> I saw an ad for a digital compass from Precision Navigation Inc. It's
> an upgrade of their "Co-pilot" model (which I've seen in the Aircraft
> Spruce catalog) and seems quite nice. Are there any U.S. regs that
> would preclude the use of a digital compass in my Europa (assume it will
> be IFR capable)?
Steve --
FAR 91.205 says only "magnetic direction indicator," and were the plane
to be certified under Part 23, FAR 23.1303 and 23.1327 don't appear to bar
it (as long as it has 10-degree resolution). For IFR certification, the FAA
could balk at any flimsy installation, as some of these digitals mount via
flimsy brackets or even velcro.
It would be good if you could ascertain how it behaves in a bank and in
turbulence. One $50 automotive digital unit I played with was useless in
even a 1/2 standard rate turn. For IFR that's bad, as if you lose the
attitude
and directional gyros in IMC, and the turn coordinator bar is dancing a bit
in yaw, and odd behavior in the compass is going to make things worse.
I'm not saying that the old whiskey compass is any good either. But, I have a
Hamilton vertical card compass that's great for partial panel, as it's well
damped,
has minimal turning error, rotates the right way like the DG, and you can
quickly
interpret small changes. With digitals, you'll be interpreting changing
digits and
(guessing from catalogue picture of the Co-Pilot) an arrow that jumps on
5-degree
(or more?) changes. If you have M$ Flight Simulator, try holding heading in
IMC
using just the digital heading digits on one of the EFIS panels (with 1-deg.
display
resolution, remember), and see if you'd like it in a real emergency.
Just me opinion, though.
Regards,
Fred Fillinger, A063
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