I was out flying my new (1 month old) Mavic Pro. I was flying near some trees, and was about 100ft in the air. Suddenly, the controller beeped and switched to ATTI mode. Shortly after, I got two of warnings popping up on the DJI GO 4 app. Here is the complete list:

-"Compass error, please recalibrate"
-"Weak GPS Signal"
-"Compass error, switch out of P-GPS (current)"

After the warnings, the Mavic switched to GPS again, then back to ATTI. Then it started flying sideways and down, without any input on my part. It almost crashed into my neighbor's house and into a tree. I frantically tried to land it, and managed to get it close, but it then decided to switch to OPTI mode and fly straight up instead of landing. Attached below are some screenshots of my flight log. Near the end, you can see it thought it was at -6.6ft and going straight up at 0.2mph, and yet it was on the ground, landed.

Anyone who knows what might have happened, please help. I am not flying this thing again until I figure out what happened here. It could have seriously injured someone, or crashed, and I would be out $1,000.

There's a DAT file stored on your Mavic that has information about the flight that can be used to diagnose what went wrong. The instructions for retrieving the DAT file are here, and the correct file will have a timestamp that corresponds to when the flight occurred and will be at least tens of megabytes in size. Once you've retrieved the file, upload it to DropBox (or something similar) and provide a link to it in this thread and someone will look at it.

DroneFlying Posted at 2017-7-16 13:11
There's a DAT file stored on your Mavic that has information about the flight that can be used to diagnose what went wrong. The instructions for retrieving the DAT file are here, and the correct file will have a timestamp that corresponds to when the flight occurred and will be at least tens of megabytes in size. Once you've retrieved the file, upload it to DropBox (or something similar) and provide a link to it in this thread and someone will look at it.

Thank you for the info. I'm finding the file now and will post again the link when I am done.

Maximd1122 Posted at 2017-7-16 13:51
Thank you for the info. I'm finding the file now and will post again the link when I am done.

Most likely you flew off your concrete patio/driveway, messed up the compass and the AC went into nowhere land.
When you hear compass error, bring the AC down in a flash, re-calibrate away from concrete slab, high power line, cell towers, metal, cars, keys, other cell phones, in your pockets or on or around you.

Also, download UAV FORECAST and check it before you fly. You live in a heavy wooded areas which would also affect GPS signals. I suggest you practice in the ACADEMY, and then go to an open area and practice first in beginner mode until you are really familiar with the AC and all the functions.

Good luck!

It looks like you picked up some compass interference, this will cause aircraft to go into Atti mode, bad compass is controlling direction , gps basically gives up and lets Atti take over, very little you could do, it may have happened from where you took off or where you were flying.

I'm sure your dat file will help you understand what happened.

The comments about magnetic interference may very well be correct, especially since it does appear that you took off from a sidewalk; those usually contain embedded (steel) rebar that can affect the Mavic's compass. On the other hand, it wouldn't explain the "flying . . . down" or when it "then decided . . . to fly straight up", though it's possible that in the heat of the moment you were unconsciously pushing the throttle and just didn't realize / remember it.

In any case, the DAT file will be the best source of information on what really happened.

When you said it flew off without any input for you, that was the problem.  In ATTI mode,you have to fly the aircraft.   It will keep going in the same direction until you alter that with stick input.

Mavicator Posted at 2017-7-16 15:25
When you said it flew off without any input for you, that was the problem.  In ATTI mode,you have to fly the aircraft.   It will keep going in the same direction until you alter that with stick input.

In ATTI mode,you have to fly the aircraft.

It's likely that what he experienced wasn't (true) ATTI mode but something like what was described here, in which case normal control of the flight isn't possible. At least his description of the flight seems to match that behavior.

It will keep going in the same direction until you alter that with stick input.

It does glide to a stop when the sticks are released in ATTI mode, but wind resistance stops it fairly quickly unless it's heading downwind. After that it just drifts with whatever wind is present, but I doubt that what he encountered was true ATTI mode.

Sorry to hear that, you can also sync the flight records, then send an email with your DJI account email and the date this occurred to support.us@dji.com, we'll submit a data analysis to find out the cause.