What would happen if I lose signal of my Mini 4 Pro behind a hill that is higher than 50m and my drone is triggering auto RTH? Would it bonk into the hill? Or go higher from its disconnecting point before trying to go back to base? Would its obstacle avoidance make it hover just over the hill? Sorry for my drawing skills 
It depends on the lost signal option. I believe there are 3 options: Land, RTH, or Hover.
If you have RTH set to 50m:
- Drone loses signal.
- Auto starts the RTH.
- The drone will reach the selected altitude (50m in this case).
- It will then return at 50m.
- If it encounters an obstacle, it will try to avoid it, but since it’s a whole mountain, it might crash into something the sensors can’t pick up, like a tree or bush.
If you plan to try this, make sure to set the RTH altitude higher than the tallest building or mountain.
@Zyler
I always tweak these settings depending on where/how I’m flying. I don’t know why they’re buried so deep in the settings.
Blaine said:
@Zyler
I always tweak these settings depending on where/how I’m flying. I don’t know why they’re buried so deep in the settings.
You can access them easily via the drop-down menu that appears when you press the status information (ready to fly or the errors).
@Zyler
Yeah, I always have mine set to 70m RTH. It is extremely rare to have obstacles near me above that height. That fly-home function has saved me a few times since I have a Mavic Mini SE, which has a limited range if anything is in the way.
It depends on your RTH settings. Generally, it will lose connection, activate RTH, fly to the specified height, and return to you.
It’s not really a good idea (and possibly illegal) to fly your drone where you can’t see it, especially behind a large hill. The obstacle avoidance may try to take it over the hill but too close to the ground and hit a small tree branch, power line, or another hard-to-see object. You’d better hope it doesn’t crash into a car or person.
Best practice is always to set RTH higher than the highest obstacle in the area.
@Jules
Thanks. I think you’re right.
A hill, not a tower. Why don’t you set up the test? I’ll give my hypothesis: I believe that while the obstacle avoidance is on, the drone would try to go above the hill, trying to return to its takeoff coordinates. In winter, there’s a good chance it could crash into the top of the trees without seeing the branches. Good question though. I had my drone fly above my RTH height because of the thick fog that came in over the hill. I put it in forced landing mode and managed to get it back, but I was thoroughly confused for a moment.
Change the RTH setting to set your altitude higher than you think the hill is, and it will fly higher to return home.
Chances are it will keep attempting to RTH at your RTH altitude until it runs into critical battery levels, where it will perform a forced landing. It really depends on what the sensors pick up from the obstacle.
This happened to me when I was flying it on a remote island and I flew around a mountain.
The drone just came back to me, and I regained the signal too.
I might get downvoted for this, but I had no way to get close to something I wanted to record, so I parked across the street, set RTH height to 350 feet, and went up and over a 20-story building. I lost signal, and it made it back to me.
If the signal is lost, it will RTH, land, or hover, depending on your settings. If it’s RTH and it flies a bit closer or higher, the signal may return, and you can fly it again… or let it come toward you.
@Zen
If I recover the signal, will auto RTH disable?
Tobi said:
@Zen
If I recover the signal, will auto RTH disable?
No, if it recovers it will still go into RTH unless you take control yourself.
I’ve faced this situation exactly. My drone never flew higher than the RTH height, so it was lost.
What happens if the drone loses signal at 70m and starts auto RTH? Will it go lower at 50m before coming back or just come back first?
This happened to me once. The drone kept trying to bump into the mountain and stopped like a mad Roomba. Luckily, I regained the signal and manually piloted it after running back to my car to grab a backup battery pack and charge the remote. It was on fumes and about to sink into a waterfall. Iceland is so beautiful, I hadn’t noticed how much remote battery I’d used!
Haha, I did this post exactly because I went to Iceland and there was some basalt waterfall behind a hill and it would have been too hard to climb on the hill that was hiding it. I think it was Svartifoss waterfall :
