Fifth flight with the Spark this afternoon over a deserted moorland area, so a chance to test things out.  Took it up to 300ft and around 150 metres away and the aircraft lost data link with controller and entered auto RTH.  A bit disapointed with the range, but let the aircraft come back towards the overhed and went to take back control when I noticed that Go4 said 'Aircraft Disconnected'.  However it wasn't and range figures were bing updatad an the video link was working so I took back control ancontinued with the flight for around another 5 minutes before returning to land, with all the time Go4 still saying 'Aircraft Disconnected'.  Probably needless to say operating under EU power levels with the enforced 5.8GHz data link to control the aircraft.  We really need either a cable connection authorised between phone and controller (why wasn't it like that from the outset?  You don't need to use radio to connect two things that are physically connected in the first place!) or the ability to use 2.4GHz to control the aircraft,  5.8 just isn't working properly in my opinion.   The screenshot was taken several minutes after I had resumed control!

I've reported the same behavior.  I'm using an android galaxy s7 edge, and I've observed where the application is reporting that the aircraft is disconnected, but I still have video feed (not even laggy) and I still have full control of the craft.

I've chalked it up to a software bug.  However unlike you, I brought the craft down and reconnected everything.  I would not recommend continuing to fly under the above conditions.  Even though you still have video and still have control, you are already under the influence of one issue (software bug), and it's impossible to say how the system might react to any additional adverse conditions.

I always advise in the forums that if there's any misbehavior or error before/during flight (compass, gps), it's best to down the craft and reset everything and then decide if you want to try again or change the environment.  There's been too many reports of downed craft or fly-aways to take any chances.

May I know what mobile device are you using? How did you connect the RC to your phone, via OTG or WiFi? I'll forward this to our engineers for analysis.

DJI Diana Posted at 2017-8-31 01:33
May I know what mobile device are you using? How did you connect the RC to your phone, via OTG or WiFi? I'll forward this to our engineers for analysis.

Hi Diana

Using an HTC 10 running Android 7.0 and connected via Wi-Fi.  Go4 version is 4.1.5 which seems to be the latest available here despite postings that people are downloading and using 4.1.8!

manxphoto Posted at 2017-9-1 07:20
Hi Diana

Using an HTC 10 running Android 7.0 and connected via Wi-Fi.  Go4 version is 4.1.5 which seems to be the latest available here despite postings that people are downloading and using 4.1.8!

Thanks for the info, I've forwarded it to our engineers for analysis, will get back to you once they got a reply from them.

manxphoto Posted at 2017-9-1 07:20
Hi Diana

Using an HTC 10 running Android 7.0 and connected via Wi-Fi.  Go4 version is 4.1.5 which seems to be the latest available here despite postings that people are downloading and using 4.1.8!

Hi, could you please export the black box data of this flight for further analysis? Here is a video for your reference.

DJI Diana Posted at 2017-9-4 18:19
Hi, could you please export the black box data of this flight for further analysis? Here is a video for your reference.DJI Quick Tips - Spark - Exporting the Flight Data

Sorry for the delay, only just back from travelling. I tried to save the Black Box data but no success.  When I connected the Spark to Assistant2 it didn't mention the Spark as an attached device, instead 'Device MM'?  However it did progress to the menu for saving Blackbox data, but when I tried to do so just came up with 'Failed'.

manxphoto Posted at 2017-9-22 03:37
Sorry for the delay, only just back from travelling. I tried to save the Black Box data but no success.  When I connected the Spark to Assistant2 it didn't mention the Spark as an attached device, instead 'Device MM'?  However it did progress to the menu for saving Blackbox data, but when I tried to do so just came up with 'Failed'.

Could you please reinstall the DJI Assistant 2 and restart the drone, then try it again? Besides, please try another computer if you can.

DJI Diana Posted at 2017-9-25 00:06
Could you please reinstall the DJI Assistant 2 and restart the drone, then try it again? Besides, please try another computer if you can.

Sorry Diana off travelling again tomorrow and don't have the time to try that now.  Spark is coming though!