High on Final, Summary

Thanks to all that have given input so far. My original intent was to
do some modeling before starting the discussion, but this is RAS and
it has a life of it's own.

So here is the issue. You are high on final and full spoilers are to
enough; what do you do?

List of options so far:

1. Slip
2. "S" turns
3. Dive until intercepting normal angle for spoilers
4. Dive until near the ground, then decelerate
5. Slow down until intercepting normal angle for spoilers
6. 360 degree turn

Unfortunately I still don't have good data for what happens to the
polar as speed increases with the spoilers open. Condor was a good
suggestion, and I am working to see if I can get meaningful data from
it.

John Cochrane brought the discussion back to the real point which is
what would you use in the real world? It is interesting but not that
useful to discuss how you do this at your home airport with 2500 to
9000 feet of runway and know precisely the field elevation. When your
aircraft and your own safety are on the line in a real off-field, what
are you going to do?

This is where I find teaching some of these other techniques
interesting, but possibly dangerous. The rule of primacy for learning
or as the Doobie Brothers album from the 70's title "What were once
vices are now habits" suggests we will do in an emergency what we have
practiced. Is someone really going to dive a glider to the ground and
pull out to land in a short off field landing? Is there really a need
to be on the ground 10 seconds faster than using some of the other
techniques? Maybe only if a severe thunderstorm is approaching and
you must be on the ground now. I think in general the high parasitic
drag technique being taught by some schools is a hyped method that may
give some less experienced pilots the idea this is a good technique to
use for off-field landings. I think it is time to get back to basics
and teach sound techniques that provide the best tools for pilots to
use day in and day out.

The dive until intercepting normal angle for spoilers has some merit,
but I still think should be used with caution. Why, because we train
to look at landings from a specific angle for a narrow range of
landing speeds. To dive at high speed leaves the aircraft with a much
greater kinetic energy that must still be lost someplace. Depending
on the ship type some may take much longer to dissipate this excess
and make it more difficult to precisely hit a touch down point. Often
the greater sink rate is held up as the reason for using this
technique. It is true that sink rate goes up with speed, but the
actual decent angle does not go up nearly as much. For my Ventus B at
45 knots descent rate is 122 ft/min while at 135 knots it is 894 ft/
min, but actual loss per nautical mile is 163 ft/ktm verses 397 ft/
ktm. The other thing we don't mention is the average pilot going to
handle the decision making process better at higher speeds and less
time? At stable speeds it takes about 11 seconds to lose 300 feet at
135 knots with the spoilers out verses 22 seconds at 45 knots. Do we
need that extra time to make proper judgment and fine adjustments to
hit a target for a tight off-field landing?

Ok, lets try a hypothetical (well maybe not, been there done that ;-)
off-field landing.

The situation: You are 70 miles from home over unfamiliar territory
(read not sure of exact elevation of the terrain below, your altimeter
is useless now). You have gone for a Cu over a dry lake bed and it
doesn't work. You have selected a landing site in the lake bed that
is about 350 feet long and 100 feet wide that looks safe to land.
There are tree stumps and other object in other parts of the lakebed.
There are no obstructions on the ends of the site so you can do a
normal approach. The winds are 15 to 20mph out of the south so you
are landing from the north to south. As you drop lower you make a
rectangular pattern over the site checking for any missed obstacles.
The downwind is fast with the tailwind, as you turn base you estimate
you are 400 feet. Your adrenaline is pumping as you prepare for a
fairly technical landing. You want to keep it close so that you don't
end up short back into the wind and you turn base a little too soon.
You are on short final about 350 feet, but about 100 feet over full
spoilers decent. What do you do?

Slip?
"S" turns?
Dive until intercepting normal angle for spoilers?
Dive until near the ground, and then decelerate?
Slow down until intercepting normal angle for spoilers?
360 degree turn?

In the real world nearly 15 years ago this was in a 1970 "A" model
Standard Cirrus. If you think the Duo will float try the Standard
Cirrus. What should we be teaching students? You are somewhere
between 11 and 30 seconds from being on the ground and that 100 extra
feet will take you past the whole safe landing area and into the tree
stumps.

Dive until intercepting normal angle for spoilers?

Maybe, but can you dive, lose the altitude, decelerate and get it on
the ground for a tail wheel first, full stall landing? I would give
this a 6 out of 10. This also shortens the time available to make
adjustments and requires rapid and precise decisions.

Dive until near the ground, and then decelerate?

My guess is your chances are slim that you can pull this off and get
the ship stopped. Especially, if you were flying my Std. Cirrus. My
rating is a 1 out of 10.

360 degree turn?

I never like to turn my back on a field. Low and with the winds a
good result is not likely. My rating is a 0 out of 10.

Slow down until intercepting normal angle for spoilers?

This technique is useful for very high approaches, but must be broken
off before 300 feet agl because you must have height to accelerate and
be able to recover from any inadvertent stalls. From about 1000 feet
to 500 feet this technique has the advantage of giving a higher decent
rate and giving the pilot more time to evaluate the situation, but the
pilot must be ready to respond to any sign of stall. My rating is a 0
out of 10 here.

"S" turns?

This might be useful. You are low, but may have time to extend the
your descent. Any turn at this point will require nearly at least 180
degrees of turning (45 away, 90 back and 45 back to final.) and up to
360 degrees with three changes in direction and roll. The advantage
is your speed stays constant and you can see the touchdown point the
whole time. A disadvantages is you are no longer lined up on the
target so your perception changes as you roll and move to the side.
My rating is a 7 out of 10 here.

Slip?

The forward slip can be very effective at bringing "most" ships down.
Check you flight manual of your aircraft and practice at altitude.
The old joke about you could always tell who the Std. Cirrus and
Libelle pilots were because they were slipping on final is true. But
we got very good at it. It would nearly double the sink rate and when
kicked out you were nearly at the correct speed. The Std. Cirrus if
flown even 5 knots too fast would float a long way before settling.
The nice thing about a slip is your speed and angles all stay the same
without speeding up the process. You can use your trained judgment to
say the angle looks about right here and kick out of the slip and
proceed with a normal landing. My rating is a 10 out of 10 here.


Summary
Each situation is different, but I think we should focus on teaching
techniques that are robust and give that average pilot the best
opportunity to have a good outcome in an off-field landing. I know of
very few off-field landings that start at 1000 feet at the end of down
wind. If I have found that much lift on downwind I have cycled the
gear and am climbing out, not landing. Any technique that requires
bleeding speed in ground effect should not be taught as anything other
than a curiosity and never considered for off-filed landings.