Other users have discussed this feature before, but I want to bring it up once again. VNAV is used to descend, FLC is used to climb.
What it will do is that it will lock a specific speed and change the desired attitude by the users’ throttle settings. It shares the same nose up/down buttons with VS in G1000 systems. The advantage of this mode is when your plane can create a large specific excessive power, you can maximise your climb rate by holding your desired climb speed. I think it will be a great avionics upgrade, how do you think?