Mavic Air automatically started RTH

[Ajotapl]

Hey everybody,
The other day I was flying my MA in a lake, I kept it at ~43meters of altitude. There was sun, no wind, it was sunset time. However after the drone was ~798 meters from the starting point, it automatically stopped and started the GO HOME action.

I had signal all the time, it was open space, nothing could have cause interference between the control and the drone, there was a direct/straight vision line between them. What happened?, the range is supposed to be up to 4KM in open space without interferences... here's the log, maybe someone with more experience could have a guess about the situation?

DJI Flight Log Viewer | Phantom Help

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• 3m 38.3s - Poor signal. Avoid blocking the antennas and keep the antennas in parallel and facing the aircraft during the flight.
• 5m 34s - The maximum flight distance has been reached. Adjust the distance in the main controller settings if you need it.
• 5m 52.7s - The signal has been lost. The aircraft is returning to the point of origin. (44 meters altitud) - 798 meters home distance

 

[Starz]

Battery strength seems a bit odd.

 

[sar104]

That's a strange one. OSD_flightAction was set to OutOfControlGoHome at 352.7 seconds, reportedly due to signal loss, but the signal appears to have been fine. I can. see no obvious explanation for that behavior.

 

[Ajotapl]

Yes, I just noticed the battery in the log.. all the time 84%.. when I stopped the GO HOME action, I think I had something around 50%

I was reading and there's a RTH triggered when the MA calculates that wont have enough battery to return to home.. maybe was this the cause?, however as I wrote, when I interrupted the action, the MA was very close to me(home point) and still had around 50%..

This situation is making me hesitant about flying the MA in a long distance, even without obstacles...

 

[sar104]

Yes, I just noticed the battery in the log.. all the time 84%.. when I stopped the GO HOME action, I think I had something around 50%

I was reading and there's a RTH triggered when the MA calculates that wont have enough battery to return to home.. maybe was this the cause?, however as I wrote, when I interrupted the action, the MA was very close to me(home point) and still had around 50%..

This situation is making me hesitant about flying the MA in a long distance, even without obstacles...

The log viewer that you are looking at is incorrect. The battery level is shown in the graph above (blue trace), and was at 72% when the FC switched to RTH. At that point the smart battery RTH calculation (also in the graph - the green trace) was at 26%, so the battery level was well above the RTH level.

 

[Ajotapl]

The log viewer that you are looking at is incorrect. The battery level is shown in the graph above (blue trace), and was at 72% when the FC switched to RTH. At that point the smart battery RTH calculation (also in the graph - the green trace) was at 26%, so the battery level was well above the RTH level.

So it seems that the battery calculation wasnt the reason... what a mysterious action by the MA

 

[sar104]

So it seems that the battery calculation wasnt the reason... what a mysterious action by the MA

There may be more information in the DAT file event stream, if you want to retrieve it. The file will be FLY068.DAT.

How to retrieve a mobile device DAT file: How to retrieve a V3.DAT from the tablet

 

[Ajotapl]

There may be more information in the DAT file event stream, if you want to retrieve it. The file will be FLY068.DAT.

How to retrieve a mobile device DAT file: How to retrieve a V3.DAT from the tablet

Sure, it's attached

 

[DanMan32]

From the discussion, it sounds like it RTH'd due to false signal loss.

 

[sar104]

Sure, it's attached

That also indicates loss of connection between the aircraft and the RC:

345.820 : 22391 [L-RC]rc_connect:1=>0​

345.820 : 22391 [L-RC]rc_func_disable @ [450612 ms]​

346.858 : 22443 [L-FMU/LED]action changed. fly limit,eg:airport0)​

351.829 : 22692 [L-N_MIS]Init plan 0 from requester 8 for reason 15. Pre plan 5​

351.839 : 22692 [L-N_MIS]Exit mis 3. New mis 12​

351.839 : 22692 [L-N_MIS]Switch new mis 12 req 8 from mis 3 req 2​

352.842 : 22743 [L-FMU/LED]action changed. rc completely lost0)​

353.022 : 22752 [L-RC]rc_connect:0=>1​

353.022 : 22752 [L-RC]rc_resume @ [457832 ms]​

353.022 : 22752 [L-RC]set rc_resume_lock​

353.042 : 22753 [L-FMU/LED]action changed. Normal Flash(0)​

353.042 : 22753 [L-FMU/LED]type:0, normal flash action:​

353.042 : 22753 [L-FMU/LED]c0:0,15;c1:0,3;c2:0,13;c3:2,3;c4:0,10;c5:0,3;c6:0,10;c7:0,3​

353.520 : 22777 [L-RC]clr rc_resume_lock​

354.219 : 22812 [L-RC]rc_connect:1=>0​

354.219 : 22812 [L-RC]rc_func_disable @ [459032 ms]​

354.817 : 22842 [L-RC]rc_connect:0=>1​

354.817 : 22842 [L-RC]rc_resume @ [459632 ms]​

354.817 : 22842 [L-RC]set rc_resume_lock​

355.016 : 22852 [L-RC]rc_connect:1=>0​

355.017 : 22852 [L-RC]rc_func_disable @ [459832 ms]​

355.316 : 22867 [L-RC]clr rc_resume_lock​

355.714 : 22887 [L-FDI][sensor_api_info] head(2,0,31,4).|​

355.755 : 22889 [L-GEO]lost app, clear app_pos_info​

356.014 : 22902 [L-RC]rc_connect:0=>1​

356.014 : 22902 [L-RC]rc_resume @ [460832 ms]​

356.014 : 22902 [L-RC]set rc_resume_lock​

356.513 : 22927 [L-RC]clr rc_resume_lock​

I still don't see an explanation for the RTH.

 

[Ajotapl]

I cant recall any lose signal, I had live view from the MA all the time... I just entered in panic when it started to comeback automatically and didnt interrupt the action until it was close to me and thought "what the.. has just happened" xD

Maybe something is wrong with the unit or control?... I used it one more time that day without any crazy behaviour...

 

[MavicFlyer]

I cant recall any lose signal, I had live view from the MA all the time... I just entered in panic when it started to comeback automatically and didnt interrupt the action until it was close to me and thought "what the.. has just happened" xD

Maybe something is wrong with the unit or control?... I used it one more time that day without any crazy behaviour...

Have you contacted DJI?

Look at the bright side: it came home on its own, leaving you with a mystery...
it could have just decided to land where it was, leaving you with a mystery AND a lost drone!!