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My MPP does not fly straight anymore [logs & video included]

laurens23

Well-Known Member
Joined
Feb 1, 2018
Messages
240
Reactions
179
Location
China
Problem?
The drone is not flying straight anymore. Sometimes it’s flying at an angle as much as 20-30 deg when trying to fly straight forward and then up to 90 deg left when braking, also giving some compass errors. I'm on holiday in the EU. In China the drone was flying fine. I did a new compass calibration when I arrived in EU.

I did 2 flights. The details below are from the second flight. I flew low and without significant wind. I have attached the .txt the .dat and a video of the flight showing the issue:

During the long run out it worked reasonable, then tuning back there was a slight offset:
104-597 sec

Then did some testing to get some clear examples to look at in the logs at:
760-785 sec
815-830 sec
848-860 sec
878-892 sec
905-915 sec

But it does not always happen for example:
1220-125 sec it works fine

Any ideas why this issue showed up and how to get it fixed? I can;t fly like this because it is not safe. I looked at the logs and clearly see the issue, but I have no idea how to fix it. Maybe someone can dive into the logs and come with a suggestion? @sar104 @msinger @MavicCF @ Anyone else.

Was unit in a crash?
no, never.

What have you tried so far?
Re-did compass calibration in the middle of nowhere with phone 2m away on airplane mode. (Both IMU and compass interference are showing “excellent”.)

After 1st flight I moved several km to a new location for the 2nd flight.

Tried flying in different directions.

What device are you using ( iphone , ipad, Samsung , etc)?
iPhone 6S, IOS v11.3.1

What firmware are you running ( aircraft, remote controller)?
Aircraft: 01.04.0300
Remote: 01.04.0300

What Go app version are you using?
DJI Go 4: v4.2.12

Any modification?
(if so what)
None.

Did you change anything or install any apps? (if so what)
Turned off the coordinate correction for use in mainland China.

Do you have a video or pictures of the problem? (if so post link)
Yes, .txt, .dat, DJI log viewer and video.

DJI Flight Log Viewer - PhantomHelp.com

 

Attachments

  • DJIFlightRecord_2018-05-20_[11-47-14].txt
    2.3 MB · Views: 14
  • 2018-05-20_11-45-32_FLY040.zip
    6.7 MB · Views: 5
Problem?
The drone is not flying straight anymore. Sometimes it’s flying at an angle as much as 20-30 deg when trying to fly straight forward and then up to 90 deg left when braking, also giving some compass errors. I'm on holiday in the EU. In China the drone was flying fine. I did a new compass calibration when I arrived in EU.

I did 2 flights. The details below are from the second flight. I flew low and without significant wind. I have attached the .txt the .dat and a video of the flight showing the issue:

During the long run out it worked reasonable, then tuning back there was a slight offset:
104-597 sec

Then did some testing to get some clear examples to look at in the logs at:
760-785 sec
815-830 sec
848-860 sec
878-892 sec
905-915 sec

But it does not always happen for example:
1220-125 sec it works fine

Any ideas why this issue showed up and how to get it fixed? I can;t fly like this because it is not safe. I looked at the logs and clearly see the issue, but I have no idea how to fix it. Maybe someone can dive into the logs and come with a suggestion? @sar104 @msinger @MavicCF @ Anyone else.

Was unit in a crash?
no, never.

What have you tried so far?
Re-did compass calibration in the middle of nowhere with phone 2m away on airplane mode. (Both IMU and compass interference are showing “excellent”.)

After 1st flight I moved several km to a new location for the 2nd flight.

Tried flying in different directions.

What device are you using ( iphone , ipad, Samsung , etc)?
iPhone 6S, IOS v11.3.1

What firmware are you running ( aircraft, remote controller)?
Aircraft: 01.04.0300
Remote: 01.04.0300

What Go app version are you using?
DJI Go 4: v4.2.12

Any modification?
(if so what)
None.

Did you change anything or install any apps? (if so what)
Turned off the coordinate correction for use in mainland China.

Do you have a video or pictures of the problem? (if so post link)
Yes, .txt, .dat, DJI log viewer and video.

DJI Flight Log Viewer - PhantomHelp.com

Sorry to hear about your problem. I'm out of town right now and will be away from my computer for another few days. Hope you/someone else get it sorted. Major bummer on a vacation like that:cool:.
 
Sorry to hear about your problem. I'm out of town right now and will be away from my computer for another few days. Hope you/someone else get it sorted. Major bummer on a vacation like that:cool:.

yes, I hope someone else can help. My Xiaomi mi 4k used to fly with no problem at the same location a year ago.
 
it looks like some kind of compass error
it has the same symptoms - reported hSpeed is zero or close to zero while in reality Mavic is flying for example at 9 m/s
but the strange thing is that this compass error is not reported by the AC itself

get the full DAT out of the AC and share it
there is a lot of clever people who can review it
 
  • Like
Reactions: Ripper7620
I think that you need to do some more tests. In the flight that you posted the log for, you powered up the aircraft and yaw was initialized from the compass, but then you moved the aircraft around for 100 seconds before finally placing it on the ground, at which point there was a yaw discrepancy of 30°. It resolved that during the first part of the flight to some degree, but the separation kept reappearing during yaw maneuvers, which makes it hard to assess the issue.

2018-05-20_11-45-32_FLY040_recstart_01.png

2018-05-20_11-45-32_FLY040_recstart_02.png
 
Problem?
The drone is not flying straight anymore. Sometimes it’s flying at an angle as much as 20-30 deg when trying to fly straight forward and then up to 90 deg left when braking, also giving some compass errors. I'm on holiday in the EU. In China the drone was flying fine. I did a new compass calibration when I arrived in EU.

I did 2 flights. The details below are from the second flight. I flew low and without significant wind. I have attached the .txt the .dat and a video of the flight showing the issue:

During the long run out it worked reasonable, then tuning back there was a slight offset:
104-597 sec

Then did some testing to get some clear examples to look at in the logs at:
760-785 sec
815-830 sec
848-860 sec
878-892 sec
905-915 sec

But it does not always happen for example:
1220-125 sec it works fine

Any ideas why this issue showed up and how to get it fixed? I can;t fly like this because it is not safe. I looked at the logs and clearly see the issue, but I have no idea how to fix it. Maybe someone can dive into the logs and come with a suggestion? @sar104 @msinger @MavicCF @ Anyone else.

Was unit in a crash?
no, never.

What have you tried so far?
Re-did compass calibration in the middle of nowhere with phone 2m away on airplane mode. (Both IMU and compass interference are showing “excellent”.)

After 1st flight I moved several km to a new location for the 2nd flight.

Tried flying in different directions.

What device are you using ( iphone , ipad, Samsung , etc)?
iPhone 6S, IOS v11.3.1

What firmware are you running ( aircraft, remote controller)?
Aircraft: 01.04.0300
Remote: 01.04.0300

What Go app version are you using?
DJI Go 4: v4.2.12

Any modification?
(if so what)
None.

Did you change anything or install any apps? (if so what)
Turned off the coordinate correction for use in mainland China.

Do you have a video or pictures of the problem? (if so post link)
Yes, .txt, .dat, DJI log viewer and video.

DJI Flight Log Viewer - PhantomHelp.com

Is it possible the aircraft is actually flying straight but the gimbal is off? I saw this with my MPP and a gimbal calibration fixed it. From the video, it looked like everything was fine until the turn was made. When this happens does the aircraft visually look like its flying straight, from your VLOS perspective?
 
Is it possible the aircraft is actually flying straight but the gimbal is off? I saw this with my MPP and a gimbal calibration fixed it. From the video, it looked like everything was fine until the turn was made. When this happens does the aircraft visually look like its flying straight, from your VLOS perspective?

The gimbal is clearly slightly off at times but that's a symptom, not a cause, of the magnetic yaw discrepancies.
 
I think that you need to do some more tests. In the flight that you posted the log for, you powered up the aircraft and yaw was initialized from the compass, but then you moved the aircraft around for 100 seconds before finally placing it on the ground, at which point there was a yaw discrepancy of 30°. It resolved that during the first part of the flight to some degree, but the separation kept reappearing during yaw maneuvers, which makes it hard to assess the issue.

you are right. because I did a compass calibration before both flights I actually picked it up and moved it around before taking off. Normally I never do a compass calibration so I just put it down and start flying. I already did an IMU calibration. Now I just need some time to do another test.
 
I believe I have the same problem. I have no solution as I have barely any drone knowledge (had mine for a week).
I'll keep an eye on this thread.

This is my problem (shows up at about 1:55 mark):
 
Did you solve it?
I'm still having these issues.
I have recalibrated pretty much everything and even replaced the props.
 
no:(. Today was the first day I had time to fly again. I had already calibrated the IMU and compass beforehand. Then I did a 10 minute flight in an area with farmland. The issue is the same. It looks a bit less extreme, but I was also being very careful. It's definitely not good and I don't trust it much like this.

If this happens at every place other than where I live, then that would be a real disappointment. I traded up from a Xiaomi mi 4k. While the MPP has a clear edge in technology, the flight characteristics of the Xiaomi were better and more consistent (it flew fine all over China and Europe).

I heard other people who had this found the issue disappeared after returning home. As I cannot get warranty here anyway I will wait until I'm back home in China. If it is still bad there I'll open a warranty claim against DJI. I know it sounds silly, but after reading about these issues it seems (some) DJI units are factory tuned for the area they are sold. Taking one half way across the world will result in bad/weird behaviour like this.
 
Well, I hope you get it solved, but in my case different country can't be the reason. I live in Sweden, I bought the drone in Sweden and I never took my drone outside the country.
 
no:(. Today was the first day I had time to fly again. I had already calibrated the IMU and compass beforehand. Then I did a 10 minute flight in an area with farmland. The issue is the same. It looks a bit less extreme, but I was also being very careful. It's definitely not good and I don't trust it much like this.

If this happens at every place other than where I live, then that would be a real disappointment. I traded up from a Xiaomi mi 4k. While the MPP has a clear edge in technology, the flight characteristics of the Xiaomi were better and more consistent (it flew fine all over China and Europe).

I heard other people who had this found the issue disappeared after returning home. As I cannot get warranty here anyway I will wait until I'm back home in China. If it is still bad there I'll open a warranty claim against DJI. I know it sounds silly, but after reading about these issues it seems (some) DJI units are factory tuned for the area they are sold. Taking one half way across the world will result in bad/weird behaviour like this.

Have you retrieved the DAT file for a flight that was started with yaw initialized correctly?
 
Have you retrieved the DAT file for a flight that was started with yaw initialized correctly?

Yes I do. These are the files from the last test. It was a pretty short test because the battery was low.
 

Attachments

  • 2018-05-28_18-18-07_FLY045.zip
    2.8 MB · Views: 0
  • DJIFlightRecord_2018-05-28_[18-18-53].txt
    1.3 MB · Views: 1
Well, I hope you get it solved, but in my case different country can't be the reason. I live in Sweden, I bought the drone in Sweden and I never took my drone outside the country.

From your post I understood yours has always had the issue. That would make sense if you got a unit that was "made/initialised" for China. Some resellers probably get units intended for other regions. Still my idea is pretty far fetched. While it is a common issue, If true, I would have expected more people to report the same issue, but maybe a lot of the first time buyers think it's normal and/or never bother to post/ask about it. If it is true that (some) DJI drones are basically secretly hardcoded for a specific region, that would expose a rather critical issue.
 
Last edited:
I asked DJI and their response was that the joystick is very sensitive and that I should practice more. Maybe they have a point, I'm still new to my drone. I will try lowering sensitivity a bit and do more flying.
 
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