Garmin GNC-430 & CDI

Thinking of getting a Garmin GNC-430 and installing it in my experimental.
Is an external CDI required for the GNC-430 like it is for the 300XL?

Thanks for your help.

Paul Lee
---------------------------------

In article ,
Paul Lee wrote:
Thinking of getting a Garmin GNC-430 and installing it in my experimental.
Is an external CDI required for the GNC-430 like it is for the 300XL?

(you mean GNS-430?)

My understanding is that you always need a CDI for IFR certification,
along with certain blinky indicators (which may be provided by the GPS
itself if it displays them (and the GNS-430 does) and it's close enough
to the primary nav instruments). The GNS-430 does have an onscreen
CDI-like display you could use alone in a VFR-only installation.

--
Ben Jackson

http://www.ben.com/

"Ben Jackson" wrote in message et...
In article ,
Paul Lee wrote:
Thinking of getting a Garmin GNC-430 and installing it in my experimental.
Is an external CDI required for the GNC-430 like it is for the 300XL?

(you mean GNS-430?)

My understanding is that you always need a CDI for IFR certification,
along with certain blinky indicators (which may be provided by the GPS
itself if it displays them (and the GNS-430 does) and it's close enough
to the primary nav instruments). The GNS-430 does have an onscreen
CDI-like display you could use alone in a VFR-only installation.

Of course, it's not clear what "IFR certification" is needed for homebuilts.
Most operating limitations say IFR is OK if the aircraft is equipped via
91.205. Since STC's aren't required for homebuilt installations (supplement
to what?)....

GNS-430 ? Yes, you need an external CDI because course guidance from the
VOR, LOC, and GS receivers is never shown on its screen.

GNC-420 ? No, you don't need once because you can use the screen.



"Paul Lee" wrote in message
om...
Thinking of getting a Garmin GNC-430 and installing it in my experimental.
Is an external CDI required for the GNC-430 like it is for the 300XL?

Thanks for your help.

Paul Lee
---------------------------------

Here is my $.02 worth, typed quickly on my way out the door.

For the Garmin GNS 430, you would need the CDI for the VOR and localizer.

I believer that you need a CDI to certify any GPS for IFR. Let's say that
you were looking at a GNS 420 or 400 without the VOR. I think that you
would still need the CDI for IFR certification even though you can navigate
quite well without the CDI.

If you were not seeking IFR approval, then I think that you could get away
without a CDI.

The data fields on the map display can be reconfigured. I would suggest
configuring one to TKE (Track Angle Error), which is the difference between
TRACK and DTK (Desired Track). It is the amount of course correction that
you need to parallel the course. Configure another field to XTK (Cross
Track Error). These two data fields are enough to track a course. You have
two fields left, perhaps distance and next waypoint would be good choices.

The map provides a good reference and the digital data provides precision.
This is a very useful navigation interface and does not require a CDI to
navigate.

John Bell
www.cockpitgps.com

John,

****I believe that you need a CDI to certify any GPS for IFR****

I'm pretty sure the CNX80 is able to be IFR certified without an external
CDI. There is an internal CDI and controls for it built into the unit. If
you have any picture of the unit the CDI is directly below the frequency
windows.

At least, I read that somewhere. I have a pile of stuff around here for the
CNX80, and have been playing with the demo unit for quite some time. My
panel doesn't have room for the CNX80 and a MX20, but I might just install
the CNX80.

GarminAT says that the CNX80 and 430 will soon talk to each other. I notice
that the CNX80 literature says that it will accept syncro heading input. I
wonder if that means directly from a King HSI 55A or if it has to go through
a air data box first, like a 430 requires. Will find out monday.

Best,
Karl

In article ,
karl gruber wrote:

****I believe that you need a CDI to certify any GPS for IFR****

I'm pretty sure the CNX80 is able to be IFR certified without an external
CDI.

If it's close enough to the main T you can install it without the
annunciators (message, parallel track) which are displayed in the lower
lefthand corner of the display. When I was reading the installation
manual I didn't see a similar exception for the CDI.

--
Ben Jackson

http://www.ben.com/

****Ben Jackson****
****When I was reading the installation manual I didn't see a similar
exception for the CDI.*****

SEE:

http://www.garminat.com/aviation_consumer/AC_CNX80.html


Karl