What went wrong, please share your experiences

[Fredrik]

Hello Mavic friends!

I need your help to understand. Last night I would fly from a place I flew several times earlier without problems. I had new calibrated IMU and compass and updated homepoint. After take off, I hovered 30-40 seconds above the starting point. The Mavic then felt a little worried but, in my opinion, within the framework of what feels OK.

Immediately when I flew away, I had big problems. The Mavic pulled off at full speed and it was extremely difficult to control it. I really got to fight to keep it in sight and not crash. After great concentration and a fight home Mavic I managed to make an OK landing but throughout the flight I thought this will never be going well.

During the flight, I repeatedly received several error messages, which I need your help to clarify and explain.

• Obstracle avoided. Revise flight route.
• Warning: In flight, workingIMUen countersheading exception, please switch to atti mode if craft behave abonormally.
• Warning: Campass error, Exit P-GPS mode.
• Current RTH route will pass a No-fly zone. Pay attention to the aircraft’s position to aviod RTH failure.

After closing down all the equipment, let Mavic cool down, then I restarted, calibrated compass and IMU. At first, I had a hard time keeping the altitude when I hovered, but after a couple of minutes, Mavic was as usual again.

Having any of your similar experiences, there is some way to prevent this from happening again. The experience was very unpleasant and I do not want to experience it again! Please share your experience and expertise regarding this issue.


Sincerely, Fredrik

 

[Robbyg]

I have never heard of all those error messages happening at once. Can you upload the DAT file from the flight? Look at the link in my signature for details on how to extract and upload it.


Rob

 

[Path Finder]

I did not think the Mavic even has a way to switch to ATTI mode? (thought it was GPS only as long as it has GPS signal)

 

[Fredrik]

I have never heard of all those error messages happening at once. Can you upload the DAT file from the flight? Look at the link in my signature for details on how to extract and upload it.


Rob

Hi Rob

Thanks for you reply and that you are interested of help me analyse the data

I am a new member at Mavicpilots and need some assistance of how to unload the DAT file from my Mavic to my PC or iPhone.

Thanks in advance

Sincerely, Fredrik

 

[Robbyg]

Hi Rob

Thanks for you reply and that you are interested of help me analyse the data

I am a new member at Mavicpilots and need some assistance of how to unload the DAT file from my Mavic to my PC or iPhone.

Thanks in advance

Sincerely, Fredrik

Hi Fredrik

Just follow the instructions in this link.

How to retrieve a .DAT

After that upload the file to a file sharing service and post a link here.
The file is probably going to be big.

Rob

 

[Qoncussion]

While you and Rib (correction: Rob) are working on the logs, this really sounds like a bad IMU/Compass calibration issue. When you calibrated them, were you near any metal or concrete? Was your calibration surface deal-level with the center of the earth (bubble level your surface). Some will say that this does not matter - but I have seen the difference, and it really helps to rule out the calibration as the cause of your problems. Personally, I use a small cut-out of plywood with adjustable feet in each corner - so I can achieve a deal-level surface anywhere.

 

[Fredrik]

Hi kevin!

Thank you for your feedback, I'm eager to understand what happened to learn more and minimize the risk of something similar happening again.

I can not say that my IMU calibration was 100% horizontal but I was careful and checked the table I was working on with a water pass before calibrating.
As for metal objects, there is always something nearby when I live in a suburb, but there was no metal within the nearest meters from Mavic.
Nor did I get a message from the Mavic about metal that interferes within compass calibration.

I hope Rob has time to give me instructions on how to download DAT file from Mavic so I can do it this weekend.

Sincerely
Fredrik

 

[Vilco]

Hi kevin!
Thank you for your feedback, I'm eager to understand what happened to learn more and minimize the risk of something similar happening again.
I can not say that my IMU calibration was 100% horizontal but I was careful and checked the table I was working on with a water pass before calibrating.
As for metal objects, there is always something nearby when I live in a suburb, but there was no metal within the nearest meters from Mavic.
Nor did I get a message from the Mavic about metal that interferes within compass calibration.

Qoncussion asked if there was any metal near you because the Mavic behavior you describe is typical of compass or IMU calibrations done in areaa with interferences. The mavic won't always signal the interferences unless they're very strong, so it's possible you calibrated it in a mildly disturbed area and the Mavic took that as the "norm", then as it got out of that disturbed area it found itself with a compass no more good for the area and went astray.
This behavior is very typical of compass calibrations done where there was metal: were you on concrete? Then there's a big chance that it was full of metal (rebar); a guy who posted here almost destroyed his mavic for having calibrated the compass while standing on a sidewalk. His Mavic did exactly what yours did, as it moved away a bit from the home point, it soon started to quickly drift on his own
Regarding the other error messages, the mix you got is a strange combination. Were you really near a NFZ?

 

[Kilrah]

Most likely bad compass calibration.

I hope Rob has time to give me instructions on how to download DAT file from Mavic so I can do it this weekend.

He did so 2 posts above yours.

 

[4wd]

It does sound like your 'newly calibrated IMU and Compass' was not entirely successful and the main reason it got horribly confused.
I would do these again under optimal conditions.
The compass rarely needs doing once you have a good calibration, however it can be badly messed up without telling you if done in a poor location.
Make sure nothing magnetic is somehow getting near e.g. some phone cases have little magnets to hold shut.
Another overlooked risk is loudspeakers in vehicles for example.

 

[Vilco]

Another overlooked risk is loudspeakers in vehicles for example.

How true, once I entered my car with the mavic on in my hand: it started beeping as hell and stopped only once out of the car

 

[julius13]

Hello Mavic friends!

I need your help to understand. Last night I would fly from a place I flew several times earlier without problems. I had new calibrated IMU and compass and updated homepoint. After take off, I hovered 30-40 seconds above the starting point. The Mavic then felt a little worried but, in my opinion, within the framework of what feels OK.

Immediately when I flew away, I had big problems. The Mavic pulled off at full speed and it was extremely difficult to control it. I really got to fight to keep it in sight and not crash. After great concentration and a fight home Mavic I managed to make an OK landing but throughout the flight I thought this will never be going well.

During the flight, I repeatedly received several error messages, which I need your help to clarify and explain.

• Obstracle avoided. Revise flight route.
• Warning: In flight, workingIMUen countersheading exception, please switch to atti mode if craft behave abonormally.
• Warning: Campass error, Exit P-GPS mode.
• Current RTH route will pass a No-fly zone. Pay attention to the aircraft’s position to aviod RTH failure.

After closing down all the equipment, let Mavic cool down, then I restarted, calibrated compass and IMU. At first, I had a hard time keeping the altitude when I hovered, but after a couple of minutes, Mavic was as usual again.

Having any of your similar experiences, there is some way to prevent this from happening again. The experience was very unpleasant and I do not want to experience it again! Please share your experience and expertise regarding this issue.


Sincerely, Fredrik

I had mine stopped abruptly at 235 feet because of obstacle avoidance and obviously nothing there. I got some alcohol at Q tip and cleaned out the front sensors. I've also had several disconnects, to the point of even having to reboot DJI go 4 app. I've also had a real problem with using Autopilot as it syncs with DJI GO 4 app. My first flight was an orbit that went fine until It got to the end of its destination and just took off. I had to fight it all the way home. My second flight at a mother location, it just took off climbing on its own and had I not had max alt set at 120 m it would probably still be climbing. I fought it home and when it finally seemed to act right, it scurried up under my car. It finally shut down, 2 nicked blades later. Swapped propellers our, did test flights and all is good. For now.

Seems to me these Mavics are like a puppy, fun to play with, but oh so unpredictable. Scary to think that, with so many flooding the market. Most being operated by a vast segment of the population unqualified to do so, or simply some rouge operator flying on the edge of legality. When someone gets unintentionally hurt, it will probably not be by foolish practices but by PIC error caused by uncontrollable issues within the software/firmware issues.
Then where does that leave us? We can only be as responsible a pilot as possible, but when the communications between devices let you down, you have no where else to turn.

 

[Jacknet007]

I had these 3 errors happen twice today:

• Warning: In flight, workingIMUen countersheading exception, please switch to atti mode if craft behave abonormally.
• Warning: Campass error, Exit P-GPS mode.
• Weak GPS

My first thought is it might be due to the iphone4 stuck to the top of the Mavic with velcro!

I was testing to see if I could use the iphone as a GPS tracker and use the Find my iPhone with it.

However after seeing the Mavic curve when it should be heading straight and also descending in small circles while landing I believe the test failed.

I have also seen compass error when I placed the running Mavic on the roof of my car.