"Jeremy Lew" wrote in message ...
I think the point of Dan's question was to inquire whether you have tested
your theory that a GPS-derived HSI's lag is 'dangerous' or not. Everything
I've read suggests that it's perfectly possible to keep the plane upright
using this, although you'll tend to oscillate around your intended attitude
a bit because of the lag. I have a Garmin 196 which has this kind of setup,
but I have not really tried to use it as my primary instrument. I'm going to
do that test soon.

I've heard good things about it, but IMO a simple
GPS moving map is very helpful partial panel,
especially if a 'direct to' button has set up
a courseline. It is not a primary instrument,
and I would not want to depend upon it to keep
the plane upright, but in any kind of rough air
where the compass and TC are bobbing a mad dance
it is very helpful in assessing how well I am
doing at holding heading (ie, at keeping the
wings level).

Obviously other people's milage can vary, and does

Sydney