So here’s what I found out that may help others - please correct me if something needs it.
1. The VKB FSM-GA box is almost a carbon copy of the Garmin GMC 507 Autopilot Control Head (picture of FSM, then the Garmin below). You can literally refer to the pertinent parts of the Garmin manual for instruction on how to use and setup your FSM module (http://daytonpilotsclub.org/wp-content/ ... Manual.pdf). This excerpt from Garmin is also a great primer on how their autopilot systems work.
Note you can benefit using Spad.next, Axes and Ohs or MobiFlight to utilize conditions, controls and variables not available in the MSFS in-game controls - it’s more work upfront but well worth it in the results. Lots of online support.
FSM-GA
![Image](https://flightsimcontrols.com/wp-content/uploads/2021/10/16_FSM-GA_4SH_750_2.jpg)
Garmin GMC-507
![Image](https://flyer.co.uk/wp-content/uploads/2018/03/Garmin-GFC_500_AP_controller.jpg)
2. It has 3 encoders (dials) - HDG, ALT and wheel for VS. Like in real life AP panels, the two HDG and ALT should always set HDG and selected ALT.
The VS wheel on the other hand has to be set for dual purpose. Changing target VS for VS mode, changing target IAS in IAS and FLC modes - in some planes and addons it does that automatically. If wheel up down command is not available for the addon (ex.) then you might need to do a conditional event yourself if using Spad, AAO or Mobi.
The left encoder controls HDG and Track. So If addon uses a similar AP module, you can set the left encoder with dual functions as well. If using Spad or other program you can use a mappable local variable as condition, (ie local variable you create is ON (1, for ON for example) dial changes HDG. If variable is a 0 (OFF) you would change TRK. Alternatively you can use AP state LVars as conditions as well if they are available for the aircraft addon. For example if TRK mode is active, send CRS increase/decrease events, if HDG mode is active send HDG BUG increase/decrease commands. etc etc.
Hope this helps - was surprised to find so little information on how to do this. I know. I know - 'You're supposed to figure out all this yourself!" Looking forward to learning more from others!