Details of RTH. Under what conditions does it climb to RTH altitude?

[DanMc]

When doing an RTH, how far away does the drone need to be in order for it to climb to the RTH altitude? How does it make these decisions? For instance, if it's only 30 feet away and 5 feet from the ground, will it climb to RTH altitude? I have a Mavic Air, so I'm particularly interested in this one, though I'm sure the MP and Spark will behave similarly.

 

[Sprocket]

When doing an RTH, how far away does the drone need to be in order for it to climb to the RTH altitude? How does it make these decisions? For instance, if it's only 30 feet away and 5 feet from the ground, will it climb to RTH altitude? I have a Mavic Air, so I'm particularly interested in this one, though I'm sure the MP and Spark will behave similarly.

Oh, boy. I get to be the first to say RTM.
Page 13 I think.

 

[Meta4]

When doing an RTH, how far away does the drone need to be in order for it to climb to the RTH altitude? How does it make these decisions?

The manual is pretty clear about this.
At the bottom of P13 you find this:

RTH Procedure
Smart RTH, Low Battery RTH, and Failsafe RTH follow this procedure:
1. The aircraft adjusts its orientation.
2. a. If the aircraft is further than 20 m from the Home Point it ascends to the pre-set RTH attitude and then flies to the Home Point.
b. If the aircraft is between 5 m and 20 m from the Home Point it flies to the Home Point at the current altitude, unless the current altitude is less than 2.5 m, in which case the aircraft ascends to 2.5 m and then flies to the Home Point.
c. If the aircraft is less than 5 m from the Home Point it lands immediately.
3. The aircraft lands and stops its motors once it reaches the Home Point.

 

[Starz]

The ac will climb to whatever rth altitude you set as long as it is under that altitude when you initiate rth. If it is above what you set when rth is initiated, it will fly back at that altitude. There is a set distance from home that you must be beyond before it will fly back but I don’t remember what it is. That info is in the manual if you can find that on DJI website. Most of the info the ac needs to do the rth comes from the gps system and compass.

 

[fdewarren]

My MA was 10 meters away from the home point when I got disconnected. Altitude was -2.5m (downhill)
According to the manual, it should have climbed to +2.5m (within 5 to 20m zone) and RTH. right?
Guess what?
It decided to land immediately (in the water below). DJI replaced it under the warranty : "not pilot error" but their explanation is "drone entered into landing mode due to close proximity from home point" Which does not match the manual description...
Any ideas?
Also, what is the use of "RTH at current altitude" option?

 

[Kilrah]

Did you take into account the potential error in GPS positioning? When you're that close a couple of meters of error matters.

 

[fdewarren]

Did you take into account the potential error in GPS positioning?

The distance between Home Point and the drone was 10.1 meters, as recorded by the flight log using 13 satellites. I believe it is that distance which is used by the drone to decide whether it is in the 0-5m zone or 5-20m zone, or beyond.

Now, on a similar note, what happens if you opt for the drone to "hover when connexion lost" and then it reaches the point when it's time to RTH because of low batterie... Does it RTH or continues to hover until 10% then lands? Did somebody try that?

 

[dazzer71]

If rth is not selected when lost connection and you choose hover it will do just that until you reconnect , if not it will land when battery is low