On Sun, 23 Sep 2007 19:37:38 -0700, Brian wrote
in . com:


The tricky part of downwind landings is the necessity to extend your
traffic pattern's Downwind Leg (actually against the wind in the case
of a downwind landing) WELL BEYOND (perhaps double or more) what you
are accustomed to in a normal into-the-wind landing. If you fail to
do this, you will overshoot.


You are getting close to one of the answers.

The answer to which question?

Yes with a downwind landing you [are] much more likely to overshoot.

Right. But I can't emphasize too much the necessity to extend the
"Downwind Leg" to WELL beyond the point where the runway threshold is
at a 45 degree angle to the aircraft's position on the Downwind Leg
(as would be normal for an into-the-wind landing approach), so that
there is enough time to descend on final approach without the wind
blowing the aircraft past the threshold while it is still too high to
touch down.

What do you teach as a rule-of-thumb to determine the point to turn
from Downwind Leg to Base Leg?

Since
you may overshoot you are much more likely need to Go Around. On the
Go around two more things happen. One, your climb out will climb out
at a much lower angle which may make it difficult or impossible to
clear obstacles.

Right. While the approach descent-rate can be increased by employing
a forward slip to increase the angle, unfortunately, there is no
reciprocal method available to increase the climb angle.

2nd you will be close to the ground with a higher
than normal ground speed. The illusion of speed when combined with
approaching obstacles will make you want to climb a[t] slower than normal
airspeed[,] setting you up for a perfect Stall/Spin scenerio.

Good point.

Fortunately, I haven't experienced a downwind go-around into rising
terrain, but wouldn't the orographic lifting of the wind against the
terrain produce some updraft (or vertical component) to assist in
increasing the rate of climb? Or is that just wishful thinking?

In fact I know of several Stall spins that have occurred exactly this
way.

The illusion is so strong, it's easy to understand how that might
happen if the pilot fails to monitor the airspeed indicator to
maintain Vx speed on climb-out.

One of my favorite demostrations is to simulate a power failure on a
windy day (and no one else in the pattern) when the only runway option
is the downwind runway. Once the student [has] shown me they have they have[sic]
the runway made or they overshoot, (as they often do) I request a go
around so they can see how poor the climb angle really is when
departing downwind. With a 15 to 20kt tailwind in a C-150 or Tomahawk
this climbout can be impressively low.

Brian
CFIIG/ASEL

I can see how that would be important.