safest RTH height for set it and forget it?

[OurAngryBadger]

I don't fly near skyscrapers so thr only thing I'd ever need to avoid when RTH is high power lines or tall trees.

According to

Transmission tower - Wikipedia

en.m.wikipedia.org

180 ft are at the high end for typical range,

and according to

Hitchcock Center for the Environment | Education for a Healthy Planet

www.hitchcockcenter.org

184 ft is the highest tree in northeast USA.

So could I set RTH height at 200ft and be mostly safe in all scenarios? Or is there any major disadvantage using that high of a RTH height? I can imagine maybe as a disadvantage, extra time needed to ascend high enough, maybe an extra minute or two. I wonder what a good battery % RTH setting would be to account for going to 200ft for RTH?

 

[old man mavic]

its really better to check the area you are flying in and see what tall objects are in your path ,then you can adjust your RTH height accordingly ,for places without tall trees or pylons then 120 ft would get you home safe

 

[Bekanne]

I'm with old man mavic on the 120. Lots of trees where I'm at but the highest one is under 100 feet.

 

[Lastrexking]

Weather on the day might have an impact, so I set mine after I’ve checked the wind.

 

[msinger]

could I set RTH height at 200ft and be mostly safe in all scenarios?

That might work if all surrounding terrain is flat.

Want to always play it safe? Find the tallest obstacle above the takeoff point and then add ~50 feet.

 

[Harold Morgan]

High power lines can go up to 200 feet. So I set myself at 250 because that saved my butt once on a waypoint mission.

 

[Goin Up]

One other consideration to be aware of--after a DJI firmware update, your settings are reset to OEM...that RTH is approx 70-ft.

 

[B52-D]

I don't fly near skyscrapers so thr only thing I'd ever need to avoid when RTH is high power lines or tall trees.

According to

Transmission tower - Wikipedia

en.m.wikipedia.org

180 ft are at the high end for typical range,

and according to

Hitchcock Center for the Environment | Education for a Healthy Planet

www.hitchcockcenter.org

184 ft is the highest tree in northeast USA.

So could I set RTH height at 200ft and be mostly safe in all scenarios? Or is there any major disadvantage using that high of a RTH height? I can imagine maybe as a disadvantage, extra time needed to ascend high enough, maybe an extra minute or two. I wonder what a good battery % RTH setting would be to account for going to 200ft for RTH?

Just to give you an additional scenario, if you set your RTH to 200 Ft. , you could be setting yourself up for an altitude bust if you were flying in controlled airspace with a 150 ft. AGL grid. ????

 

[Dave Maine]

There will never be a set and forget safe setting. You will need, as the pilot in command, to use your airmanship skills to avoid trouble.

It is not just terrain problems - gradients, trees, buildings etc. The wind will be higher at altitude, and a high wind from the wrong direction will keep the drone from being able to return. As all the lost minis attest, each drone type has different wind limits.

 

[Capt KO]

In Florida, where I live, it is relatively flat. 100ft is my stand by height but reduce it to 60 feet over water. Mainly to avoid the winds aloft. If sailboats or bridges are nearby, I’ll adjust up accordingly. WIND is my priority after obstacles. “Not a ripple on the water” he says from 200ft. “ Why oh why did it just fly away?“?

 

[OurAngryBadger]

Just to give you an additional scenario, if you set your RTH to 200 Ft. , you could be setting yourself up for an altitude bust if you were flying in controlled airspace with a 150 ft. AGL grid. ????

This is probably the best point here.

 

[OurAngryBadger]

its really better to check the area you are flying in and see what tall objects are in your path ,then you can adjust your RTH height accordingly ,for places without tall trees or pylons then 120 ft would get you home safe

I agree this is the best overall course of action. But personally I find it hard how to eyeball a tree and judge how tall it is.

 

[old man mavic]

well unless there is a particular tree that looks much higher than those surrounding you then go up to one close by and see what height is showing on your app screen,and add 50 ft to that for your RTH height

 

[Camino Ken]

Similar to OMM’s comment I use a technique for each location where I fly up to near the height of the tallest object and do a slow rotate and adjust my altitude until every object I can see is below the midpoint of the level camera view and then just add 50 ft or so.

 

[Checki]

There is still obstacle avoidance active, so a tree shouldn't be a big problem. Power lines of course are invisible to the system..

 

[umanbean]

You've gotten some good advice, so I'll just add...

Make a comprehensive Pre-Flight Checklist, and include 'Set RTH Elevation' as one of the checkpoints. Use the checklist every time you fly... and keep it as relatively simple as possible or else you won't use it.

 

[GadgetGuy]

So could I set RTH height at 200ft and be mostly safe in all scenarios? Or is there any major disadvantage using that high of a RTH height? I can imagine maybe as a disadvantage, extra time needed to ascend high enough, maybe an extra minute or two. I wonder what a good battery % RTH setting would be to account for going to 200ft for RTH?

If you set RTH height to 200 feet, that height is above your home point, and not AGL. DJI knows nothing about AGL height. For all purposes, DJI assumes the earth is flat, and we know it isn't! If there are any hills you intend to fly over above your launch point, you will have to add their total height above your launch point to your 200 foot minimum RTH height. I often fly over a nearby mountain top which is 650 feet above my launch point, while following the terrain uphill at 100 feet AGL, so I set my RTH to 250m when flying over it, so RTH will clear any radio towers, should I lose signal on the other side of the mountain, while orbiting the peak. Goal is to restore signal in case LOS gets blocked, and elevation is the best way to do that. Ascending even 50 feet will generally restore signal from blocked LOS behind a tree or a house, or a hilltop. Loss of signal RTH never lasts more than 30 seconds in this scenario, if it occurs at all.

 

[Phantomrain.org]

I don't fly near skyscrapers so thr only thing I'd ever need to avoid when RTH is high power lines or tall trees.

According to

Transmission tower - Wikipedia

en.m.wikipedia.org

180 ft are at the high end for typical range,

and according to

Hitchcock Center for the Environment | Education for a Healthy Planet

www.hitchcockcenter.org

184 ft is the highest tree in northeast USA.

So could I set RTH height at 200ft and be mostly safe in all scenarios? Or is there any major disadvantage using that high of a RTH height? I can imagine maybe as a disadvantage, extra time needed to ascend high enough, maybe an extra minute or two. I wonder what a good battery % RTH setting would be to account for going to 200ft for RTH?

So we look at RTH a lot differently than most.

This is because we use it in several different ways , We use it to film a completely different angle and we use it gain quick orientation.

So Wind is a Constant Negotiating factor: If you have lost VLOS than going up to 200 ft just because may cost you the flight back.

If your using RTH for quick Orientation than you might not want to go to 200 ft either.

As other have pointed out 50 to 75 is more than enough and will allow you the best chance to utilize RTH it to its full potential.

So will use RTH sometimes 10 times in a single flight , just for quick execution and turn around and than cancel , this way we can focus on the camera quickly for the ride back. , comes in handy in our extreme weather flying for example.

Knowing your Lowest RTH levels just makes for a confident ride back when needed .

Phantomrain.org
Gear to fly in and out of the Storm
Coal

 

[Steve_UK]

In my view, anything to do with flying should never be "set and forget", even if it just demonstrates that you don't have situational awareness. You should always be checking the settings and adjusting according to your situation.

 

[old man mavic]

In my view, anything to do with flying should never be "set and forget", even if it just demonstrates that you don't have situational awareness. You should always be checking the settings and adjusting according to your situation.

well said i could not agree more