Beginner 1 st crash....why? log file

[BudWalker]

If I understand you correctly you are asking if the direction of the MP on the ground was exactly the same as a the digital compass on screen? Unfortunately this is not a check I can ever recall making because it was my naive assumption the two would always line up. I do a check for a number of things, but I wouldn't check things that are never out of true (by my beginners assumptions). BTW I have calibrated the compass the day before and there was no flag to do this again, although I appreciate it is always good practice.

I was asking if you remember the orientation of the AC prior to launch for this particular flight. The .txt shows it pointing -6.38 degrees. Was that it's actual heading while on the ground? Most times when I fly I have a particular direction I'm gonna wanna go and point it that way before launch.

Often a difference in Yaw vs actual can be seen by looking at the .txt and any lateral movement that results from elevator and/or aileron input. But, your flight didn't have elevator and/or aileron input until the fly away was well under way. If we had the .DAT we could know for sure what happened.

If this incident was caused by ferrous material at the launch site then the compass calibration is unrelated.

 

[BudWalker]

Actually, you should generally never calibrate the compass unless it tells you to do so or you are trying to fix a compass related issue. It is actually bad practice to calibrate it when not needed as you risk screwing something up.

I'll have to, respectfully, disagree with that. IMHO the risk of getting a bad calibration is way, way overstated. If there is going to be a problem the calibration will be rejected and the "magnetic interference detected. move to a better location" message will be issued. AFAIK, there has never been a documented case where a bad calibration was successful.

 

[stressor]

I was asking if you remember the orientation of the AC prior to launch for this particular flight. The .txt shows it pointing -6.38 degrees. Was that it's actual heading while on the ground? Most times when I fly I have a particular direction I'm gonna wanna go and point it that way before launch.

Often a difference in Yaw vs actual can be seen by looking at the .txt and any lateral movement that results from elevator and/or aileron input. But, your flight didn't have elevator and/or aileron input until the fly away was well under way. If we had the .DAT we could know for sure what happened.

If this incident was caused by ferrous material at the launch site then the compass calibration is unrelated.

The reason I cannot recall is that many of my flights are literally straight up / hover /rotate 360 / straight down because I am doing a lot of pano photography. so I wasnt necessarily going to fly anywhere.....in a way thats what made the spiral movements more alarming as I wasn't necessarily going anywhere away from my position except straight up.

on the topic of the DAT files, I have tried three times, with two usb leads including the original, and it is reporting "no files" currently. Perhaps need to install on another computer.

 

[f3honda4me]

I'll have to, respectfully, disagree with that. IMHO the risk of getting a bad calibration is way, way overstated. If there is going to be a problem the calibration will be rejected and the "magnetic interference detected. move to a better location" message will be issued. AFAIK, there has never been a documented case where a bad calibration was successful.

Ive personally had a bad calibration happen that caused erratic flight. P4P I did a calibration and my phone in my pocket appeared to have gotten close to the drone while turning it, offset the values just enough to cause erratic flight but it took the calibration. I took off and noticed the drone was constantly yawing right. And in forward movement the drone was very difficult to control. When I brought it down to land where it was it was constantly spinning to the right and having a hard time maintaining level flight. Landed and the values were in the yellow for both compasses.

Did another calibration this time without the phone in my pocket, values back to green, drone flew perfectly.

I’d imagine this would be easy enough to replicate.

 

[BudWalker]

The reason I cannot recall is that many of my flights are literally straight up / hover /rotate 360 / straight down because I am doing a lot of pano photography. so I wasnt necessarily going to fly anywhere.....in a way thats what made the spiral movements more alarming as I wasn't necessarily going anywhere away from my position except straight up.

on the topic of the DAT files, I have tried three times, with two usb leads including the original, and it is reporting "no files" currently. Perhaps need to install on another computer.

"no files" suggests to me that you're expecting to see a disk mounted on your PC that contains files like FLYXXX.DAT. If the FW is version 1.03.0900 or later this has changed - it doesn't mount a disk. You'll need to use DJI Assistant 2 V 1.1.6 and use these instructions
How to retrieve a V3 .DAT File

 

[BudWalker]

Ive personally had a bad calibration happen that caused erratic flight. P4P I did a calibration and my phone in my pocket appeared to have gotten close to the drone while turning it, offset the values just enough to cause erratic flight but it took the calibration. I took off and noticed the drone was constantly yawing right. And in forward movement the drone was very difficult to control. When I brought it down to land where it was it was constantly spinning to the right and having a hard time maintaining level flight. Landed and the values were in the yellow for both compasses.

Did another calibration this time without the phone in my pocket, values back to green, drone flew perfectly.

I’d imagine this would be easy enough to replicate.

Please do. Do you have any of the .DATs from this incident? If you can duplicate this then please provide a .DAT 1) before the incident, 2) the flight where the calibration is done 3) the flight with the incident, 4) a flight after the incident, same (bad) calibration and in a different location 5) flight after a calibration. What I'm looking for is data that will differentiate between the cause being a bad calibration and launching from a geomagnetically distorted spot.

 

[f3honda4me]

Please do. Do you have any of the .DATs from this incident? If you can duplicate this then please provide a .DAT 1) before the incident, 2) the flight where the calibration is done 3) the flight with the incident, 4) a flight after the incident, same (bad) calibration and in a different location 5) flight after a calibration. What I'm looking for is data that will differentiate between the cause being a bad calibration and launching from a geomagnetically distorted spot.

I’ll try to keep in mind to do this. Most flights are from my yard, so no geomagnetic distortions. Getting cold here though so not as many flights these days.

I also am not sure I want to do this on purpose. I thought the drone was going to crash. I don’t want a crashed drone in the name of science.

 

[stressor]

"no files" suggests to me that you're expecting to see a disk mounted on your PC that contains files like FLYXXX.DAT. If the FW is version 1.03.0900 or later this has changed - it doesn't mount a disk. You'll need to use DJI Assistant 2 V 1.1.6 and use these instructions
How to retrieve a V3 .DAT File

under "If the correct tab is selected a list of flights will be shown." ...........................nothing is shown under list of flights.

 

[BudWalker]

under "If the correct tab is selected a list of flights will be shown." ...........................nothing is shown under list of flights.

Bummer. Mavic FW version 1.03.09000 or later and DJI Assistant 2 V1.1.6 ?

 

[rfc]

If the mavic had a user selectable Atti mode, things like this could be avoided.

Is that because you don't need the compass in Atti mode at all?

 

[stressor]

ok I got the DAT file. I had an earlier version of the DJI Assistant 2 V1.1.6; here it is Dropbox - DJI_ASSISTANT_EXPORT_FILE_2017-11-19_20-08-43.DAT

 

[BudWalker]

ok I got the DAT file. I had an earlier version of the DJI Assistant 2 V1.1.6; here it is Dropbox - DJI_ASSISTANT_EXPORT_FILE_2017-11-19_20-08-43.DAT

Interesting. This was not a launch-from-a-geomagnetically-distorted-site incident. At launch there was a 73 degrees difference between Yaw and magYaw (heading determined by the compass)

It looks to me like the Mavic was turned on and then was transported in a car to the launch site about .3 miles away? Took about 10 minutes to get to the launch site. During those 10 minutes there were many, many compass errors and switching between the compasses. In addition there were many compass related warnings/errors in the eventLog stream.



Once at the launch site the Mavic sat for about 70 secs before launch. I would've expected that the compass problems would have slowly gone away during those 70 secs. But, just to be sure about this can you do a test? Place the Mavic at the launch site with a northerly heading and then turn it on. Let it sit for 2 minutes, turn it off and provide the .DAT.

 

[stressor]

yes that's correct. I turned the MP on in the car park (location 1).....there were no cars there at the time BTW it was around 745 am sat morning. I was going to take off from the car park, but I got the MAG error message, so I decided to move to the park. I drove to the park, I didnt worry about turning it off or on because I never ever heard that was an issue. At site two (the park) I would say I was there at least 5mins before taking off, because I had to find a parking spot (but for 3 of those 5mins, I think the mavic was still in the car). Probably took 2mins to walk to the launch location. From there I reset the home coordinates and did auto-take off and then it all went wrong. Cant recall getting any error messages. BTW I already

But, just to be sure about this can you do a test? Place the Mavic at the launch site with a northerly heading and then turn it on. Let it sit for 2 minutes, turn it off and provide the .DAT.

Are you suggesting going back to the exact same location? Not super convenient and its busy in the week. btw I already flew the MP again in a huge field to check it was working, and it was fine (mechanically), broken gimble tho from the crash. I can do your test in a big field nearer my house though if that helps.

thanks for looking into this whole issue for me, anyway.

 

[BudWalker]

yes that's correct. I turned the MP on in the car park (location 1).....there were no cars there at the time BTW it was around 745 am sat morning. I was going to take off from the car park, but I got the MAG error message, so I decided to move to the park. I drove to the park, I didnt worry about turning it off or on because I never ever heard that was an issue. At site two (the park) I would say I was there at least 5mins before taking off, because I had to find a parking spot (but for 3 of those 5mins, I think the mavic was still in the car). Probably took 2mins to walk to the launch location. From there I reset the home coordinates and did auto-take off and then it all went wrong. Cant recall getting any error messages. BTW I already



Are you suggesting going back to the exact same location? Not super convenient and its busy in the week. btw I already flew the MP again in a huge field to check it was working, and it was fine (mechanically), broken gimble tho from the crash. I can do your test in a big field nearer my house though if that helps.

thanks for looking into this whole issue for me, anyway.

That's OK, you've already done the test. I'm still kinda puzzled why the compass error persisted after it sat at the launch site for 70 secs.But, I think that's what happened - maybe a longer wait would've helped. Recycling the power would have eliminated the compass error.

BTW, I had asked what direction the Mavic was pointed prior to launch - it was about 55 degrees. And as I mentioned the Mavic thought it was -6 degrees.

 

[Glennyboy]

Interesting. This was not a launch-from-a-geomagnetically-distorted-site incident. At launch there was a 73 degrees difference between Yaw and magYaw (heading determined by the compass)

It looks to me like the Mavic was turned on and then was transported in a car to the launch site about .3 miles away? Took about 10 minutes to get to the launch site. During those 10 minutes there were many, many compass errors and switching between the compasses. In addition there were many compass related warnings/errors in the eventLog stream.
View attachment 25194
View attachment 25195

Once at the launch site the Mavic sat for about 70 secs before launch. I would've expected that the compass problems would have slowly gone away during those 70 secs. But, just to be sure about this can you do a test? Place the Mavic at the launch site with a northerly heading and then turn it on. Let it sit for 2 minutes, turn it off and provide the .DAT.

Read through all this thread, and I’m genuinely impressed with the help you’ve given this guy. Great work by you Budwalker and what a great advert for this forum and the help some fellow users can give.

 

[stressor]

I agree, first time

Read through all this thread, and I’m genuinely impressed with the help you’ve given this guy. Great work by you Budwalker and what a great advert for this forum and the help some fellow users can give.

I agree first time here, 1 week old mavicpilot, very impressed with the help received from Budwalker and others and also impressed with the amount of data available.

 

[3VP]

BudWalker - now there’s a person who knows their stuff. Excellent assessment of the data and well explained.

 

[stressor]

Just to update you. I filed a repair request (didn't have refresh); DJI assessed the situation quickly and agreed to repair for free (gimbal/camera cable/etc). Received the repaired drone this week, appears to be 100% fine now. In addition although its the same drone....DJI refresh was also suddenly an available option. Great service from dji and thanks everyone for your help here.