Autopilots... failure modes

"Michael" wrote in message
om...

http://avionicswest.com/articles/kno..._autopilot.htm

That's not a bad article. I do have some issues with it.

First off, it ignores the most important difference between rate-based
and attitude-based autopilot - performance in turbulence in a slick
airplane. Attitude-based autopilots (those that use pickoffs on the
horizon gyro) work all the time. Rate-based autopilots (those that
use pickoffs on the turn coordinator) work in smooth air or with
light, draggy airplanes. In a heavier slicker airplane, especially a
twin, turbulence makes for a very uncomfortable ride because all the
corrections are too much too late. There are NO rate-based autopilots
in the transport category - they just wouldn't work.

You might want to take a gander at this article. I'm not sure what you mean
by slow corrections, but evidently S-TEC (taken with a grain of salt) has
optimized the corrections, as well as smoothed them to avoid overstressing
the aircraft in turbulence.

See Pages 6 & 7.

http://www.s-tec.com/pdf/autopilotbook.pdf


Matt
---------------------
Matthew W. Barrow
Site-Fill Homes, LLC.
Montrose, CO