Mavic Air yawing during flight

[sar104]

Unless anyone can find an issue in the DAT file the drone is in the box and being sent to DJI Europe tomorrow. After speaking to DJI live tech support this morning and showing them the videos, they have admitted that something is not right and it needs to go in for repair. Refurbished drone coming my way I guess!
Crossing my fingers and hoping @sar104 finds something.

Okay - there is a serious problem with something on this aircraft. If you look at the comparison of magnetic yaw with IMU yaw the problem is quite obvious:



At -70 seconds the FC computes the declination and inclination as follows:

-60.921 : 1365 [L-NS][AHRS] wmm dec: -1.839030
-60.921 : 1365 [L-NS][AHRS] wmm inc: 65.357033

The difference between the magnetic yaw and initialized IMU yaw values should therefore be 1.84°, but in fact the difference is 23°. Worse than that, the difference varies with yaw:




Both IMUs are showing a similar problem, which probably rules out fault rate gyros etc. In any case, that characteristic sinusoidal variation with a period of 360° usually indicates that the compass is not properly calibrated to subtract the magnetic field of the aircraft, but that doesn't explain the incorrect initialization. If careful compass calibration doesn't fix it then it will need to be replaced.

@BudWalker ?

 

[Jamielee96]

Thanks @sar104, what would you do from here? Get it back out of the wrapped box and try recalibrating before the delivery driver arrives or just send it off?

 

[sar104]

Thanks @sar104, what would you do from here? Get it back out of the wrapped box and try recalibrating before the delivery driver arrives or just send it off?

If you have already calibrated the compass and IMU with reported success then I'm not sure that it's worth repeating, unless you were wearing magnetic items while calibrating or calibrating in a magnetically compromised location - inside a steel building for example. I'm not aware of any particular magnetic anomalies around Plymouth.

 

[Jamielee96]

Yeah, looks like it's on it's way back to DJI tomorrow then!

 

[stberlin]

i still have the same issue with my mavic air. today it kept climbing straight up, drifted and yawed without input. but i'm used to this because and it only lasts 4-5 seconds. it's usually in the first minute of the first flight / battery.

 

[Red Baron]

Does the drone rotate when descending????? If it does you have a bad mother board

 

[sar104]

Does the drone rotate when descending????? If it does you have a bad mother board

That's an intriguing statement. Can you explain why you think that?

 

[Jamielee96]

I have created a PDF detailing the initial fault, action taken and @sar104's analysis making easy reading for anyone new to the thread or anyone investigating a similar issue with their own aircraft. Once again, thanks to Sar for the analysis. Will keep the thread updated on what response I get from DJI.

 

[stberlin]

Does the drone rotate when descending????? If it does you have a bad mother board

mine, no. only during the first ascent or hover. subsequent flights and batteries are ok. it started doing this since V01.00.0400

 

[Red Baron]

That's an intriguing statement. Can you explain why you think that?

My air started doing that after 3 months-- Took it to a dji store and they thought it was the controller-That was a big waste of time- Soo I sent it in to dji - Thank God it was under warranty as they came back and said both mother boards were bad and it was covered under warranty- The quote was for $400- They gave me a new drone. Rep told me the tell tale sign of a bad mother board was rotation while descending.

 

[sar104]

My air started doing that after 3 months-- Took it to a dji store and they thought it was the controller-That was a big waste of time- Soo I sent it in to dji - Thank God it was under warranty as they came back and said both mother boards were bad and it was covered under warranty- The quote was for $400- They gave me a new drone. Rep told me the tell tale sign of a bad mother board was rotation while descending.

Interesting. Unfortunately I've seen and heard enough completely inaccurate information from DJI reps that it's hard to know whether that was true, but a somewhat isolated case, or whether it actually is the most likely explanation for that behavior.

 

[CaveDrone]

I had the same issue on Mavic Pro. Very slow yaw, correctable with stick input. Calibrated compass, fixed it instantly.

 

[Maddendec]

Open to try anything before having to send it back. Will be making a list of actions to take a tests to perform tomorrow

Hi had this problem on my mavic , re calibrated my imu and compass and the problem resolved

 

[Hogg]

Hi all,
You may recognise the video posted in this thread as I have posted once before but it went a little off topic, and I am still seeking some more advice.
A few weeks ago I crashed my perfectly working drone and received a new one from DJI Care (DJI Refresh). On my first flight of this drone I noticed a problem. I sent the drone about 40 metres above my house (no wind) and just let it hover. Whilst it was hovering I noticed it was yawing (video below). It was doing this with no controller input from my whatsoever.
Since then I have had a few flights since with the problem persisting.
This evening I was having a small test flight in my garden. The drone took off and instantly yawed right and behaved erratically. I instantly brought it down and landed it, then retook off to see if it occurred again. It did. Not on the same scale but definitely was not behaving normally (this is the log I managed to extract and post).
Any suggestions on possible cause/action for me to take?
Thanks

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Overview:
Issue 1
Aircraft yawing with no controller input and behaving irratically

Issue 1
Having trouble extracting .DAT log from mobile device. Found them in MCFLIGHTLOGS folder and then managed to get the log from todays test flight (extremely short) into DatCon to convert to .txt.
Cannot get any other files into the software. I have attached what I have but need advice on which logs I need and what to do with them. (saying the .txt files are empty and cannot upload them).

Any help at all greatly appreciated
Thanks
Jamie

I had this problem with my mavic air, never crashed, multiple remote calibrations and no success, I had to send my remote in under warranty, and new remote came, problem solved. Hope this helps, & good luck!

 

[JSKCKNIT]

My mav air sometimes yaws 15 to 30 degrees right on take off, its quick and in the first 3 or 4 seconds. recalibration of compass, imu and still happens. I just write it off to interference. It hasnt gotten any worse in the 9 months I have owned it so I just always go straight up to 100 ft at least before I start flying around.

Mine does the same. Has since day 1. It's just a quick jerk.

 

[Jamielee96]

I had this problem with my mavic air, never crashed, multiple remote calibrations and no success, I had to send my remote in under warranty, and new remote came, problem solved. Hope this helps, & good luck!

Had a previous mavic air with the same controller which worked perfectly, so would be surprised if the controller is now faulty.

 

[Hogg]

Had a previous mavic air with the same controller which worked perfectly, so would be surprised if the controller is now faulty.

The left stick went bad for no apparent reason. I wouldn't be surprised at all if the controller is faulty, it's exactly what happened to mine.

 

[Jamielee96]

DJI have reported back stating the issue is a faulty power board and it will be replaced free of charge. Will wait and see if it has fixed the problem.

 

[Jamielee96]

Unfortunately we will never know if the power board was indeed the faulty component. Just received a despatch email from DJI telling me my drone is on its way back, however it has a different serial number. I questioned them as to why this is and they have said that the "faulty power board" is a default system message.