Smart RTH altitude setting

[Coyyote]

Using DJI GO4 you are limited in setting the max RTH altitude to 50 meters, but are told the craft will detect obstacles and ascend to avoid them. My question is does the 50 meters mean the altitude above the location or waypoint where RTH is executed. Or does that mean 50 meters above the Home or Take off altitude.

My concern is my flying is mostly up into the mountains so elevations of 400-500 feet above take off are required to get to the object I want to film. RTH would then be initiated at this point. Say I am at 400 feet and RTH initialed with RTH altitude of 20 meters set, does the craft ascend to 465 feet and RTH: or does it try to descend from 400 feet to the 65 feet I have set on the RTH altitude max and then try to RTH????

If its the former than I will stand little chance of a collision on the way home. If its the latter I am concerned.

 

[msinger]

Using DJI GO4 you are limited in setting the max RTH altitude to 50 meters

The limit is 500 meters.

My question is does the 50 meters mean the altitude above the location or waypoint where RTH is executed

It's the altitude above the takeoff point.

When RTH is initiated, your Mavic will ascend from the current altitude displayed in DJI GO to the set RTH altitude. So, if your RTH altitude is set to 100 meters and DJI GO is currently showing your Mavic is flying at 50 meters, it will ascend 50 meters before returning back to the home point.

 

[Coyyote]

Yeah if I am at 50 and the set point is 100 then no problem. My concern is if I am at 250 and the set point is 100 and there are pine trees and some 200 meter high hills on the path to RTH.

I did not know the max alt was 500m so that in itself prob solves my problem.

 

[MAvic_South_Oz]

My understanding is (not tested) is that your RTH height is set above your home point, and will return at whatever level you set it to (or hover, or land) . . . But, if you are above this, the RTH will not drop, it will stay at the height you are at, at that time you initiate RTH.

 

[msinger]

But, if you are above this, the RTH will not drop, it will stay at the height you are at, at that time you initiate RTH.

Right. The Mavic will never descend before returning back to the home point. (I've tested this.)

 

[MAvic_South_Oz]

OP is safe then.
I recommend a little test for yourself Coyyote, just to satisfy your own mind.
Will do the same myself, I've been flying off cliff tops down to foreshore a bit lately, so might reverse that and see for myself how this works.

 

[Coyyote]

Thanks I plan to carefully test this before I lose my Mavic up the mtns. This is good news. BTW the max RTH is 50M not 500 as previously posted, that is the Max altitude for flight.

 

[Xtreme Drone Pilot]

Did you see this?

 

[Xtreme Drone Pilot]

BTW the max RTH is 50M not 500 as previously posted, that is the Max altitude for flight.

No. It shows 50m max when you're not connected to RC/Mavic. Once you do, RTH max is 500m.

 

[Xtreme Drone Pilot]

BTW, max RTH of 500m does not mean it will start descending to 500m ATOP *if* you're flying higher than 500m. It will RTH at current altitude ATOP. Fact.

 

[Coyyote]

Thanks for that info. Sounds like I am safe descending from the mtns, however will run a small test to be sure my copy of the Mavic conforms.

 

[Mr. Salty]

A link to the owner's manual, which was updated to the latest information just yesterday: https://dl.djicdn.com/downloads/mavic/20171219/Mavic Pro User Manual V2.0.pdf

 

[Coyyote]

Thanks for that link.

 

[Coyyote]

You guys were right on. Flew the drone up the mtn to altitude of 666 feet (interesting elevation huh). Drone was only 12 feet AGL for me to take a picture of a target hanging on a cliff face that we shoot at with our precision rifles. Turned it around and hit RTH. Drone maintained 666 feet for a flight of 1000 meters till over home, then initiated descent and landing.

 

[msinger]

FYI, the most recent Mavic manual is always available on the Mavic downloads page.

 

[rfc]

I've tested this as well, and it's true: If above the RTH altitude, it will not decend. The only issue I've thought of is if you take off, then ascend to greater than 500m (to the top of a ski area, say), then descend beneath the tree line, if things go awry, you could be in trouble, as the A/C could not ascend any higher to avoid the trees as it heads home. Makes me nervous.

 

[msinger]

The only issue I've thought of is if you take off, then ascend to greater than 500m

You cannot ascend to an altitude greater than 500m.

 

[rfc]

You cannot ascend to an altitude greater than 500m.

So, if I understand correctly, to be totally "safe", you should never use smart RTH if the very tops of the highest trees at the top of your site are higher than 500m. The maximum RTH altitude would therefore be 500m.

 

[Xtreme Drone Pilot]

You cannot ascend to an altitude greater than 500m.

Everybody who didn't update to 1.4.0100 FW, can. 500m limit is nothing but a brick placed under gas pedal in the car - "you can't drive faster than 30mph, because I said so!" You just toss that brick away and you're only limited by your car's capabilities and of course, by laws - which do not prohibit recreational flying above 400ft and even 500m in unrestricted airspace.

 

[Xtreme Drone Pilot]

I've tested this as well, and it's true: If above the RTH altitude, it will not decend. The only issue I've thought of is if you take off, then ascend to greater than 500m (to the top of a ski area, say), then descend beneath the tree line, if things go awry, you could be in trouble, as the A/C could not ascend any higher to avoid the trees as it heads home. Makes me nervous.

If 500m is an issue for your flying and everything else is legit, you can disable 500m limit and still be 100% legit. My Go 4 shows 120m altitude ATOP limit, but I can fly to any altitude I want.