Hello Mavic Forum.   

I lost my Mavic Air out at sea.  I received the analysis from DJI and it says that I pressed descent and so it went down into the ocean as a result

Still things do not add up especially why the drone did not return home or lose signal at 1087 feet over an ocean overlooking a sparsely populated beach.

I've attched a picture of the flight data that notes the time it took off, Just before I lost signal with the drone, and when the altitude was pretty much sea level.

The video I took lasted 3 minutes 58 seconds (not attached) because signal was lost then; The highlights of flight log is below (pics attached) and lasts 1min 27 sec beyond the video:

4m20: Flight started (attached picture)

8m15: Signal weak notification (attached picture)

8m18:  This is when the signal was lost as the video cuts off at 3min58 into the flight(4min20+3min58=8min18):  Altitude at this time is 96 feet, and distance is 1087 feet

9m42: Last log on flight data and height was at 1.6 feet.  This means that 1min and 27 sec had passed since the signal lost.  (attached picture)

1) Why did the drone not return to home when it lost signal?  It had always returned home when signal lost but did not this time.  I remember hitting the return to home many times on my phone but couldn't verify that this was taking place.  I do not doubt that I pushed "descent" but this was only after I was not able to communicate with the drone.  

2) Why did I lose signal at 1087 feet, on the water in a place that is not densely populated?

3) I was at 96 feet when the feed was lost.  DJI claims that I was decending 2m/s and that is the reason I lost my drone.  I did not - it was almost 1min 30 sec later after losing signal that it perished.    Why was I not able to communicate with the drone for 1min 30 sec?

Because of these reasons, I'm thinking it is more of a hardware issue or an issue with return to home function/signal unless I'm missing something that the people of this forum knows (which may well be the case).  From my analysis, the drone had 1 min and 27 seconds to recover and return to home after it lost signal but it did not despite my attempts.

I don't deny that it's partially my fault as I pushed down on the controller after the signal was lost but when the screen goes blank for almost a minute and a half, and the drone does not return home as it is supposed to I dont' think I'm totally to blame.

I've asked DJI these questions and haven't received a satisfactory answer yet.  I have a phantom 3 pro that did not have these issues and have a Mavic Pro 2 on order - although I kind of regret that as I will be hesistant to fly it over water unless I know what truly happened.  

DJI offered a 15% discount on a replacement DJI air without the controller/charger - I think at least 25% or 50% would be a more fair.  Honestly I'm trying to figure what could have happend to my drone before making another purchase from DJI/deciding to keep Mavic Air Pro2.

Any help in trying to figure out what could have happened would be appreciated.

I am very sorry for your loss! It appears that you have lost the video signal, but not the connection betwwen RC and aircraft. Auto RTH will only trigger in the latter case. If you share the link to your flightrecord with us, we might be able to tell you more.

upload using > http://www.phantomhelp.com/LogViewer/Upload/
post your link on here.

Oops, you have found that link already, just the link we need.

cheers
JJB

Sorry to read that mate

As JB asked post your flight log, it should give you an understanding of what occurred .

Too bad, it really sucks.

May I ask what was your reasoning before pressing down?

Below is the data files -both .txt and .dat (when the "XXX files cannot be previewed comes up," choose the download option)

https://www.dropbox.com/s/0kucvk ... -49_FLY062.DAT?dl=0

https://www.dropbox.com/s/dqd6sa ... 5-39-30%5D.txt?dl=0

I've flown that route many times and 3 times that distance passing that same point in the past using the same Mavic Air but the first time that I lost signal like that.  As Wachtburger noted, I guess the RC did not disconnect so what I inputed affected the signal breakage the drone - not sure why I pressed down but was definitely freaking out at that point especially after not seeing any video for what seemed like eternity.  Still can't understand why I lost signal at 1000 feet in a remote location off the coast where I have flown plenty of times before and why when I pressed on the RTH on my  remote/screen (pushing that is one thing that I do remember), it did not register.  Would the return home signal have shown up on the log?   Thank you guys for your input.  

Here's the uploaded flight log:
http://www.phantomhelp.com/logviewer/K6TZH01LFIMPGPLC1FA3

As I had guessed, I cannot see a connection loss in the flightrecord. Thus it must have been just the video link. Which stick mode do you use?

Your flight log does not show any signs of a lost signal at 1,000 feet. If you pressed RTH, you either didn't hold the button long enough or you did it after your Mavic Air descended into the ocean.

Sorry to read that.
I also lost my first spark

Fly safe.
Alex.

At 1.6 feet could have it been hit by a wave?? seems a bit low to be flying over an ocean.

Hi,

Sorry for your loss!

No errors in your log. Guess you only lost the video connection, data up and down stream (RC>craft>RC) seems ok.
My conclusion is that you flew your drone into the water, see my charts.

My advice is to always press RTH on the controller, never on the mobile device. Why, RC works always and no mistake possible to RTH and Autoland soft buttons.
When loosing video contact the little compass still works, using that can bring your craft manually home. A complete disconnect will start the RTH procedure, if not in ATTI ofcourse.
You had full control of your craft, but did not were aware of that.

cheers
JJB

Wachtberger Posted at 2018-9-2 02:51
As I had guessed, I cannot see a connection loss in the flightrecord. Thus it must have been just the video link. Which stick mode do you use?

Pitch = UpDn and v.v.

Yes -I can guess very well what happened after 1.6 feet above the ocean (either wave took it or descended into the water) - my intent was not to commit kamikaze over the water!  It took a minute and a half  for me to lose video signal to when it went under and in that timeframe, I do remember hitting return to home a good bunch of times (as well as other buttons/joystick shifts and yes - I pressed RTH it long enough for it to have responded if it as I had used that function alot in the past).  

I'm not sure I'll be able to figure out why the video signal went out at 1000 feet in a remote place that I've flown thru alot and why RTH did not work (It didn't look like I could communicate with the drone on my phone/remote at that period of time) but I do have a last question for the group as a learning point for me.  What would you do in a similar scenario - I guess if good line of sight, fly it in manually?  Wait to see if video link kicks in - if the battery would run low, then would RTH would have kicked in?  Any other ideas?   Thank you.

JJBspark - good points.  The drone was not in ATTI mode (I don't have the drone anymore but GPS mode I think).  I did not use the controller, just my attached iPhone for RTH.  I will use the controller to RTH in the future as I can see why that would be more reliable.  Also use of a compass is a good point too.  Thank you.

Have you searched for it? The water does not look too deep in the place it went in, but I can be wrong of course.

We completely understand how you feel about the result. We are very sorry about this. We would like you to know that before coming to a conclusion we made sure that our Data Analysis are fair enough about the result of investigation. The data analysis result was made by an independent technical team based on all the information and flight data you’ve provided. We have reviewed your case and found that the result of the investigation is already final. Unfortunately, DJI cannot apply warranty service for this case that has no product malfunction found. If you could not retrieve the drone and still want to purchase a new one, you can reply "I accept"  and provide the information needed if you agree to the offer, but if not, we can request someone from the respective department contact you to discuss this but there is no guarantee that final result can be disputed. Once again, Sorry for the unfortunate experience and thank you so much for your understanding.

Wachtberger - unfortunately that is a beach with pretty decent swells and it's difficult to go beyond 50-75 feet beyond the shoreline for those reasons.  I have tried but just did not find it safe going so far myself.  DJI Diana, thanks for reaching out.  I e-mailed a reply to the e-mail sent from DJI before posting on here.  This forum has been great but I still have a couple of questions for DJI tech support and would like to think about things for another week or so before agreeing to the offer.

fansd151108e Posted at 2018-9-2 21:32
Wachtberger - unfortunately that is a beach with pretty decent swells and it's difficult to go beyond 50-75 feet beyond the shoreline for those reasons.  I have tried but just did not find it safe going so far myself.  DJI Diana, thanks for reaching out.  I e-mailed a reply to the e-mail sent from DJI before posting on here.  This forum has been great but I still have a couple of questions for DJI tech support and would like to think about things for another week or so before agreeing to the offer.

Hi there, we understand there are still many things we still need to improve and we will keep learning, please consider the offer, once you make your decision, please reply the email and let us know if you have further concerns.

I had one very last question for the group - if the video goes out but connection to the drone is intact, can I initiate a RTH by simply closing the DJI App?  This seems like a quick and easy solution if I encounter this scenario again.

Thanks for the reply DJI Mindy.  I've e-mail back with acceptance of the offer and waiting to hear back.

fansd151108e Posted at 2018-9-7 19:54
I had one very last question for the group - if the video goes out but connection to the drone is intact, can I initiate a RTH by simply closing the DJI App?  This seems like a quick and easy solution if I encounter this scenario again.

Thanks for the reply DJI Mindy.  I've e-mail back with acceptance of the offer and waiting to hear back.

As long as the connection between the RC and the aircraft is OK, the drone will not trigger RTH when the image transmission lost or the APP is closed, please keep us updated if you have further concern.

fansd151108e Posted at 2018-9-7 19:54
I had one very last question for the group - if the video goes out but connection to the drone is intact, can I initiate a RTH by simply closing the DJI App?  This seems like a quick and easy solution if I encounter this scenario again.

Thanks for the reply DJI Mindy.  I've e-mail back with acceptance of the offer and waiting to hear back.

RTH is only automatically initiated if the remote controller connection is lost for 3+ seconds. If the video is lost (which happens when the downlink drops), you won't be able to initiate RTH using the icon on the left side of DJI GO. Instead, you should press and hold the RTH button on the remote controller until the remote controller starts beeping.

That's right... the controller and not the app has to disconnect for the RTH (or easier option is to hold RTH button on the controller).  Thank you guys.

fansd151108e Posted at 2018-9-8 10:59
That's right... the controller and not the app has to disconnect for the RTH (or easier option is to hold RTH button on the controller).  Thank you guys.

You are welcome, please let us know if you have any further issue.