I understand that if one loses signal between the controller and the drone for more than a short period (is it 11 seconds?), the drone tries to reestablish connection by back tracking (or reverses course) by 50 feet? If communication still isn't established, the drone goes into RTH mode.
Now, I understand the need to ensure trees and tall buildings and the like must be calculated so the drone doesn't collide with them during normal flight planning. And, I expect the backtrack of 50 feet? will probably mean that no collision damage occurs. Nevertheless, is this another reason to ensure that one flies higher than the reasonable distances around such structures just in case the 50 feet retreat puts the mini 2 into danger?

I've never heard of the Mini "back tracking" on itself when losing connection.  

When the connection between the controller and drone is lost, I believe the drone will hover for about 20 seconds because following the RTH (Return To Home) procedure - at which point it will fly to the altitude set by the user before returning home.

It seems I stand corrected.  The below is taken from the manual:
If the Home Point was successfully recorded and the compass is functioning normally, Failsafe RTH automatically activates after the remote controller signal is lost for more than 11 seconds.

When the firmware is updated to v1.1.0.0 and above, the aircraft will fly backwards for 50 m on its original flight route and ascend to the preset RTH altitude to enter Straight Line RTH. The aircraft enters Straight Line RTH if the remote controller signal is restored during Failsafe RTH. When the aircraft flies backwards along the original flight path and the distance from the Home Point is less than 20 m, the aircraft stops flying backward on the original flight route and enters Straight Line RTH at the current altitude.

I can't say that I've ever noticed the drone fly backwards for 50 meters when losing the signal.  I shall try this again when I am flying next, by turning my controller off deliberately.

neoborg Posted at 12-23 05:41
It seems I stand corrected.  The below is taken from the manual:
If the Home Point was successfully recorded and the compass is functioning normally, Failsafe RTH automatically activates after the remote controller signal is lost for more than 11 seconds.

Let us know how it goes (turning off the controller) Neoborg. The video I saw on Youtube actually showed a chap doing just that to prove the sequence but your confirmation would be useful.

The flight route preceding a disconnection can be a three dimensional thing, i.e. it can involve changes in height as well as horizontal position.

I would suggest that you go somewhere safe i.e. a wide open space with no trees, buildings or other obstacles 'for miles', and fly a distinctive flight path to a certain location, that is 'well' beyond any distance thresholds but well within your VLOS,  and there cause a disconnection. i.e. switch the controller off.  The route should involves a discernable change of height within the 'last' 50m of that portion of the flight.
It would be best to make the last 50m ACROSS your field of view so that you have a better perception of height changes. Watch the drone closely during its "retrace" to see if it follows the outbound flight track in three dimensions.
It might be sensible to have a screen capture app running on phone during the experiment, though you will, of course, record a blank screen during the disconnection. It might also be useful to have the drone record video. Once the drone is in the RTH 'proper' switch the controller back on.

Once you have seen what the drone does 'at distance', repeat it in such a way that the drone crosses the 20m threshold during the retrace and see what happens.

I tried the above 'at distance' test but the only fight route available was along my line of sight, so I am not happy that I can judge whether or not the drone climbs and or descends during the 50m retrace. The location was not suitablle for trying anything that would cause thev retrace to cross the 20m threshold.

JJB did similar experiments with, I think, a mini 3 but, from memory, one RTH did not follow a 3D retrace whilst others did.

Sean-bumble-bee Posted at 12-23 06:23
The flight route preceding a disconnection can be a three dimensional thing, i.e. it can involve changes in height as well as horizontal position.

I would suggest that you go somewhere safe i.e. a wide open space with no trees, buildings or other obstacles 'for miles', and fly a distinctive flight path to a certain location, that is 'well' beyond any distance thresholds but well within your VLOS,  and there cause a disconnection. i.e. switch the controller off.  The route should involves a discernable change of height within the 'last' 50m of that portion of the flight.

Yes Sean, but as a newbie I will leave it to neoborg to tell us how it tests.
As I mentioned, there is a Youtube video that the poster turned off the controller and it seemed to handle everything according to script.

I would suggest that at some point you should do the experiment yourself, it's all well and good reading about things around RTH but nothing beats experiencing them for driving the message home.
Every type of DJI drone I have flown has caught me out with some aspect of their RTH behaviour and I read the manual several times before I first fly the type.

As an example,  what happens if you have the Failsafe response set to either "land" or "hover" and, if "land", what happens if the drone rejects the landing site? Whilst Failsafe is, in itself, not an RTH, 'investigating' its responses is worthy of your attention, BTW "what happens if the drone rejects a failsafe "land" landing site" caught me out too.
WARNING, if you experiment with the failsafe responses BE SURE to reset the response to RTH when you finish experimenting.

GT2022 Posted at 12-23 06:29
Yes Sean, but as a newbie I will leave it to neoborg to tell us how it tests.
As I mentioned, there is a Youtube video that the poster turned off the controller and it seemed to handle everything according to script.

The weather here hasn't been the best the flying, especially with sudden and intermittent showers.  So it could be a few days before I am able to test, especially with the Christmas period.  Who knows, the weather might improve enough for a couple of hours for me to test over Christmas.

neoborg Posted at 12-23 08:34
The weather here hasn't been the best the flying, especially with sudden and intermittent showers.  So it could be a few days before I am able to test, especially with the Christmas period.  Who knows, the weather might improve enough for a couple of hours for me to test over Christmas.

No worries neoborg. I must see if I can locate that video. Is it acceptable to post links to Youtube videos in the forum?

Sean-bumble-bee Posted at 12-23 06:58
I would suggest that at some point you should do the experiment yourself, it's all well and good reading about things around RTH but nothing beats experiencing them for driving the message home.
Every type of DJI drone I have flown has caught me out with some aspect of their RTH behaviour and I read the manual several times before I first fly the type.

Thanks Sean, I will keep your advice in mind as I progress with my learning of this exciting product.

It was mentioned in the quote from the manual, but just to point out out because it's easily missed....

If the drone is less than 20m from you when the disconnect happens, the drone will immediately initiate a straight line RTH.

So, if you fly around trees or (small) buildings to get to the position where you lose connection, then the drone will not retrace the 50m, instead of will just head straight home - potentially into those trees or buildings that you flew around!

So, as others have said, have a play somewhere safe so that you know what to expect when it happens unexpectedly.

No Original Thought Posted at 12-23 15:39
It was mentioned in the quote from the manual, but just to point out out because it's easily missed....

If the drone is less than 20m from you when the disconnect happens, the drone will immediately initiate a straight line RTH.

I think what happens if the RETRACE bringings the drone inside the 20m zone, even if theoretically only temporarily, needs investigating.

No Original Thought Posted at 12-23 15:39
It was mentioned in the quote from the manual, but just to point out out because it's easily missed....

If the drone is less than 20m from you when the disconnect happens, the drone will immediately initiate a straight line RTH.

NOT, it's a little confusing (the manual version 1.4 06/21) at Page 15, under Failsafe RTH and then seemingly contradictory RTH Procedure Straight Line. The contradiction seems to relate to the former section saying one thing about RTH straight line and the latter saying another at Point 3  (the aircraft will hover). So I wonder if this needs clarification by DJI? I will paste the relevant page from the manual.

Failsafe RTH If the Home Point was successfully recorded and the compass is functioning normally, Failsafe RTH automatically activates after the remote controller signal is lost for more than 11 seconds. When the firmware is updated to v1.1.0.0 and above, the aircraft will fly backwards for 50 m on its original flight route and ascend to the preset RTH altitude to enter Straight Line RTH. The aircraft enters Straight Line RTH if the remote controller signal is restored during Failsafe RTH. When the aircraft flies backwards along the original flight path and the distance from the Home Point is less than 20 m, the aircraft stops flying backward on the original flight route and enters Straight Line RTH at the current altitude. In DJI Fly, users can change the settings of how the aircraft responds when the remote controller signal is lost. The aircraft will not execute Failsafe RTH if land or hover has been selected in the settings. Other RTH Scenarios There will be a prompt to initiate RTH if the video link signal is lost during flight while the remote controller is still able to control the movements of the aircraft. RTH can be cancelled. RTH Procedure (Straight Line) 1. The Home Point is recorded. 2. RTH is triggered. 3. If the aircraft is less than 20 m from the Home Point when RTH begins, it will hover in place and not return to home (firmware version v1.1.0.0 is required. Otherwise, the aircraft will land immediately). If the aircraft is further than 20 m from the Home Point when RTH begins, it will return home at a horizontal speed of 10.5 m/s. 4. After reaching the Home Point, the aircraft lands and the motors stop.

GT2022 Posted at 12-23 21:33
NOT, it's a little confusing (the manual version 1.4 06/21) at Page 15, under Failsafe RTH and then seemingly contradictory RTH Procedure Straight Line. The contradiction seems to relate to the former section saying one thing about RTH straight line and the latter saying another at Point 3  (the aircraft will hover). So I wonder if this needs clarification by DJI? I will paste the relevant page from the manual.

Failsafe RTH If the Home Point was successfully recorded and the compass is functioning normally, Failsafe RTH automatically activates after the remote controller signal is lost for more than 11 seconds. When the firmware is updated to v1.1.0.0 and above, the aircraft will fly backwards for 50 m on its original flight route and ascend to the preset RTH altitude to enter Straight Line RTH. The aircraft enters Straight Line RTH if the remote controller signal is restored during Failsafe RTH. When the aircraft flies backwards along the original flight path and the distance from the Home Point is less than 20 m, the aircraft stops flying backward on the original flight route and enters Straight Line RTH at the current altitude. In DJI Fly, users can change the settings of how the aircraft responds when the remote controller signal is lost. The aircraft will not execute Failsafe RTH if land or hover has been selected in the settings. Other RTH Scenarios There will be a prompt to initiate RTH if the video link signal is lost during flight while the remote controller is still able to control the movements of the aircraft. RTH can be cancelled. RTH Procedure (Straight Line) 1. The Home Point is recorded. 2. RTH is triggered. 3. If the aircraft is less than 20 m from the Home Point when RTH begins, it will hover in place and not return to home (firmware version v1.1.0.0 is required. Otherwise, the aircraft will land immediately). If the aircraft is further than 20 m from the Home Point when RTH begins, it will return home at a horizontal speed of 10.5 m/s. 4. After reaching the Home Point, the aircraft lands and the motors stop.

You aren't going to be within (or close to) 20 metres of your drone and losing signal unless you are doing really stupid things with it.

Labroides Posted at 12-23 22:22
You aren't going to be within (or close to) 20 metres of your drone and losing signal unless you are doing really stupid things with it.

Or something fails - electronics have been known to fail at times.... Have you not read the threads about the RC just dying and failing to power back on, just for one example!?

Not to mention the fact that software can have bugs...

Or do electronics only fail for people who do stupid things?

GT2022 Posted at 12-23 21:33
NOT, it's a little confusing (the manual version 1.4 06/21) at Page 15, under Failsafe RTH and then seemingly contradictory RTH Procedure Straight Line. The contradiction seems to relate to the former section saying one thing about RTH straight line and the latter saying another at Point 3  (the aircraft will hover). So I wonder if this needs clarification by DJI? I will paste the relevant page from the manual.

Failsafe RTH If the Home Point was successfully recorded and the compass is functioning normally, Failsafe RTH automatically activates after the remote controller signal is lost for more than 11 seconds. When the firmware is updated to v1.1.0.0 and above, the aircraft will fly backwards for 50 m on its original flight route and ascend to the preset RTH altitude to enter Straight Line RTH. The aircraft enters Straight Line RTH if the remote controller signal is restored during Failsafe RTH. When the aircraft flies backwards along the original flight path and the distance from the Home Point is less than 20 m, the aircraft stops flying backward on the original flight route and enters Straight Line RTH at the current altitude. In DJI Fly, users can change the settings of how the aircraft responds when the remote controller signal is lost. The aircraft will not execute Failsafe RTH if land or hover has been selected in the settings. Other RTH Scenarios There will be a prompt to initiate RTH if the video link signal is lost during flight while the remote controller is still able to control the movements of the aircraft. RTH can be cancelled. RTH Procedure (Straight Line) 1. The Home Point is recorded. 2. RTH is triggered. 3. If the aircraft is less than 20 m from the Home Point when RTH begins, it will hover in place and not return to home (firmware version v1.1.0.0 is required. Otherwise, the aircraft will land immediately). If the aircraft is further than 20 m from the Home Point when RTH begins, it will return home at a horizontal speed of 10.5 m/s. 4. After reaching the Home Point, the aircraft lands and the motors stop.

I agree, I think the manual is generally very good, but this bit is not 100% clear.. though I think it makes a bit more sense when you read it back after experimenting first hand.

No Original Thought Posted at 12-24 03:06
I agree, I think the manual is generally very good, but this bit is not 100% clear.. though I think it makes a bit more sense when you read it back after experimenting first hand.

If I question my understanding of anything in the manual and if I am likely to be in a situation where I need to understand the 'consequences', I try to conduct experiments to test my understanding.
This relates, in particular, to all the RTH behaviours and, and entirely unrelatedly to the thread, the use of the CSC to stop the drone's motors in mid air if, heaven forbid, I encounter a situation where it would be better to have the drone fall rather than continue its flight. (Mavic type drones have a 'complicated' behaviour where this is concerned.)
And yes I HAVE been in a situation where I wanted to crash the drone rather than let it continue its flight. It, a P3, was low and out of control and heading for a road at windscreen height. I attempted the CSC but the drone caught the top of an intervening wall and crashed before the CSC could take effect. Phew.

i paid 2000 £ for mavic 3 and while flying it started to give me singals like controller is disconnected and the drone did not hover but started to do thinks by itself ending up at the bottom of a big river.  and i was telling it not to land in the water with increasing speed. my mavic 3 was spouse to be connected up to 15miles. and the drone was rite in my bloodin eyes less then 50 meters away. fuck this. i lost all mos tthe same all the other drones that dji has made in the past I never had a drone that stay or act like a drone. Why did i paid so much money for it.

Have you compared the behaviour you witnessed with how the manual says it should behave?
You may be annoyed but I don't think there is need for f*** in your post.
If you want to find out what happened, post the flight log or upload it to https://www.phantomhelp.com/logviewer/upload/ and post a link here.
I am not sure what you mean by " i lost all mos tthe same all the other drones that dji has made in the past ".