I live in the Adirondack mountains on the side of the mountain at an MSL of 253 feet and the mountain I live on height goes to 1500 feet.  If I set my return to home elevation at its max which is 50m, and I fly to the top of the mountain which is 1500 feet and I lose connectivity with my controller will the drone drop down  and hit the mountain or will it stay 150 feet above the ground as it returns home.

if you are unsure, i wont use the RTH, just fly it back to starting point manually until you get a feel for it.

You should be able to set your RTH higher than 50m if needed. But setting that aside, all heights are relative to the take off point. So if you fly to top of mountain that's 1500-253=1247 feet above take off point. It's always best to fly home under your control, but if you were to use RTH then it would stay at 1247 feet as that is above the 50m altitude you set, all relative to take off point. If you flew 100m from take off and were at an altitude of 20m (65ft) and pushed RTH it would then climb another 30m to take it to the 50m above take off point, and then it would fly straight back before landing.

From my understanding when RTH is initiated if the drone is already above the RTH height it will not drop. You can set RTH at any altitude, the max is not 50m

Aardvark Posted at 2017-12-30 08:58
You should be able to set your RTH higher than 50m if needed. But setting that aside, all heights are relative to the take off point. So if you fly to top of mountain that's 1500-253=1247 feet above take off point. It's always best to fly home under your control, but if you were to use RTH then it would stay at 1247 feet as that is above the 50m altitude you set, all relative to take off point. If you flew 100m from take off and were at an altitude of 20m (65ft) and pushed RTH it would then climb another 30m to take it to the 50m above take off point, and then it would fly straight back before landing.

In that scenario, the drone would be at a heck of a height relative to home point when it got "home" if returning under RTH command. Would that not infringe Max Height (relative to ground) regulations? In France it's 150 metres in many places, and just 50 metres or even as little as 30 metres in many others.

Blériot53 Posted at 2017-12-30 09:15
In that scenario, the drone would be at a heck of a height relative to home point when it got "home" if returning under RTH command. Would that not infringe Max Height (relative to ground) regulations? In France it's 150 metres in many places, and just 50 metres or even as little as 30 metres in many others.

You are correct in what you say, and that might be one good reason where it is better to manually fly home rather than using RTH.

post #3  is correct if it is above your RTH setting it will stay at that height even in the case of loss of signal...............

Aardvark Posted at 2017-12-30 09:19
You are correct in what you say, and that might be one good reason where it is better to manually fly home rather than using RTH.

I would do the same too, fly manually rather than using RTH

BagoDJIoperator Posted at 2017-12-30 12:52
I would do the same too, fly manually rather than using RTH

The only time I have used RTH is when testing in an open area to make sure it works as expected. I've not used it yet during a flight, if I've ever lost sight of P4 then I've always used 'radar' to point it in the right direction until I get visual on it again. And of course the nice 720P FPV view helps as well :-)