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Path: utzoo!linus!philabs!cmcl2!lanl-a!ths
From: ths@lanl-a.UUCP
Newsgroups: net.aviation
Subject: Turning Back
Message-ID: <14163@lanl-a.UUCP>
Date: Mon, 1-Oct-84 12:12:26 EDT
Article-I.D.: lanl-a.14163
Posted: Mon Oct  1 12:12:26 1984
Date-Received: Tue, 2-Oct-84 07:38:14 EDT
Organization: Los Alamos National Laboratory
Lines: 41


This morning I gave my student a simulated engine failure at 350' AGL
over the departure end of rwy 20 at Santa Fe (field elevation 6344' MSL).
I had previouly requested that she attempt to turn back when I called the
engine failure, so she was briefed and ready (so was the tower).

IAS was 65 knots (approx best angle) in a C-172, about 200 lbs below gross
with OAT at 42 degrees. When I reduced power to zero, she looked out the left
side, determined that since she was slightly right of the center line, a left
was most appropriate. She then executed a 35 to 45 degree banked turn while
putting in full flaps. I suggested that perhaps full flaps might bring her
to the ground before she completed the turn, so she immediatly backed-off
to 20 degrees.

I have to admit to being very suprised at the outcome. We not only were able
to complete a 180 but also had enough altitude left to maneuver back to
the center line of the runway. We touched down about 1500 feet down the
runway.

The key to the maneuver seems to be:
1) Start the turn ASAP,
2) keep the airspeed reasonably low to reduce the radius of turn and to keep
   the rate of turn high. The flaps seemed to do this almost automatically.
3) Use at least 35 if not 45 degrees of bank angle.

I recall going thru this exercise with another student in his C-182 a few
years back but I don't have the numbers we came up with. The conclusion about
airspeed and bank angle were the same.

As far as "teaching" the maneuver I am still somewhat divided. Performing
in a C-152, C-172 or even a C-182 is quite a bit different than in a
higher wing loading a/c like a Bonanza or Lance. I think the student is
better-off being taught the method BUT carefully advised that an unexpected
power failure within 500' AGL might best be handled by the "whatever you can
see out the front windscreen is where you should set it down". The odds for
survival are almost 100% using that axiam. Turning back to the runway will
probably result in a stall/spin  perhaps 25% of the time. Even if sufficient
altitude would have allowed completion of the maneuver.

I am also a firm believer in nothing greater than a medium bank turn under
"normal" conditions in the pattern.