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RTH behaviour in altitude limited zone

Tolly

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Talking to a fellow drone enthusiast an intriguing question cropped up and I'd love to know the answer. If I fly in an altitude restricted zone, say 150ft for arguments sake, and I have a RTH altitude of 200ft set how will the drone behave when I press RTH? Will it return to home at below 150ft or will RTH fail and the drone just hovers or worse still lands? Love to hear your views.
 
My experience shows that it will not climb to 200 , it will just come back to the Home Point .
The Alt Zone for my area is 492 ft and the drone will not go any higher.

Phantomrain.org
Gear to fly in the Rain.
 
If I fly in an altitude restricted zone, say 150ft for arguments sake, and I have a RTH altitude of 200ft set how will the drone behave when I press RTH?
The best thing to do would be to run your own experiments. Just make sure that you are always within radio range with your controller so that you can cancel RTH and take control if things don't go as expected.

In this situation the best solution would be to ensure your RTH height is configured to less than 150ft, as that will always allow the drone to come back under that altitude restricted zone.

But, if your RTH is configured to 200ft, my guess is that there are two scenarios.

One, you're currently flying safely under the altitude restricted zone. If you press RTH, the drone will first try to climb to its configured 200ft RTH height, but will bump into the 150ft ceiling restriction and be stopped from climbing any higher. What happens then? I don't know. But you can cancel RTH and resume control.

Two, you're flying somewhere outside of and beyond the altitude restricted zone. Press RTH and the drone will first climb to its configured 200ft RTH height, then turn for Home. When it bumps into the outer edge of the 150ft altitude restricted zone it will stop and be prevented from entering the altitude restricted zone. If you still have control signal, you can either cancel RTH and/or simply decrease throttle to descend to less than 150ft to allow the drone to safely traverse under the altitude restricted zone.

It's similar to other GEO zones. If you fly your drone around to the backside of a GEO zone, and then lose the control signal, the drone will go into RTH mode and fly a straight direct line back Home. If that straight line intersects a GEO zone boundary, it's like running into a brick wall. It'll stop. If you regain control signal that gives you options to navigate back around the perimeter of the zone. But I suspect if you have no control signal the drone will just sit there until low battery forces it to land.
 
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It will depend on the simple fact if the restrictions is "hard" or "soft"
A hard restriction is one that is enforced in the fly-safe-software. I assume that the fly-safe will block exceeding the permitted altitude.
A soft restriction is one that is in place, but not enforce through DJI. I had several of those flying in Sweden, relativly close to an airport. The tower permitted me to fly up to 50 meter, the software didn't care. So it was me who told my drone to behave by setting the limits to 49,50 meter.
 
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A hard restriction is one that is enforced in the fly-safe-software. [...]
A soft restriction is one that is in place, but not enforce through DJI.
That's certainly also something to be aware of. The various types of DJI fly-safe GEO zones will affect how your DJI drone operates. But those don't always accurately correspond to actual legal restrictions.

For example, DJI puts only an Enhanced Warning Zone over Niagara Falls, or over our Parliament Buildings in Ottawa . According to DJI, those only require your acknowledgement of the risks to self-authorize and cancel the warnings and then you're good to fly.

However, both of those areas are legally Flight Restricted Zones surface to 3000ft, CYR518 & CYR537 respectively, applicable to ALL aircraft without explicit permission. Those are actually "hard" legal restrictions, but only "softly" enforced by DJI.
 
That's certainly also something to be aware of. The various types of DJI fly-safe GEO zones will affect how your DJI drone operates. But those don't always accurately correspond to actual legal restrictions.

For example, DJI puts only an Enhanced Warning Zone over Niagara Falls, or over our Parliament Buildings in Ottawa . According to DJI, those only require your acknowledgement of the risks to self-authorize and cancel the warnings and then you're good to fly.

However, both of those areas are legally Flight Restricted Zones surface to 3000ft, CYR518 & CYR537 respectively, applicable to ALL aircraft without explicit permission. Those are actually "hard" legal restrictions, but only "softly" enforced by DJI.
That's what I meant with the "hard" and "soft" ones. The hard ones ar the easiest, for the soft ones, you need to act as a responsible pilot (as all visitors in this forum always do...)
 
This is a bit off topic but you might be interested in what happened to me last week. When I took off from a place that I had never flown from before a warning came on telling me that return to home had been turned off by the software. The reason was that I was relatively close to a youth detention center. Of course, I landed manually, but had a spotter help me keep track of my Mavic 2 pro so that I did not have to worry about about trying to trigger RTH. I use RTH fairly often. I guess DJI did not want anyone using a drone at the detention center.
 
... a warning came on telling me that return to home had been turned off by the software. The reason was that I was relatively close to a youth detention center.
Did it actually say RTH was "turned off"?

It probably said something more like you were near the no fly zone around the youth detention centre, and entering this area "may interrupt RTH" and cause the aircraft to hover.

It's like I said above. If you flew around to the far side of this GEO zone and then lost signal, and your straight line RTH path to Home crossed the GEO zone, the drone would stop and hover when it encountered the farside edge of that zone. If you had no control signal at that point, you'd be out of luck. The drone could no longer automatically return home because it's stopped at the edge of the GEO zone. It would just hover there until it auto-landed with low battery.

The edges of the GEO zones are clearly shown on the app's map display. It's important to take note of those to ensure your RTH path never encounters any of those zones.
 
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Yesterday I flew around an abandoned resort which had its own airstrip. There was a height restriction lower than where I had RTH set, so on take-off it said the RTH altitude had been adjusted. Strangely, even though it was lower than it had been, it was still 7m above the height restriction.
 
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