain height the path will be
> counter to the turning direction, below that height it will be in the
> same direction. Do the math to convince yourself.

I guess you didn't do the math yourself :-)

The height at which the change from wingtip-goes-backwards to wingtip-
goes-forwards occurs is too low to be used for normal circuit entry.
At 40 knots it's only 140 ft, and at 60 knots it is about 320 ft. If
you want to use this to judge a 700 ft circuit entry then you'll have
to be flying at 90 knots.

[tstock]

On Oct 27, 7:47*pm, Bruce Hoult > wrote:
> On Oct 28, 3:13*am, Andy > wrote:
>
> > For the circling over the airport problem you can get some indication
> > of altitude by looking at the path the wingtip traces on the ground
> > from a known bank angle. *Above a certain height the path will be
> > counter to the turning direction, below that height it will be in the
> > same direction. Do the math to convince yourself.
>
> I guess you didn't do the math yourself :-)
>
> The height at which the change from wingtip-goes-backwards to wingtip-
> goes-forwards occurs is too low to be used for normal circuit entry.
> At 40 knots it's only 140 ft, and at 60 knots it is about 320 ft. If
> you want to use this to judge a 700 ft circuit entry then you'll have
> to be flying at 90 knots.

Glad you mentioned this. I did think of this myself also, and tried it
on a simulator many many times before reading these posts and in every
case the wingtip appeared to move backwards over the terrain. Decided
it would not work.

[ZZ]

Tom:

How many patterns have you flown since you began your training? Until
you develop a clear picture in your mind of how your airfield looks at
different points in the pattern, you are experimenting and this will
work eventually. I have found a way to accelerate this process a bit. I
have my students fly their patterns at precise altitudes at specific
points in the pattern. And I insist on precise airpeed control as well..
This accomplishes two things..precise pattern flying...the same picture
every time and this "groove becomes epoxied into their brain more
quickly. Then, when I take their altimeter away and change runways, they
have no problems repeating the maneuver properly. Now I am all too
familiar with the argument against this technique i.e. what are they
going to do if they are landing at a field without the familiar
landmarks? It's that profile to the runway that they are really learning
by repeating the same profile time after time.





tstock wrote:
> Hi, as a beginner I am still a little rough at this. I've done 3
> successful patterns with no altimeter, but today I failed one
> miserably with my instructor. There were two issues which threw me
> off. 1) we towed higher than the past attempts, and 2) instead of
> entering the pattern at a familiar entry point, he had me circle
> directly over the airport which made judging the angle a bit
> difficult.
>
> While we did eventually land safely, I failed miserably at setting up
> the first pattern (way too high) and was forced to land on the
> opposite runway (which left me way too low). A little scary but a
> good learning experience... one I do not care to repeat anytime soon.
>
> I know I should be looking for the landing strip to be about 30
> degrees below the horizon. But how can I do this when circling
> directly over the field looking down at it?
>
> I made a second attempt and moved my circle so that the outermost edge
> of the circle was where I would enter the downwind.. I succeeded this
> time. Unfortunately we also only towed to 1500' AGL which left me
> with a much smaller chance of messing things up... so I can't say I am
> completely confident despite the success.
>
> Are there any easy methods for estimating the angle from the horizon?
> For example a fist at arms length is 10 degrees, but obviously I can't
> hold my first at arms length through the canopy. The method I've
> used is to wait until my aim point aligns with the outer most edge of
> the air brakes. To measure 45 degrees I look directly over the top of
> my shoulder... is there a better method?
>
> Thanks
> -tom
>
>
>
>

[ZZ]

ZZ wrote:
> Tom:
>
> How many patterns have you flown since you began your training? Until
> you develop a clear picture in your mind of how your airfield looks at
> different points in the pattern, you are experimenting and this will
> work eventually. I have found a way to accelerate this process a bit. I
> have my students fly their patterns at precise altitudes at specific
> points in the pattern. And I insist on precise airpeed control as well..
> This accomplishes two things..precise pattern flying...the same picture
> every time and this "groove becomes epoxied into their brain more
> quickly. Then, when I take their altimeter away and change runways, they
> have no problems repeating the maneuver properly. Now I am all too
> familiar with the argument against this technique i.e. what are they
> going to do if they are landing at a field without the familiar
> landmarks? It's that profile to the runway that they are really learning
> by repeating the same profile time after time.

Tom
I mashed on the Send Button prematurely.

So to wrap this up, fly your patterns as precisely as possible, as you
progress, learn to detect smaller and smaller errors and correct them
early. Fly the same groove to the runway every time and you will soon be
comfortable landing almost anywhere without no stinking altimeter.

Paul
ZZ
>
>
>
>
>
> tstock wrote:
>> Hi, as a beginner I am still a little rough at this. I've done 3
>> successful patterns with no altimeter, but today I failed one
>> miserably with my instructor. There were two issues which threw me
>> off. 1) we towed higher than the past attempts, and 2) instead of
>> entering the pattern at a familiar entry point, he had me circle
>> directly over the airport which made judging the angle a bit
>> difficult.
>>
>> While we did eventually land safely, I failed miserably at setting up
>> the first pattern (way too high) and was forced to land on the
>> opposite runway (which left me way too low). A little scary but a
>> good learning experience... one I do not care to repeat anytime soon.
>>
>> I know I should be looking for the landing strip to be about 30
>> degrees below the horizon. But how can I do this when circling
>> directly over the field looking down at it?
>>
>> I made a second attempt and moved my circle so that the outermost edge
>> of the circle was where I would enter the downwind.. I succeeded this
>> time. Unfortunately we also only towed to 1500' AGL which left me
>> with a much smaller chance of messing things up... so I can't say I am
>> completely confident despite the success.
>>
>> Are there any easy methods for estimating the angle from the horizon?
>> For example a fist at arms length is 10 degrees, but obviously I can't
>> hold my first at arms length through the canopy. The method I've
>> used is to wait until my aim point aligns with the outer most edge of
>> the air brakes. To measure 45 degrees I look directly over the top of
>> my shoulder... is there a better method?
>>
>> Thanks
>> -tom
>>
>>
>>
>>

[Surfer!]

In message >, ZZ
> writes
>Tom:
>
>How many patterns have you flown since you began your training? Until
>you develop a clear picture in your mind of how your airfield looks at
>different points in the pattern,
<Snip>

I would say it's 'how the reference point looks'. We can have a
reference point anywhere, but if landing out we won't be seeing our own
familiar airfield. Is the reference point technique taught in the US?

--
Surfer!
Email to: ramwater at uk2 dot net

[Andy[_10_]]

On Oct 27, 4:47*pm, Bruce Hoult > wrote:
> On Oct 28, 3:13*am, Andy > wrote:
>
> > For the circling over the airport problem you can get some indication
> > of altitude by looking at the path the wingtip traces on the ground
> > from a known bank angle. *Above a certain height the path will be
> > counter to the turning direction, below that height it will be in the
> > same direction. Do the math to convince yourself.
>
> I guess you didn't do the math yourself :-)
>
> The height at which the change from wingtip-goes-backwards to wingtip-
> goes-forwards occurs is too low to be used for normal circuit entry.
> At 40 knots it's only 140 ft, and at 60 knots it is about 320 ft. If
> you want to use this to judge a 700 ft circuit entry then you'll have
> to be flying at 90 knots.

[Andy[_10_]]

On Oct 27, 4:47*pm, Bruce Hoult > wrote:
> On Oct 28, 3:13*am, Andy > wrote:
>
> > For the circling over the airport problem you can get some indication
> > of altitude by looking at the path the wingtip traces on the ground
> > from a known bank angle. *Above a certain height the path will be
> > counter to the turning direction, below that height it will be in the
> > same direction. Do the math to convince yourself.
>
> I guess you didn't do the math yourself :-)
>
> The height at which the change from wingtip-goes-backwards to wingtip-
> goes-forwards occurs is too low to be used for normal circuit entry.
> At 40 knots it's only 140 ft, and at 60 knots it is about 320 ft. If
> you want to use this to judge a 700 ft circuit entry then you'll have
> to be flying at 90 knots.

Thanks - I didn't do the math. I usually do the math but was feeling
lazy. :-(

I would argue that pattern traced by the wingtip changes even if it
doesn't reverse direction at higher elevations - the reverse circle
gets bigger and bigger as you go higher.

I generally enter the pattern at about 75-80 knots. You could
certainly do a circle at 90 knots if you really needed to see the
wingtip rotate the other way and had no idea how high you were - at
that speed your energy would take you back up to 1000' AGL.

The general point is that all the angular rates versus ground
references change as you get closer to the ground and you should be
aware of them. Turning flight likely gives you more cues than flying
straight ahead.

9B

[bildan]

On Oct 28, 2:25*am, Surfer! > wrote:
> In message >, ZZ
> > writes>Tom:
>
> >How many patterns have you flown since you began your training? Until
> >you develop a clear picture in your mind of how your airfield looks at
> >different points in the pattern,
>
> <Snip>
>
> I would say it's 'how the reference point looks'. *We can have a
> reference point anywhere, but if landing out we won't be seeing our own
> familiar airfield. *Is the reference point technique taught in the US?
>
> --
> Surfer!
> Email to: ramwater at uk2 dot net

The best 'reference point' is the intended landing surface. Anything
else is likely to be misleading. Even telephone poles are not all the
same height or spacing.

There are lots of clues to height which taken together can give a
pretty accurate estimate. Pilots may not even be aware of all the
clues they're using, just that with increasing experience, their
estimates begin to work.

One old skydiver clue is that when people stop looking like ants and
start looking like people, it's time to pull. That's about 2000' AGL
and not a bad height to be over the landing area looking for wind and
obstacles.

[nate_fl]

On Oct 28, 1:08*pm, bildan > wrote:
> On Oct 28, 2:25*am, Surfer! > wrote:
>
>
>
>
>
> > In message >, ZZ
> > > writes>Tom:
>
> > >How many patterns have you flown since you began your training? Until
> > >you develop a clear picture in your mind of how your airfield looks at
> > >different points in the pattern,
>
> > <Snip>
>
> > I would say it's 'how the reference point looks'. *We can have a
> > reference point anywhere, but if landing out we won't be seeing our own
> > familiar airfield. *Is the reference point technique taught in the US?
>
> > --
> > Surfer!
> > Email to: ramwater at uk2 dot net
>
> The best 'reference point' is the intended landing surface. *Anything
> else is likely to be misleading. *Even telephone poles are not all the
> same height or spacing.
>
> There are lots of clues to height which taken together can give a
> pretty accurate estimate. *Pilots may not even be aware of all the
> clues they're using, just that with increasing experience, their
> estimates begin to work.
>
> One old skydiver clue is that when people stop looking like ants and
> start looking like people, it's time to pull. *That's about 2000' AGL
> and not a bad height to be over the landing area looking for wind and
> obstacles.

Anyone try using the wing vs. runway relationship? In the Skyhawk I
was taught to keep the runway 1/2 to 2/3 up the strut, correcting for
wind. I know that this would lead to flying an ever closer pattern as
you descend, but could it not be used to get you in the groove up to
abeam the touchdown point? Then it would be a matter of TLAR from
there to touchdown.

I offer this as a question, not a suggestion. I've done very little
flying away from the home field, and I live in a very flat state.

[ZZ]

The reference "point" assuming that you can see it, is the the runway or
more specifically, the TDZ.

Paul
ZZ



Surfer! wrote:
> In message >, ZZ
> > writes
>> Tom:
>>
>> How many patterns have you flown since you began your training? Until
>> you develop a clear picture in your mind of how your airfield looks at
>> different points in the pattern,
> <Snip>
>
> I would say it's 'how the reference point looks'. We can have a
> reference point anywhere, but if landing out we won't be seeing our own
> familiar airfield. Is the reference point technique taught in the US?
>

[delboy]

If you can only see whole woods or forests you are quite high. If you
can see individual trees you are getting a bit low. If you can see the
branches you are very low, If you can see the leaves...don't even
ask!

If you can see your reference point, estimate your distance away from
it and judge the angle (should be about 15 degrees), you should be
able to land accurately with a bit of practice, without reference to
the altimeter. Remember that the altimeter is pretty useless when
outlanding at a field of unknown elevation.

Derek Copeland (UK gliding instructor)


On Oct 29, 2:52*am, ZZ > wrote:
> The reference "point" assuming that you can see it, is the the runway or
> more specifically, the TDZ.
>
> Paul
> ZZ
>
>
>
> Surfer! wrote:
> > In message >, ZZ
> > > writes
> >> Tom:
>
> >> How many patterns have you flown since you began your training? Until
> >> you develop a clear picture in your mind of how your airfield looks at
> >> different points in the pattern,
> > <Snip>
>
> > I would say it's 'how the reference point looks'. *We can have a
> > reference point anywhere, but if landing out we won't be seeing our own
> > familiar airfield. *Is the reference point technique taught in the US?- Hide quoted text -
>
> - Show quoted text -

[ZZ]

I knew that my original comment was going to start fist fights. But it's
winter in the northern hemisphere and we need something to do.

We have a student pilot who says that he is having trouble estimating
his altitude in the pattern. So instead shall we will advise him to
estimate angles? What this pilot really lacks is experience. What I
contend is that INITIALLY forcing him to see many "ideal" patterns,
i.e. repetition, is an important step in learning what a "normal"
pattern looks like and when the pattern is poorly flown, he will then
recognize it right away. Certainly, angles are part of what is being
learned but quantifying the angle is not required to learn. Of course
lift/sink, wind, low arrivals at the field, rope breaks, rock-offs, last
minute runway changes and buffoonery from the guy in the pattern in
front of him will force him to modify his pattern. My students are
trained to fly all of these problems without altimeter reference. But
initially, I begin by giving them a solid grounding in what "normal"
LOOKS LIKE.

As for our student who is trying to estimate his altitude, keep flying.
It will come all together.

Paul Corbett
ZZ








delboy wrote:
> If you can only see whole woods or forests you are quite high. If you
> can see individual trees you are getting a bit low. If you can see the
> branches you are very low, If you can see the leaves...don't even
> ask!
>
> If you can see your reference point, estimate your distance away from
> it and judge the angle (should be about 15 degrees), you should be
> able to land accurately with a bit of practice, without reference to
> the altimeter. Remember that the altimeter is pretty useless when







> outlanding at a field of unknown elevation.
>
> Derek Copeland (UK gliding instructor)
>
>
> On Oct 29, 2:52 am, ZZ > wrote:
>> The reference "point" assuming that you can see it, is the the runway or
>> more specifically, the TDZ.
>>
>> Paul
>> ZZ
>>
>>
>>
>> Surfer! wrote:
>>> In message >, ZZ
>>> > writes
>>>> Tom:
>>>> How many patterns have you flown since you began your training? Until
>>>> you develop a clear picture in your mind of how your airfield looks at
>>>> different points in the pattern,
>>> <Snip>
>>> I would say it's 'how the reference point looks'. We can have a
>>> reference point anywhere, but if landing out we won't be seeing our own
>>> familiar airfield. Is the reference point technique taught in the US?- Hide quoted text -
>> - Show quoted text -
>

[delboy]

If you can estimate the distance and judge the angle, this fixes the
height - this is simple trigonometry.

In the UK we teach an exercise called the zig-zag circuit where the
instructor demonstrates a circuit starting at the right high key
distance, height and angle to the reference point, but allows the
gider to drift in so the low key point is reached at about the right
height, but much too close in. Thus the student can see that the
angle looks much too steep (the impression given is that you are much
too high, but you are not). Then you move back out until the angle
looks right and complete the circuit normally.

I do not disagree with ZZ that regular experience of what a circuit
should look like is a necessary part of training. Also learning to
judge what items on the ground, such as trees, vehicles and houses
look like from different heights.

Derek Copeland

P.S This is posted from Google Groups, as I can't seem to access
r.a.s. directly from gp.net. Is there a problem with my email address
or UK postings Andy?

[tstock]

On Oct 27, 11:07*pm, ZZ > wrote:
> Tom:
>
> How many patterns have you flown since you began your training? Until
> you develop a clear picture in your mind of how your airfield looks at
> different points in the pattern, you are experimenting and this will
> work eventually. I have found a way to accelerate this process a bit. I
> have my students fly their patterns at precise altitudes at specific
> points in the pattern. And I insist on precise airpeed control as well..
> This accomplishes two things..precise pattern flying...the same picture
> every time and this "groove becomes epoxied into their brain more
> quickly. Then, when I take their altimeter away and change runways, they
> have no problems repeating the maneuver properly. Now I am all too
> familiar with the argument against this technique i.e. what are they
> going to do if they are landing at a field without the familiar
> landmarks? It's that profile to the runway that they are really learning
> by repeating the same profile time after time.

I have about 31 patterns (including my solo flights). What you
describe is exactly how I was taught to do my patterns. I enter the
pattern at 1000' AGL, then I am at 800' AGL when I pass my aim point
(this will be the my flare point not TD point), make my turn to base
at 600' AGL, and my turn to final at 400' AGL.

Once I get into the down wind leg at the correct altitude the rest is
no problem without the altimeter. It's estimating when to enter the
pattern without altimeter which I find difficult.

I'll try to pay more attention to how things look at that point and
hopefully it'll get easier.

-tom

[tstock]

> Anyone try using the wing vs. runway relationship? In the Skyhawk I
> was taught to keep the runway 1/2 to 2/3 up the strut, correcting for
> wind. I know that this would lead to flying an ever closer pattern as
> you descend, but could it not be used to get you in the groove up to
> abeam the touchdown point? Then it would be a matter of TLAR from
> there to touchdown.
>
> I offer this as a question, not a suggestion. I've done very little
> flying away from the home field, and I live in a very flat state.

This is sort of how I ultimately did it... when my aimpoint was at 9
o'clock, it appeared about 1/3 of the way down from the wing tip, just
under the air brake. This was about 800'.

-tom

[mattm[_2_]]

On Oct 30, 10:47*am, tstock > wrote:
> On Oct 27, 11:07*pm, ZZ > wrote:
>
>
>
> > Tom:
>
> > How many patterns have you flown since you began your training? Until
> > you develop a clear picture in your mind of how your airfield looks at
> > different points in the pattern, you are experimenting and this will
> > work eventually. I have found a way to accelerate this process a bit. I
> > have my students fly their patterns at precise altitudes at specific
> > points in the pattern. And I insist on precise airpeed control as well...
> > This accomplishes two things..precise pattern flying...the same picture
> > every time and this "groove becomes epoxied into their brain more
> > quickly. Then, when I take their altimeter away and change runways, they
> > have no problems repeating the maneuver properly. Now I am all too
> > familiar with the argument against this technique i.e. what are they
> > going to do if they are landing at a field without the familiar
> > landmarks? It's that profile to the runway that they are really learning
> > by repeating the same profile time after time.
>
> I have about 31 patterns (including my solo flights). *What you
> describe is exactly how I was taught to do my patterns. *I enter the
> pattern at 1000' AGL, then I am at 800' AGL when I pass my aim point
> (this will be the my flare point not TD point), make my turn to base
> at 600' AGL, and my turn to final at 400' AGL.
>
> Once I get into the down wind leg at the correct altitude the rest is
> no problem without the altimeter. *It's estimating when to enter the
> pattern without altimeter which I find difficult.
>
> I'll try to pay more attention to how things look at that point and
> hopefully it'll get easier.
>
> -tom

Hey, fst learner! I actually can't tell you what altitude I do the
turns at,
because I never look at the altimeter once past the aimpoint on
downwind leg (at 600 feet). When I was first learning to fly we used
the Tom
Knauff textbook, which had as the last entry on the landing
checklist "ignore altimeter". I fly and teach the pattern judgement
mainly based on seeing the desired final approach glideslope while
you are on downwind leg. It's fairly easy to turn base so you hit
that
slope, plus you have your mind two legs ahead of where the airplane
is instead of a leg or two behind.

-- Matt

[Burt Compton - Marfa]

Someone wrote: "make my turn to base at 600' AGL, and my turn to
final at 400' AGL. "

(Oh my gosh. Now I must comment. Note to my students -- ignore this
"fly to an altitude before turning base" concept.)

I gotta ask: If you plan to turn base at 600' AGL and you've gone
thru lift on the downwind -- do you keep flying far downwind until you
descend to 600' AGL, far away from the airport?

HECK NO. Fly the angles! Follow Tom Knauff's advice. Ignore the
Altimeter, but use the Variometer to check your vertical speed on
downwind. I teach 500 fpm (or 5 knots) down is the maximum you need
until final. If the variometer is showing lift then add airbrakes but
be ready to respond with less airbrake in the sink beyond that lift
you just encountered. Watch the TREND of your variometer as well --
to see the near-future. I often fly thru 1,000 fpm DOWN (with no
airbrakes) and UP (full airbtrake) in my patterns year-round in west
Texas. Recognize and react to what's happening to your glider.

My perception is that we glider pilots fly lightly wing-loaded, slow
moving aircraft thru a constantly changing air mass (typical on a
thermic or windy day) so your glider is greatly affected by vertical
and horizontal changes in the air mass. Trying for the airplane type
"stabilized approach" for every pattern doesn't always work for me in
gliders. Most airplanes have heavier wing-loadings than gliders and
fly much faster thru the air mass in the pattern. And they have that
stinkin' motor.

So I fly the "goal-oriented approach" which means recognize and react
as needed (early turn to base if required by the "angle" / use
airbrakes in or out) to air mass and wind changes to fly to your
touchdown point and roll to your pre-determined stop point. Glider
patterns are rarely the exact same slope or route over the ground on
any landing. Another common mistake is to fly too close to the runway
on downwind, then fly too far downwind before turning base. A long
final back into a headwind combined with a bit of sink and you are
sunk. So the idea of flying downwind to 600' AGL may be hazardous.

Keep in mind on windy days that flying 55 knots on downwind translates
to perhaps 70 knots over the ground (with your tailwind aloft), so
your glider is traveling about 100 feet PER SECOND over the ground,
downwind from the runway. Any delay (5 seconds for instance) in
deciding when to turn base may mean you are 500 hundred feet further
downwind that you wanted to be, and now you must "buy back" those
extra 500 hundred over the ground, into a headwind and a lot slower
ground speed, and likely will lose more altitude than planned with
some sink / wind gradient effect on final.

Now consider how "time" is a huge factor in planning your pattern.
You have about 60 seconds from the moment you enter a pattern to
touchdown. How you use that time is based on your decisions on how to
respond to the air mass changes, and the path thru the sky that you
chose to fly to your pre-determined touchdown point. You are the
Pilot In Command. Don't wait for things to happen -- MAKE things
happen to a successful outcome. Indecision, wallowing around the sky
allowing wind drift and sink to put you deeper in jeopardy, then
making uncoordinated turns under stress is simply poor airmanship.
These airmanship skills must be taught and learned BEFORE solo.

So glance at the variometer, respond as needed to vertical changes
with airbrake in/out. Look outside 99% of the time and don't fly too
far downwind, Hold airspeed for the wind conditions aloft and your
drift over the ground. Watch the angles to your touchdown point (the
British call it the Reference Point, as I recall) and roll to your
desired stop point.

If another method works for you then so be it, but "landing short" of
a perfectly good runway you just passed on downwind seems silly, and
is a common incident worldwide. Long landings also occur quite
often, so learn to control your energy, nail your touchdown point and
stop point every time. I also teach flying thru the imaginary narrow
"mail slot" over your last obstacle (wires, trees, fence) on every
final approach.

So I had to comment. Honestly, I teach the glider landing pattern
alot different now at Marfa, in west Texas than I did back in Miami,
Florida a decade ago. The Miami air mass was relatively passive, so
we flew big rectangular patterns with the old school "hold 1/2
airbrake and wait until something changes" method, somewhat "behind"
the glider. But travel elsewhere to fly gliders and "interesting" and
sudden changes in the air mass near the ground will require more pilot
awareness, skills, flexibility in the pattern shape and faster
responses.

To the old-school CFIG's (like me), learn to embrace alternate methods
and consider teaching students to be flexible and creative in their
thinking. I did, and it works.

Burt
Marfa
www.flygliders.com

[tstock]

On Oct 30, 12:47*pm, Burt Compton - Marfa > wrote:
> Someone wrote: *"make my turn to base at 600' AGL, and my turn to
>
> final at 400' AGL. "
>
> (Oh my gosh. *Now I must comment. *Note to my students -- *ignore this
> "fly to an altitude before turning base" concept.)
>
> I gotta ask: *If you plan to turn base at 600' AGL and you've gone
> thru lift on the downwind -- do you keep flying far downwind until you
> descend to 600' AGL, far away from the airport?
>
> HECK NO. *Fly the angles! *Follow Tom Knauff's advice. *Ignore the
> Altimeter, but use the Variometer to check your vertical speed on
> So I had to comment. *Honestly, I teach the glider landing pattern
> alot different now at Marfa, in west Texas than I did back in Miami,
> Florida a decade ago. *The Miami air mass was relatively passive, so
> we flew big rectangular patterns with the old school "hold 1/2
> airbrake and wait until something changes" method, somewhat "behind"
> the glider. *But travel elsewhere to fly gliders and "interesting" and
> sudden changes in the air mass near the ground will require more pilot
> awareness, skills, flexibility in the pattern shape and faster
> responses.
> (CUT)
> To the old-school CFIG's (like me), learn to embrace alternate methods
> and consider teaching students to be flexible and creative in their
> thinking. *I did, and it works.
>
> Burt
> Marfawww.flygliders.com

Burt, thanks for taking the time to write that lengthy and detailed
reply. I should clarify that I do not just fly down wind UNTIL I
reach 600 (!), but rather I watch the position of the aim point and
use air brakes as required to keep the angle "looking right" until it
is at my 45. At this point I have a quick glance to confirm I am
somewhere around 600 while I turn to base and from that point on I do
not typically look at the altimeter. I am primarily keeping an eye on
my glide angle and airspeed. Usually I'll try to get a quick glance
just to see if I am where I think I am. There was wind through most
of my training so I am used to altering my pattern to compensate for
tail wind or head wind.

Since I am flying in Florida, what you mentioned regarding altering
pattern in regards to sudden air mass changes is also good info.

So basically my issue is the first angle... knowing when I am between
800' and 1000' agl. Sounds like I just need to keep practicing.

Thanks
-tom