Originally Posted by Maverick972
I upgraded to the vision 385 this year and it is wired up to the Garmin 430 and the GRT HXr.
I also have a switch that is GPS or EFIS.
According to the drawing. RS232 data drives the auto pilot when the switch is in GPS position.
I am assuming that it uses ARING data when in EFIS position as it is wired up that way.
My question is why cannot I control my auto pilot from the HXr or the unit go into GPSS mode when the switch is in EFIS mode. What am I missing? Settings? User error? (More than likely)
Thanks for the help. Sean
I also upgraded to a Vizion 385 from an older TruTrak A/P after Oshkosh. My setup was a GRT Sport SX EFIS (with external ARINC), TruTrak 385 A/P, Garmin 430 (non WAAS), and a switch for EFIS or 430 to drive the A/P. I also had to add the A/P software to the SX as I did not have that installed, I believe the HXr has it as standard.
I had an issue when I first installed the EFIS where I could not get the GPSS on my old A/P, it turned out to be two wires installed on the wrong pins on the switch.
In learning the new A/P I was told other than engaging the A/P I was to control it through the EFIS, which it did, sort of.
I am nearing a point where I have the process down.
One very important step is to not move the aircraft until the A/P is powered up and ready. The A/P does sync the altimeter with the EFIS so I do not have to set that, with the switch in the EFIS position.
I set the desired altitude on the EFIS by accessing the A/P commands, set desired climb speed, and descent rate, turn on the flight director, select source (heading, ENAV, or GNAV), and arm the approach if necessary. The A/P must be engaged by pressing the large knob, there is no way to engage the A/P from the EFIS, I wish there was. I engage the A/P after takeoff, the EFIS drives the A/P based on the altitude set and the GPS navigation from the 430, assuming the nav source is set to the 430.
The unit worked fine with the 430 except it would climb through the altitude set on the EFIS. Since it was a non WAAS unit I did not get any vertical GPS approach commands from it, I decided to upgrade to an Avidyne IFD440.
I am still working on a process to get the A/P to not climb through the altitude set on the EFIS. As of now I have to disengage the A/P and re-engage it while level, this is not desirable and I am working on why it behaves this way. I have contacted GRT, Trutak, and Avidyne but am still working on the issue.
As of now I believe the issue is not the EFIS or the IFD440, it is the behavior of the A/P. I have spoken to TruTrak/BendixKing twice but have gotten no where with them, each time I get another person at BendixKing support with no record of my previous call.
Once re-engaged while level the A/P works flawlessly with the EFIS and IFD440.