I had a unusual event today – while flying my Mavic Pro a few hundred meters out to sea I suddenly got a Aircraft Disconnected message, the AC stopped responding to controls and just hovered.  During what seemed an eternity (but was in fact a little over 4 minutes) I did everything I could think of to try and reconnect.  The Mavic just hovered and did not return to home.   I tried pushing the return to home button on the controller – to no effect.  The app was still showing Aircraft Disconnected,  I thought I'd be watching my Mavic hover until its batteries gave out and it descended into the sea.  Finally in desperation I turned off the controller – at which point the AC started its RTH process – phew!

As far as I can tell there is no reason the Mavic should disconnect – no close radio transmitters – clear line of sight to the aircraft – well within range.   I checked the settings in Go4 and the AC was set to return home on loss of signal.    Clearly the AC had been connected to the controller until I turned it off – yet the app was showing Aircraft Disconnected and the controller controls were ineffective.

I've uploaded the logs:  Flight Log Viewer   but it just stops at the point the AC disconnected.

Here is the video from the flight:   AC disconnect a bit over 2min in - Controller turned off and RTH starts at about 6:40

I think I need to go lie down in a dark room – I certainly lost a lot of confidence in the MP today.

Thoughts on what I might have done wrong?

You did nothing wrong.  Strange things happen sometimes.  Good job not panicking and making a smart decision!

This is normal, your device was disconnected not your controller.
When you turn your controller off it start RTH after 3 seconds.
If you were using the side port on controller this is not unheard.
You should always use the lower middle USB port on controller.

G_Sig Posted at 5-22 17:34
This is normal, your device was disconnected not your controller.
When you turn your controller off it start RTH after 3 seconds.
If you were using the side port on controller this is not unheard.

Thanks - the Mavic was certainly not responding to the controller sticks or controller RTH button.  
I was using the middle port.

RocketChap Posted at 5-23 00:58
Thanks - the Mavic was certainly not responding to the controller sticks or controller RTH button.  
I was using the middle port. [view_image]

No there is no respond from the drone, it's more like the controller is frozen.
The drone seam to get some sort of signal from the controller and do not RTH because of that.
Restarting the app alone has  no affect on this. Restarting the controller and the app is the only way back.

Good thing you recovered!

Hello and good day RocketChap. Thank you for sharing these information, this video and your experience with us today. Just a friendly reminder that we are not recommending you to fly your drones above the sea especially if it's on low altitude over the water surface, I'm afraid that your aircraft will recognize the first location when the aircraft took off and it greatly reduces your emergency landing area. The DJI Mavic Pro might land to in the sea since the boat is moving. Have a safe and happy flying always.

G_Sig Posted at 5-22 17:34
This is normal, your device was disconnected not your controller.
When you turn your controller off it start RTH after 3 seconds.
If you were using the side port on controller this is not unheard.

Can you explain why one should always use the lower middle USB port on controller?

Same thing happened to me in Lake Tahoe where I had clear line of sight and great connection. All of the sudden the AC gets disconnected and I cannot get it to connect to my mavic zoom. Like in your case it returned home safely on it's own. These things make this an unsafe product in my opinion, just like people experiencing auto landing when in NFZ without ability to control the aircraft. DJI really needs to address these issues or nobody is going to buy a drone. Now every time I go out  to fly my drone I feel like a nervous wreck.

DJI Stephen Posted at 5-23 08:49
Hello and good day RocketChap. Thank you for sharing these information, this video and your experience with us today. Just a friendly reminder that we are not recommending you to fly your drones above the sea especially if it's on low altitude over the water surface, I'm afraid that your aircraft will recognize the first location when the aircraft took off and it greatly reduces your emergency landing area. The DJI Mavic Pro might land to in the sea since the boat is moving. Have a safe and happy flying always.

I had a similar situation happen to me at the Lake, and I was 175 ft above water level, so why does my AC suddenly disconnect where I have absolutely no control? Luckily it returned home but it should not happen. What about auto landing in a NFZ where you cannot even get a RTH, this is dangerous.

Just wondering if anybody has seen this happen with the M2x and Occusync? Going on vacation soon and plan on doing a fair amount of flying over ocean from a land based launch site. This is indeed scary.

Had it quite a few times. Tried a lot, from changing firmware, cables, phone and app. I am now flying with the side usb, ac and rc on the latest firmware, app version 4.3.11. This works for me.

The worst was when my app crashed, phone was black when I was hovering in the ocean w/ the Spark.  I realized the app crashed so I put it back and got signal.  Could've crashed into the sign in the ocean!

I feel like flying the Spark today.

"High wind velocity. Fly with caution and land in a safe place ASAP."  I think this can overload the computer because it's trying to calculate so many things.  My Mavic 2 Zoom flies slower in Sport than Normal with OA off when that warning happens.  The acceleration was incredibly slow.

Wish move and all's well that end's well

It shows you are full right stick the whole time at the end..

TrippleDelta Posted at 5-23 09:14
Can you explain why one should always use the lower middle USB port on controller?

It has less fault and normally works better.
Some of it might bee do to cable quality of original cables
You can also charge the controller while flying if you need to.

Woah that's crazy!

DJI Stephen Posted at 5-23 08:49
Hello and good day RocketChap. Thank you for sharing these information, this video and your experience with us today. Just a friendly reminder that we are not recommending you to fly your drones above the sea especially if it's on low altitude over the water surface, I'm afraid that your aircraft will recognize the first location when the aircraft took off and it greatly reduces your emergency landing area. The DJI Mavic Pro might land to in the sea since the boat is moving. Have a safe and happy flying always.

Thanks for DJI's view.  The Mavic was about 4m above the takeoff point and the takeoff point about 16m above the sea (low tide) - so the Mavic was flying about 20m (65ft) above the sea - I thought plenty high enough to stop it auto descending.   Is there a minimum recommended altitude when flying over water? Not that its relevant to the issue being discussed here.

AntDX316 Posted at 5-23 11:35
It shows you are full right stick the whole time at the end..

Its the only way to fly!

G_Sig Posted at 5-23 02:21
No there is no respond from the drone, it's more like the controller is frozen.
The drone seam to get some sort of signal from the controller and do not RTH because of that.
Restarting the app alone has  no affect on this. Restarting the controller and the app is the only way back.

Yes - that seems to be what happened - controller not responding to user- yet Mavic not returning home because its still in contact with the controller.