Thomas Pappano wrote:

The 196 update rate is still only once per second, (same as inexpensive
units)

Interesting!

Well, when able, I will try the "rudder only" bit and report on
my experience. In theory, if the heading info is all that matters
and the update rate is 1 per sec, any GPS should do...

I'll confess my suspicion.

My suspicion is that some GA aircraft, such as little Pipers and
Cessnas esp. fixed gear models of same, are sufficiently stable
that the plane will stay in control so long as the pilot doesn't
flagrently get in its way.

My suspicion is that other GA aircraft, such as Mooneys and
Bo's and perhaps little fixed-gear Grummans, Katanas, maybe
the RV series (basically anything with a reputation for being
'sporty' to fly, are sufficiently light and sensitive in pitch
that this has to be paid attention, it really won't take care
of itself.

I think there's some evidence to this regard. I don't think it's
coincidence that in the vacuum failure study, the C172 and Archer
pilots all kept control of the plane and a good portion of the Bo
pilots "lost it".

It's possible that there's a work-around -- power back and dirty
it up perhaps.

Please note I'm not trying to say these planes can't be flown
partial panel or with limited instruments. They can. But I don't
think a GPS for heading info suffices, no how no way.

I will also try a repeat of all or part of this excercise at night for a
closer
to IMC experience. My experience has been that "actual" is easier to
fly because the sun, shadows, and glimpses seem to distract more
than help. 8-)

They may distract your conscious mind, but what research I'm aware
of suggests that they are keeping your primitive vestibular system
calibrated and happy (whether you know it or not), so that you don't
have to deal with your reptile brain screaming at you "WE'RE TURNING!
WE'RE STILL TURNING YOU DAMNED FOOL TURN THE OTHER WAY! RIGHT NOW!".

Thanks again for posting,
Sydney