I am wondering what happens when i launch at the bottom of a hill/mountain and want to fly up the side of a hill which is higher than 120 meters from where it was launched.
My Mavic is limited to 120 meters height (Aus rules), but what happens when the terrain gets higher and higher?
Will the Mavic climb with the terrain? (manually or will it recognise rising terrain and maintain the height i have sent it too)
Also the inverse. If i launch at higher altitude and fly downwards past the launch height but still at approx 120 m, will it allow the drone to climb back up to me?
Just wondering before i give it a go so theres no Mavic tragedy.

If you launch from the bottom of the hill, you will still be limited to whatever max height you set... i.e. If you set the height to 120M, then the Mavic will not fly above 120M... However, I think the rules regarding flying next to a physical feature like a mountain/building is that you are allowed to exceed the max height restriction if you are within 120M of the object... i.e. you are allowed to follow a mountain up above 120M from your take off point as long as you are within 120M of the mountain at all times.

If you take off from the top of the hill/mountain, you will be able to fly all the way down to the bottom of the hill/mountain and fly back up to your take off location, + up to the max height of 120M above your location.  Again, if I remember the rules correctly, you will need to keep within 120M of the hill/mountain at all times when you are descending...

You'll need to confirm if the UAS rules are correct... I'm going by what I remember reading...

The 120m is taken from your launch point so unless you alter the settings within the app relating to max altitude then 120m from that point is all you will achieve regardless of the terrain.

You cannot exceed the limit set within the app but you can go down past it. When you do a minus altitude will be displayed. I've taken mine as far as -25m from takeoff point without any issues. When landing, it reported as being at 1.5m which isn't unusual following large differences in altitude during flight.  I haven't tested the bahviour of RTH during such a flight however.