What's new
Van's Air Force

Don't miss anything! Register now for full access to the definitive RV support community.

Garmin GNC-255A question

P

PH-SCP

Well Known Member
Hi,

Recently installed a Garmin GNC-255A NAV/COM in my RV-9. No external CDI/HSI.

When pushing the NAV side of the unit, I see T/F and OBS fields below the selected and stand-by NAV-frequencies.
The handbook says that the display of OBS and T/F information is only available when an external CDI/HSI is connected but is there any way around this ?
In other words, can I get VOR radial information on my GNC255A without any external CDI/HSI connected ? My other radio is the Garmin SL-40 and it has no problem showing this information without an external CDI/HSI...

Your comments are welcome.
 
Don't know much about your 255A but your SL-40 is com only, no nav. You probably meant SL-30.

Michel
 
You can manually enter a radial and get the digital CDI to work if you have no external indicator connected. From the pilot's guide:

2.3 OBS Mode
There are four different CDI configurations, which allow the installer to
configure the GNC 255 to the type of CDI indicator that is connected. The
installer-set CDI configuration will determine the operation of the OBS Mode.
If the system is configured with an analog or digital external CDI/HSI, the OBS
radial of the remote display will be decoded and displayed on the screen of the
GNC 255.
Press the OBS key to see the current OBS setting and graphic CDI.
NOTE: The Identifier is the decoded NAV identifier from the Morse code
broadcast by the station.
If the system is configured with a composite external indicator, the OBS mode
will be unavailable. If there is no external CDI/HSI providing OBS control, the
outer and inner knobs can be used to change the displayed OBS value.
The GNC 255 graphic CDI is shown as a graph of five dots right or left of the
triangle icon. Each dot indicates two degrees deflection with ten degrees full
deflection to each side. Fly towards the bar to be on-course.
 
You must log in or register to reply here.
Back
Top