So, it's day 4 with my Mavic. I love it!
However.

I had a close call. Part way through a short and thankfully low level flight, the Mavic lost all 16 of it's GPS Satellites. It switched to ATTI mode in flight and started to drift off in the direction of the wind.

I managed to get it under control and bring it down safely but it's got me spooked.

I've grounded myself now until I can get some answers. I've tried opening the DAT file myself but the main app for it seems to be Windows only and I'm using a Mac. I'm sure I don't know enough to interpret the DAT anyway...

Can anyone help with this?

https://www.dropbox.com/s/a7lnlosjhllzqgl/FLY026.DAT?dl=0 - this is the DAT file
https://www.dropbox.com/s/b63fix1av7xv722/FLY026.MOV?dl=0 - this is a screen capture of the flight recorder in the DJI Go app

The error on screen seems to suggest IMU & Compass may need to be re calibrated ?

I'm so sorry for this situation, like RCNJ mentioned, please check whether there is an error with the compass. The GPS mode will be disabled when the compass is not working well. Compass must be calibrated in every different place. Please let us know if this situation persists after changing another flight environment.

I had a same error and situation, for me it happened after FW upgrade . Never have it after , so i continue fling but of course avoiding in habitat areas ;)

DJI Mindy Posted at 2017-7-5 22:52
I'm so sorry for your loss. After you get some suggestions on thread, please contact our support in time to create a ticket via the link below: http://www.dji.com/support We have professional data analysis team who will help to analyze the reason, and if it's malfunction, your drone will be compensated according to After-Sales Policy.

Edited to reflect Mindy.

Mike-PNW Posted at 2017-7-6 05:55
Did you even read the post?

He didn't loose anything.

Actually, Mindy's a real person who has helped many people on this forum and is consistently very polite, even when people make rude and uncalled-for comments to / about her.

DroneFlying Posted at 2017-7-6 08:33
Actually, Mindy's a real person who has helped many people on this forum and is consistently very polite, even when people make rude and uncalled-for comments to / about her.

Ok, I will take back my last comment about being a bot. But clearly she didn't read the OP

Mike-PNW Posted at 2017-7-6 08:52
Ok, I will take back my last comment about being a bot. But clearly she didn't read the OP

I'd find it interesting if you could read a Chinese forum and not lose anything in the translation . She may very well have been talking about his loss of confidence in the drone .

rydfree41 Posted at 2017-7-6 09:01
I'd find it interesting if you could read a Chinese forum and not lose anything in the translation . She may very well have been talking about his loss of confidence in the drone .

Edited: Mindy correceted her statement.

Mike-PNW Posted at 2017-7-6 11:05
I cant read Chinese and never mentioned that.  Im on this forum every day to read what the problems are and help out when i can. Mindy always says the same thing when the word "loss" is in the sentence ( sorry for your loss) .  Im sure she is a real nice person and does offer to speed the processes up when people have problems. I am not trying to bash anyone.

Mike, I'm sincerely sorry for the misunderstanding of the post and wrong comment, thank you for getting me correct. I will read clearly about the post in the future and try my best to help customer who needs any assistance.

DroneFlying Posted at 2017-7-6 08:33
Actually, Mindy's a real person who has helped many people on this forum and is consistently very polite, even when people make rude and uncalled-for comments to / about her.

Thank you very much for helping and supporting me, I admit I made mistake and feel very sorry about that, I will be more cautious  in the future. And I also appreciate that you helped so many customers with their cases, you have my respect from heart.

Hey guys!

Apologies for the delay in coming back to you... I took RCNJ's advice and calibrated the compass pre flight and all was well. I calibrate the compass every time now and everything has been spot on since! I've been too busy flying and forgot to reply!!

I LOVE this thing!!

FYI Mindy, I read your initial comment (pre edit) and I knew what you meant, so no worries

Thanks again everyone

The Mavic loses GPS lock when the compass isn't working correctly?   Can someone explain this design logic to me?   I fully understand the need for the compass to maintain a heading WHEN STATIONARY....but I see no reason to turn off the GPS when the heading gets confused.   The Mavic should still know where it is, where home is and be able to move in that direction...although maybe without the ability to look for obstacles if not pointed forward.   Maybe the right thing to do is send a warning that obstacle detection is turned off due to the compass error rather than turning off GPS and going to ATTI mode?    What am I missing here?

Granted I'm still learning, but I really thought the intent of the IMUs, Compasses, GPS, were to provide some level of overlap/redundancy.  The more I read, the more it starts to sound like if one fails, the thing gives up and goes right to ATTI mode.

LP

LeafPeeper Posted at 2017-7-14 11:57
The Mavic loses GPS lock when the compass isn't working correctly?   Can someone explain this design logic to me?   I fully understand the need for the compass to maintain a heading WHEN STATIONARY....but I see no reason to turn off the GPS when the heading gets confused.   The Mavic should still know where it is, where home is and be able to move in that direction...although maybe without the ability to look for obstacles if not pointed forward.   Maybe the right thing to do is send a warning that obstacle detection is turned off due to the compass error rather than turning off GPS and going to ATTI mode?    What am I missing here?

LP

If GPS says you are west of Home Point, but compass is off from North by 90 degrees and it turns to what it thinks is the correct compass heading the Mavic will move the wrong actual direction.  GPS calculates you are further away and gives a heading to autopilot, which uses the compass to turn to that heading which is not the real heading it needs to take.  The drone's GPS correctly computes the distance and direction, but that does not determine the direction the drone is pointing.  

So maybe I don't understand how GPS works.   It seems to me that the satellites send a set of timing signals, the difference of which are used by the GPS chip to calculate a longitude and latitude.   If home is at a different longitude and latitude, as soon as the Mavic starts moving, it should be able to figure out what direction it is going simply by looking at how the longitude and latitude numbers change....and adjust itself to make sure it's going in the right direction.   Is this not feasible?

LP