During the last week I have been experiencing uncommanded yaw. I am flying in the area where I have done 99% of my flying and never had any issues with GPS or any other type with either this drone or my original Mavic. Occasionally I get a strong wireless interference at low level (1 meter) but it always clears as soon as I climb. Today while flying I again experienced uncommanded yaw and received an Warning:[IMU]Heading exception (In Flight)... The reomte displayed SYSTEM ERROR then the drone switched to ATTI mode. Landing was very difficult as control seemed erratic. There was a slight wind but I never received a high wind warning.

I calibrated the remote sticks but have not calibrated the IMU, compass, or vision system. Playback of the flight log shows no control input when the yaw happens. Recommendations before next flight?

It sounds a little like the old BATTI problem we used to hear about pretty often that apparently was fixed by a firmware update a while back, but I'm guessing you're using a reasonably current version so the only thing I can think of to suggest at this point is to upload the logs from the flight and provide a link.

With the "System error", you clearly had a failure of some type.  One question is whether is is a one-off glitch or something needs to be repaired.

can i get some help please... it wont allow me to create a new post.... my IMU calibration is stuck.... being trying since yesterday.....
i even reverted to the prior firmware and then upgraded again.... why isnt it working?

edo87 Posted at 2017-4-2 10:19
can i get some help please... it wont allow me to create a new post.... my IMU calibration is stuck.... being trying since yesterday.....
i even reverted to the prior firmware and then upgraded again.... why isnt it working?

Try to contact one of the mods here directly (Mindy, Ken, Natalia...). They reply fast usually.

Hi Yraegel, could you please export the flight data via DJI Assistant then upload it to dropbox and send me the link?
Besides, please sync your flight records and provide me with your DJI account email. I'll help to review your flight records.
Is your forum email address the same as your DJI account email?

Hello,
Does anyone know why IMU Initialization takes so much time?
I am trying to start my Phantom 3 Pro but it says IMU inializing. Please wait. How long should I wait? Is it a common problem.
I just recently purchased it.

Kind regards,
Andrii

DJI Mindy Posted at 2017-4-4 23:55
Hi Yraegel, could you please export the flight data via DJI Assistant then upload it to dropbox and send me the link?
Besides, please sync your flight records and provide me with your DJI account email. I'll help to review your flight records.
Is your forum email address the same as your DJI account email?

My logs are synched and I have uploaded the flight data. Link sent via PM. Thanks Mindy!

Andrii.Shybanov Posted at 2017-4-5 07:39
Hello,
Does anyone know why IMU Initialization takes so much time?
I am trying to start my Phantom 3 Pro but it says IMU inializing. Please wait. How long should I wait? Is it a common problem.

This is the Mavic Pro forum, you should post to the Phantom forum for assistance.

Andrii.Shybanov Posted at 2017-4-5 07:39
Hello,
Does anyone know why IMU Initialization takes so much time?
I am trying to start my Phantom 3 Pro but it says IMU inializing. Please wait. How long should I wait? Is it a common problem.

Hi Andrii, please cool down the aircraft then do the IMU calibration again.

Yraegel Posted at 2017-4-5 15:26
My logs are synched and I have uploaded the flight data. Link sent via PM. Thanks Mindy!

Thank you. Copy that.
I have forward your flight data to our engineers.
If we have any update or need any further information, I'll let you know.

hi Yraegel,  sorry for your experience. After  a look at your flight log data, I find the compass should be calibrated. There was bias information in the earth magnetic measurement.  Please keep your craft away from  ferromagnetic substance, which is a possible reason for the compass get a bias.

wisnia.sebastia Posted at 2017-4-17 19:04
hi Yraegel,  sorry for your experience. After  a look at your flight log data, I find the compass should be calibrated. There was bias information in the earth magnetic measurement.  Please keep your craft away from  ferromagnetic substance, which is a possible reason for the compass get a bias.

Thank you, I will calibrate the compass and test.

wisnia.sebastia Posted at 2017-4-17 19:04
hi Yraegel,  sorry for your experience. After  a look at your flight log data, I find the compass should be calibrated. There was bias information in the earth magnetic measurement.  Please keep your craft away from  ferromagnetic substance, which is a possible reason for the compass get a bias.

It appears that the problem is resolved which is fantastic! 99% of my flights are in the same area and I did not experience any issue with my first Mavic. One question: was the magnetic bias you observed in the logs insufficient to trigger a compass calibration alert (or should it do that)? I should have recalibrated regardless but I was more concerned with the IMU heading error at the time. In any case, thank you.