I'm trying to figure out my (new to me) RV-7. It has an ADV-5600 non-touch,ADV-AP, GTN-650. Everything works great minus the VNAV. I have NAV and VNAV Selected, after capturing my initial altitude, I tried selecting my DA in the altitude pre-select but it's starts to descend prior to intercepting the Glide path. Should ALT be selected as well as VNAV to make it descend at the Glide path intercept? If so, how is that achieved?
My background is Collins, so this is all Greek to me.
Thanks in advance.
Ricky