GPS/NAV source configuration suggestions. AF-A/P question.

[ArjanPlomp]

The following question will be asked to Ken at Advanced as well, when he returns from S&F, but I thought it would be good to have it here as well.
We have Dual 3400s's, Arinc module, AFS GPS, AFS A/P and a 430W.

Configuration (on main screen) is as follows:
Serial 1: AVTN/ARNAV (from 430W)
Serial 2: TRFC/ICARUS
Serial 3: ARINC
Serial 4: AF-GPS

GPS/Nav 1 Datasource: Serial port 3 (ARINC)
GPS/Nav 2 Datasource: Serial port 4 (AF-GPS as backup)
GPS/Nav 3 Datasource: Serial port 1 (AVTN/ARNAV coming from 430W)

LAT/LON Data Source: Serial port 1

Question is that if I set a direct to on the 430W, only when I switch the map source to GPS/Nav3 will the direct to line appear on the 3400. Is this correct? Am I correct assuming that Arinc is only used for NAV of the 430W? If this is the case I might want to swap GPS/Nav1 and GPS/Nav3 as GPS of the 430W will be our primary means of navigation.

Also, should the AF-A/P not show the identifier the waypoint it is flying to? It shows correctly that it has a 'GPS fix', but how do I test that it correctly receives ARINC data?

We had a wiring problem (the shop doing our wiring made a few mistakes), but I believe I have it fixed. This post is just to confirm my findings.

Alexander Plomp

[ArjanPlomp]

Me=dummy. Switching between GPS and NAV is done using the CDI button on the 430W. Still don't quite understand the difference between using ARINC as input vs. GPS. Also, I like to change the data fields on the MAP page so that I can say 'distance to destination' rather than distance to next waypoint when on an approach (for radio calls for instance). Any way to modify this?

[AltonD]

Here is the way I understand ARINC and trutrak auto pilots (AKA AFS autopilot):
The 430 GPS provides ARINC steerng commands.
Arinc steering commands will begin a turn BEFORE the ap reaches the turn point. It will not over shoot (it rounds the corners). GPS steering commands will not command the turn until you have actually reached the turning point. It overshoots and comes back t course.

The AFS/Trutrak AP does not really accept Arinc steering commands from the 430W. The AFS 43 module fixes this.

[Rob Hickman]

Alexander,

Your problem is that you have the nav3 data source set to serial port 1, set it to none and it will be fixed. when you select a Nav source to our Arinc module it also gets the waypoints from the aviation serial port. All examples in the manual show it correct.

[Rob Hickman]

Configuration (on main screen) is as follows:
Serial 1: AVTN/ARNAV (from 430W)
Serial 2: TRFC/ICARUS
Serial 3: ARINC
Serial 4: AF-GPS

GPS/Nav 1 Datasource: Serial port 3 (ARINC)
GPS/Nav 2 Datasource: Serial port 4 (AF-GPS as backup)
GPS/Nav 3 Datasource: None
LAT/LON Data Source: Serial port 4

NOTE: YOU SHOULD NEVER HAVE A NAV SOURCE POINTED TO THE 430w RS-232 Serial Data port if you are using the ARINC adaptor. The EFIS knows to merge both data sources together to make it work. If you have a NAV source pointed to the 430w RS-232 serial port and one pointed to the ARINC it will mess it up and you will not get your waypoint ID labels.

[ArjanPlomp]

Hi Rob,
This is now clear to me, although I did not see that in the documentation.

You state to use LAT/LON Data Source: Serial port 4 (AFS-GPS), but the latest software release does not have this as an option anymore. It has something called VPX(?) instead? Also, is the data from the AFS-GPS not less accurate for Lat/Long purposes than the 430W GPS? That was the reason I configured the 430W into a serial port and used that for Lat/Long.

Best regards,
Alexander