So I'll just sketch out this scenario:


What happens if my Spark is, say 10 m above the treetops in this picture and 15 m away, as shown, and it runs out of power and switches to RTH mode?  The manual is not clear what happens between the 3 - 20 m horizontal range and I'm guessing it would just descend into the trees.  I'm not sure what happens once the optical sensors detect the trees (or do they?)

I have a back yard flying space here which works great, and is similar to the diagram.  What I really want is for it to ALWAYS fly to "A" and begin its descent but I am not clear on how to set this up.

in your scenario above, Spark will return to home at the current altitude. that means it will flow above tree tops until reaches the Home Point position then will start descending then land.
if critical low battery message pops up, then the aircraft will start landing at current position.

dj_dread Posted at 2018-5-25 10:31
in your scenario above, Spark will return to home at the current altitude. that means it will flow above tree tops until reaches the Home Point position then will start descending then land.
if critical low battery message pops up, then the aircraft will start landing at current position.

Exactly! If I remember correctly, until the 100 meters the drone will return home at the same altitude, with the avoid obstacles sensors activated. After the 100 meters distance the drone will go up to the selected altitude and return home, in sport mode and with the avoid obstacles sensors deactivated.

dj_dread Posted at 2018-5-25 10:31
in your scenario above, Spark will return to home at the current altitude. that means it will flow above tree tops until reaches the Home Point position then will start descending then land.
if critical low battery message pops up, then the aircraft will start landing at current position.

EDIT:   I stand corrected..  See below.. I can't delete the comment :



I don't think so.. if it is less than 20 meters away (horizontal distance) I think it will descend where it is into the tree.

LouisP Posted at 2018-5-25 11:14
I don't think so.. if it is less than 20 meters away (horizontal distance) I think it will descend where it is into the tree.

it will descend only if is less than 3m from Home Point.

dj_dread Posted at 2018-5-25 11:31
it will descend only if is less than 3m from Home Point.

Thanks.. I can never remember the distances for the various RTH modes.

Thanks all, the replies are much appreciated.

I had been looking at this flowchart https://forum.dji.com/thread-145655-1-1.html but it appears it's dependent on the "RTH at altitude" toggle, it sounds like if it's false, the drone would indeed land on the trees.  But when "RTH at altitude" is true, the flowchart says it 'flies to home position' -- but is vague on how it accomplishes this.  I guess you all said it flies horizontally at altitude to Home, the  descends.  Agreed?

Nobody said anything about the "RTH at altitude" toggle, so is the flowchart correct about its role?

Tomorrow I might edit it in Paint Shop Pro and post it for you all to scrutinize so we have this whole thing down.

G'day.
I agree that the RTH procedure & options become confusing. It all depends on the distance to the home point.
1) 100 m +, RTH at pre-set altitude at 10 m/s without obstacle avoidance. Aircraft returns to hope point.
2) 100 - 20 m, RTH at pre-set altitude (at 3 m/s ???) with obstacle avoidance.  Aircraft returns to hope point.
3) 20 - 3 m, RTH at current altitude disabled.  3 m/s ??? with obstacle avoidance. Aircraft lands where it is.
4) 20 - 3 m, RTH at current altitude enabled.  3 m/s ??? with obstacle avoidance. Aircraft returns to home point.
5) 3 m or less, Aircraft lands where it is. I believe the aircraft can be moved prior to accepting the final landing prompt.
6) Note: The aircraft will stop ascending & immediately return to the home point if you move the throttle stick, if the aircraft reaches 20 m altitudes or beyond during RTH.  

I guess the use of the various options may depend on where the aircraft is flying. Activating RTH above or below trees, bridges, near water, power lines or any other obstacle may require different altitude settings. If flying low under a tree 10 m away, you may not want the aircraft to ascend 2.5 m & hit a branch. It may be safer to turn off RTH at current altitude & land under the tree. If flying above a tree or water the reverse would apply.      

The RTH procedure is in the tiny user manual.  Fortunately there is a pdf version available.  https://dl.djicdn.com/downloads/ ... 0Manual%20V1.6-.pdf

Page 14 explains under 4.b. - when the aircraft is between 3 m & 20 m from the home point it will land automatically with the RTH at current altitude option disabled (default setting).
When RTH at current altitude is enabled the aircraft will return to the home point at current altitude. If below 2.5 m is will ascend to 2.5m then return home.
If the aircraft is within 3 m from the home point it will land where it is.  






Good luck. I still get confused!

rolypolyman Posted at 2018-5-25 20:57
Thanks all, the replies are much appreciated.

I had been looking at this flowchart https://forum.dji.com/thread-145655-1-1.html but it appears it's dependent on the "RTH at altitude" toggle, it sounds like if it's false, the drone would indeed land on the trees.  But when "RTH at altitude" is true, the flowchart says it 'flies to home position' -- but is vague on how it accomplishes this.  I guess you all said it flies horizontally at altitude to Home, the  descends.  Agreed?

wondering  why noone mentioned klogee...