[Jim Ellis]

I have been trying to find out if anyone has ever been able to make a working serial connection between a Blue Mountain EFIS and a TruTrak autopilot. I have made many phone calls and searched all the web sites.

According the BMA the G3 Lite will provide a gps output through one of its two serial ports in either GPSS (UPS GPS) or standard NMEA-0183 format.
According to TruTrak their autopilots will accept and read GPSS or NMEA-0183 format (with the correct baud setting programed into the autopilot).

Here's the strange part. None of the tech reps at either company can confirm that their units will work with the other. Nor do they know if anyone anywhere has ever made a working connection between the two systems. I find this very odd that the manufacturers don't know the basic compatibility of the equipment they sell.

Here is my question for the Forum. Do you know or have you heard of anyone who has ever made a working gps serial connection between any Blue Mountain EFIS and any TruTrak autopilot? If so, I would love to hear from you.

Jim Ellis
RV9-A, Flying (Yippee!)

 

[tomcostanza]

I asked the same question of BMA. Their reply was that their EFIS worked great with THEIR autopilot. I can understand why they would prefer to sell their own AP, but can't understand why they wouldn't test for compatibility. Some people do buy the AP first, and their AP won't work without their EFIS. I would be interested in anything else you are able to discover.

Regards,

 

[Kahuna]

It works with a G3 driving a Trio via NMEA.
Best,

 

[Jim Ellis]

Blue Mountain Avionics has discovered that the Serial B port on the G3 Lite is inoperative. Regardless of the settings placed in the Setup window there is no output from the unit on this pinout. There is no GPSS or NMEA-0183 information sent even if one selects "none" on the Serial A port.

This means that, in spite of the fact that the Install Manual clearly states that you can drive a Trutrak autopilot with the G3 using the settings provided, the G3 Lite efis is incapable of providing the needed information.

BMA has told me that that have looked at the BIOS software and cannot find the cause of the problem and they are now looking at the hardware as the source of the malfunction.

Jim Ellis
RV9-A, Flying