Help estimating altitude without altimeter?

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?

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 -

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 -

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?

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

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

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

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