CNS-80 VNAV

On Tue, 26 Oct 2004 03:37:16 GMT, "John R. Copeland"
wrote:

Now, though, non-precision LNAV approaches with defined vertical paths will
display vertical guidance only on the new NAV display page of the CNX-80,
but the external VDI instrument will not display that same vertical guidance.
In LNAV, my glideslope flag is retracted, but the glideslope pointer is driven
beyond the end of the scale, hiding it from view throughout the approach.

That's unfortunate. But I would think it would be more logical to also
flag the glideslope.


In the remaining case of LNAV approaches without defined vertical path,
the VDI portion of the CNX-80's NAV page is entirely absent.

That makes sense.


As I mentioned in a follow-up post, later than the one you replied to,
the intentional suppression of drive to external VDIs effectively prevents
a 3-axis autopilot from locking onto the vertical guidance information
during a non-precision approach. The pilot must manage the descent.

I do not know whether that choice was at Garmin's volition,
or whether it was an FAA requirement.

I suspect the latter.


--ron