Aircraft lost connection with RC. What happens?

[Freddy K]

Hi everyone,
I just had a scary moment while flying my Mini 2. I was flying back home (manually), still about 200m away, 4 bars of signal, when all of a sudden, the video turned grey and the message "aircraft not connected to RC" appeared.
I didn't panic, but instead tried positioning the RC to the direction of the bird to reconnect again. This took about 30 seconds.
To my surprise however, two things had happened during this time:
1. The mini 2 had initiated a RTH and had already started ascending, which makes sense because it had lost connection
2. The drone was NOT where I expected it to be. Apparently it had kept flying in the direction and speed when the connection was lost until the RTH was started. Checking this new location, I realized I was really lucky, because 10 seconds further, big trees were waiting to embrace the drone.

My question: if the connection between drone and RC is lost, is it normal that the drone keeps flying instead of remaining in the same location (for safety)?
Then, if the connection is not restored after a while, start a RTH?

 

[Yorkshire_Pud]

There is some 'braking distance' before the drone will halt.
Of course there is also the retrace that I forgot to mention but I see that Meta 4 has covered that.
See

Does Mini 2 continue flying at 21 mph for 11 seconds after controller Signal Loss , does it stop, or backup 50 meters-then try Failsafe RTH?

Can you please help with your flight experiences for these circumstances ? Mini 2 controlled with Litchi Failsafe RTH = Set at RTH (not landing or hovering) No RTH Height was set (Blank in Litchi, might have been set at 165 feet in DJI-Fly) Compass & IMU are good. Returning home under manual...

mavicpilots.com

From memory there are either two threads in here about that flight or one thread here and another thread over in the DJI forum.

You might post the log for the flight and if there is a separate log for the reconnected portion of the flight, could you post that too ?

 

[Meta4]

My question: if the connection between drone and RC is lost, is it normal that the drone keeps flying instead of remaining in the same location (for safety)?
Then, if the connection is not restored after a while, start a RTH?

Your question is answered on page 15 of 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.

 

[DARKSeifer]

Wait for the GPS lock before launch, else the drone will randomly choose a homepoint midflight that doesn't correspond with the real homepoint.

 

[Yorkshire_Pud]

Wait for the GPS lock before launch, else the drone will randomly choose a homepoint midflight that doesn't correspond with the real homepoint.

The choice of home point location would not be "random", it will be where the drone first acquires sufficient satellites to set the home point.

 

[Freddy K]

Thank you for the feedback.
The link to the other post was interesting, especially the trial of purposefully turning off the controller to see how the drone responds.

I have been looking to the flight recording that is available in the DJI Fly app and it did mention the moment where it lost connection and when it started the failsafe RTH, but it doesn't say when it got reconnected again.

I tried finding the log file on my android phone, but can't seem to find it. According to the sticky post on the forum about retrieving log files, it should be in
DJI.go.v5/flight record
but this subfolder doesn't exist.
I also did a search for DJI*.txt on my complete phone: no success either.
Any idea what I'm doing wrong here?
Have these files moved to a different location recently?

 

[Meta4]

DJI.go.v5/flight record
but this subfolder doesn't exist.

The full address is:
Android\data\dji.go.v5\files\FlightRecord
The files will be there

 

[Mrktn]

Your question is answered on page 15 of 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.

I had the exact same thing happen to me yesterday flying my mini 3 pro at about a distance of 850m from RTH point. Fortunately I got a satellite lock before taking off