Sender: <marv@lancaironline.net> (Marvin Kaye)
To: lml
Date: Thu, 31 Oct 2002 07:24:17 -0500
Message-ID: <redirect-1849254@logan.com>
From: "Ted Stanley" <ted@vineyard.net>
Subject: Twins and Things
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I've been reading many of the posts regarding the Duke crash and in
particular Doug Pohl's post containing the preliminary report about the
crash. Allow me to share a couple of observations:

I have some time in twins (about 2000hrs in a Piper Seneca III and 4000 in a
Beech Baron 58) and I've passed a FAR 135 checkride every 6 months for the
last 18 years or so. Controlling a twin on one engine can be easy or
impossible depending on a variety of factors. Weight, CG, airspeed,
configuration (flaps or gear), equipment (vortex generators for example),
temperature, altitude, available power, etc. all enter into the equation.
The most dangerous time for a twin is low airspeed and high power. Vmc is
the speed at which directional control cannot be maintained in a specified
configuration. The loss of directional control is typically the result of
yaw produced by either too much thrust on one side and/or too much drag on
the other. If you get too slow and add power a roll can ensue which
increases stall speed and then you're in deep trouble. The ONLY solution is
to reduce power, which if you're close to the ground presents its own
issues. During my initial multi-engine training in a Beech Duchess we did a
Vmc demonstration at 5000' msl. We hit Vmc and stall speed nearly
simultaneously and the plane almost went on its back. It all happened in a
split second and I've never forgotten it.

If you want to get some idea of the difficulty of flying a light twin on one
engine see if you can borrow one sometime and simply try to taxi it on one
engine. I can be done but requires special techniques and planning ahead and
some maneuvers will not be possible.

Based on the information provided by Doug it seems that the pilot decided to
depart with known deficiencies in his aircraft. As has been the case of
thousands of pilots who preceded him, that was a poor choice. Very few
accidents occur because only one thing went wrong. They almost always occur
because two or more problems developed at the same time which imposed
challenges on the pilot that he/she was unable to cope with. On this list
I've read of various exploits of people who explored the edges of safety and
were fortunate enough to return to earth unscathed. If you have a known
problem, fix it first and fly later lest an unknown problem be added to the
mix which is a recipe for disaster.

Ted Stanley