I've done a few flights now, and I'm a bit puzzled by the automatic navaid tuning. What logic does it use to choose the next navaid to tune, and is there a way to influence this? Om my flights it seems to only automatically tune a navaid on or close to the departure airport and maybe one more along the route before it stops. I can manually find and tune navaids that are in range even though the FMS doesn't.

For example I flew from TNCM to TNCA. The FMS had tuned a navaid on departure (might have been PJM, I can't remember), but never tune the next one even though several were in range (for example ABA at Aruba).

Just curious if this is expected behavior from this FMS, what logic it uses to tune the next navaid, and if there is a way to tell it which navaids to tune automatically.

Thanks again!