High on Final, Summary; was Polar with spoilers extended?
Tim Taylor wrote:
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?
What I do must be taken with a grain of salt, because I'm not an
instructor, pretty much learned how to deal with field landings by trial
and error, have 20 or 30 of them under my belt (5 to 10 in "small"
fields), and have yet to do any more damage than scuff up the underside
of the nose.
First, I *never* fly a normal pattern. I fly directly overhead high
enough to make one or more big lazy circles around the field at approach
speed, so I can look carefully for fences, wires, rocks, figure out
which way the field is sloped, get an idea of the actual wind direction,
potential for sink, get a picture of just how high I am above the field,
and pick the spot where I plan to touch down. When it becomes clear
that I won't be able to make another 360 (and I've found that pretty
easy to determine), I shift the circle as needed to approximate an
abbreviated downwind, base, and final, and will use spoilers, landing
flaps, slips, adjustments to the circle, etc., to get myself into the
field as best I can. I never let myself get out of reach or visibility
to the touch down point, and keep plenty of energy in case it becomes
clear that I need to make a last second shift to a different touch down
point (and that has happened more than once). Using this approach, I've
never found myself too high or low to land when I commit to final
approach...
Marc
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