Greetings,  I recently bought a Mavic Pro and have been enjoying learning about the drone.   I've practiced now for about 2 hrs of flight time and have enjoyed approx 12 flights.  However, yesterday I was in my backyard and launched from my back porch.  I noted that my controller and phone app kept indicated "lost connection".  The drone was hovering about 15 feet off the ground when it took off strait up.  It all happned rather fast but it seemed that it was during the "lost connection" phadse of the issue .  I tried to shut down the drone and or land it, but it rose too fast for me to controll it ( or it was just completly out of my control as  it seemed ).  The drone crashed into a tree as it rose some 25 feet high.  I was able to get a ladder and get it down.. no damage.  I replaced the usb / phone wired connection and did a few test flights after the incident.  All went well.   My question is:  Under emergencies such as loss of communication between controller and the phone app does the drone attempt to go back home?  I have the hight for return to home set for 30 m . Indeed it seemed to go skyward possibly in it's attempt to get home "safe", alas the tree was in the way.  At that point "home" base was a mear 10-15 feet away, but I guess it would first head up to 30 meters and then head home?   All my software is up to date, no further issues after the connecton cable was swapped out.   Is it required to have connection from the phone app to the controller to fly safely?

I wish I had a replay of the event to study ( like an NTSB investigation), but it all happened so fast it's hard to reflect in my mind just what happened.  For that matter in my haste I my in fact hit the "home" command.  The one thing I know for sure none of the controlls were working as she rose skyward and into the branches...  I later looked at the flight log and noted that  I had gps coverage with 12 sats.

Any insight given the details I've offered would be appreciated.

Thanks..

You most likely lost radio control and RTH was initiated at least looks like it because you tried to cancel with nothing happening I will check RTH for Pro but I’m sure there is option to set to hover to land within 20 metres from home, I’m not 100% sure if this is set as failsafe if so it should have just landed. I will get back to you.

Thanks. When you say lost radio control are we talking about the phone app to controller,  or controller to aircraft.  What can I do to prevent this from happening again?

Captdan555 Posted at 2018-5-7 10:08
Thanks. When you say lost radio control are we talking about the phone app to controller,  or controller to aircraft.  What can I do to prevent this from happening again?

Controller which will initiate RTH after 3 seconds, you will see in note below you were not high enough so when RTH was initiated it is programmed to first rise to correct altitude to fly home, this looks like what happened, great that it is ok I suppose.

hallmark007 Posted at 2018-5-7 10:13
Controller which will initiate RTH after 3 seconds, you will see in note below you were not high enough so when RTH was initiated it is programmed to first rise to correct altitude to fly home, this looks like what happened, great that it is ok I suppose.

[view_image]

Ok,  let me get this strait.   I lost connection between my phone / app and the controller, after 3 seconds the RTH function initiated and due to my setting of 30 meters in altitude the drone attempted to gain altitude before returning home  ( as I programed it to do).  In replacing the phone cable it would seem this is corrected.

Is this right?     Lesson learned:  don't fly in airspace that is highly restricted such as the back yard. I've been a commercial pilot for 45 years and you would think I'd know better.

Captdan555 Posted at 2018-5-7 10:25
Ok,  let me get this strait.   I lost connection between my phone / app and the controller, after 3 seconds the RTH function initiated and due to my setting of 30 meters in altitude the drone attempted to gain altitude before returning home  ( as I programed it to do).  In replacing the phone cable it would seem this is corrected.

Is this right?     Lesson learned:  don't fly in airspace that is highly restricted such as the back yard. I've been a commercial pilot for 45 years and you would think I'd know better.

No not strictly correct.
If you are within 20 metres of homepoint and less than 10 metres altitude, aircraft will rise to 10 metres only and RTH not your settings of 30 metres which will only happen when you are outside 20 metres from home.
It’s a strange one and certainly for me not a really safe procedure I can think of many situations one could get into trouble with this failsafe.

Lost connection between controller and phone happened to me 2 times. Connection between controller and mavic was inact. Problem is not definitly solved but some tips in my thread:
Hope this helps

hallmark007 Posted at 2018-5-7 10:47
No not strictly correct.
If you are within 20 metres of homepoint and less than 10 metres altitude, aircraft will rise to 10 metres only and RTH not your settings of 30 metres which will only happen when you are outside 20 metres from home.
It’s a strange one and certainly for me not a really safe procedure I can think of many situations one could get into trouble with this failsafe.

Thanks BTW for the fast response.  Actually, I think you answered the question.  I was indeed within 20 meters from home point.  If  indeed it rose to 10 meters after 3 seconds of disconnect from the controller, problem is, the tree branch in question was within that 10 meter altitude.  So, it seems it flew into the branch from as it climbed to 10 meters to RTH.  
Sorry for the questions. I'm just trying to narrow down the issues before another mishap.  I did not know the drone will attempt to RTH after 3 seconds of disconnect with the controller.   I suppose this is a good thing but I can see where it would be an issue depending on the situation and location.

I hope I have it right now...

Thanks

Captdan555 Posted at 2018-5-7 10:25
Ok,  let me get this strait.   I lost connection between my phone / app and the controller, after 3 seconds the RTH function initiated and due to my setting of 30 meters in altitude the drone attempted to gain altitude before returning home  ( as I programed it to do).  In replacing the phone cable it would seem this is corrected.

Is this right?     Lesson learned:  don't fly in airspace that is highly restricted such as the back yard. I've been a commercial pilot for 45 years and you would think I'd know better.

Honest with your accident.

If your APP stops working, it will not affect the connection between RC and your drone. That's why your sticks are still working and you have full control. When that happens, DJIGO4 writes "Disconected" on the line at the top left corner where the status is displayed. RTH will not be automatically triggered here.

If you read "Aircraft disconected" instead, you lost the connection between RC and the drone. In this situation, RTH or landing is triggered after 3 seconds and the drone lands or RTH depending on how close you are to your takeoff location.

Regards Leif.

chiplifter Posted at 2018-5-7 10:56
Lost connection between controller and phone happened to me 2 times. Connection between controller and mavic was inact. Problem is not definitly solved but some tips in my thread:
Hope this helps

Chip,  Ok,  after reading this it seems my "correction" in replacing the phone to controller cable it not a real fix.   Wow... I sure hope there is a future software update that corrects this issue.

Landbo Posted at 2018-5-7 11:00
Honest with your accident.

If your APP stops working, it will not affect the connection between RC and your drone. That's why your sticks are still working and you have full control. When that happens, DJIGO4 writes "Disconected" on the line at the top left corner where the status is displayed. RTH will not be automatically triggered here.

Leif,  in my case the phone app indicated " disconnected".   So, seems that would not force a RTH?

Captdan555 Posted at 2018-5-7 11:08
Leif,  in my case the phone app indicated " disconnected".   So, seems that would not force a RTH?

Correct yes, you should have full control of your aircraft with the Radio Controller in that situation.

Regards Leif.

Landbo Posted at 2018-5-7 11:27
Correct yes, you should have full control of your aircraft with the Radio Controller in that situation.

Regards Leif.

Interesting,  in my case not..

Captdan555 Posted at 2018-5-7 11:07
Chip,  Ok,  after reading this it seems my "correction" in replacing the phone to controller cable it not a real fix.   Wow... I sure hope there is a future software update that corrects this issue.

Yes i do too. It happened to me on holiday. I did take some nice footage but after the disconnection issues I was scared to make another flight. Safety first.