Return to Home from altitude below takeoff point

[JeffS]

Greetings. First message here. I myself do not own a DJI product yet, but will most likely soon. I've been watching videos and following discussion threads for some time to see what the capabilities and occasional flaws (and their consequences) are. I do have a 'toy grade" drone that I practice with, but the camera is crap, and it gets pushed all over the place in the mildest of breezes. I'm afraid to take up much higher than myself for fear of loosing orientation and control until I have more experience in manual control.

Which is one reason I want to get a unit that has some degree of automation.

This leads to my question after that brief intro. Regarding Return to Home, I've seen numerous examples of return to home, but all are examples of coming back from a condition where the craft is above the pilot.

What if one takes off from the side of a mountain (this is a real world scenario I could one day fly), assume takeoff altitude of 400 ft above sea level and then flies out and down into a river valley (the Hudson River valley). The mid point of the flight would be say 1000 feet out, and 400 feet below the takeoff altitude (all still within line of sight), would your display would show a negative altitude? At this point you'd be just over the river.

Now, what happens if RTH is triggered? Will the craft first ascend the 400 feet, then continue up another (user set) number of feet to what you have the RTH altitude set to, then fly back to your position and land?

Assume I had the RTH altitude set to 200ft, I am assuming the craft would ascent 600 feet, come over me at 200 ft, then land.

I can't find any forum message or video describing the scenario. So I apologize if it's been covered.

Thanks

 

[msinger]

At the takeoff point, the altitude is 0 feet. When you ascend above that point, the altitude will increase (displaying a positive number in DJI GO). When you ascend below that point, the altitude will decrease (displaying a negative number in DJI GO).

When RTH is initiated, your Mavic will ascend from the current altitude displayed in DJI GO up to the RTH altitude before returning back to the home point. If the altitude is a negative number, the Mavic will ascend up to 0 feet and then up to the RTH altitude. If the Mavic is already flying above the RTH altitude, it will return at its current altitude.

Check out the Mavic manual for more details on the RTH feature.

 

[RawRock]

Thanks for this because I was just pondering the same question about negative altitude.

 

[picanocker]

I am quite certain that was the reason I lost my Mavic Pro on the side of a mountain, thankful though that I did recover the craft, but I will read the manual carefully.