Need some help from some you that know These much better, Please!!

[mrreddog]

So I was flying Mavic pro a couples weeks ago and landed down into very thick weed and crab grass, it was freshly cut, but I didn't realize it was so thick and still about 5-6 inches tall. So took it home, blew everything off with air compressor and wiped it all down, this stuff was surprisingly thick and coarse weed stalks, it looked ok from 100 yards.
Any ways, looked like no damage. Then within 3 or 4 flights I started getting jello video here and there, but it seemed to jello approximately every 15 seconds or so, but it seamed like some sort of oscillation. then I made several more test flights and it would jello just quickly and randomly , sometimes none??
then yesterday did another test run, I'm using Super patcher, so Galileo was active, I had 22 sats. then suddenly app says "atti mode", so I headed home and the Mavic would not fly Straight. It had about a 45 Degree angle to the left while right stick was straight forward?? So no big deal, I fly Manual on other drones often. I bring to about 1200 feet of Home Point and decide to try RTH just to see what it does, well it came directly overhead like normal.??
so I take a look at Airdata, and it says "Compass Error (repeated 30 times)" at the same point the app said "Atti mode" and same time Mavic was crabbing to the left 45 Degree's ??? So I rotate props, front to back, back to front, run another test run and all seemed fine??
So Im wondering if the props became unbalanced or damaged from bad landing in 5-6in. thick weeds and caused this jello on the couple of flights, then the atti mode & ""Compass Error (repeated 30 times)" on Airdata??
I remember back in the old day of APM that too much vibration would cause flight controller & compass issues..
This bird has over 200 perfect flights up till now. So now its my turn for my 1st deep analysis, sorry for the long post, but I really am trying to narrow this down, I have props marked from before and after rotate..(but have NO replacements)
I have forgotten how to download flight info from bird, if its still done that way?
I would really appreciate @sar104 & other specialists to give me a hand with this, Thanks guys,Rodger.

 

[Meta4]

I have forgotten how to download flight info from bird, if its still done that way?

Go to DJI Flight Log Viewer | Phantom Help
Follow the instructions there to upload your flight record from your phone or tablet.
That will give you a detailed report on the flight data.
Come back and post a link to the report it gives you.

 

[mrreddog]

Starts at 8m 49.5s The 2nd most southern ring

DJI Flight Log Viewer | Phantom Help

Upload and view flight logs from your DJI drones

www.phantomhelp.com

 

[RadioFlyerMan]

So I was flying Mavic pro a couples weeks ago and landed down into very thick weed and crab grass, it was freshly cut, but I didn't realize it was so thick and still about 5-6 inches tall. So took it home, blew everything off with air compressor and wiped it all down, this stuff was surprisingly thick and coarse weed stalks, it looked ok from 100 yards.
Any ways, looked like no damage. Then within 3 or 4 flights I started getting jello video here and there, but it seemed to jello approximately every 15 seconds or so, but it seamed like some sort of oscillation. then I made several more test flights and it would jello just quickly and randomly , sometimes none??
then yesterday did another test run, I'm using Super patcher, so Galileo was active, I had 22 sats. then suddenly app says "atti mode", so I headed home and the Mavic would not fly Straight. It had about a 45 Degree angle to the left while right stick was straight forward?? So no big deal, I fly Manual on other drones often. I bring to about 1200 feet of Home Point and decide to try RTH just to see what it does, well it came directly overhead like normal.??
so I take a look at Airdata, and it says "Compass Error (repeated 30 times)" at the same point the app said "Atti mode" and same time Mavic was crabbing to the left 45 Degree's ??? So I rotate props, front to back, back to front, run another test run and all seemed fine??
So Im wondering if the props became unbalanced or damaged from bad landing in 5-6in. thick weeds and caused this jello on the couple of flights, then the atti mode & ""Compass Error (repeated 30 times)" on Airdata??
I remember back in the old day of APM that too much vibration would cause flight controller & compass issues..
This bird has over 200 perfect flights up till now. So now its my turn for my 1st deep analysis, sorry for the long post, but I really am trying to narrow this down, I have props marked from before and after rotate..(but have NO replacements)
I have forgotten how to download flight info from bird, if its still done that way?
I would really appreciate @sar104 & other specialists to give me a hand with this, Thanks guys,Rodger.

Did you loosen a connection to the IMU by blowing too hard?

 

[mrreddog]

No, I the pressure was set low, and just enough to get all the grass/weeds that the props flung around off, it wasn't that bad, I just treat it well, usually always wipe it down after a few flights. But I never blew air into the vents or intake, just blew air over the whole craft.
I really think its vibration from those props, the video shows jello here n there now too. So can prop vibration cause compass error??

 

[RadioFlyerMan]

No, I the pressure was set low, and just enough to get all the grass/weeds that the props flung around off, it wasn't that bad, I just treat it well, usually always wipe it down after a few flights. But I never blew air into the vents or intake, just blew air over the whole craft.
I really think its vibration from those props, the video shows jello here n there now too. So can prop vibration cause compass error??

It could conceivably affect the accelerometer but not the compass. But a gimbal stuck on top of the support tab can cause jello. Compass errors don’t make sense. This is weird!

Guess I’m no help.

 

[RadioFlyerMan]

Just curious. Check that your gimbal is above the tab (looking right side up).

I’m wondering if there are two separate issues. What if jello and compass are due to unrelated causes?

 

[sar104]

I'm not seeing any clear issues in the log file. The compass errors are a bit odd, but do correspond to an increased discrepancy between the IMU and position data. I'd need to see the mobile device DAT file (FLY068.DAT) to look into that.

Mobile device DAT file: How to retrieve a V3.DAT from the tablet

 

[mrreddog]

Yep, I will get it up here tomorrow, its gettin late and im still working another project, Thanks for the help this far, you too @RadioFlyerMan

 

[InvisibleName]

Excuse my ignorance, but what is “jello video”?

 

[RadioFlyerMan]

Excuse my ignorance, but what is “jello video”?

Jello video is a term for video that has unstable, optical waves or ripples sometimes caused by the gimbal/camera inability to compensate for the aircraft movements or vibration.

 

[InvisibleName]

Jello video is a term for video that has unstable, optical waves or ripples sometimes caused by the gimbal/camera inability to compensate for the aircraft movements or vibration.

Thanks - every day’s a school day!

 

[mrreddog]

Thank You very much @sar104 and everyone else helping. Here is the FLY068.DAT from that day July 25th.
THIS IS THE CORRECTED DAT FILE, SORRY GUYS...
DJI Flight Log Viewer - PhantomHelp.com

 

[mrreddog]

So I downloaded Datcon & Csview, and Im trying to learn what to look for?? I see the Magmod/Compass data, but it seams ok to me?? Ive never used this so I could be missing something??

 

[Texas Mavic]

So I downloaded Datcon & Csview, and Im trying to learn what to look for?? I see the Magmod/Compass data, but it seams ok to me?? Ive never used this so I could be missing something??

Probably a silly question but did you calibrate EVERYTHING after the incident?

 

[mrreddog]

Hey.... I was getting ready to throw this at you too...No, I did not!! I really wanted to save all evidence just to learn more. way back, I got pretty good with APM, that's all I ever knew, till the Mavic came out. now after landing in this nasty thick weedy grass is where the 1st problem that I cant resolve on my own. I know back in the day with apm that vibrations could upset the FC and give compass errors. I just dont know how to use these tool for Mavic and if this is a similar issue? I want to learn, not just do a re-cal and be done, Im looking for the root cause..

 

[mrreddog]

Im very sorry guys, but I attached the wrong DAT file. There are 3 from that day, and after I reviewed the data in Csview, it showed the wrong path I took when I had the 30 Compass Errors. This is the correct file.. And I will edit the file above to show the correct file. sorry guys, Im new at this..
DJI Flight Log Viewer - PhantomHelp.com

 

[sar104]

The compass errors were clearly caused by a significant separation of magnetic and IMU yaw starting around 510 seconds. The subsequent magnetic yaw values don't look right when compared with the rudder inputs.



The error isn't periodic with yaw, but it does correlate strongly with pitch:




That suggests to me that the compass is out of calibration.

 

[mrreddog]

It was definitely pitch that was off after 1 audible of ''ATTI MODE''. right stick forward center produced 45ish degree angle to the left......
1. Thank you for helping, I'm learning csview/Datcon now too because of this.
2. Could unbalanced props or vibrations have anything to do with this??
3. Could the landing in the thick freshly cut, but very thick weeds caused any of this from previous flight??
4. I forgot to mention this was a non visual emergency landing, but soft, due to low battery, upon arriving to landing spot within 3 minutes, there was a deer that was hovering over the craft, (video shows 2 in area and 1 nudging craft) and lightly nudged Mavic with uncertainty of what it was, seen from deep in the grass video recording, Mavic was still powered and filming, but it was a very light tap, hardly moved??
These are 2 stills of where she landed and how thick and deep it was....

 

[sar104]

It was definitely pitch that was off after 1 audible of ''ATTI MODE''. right stick forward center produced 45ish degree angle to the left......
1. Thank you for helping, I'm learning csview/Datcon now too because of this.
2. Could unbalanced props or vibrations have anything to do with this??
3. Could the landing in the thick freshly cut, but very thick weeds caused any of this from previous flight??
4. I forgot to mention this was a non visual emergency landing, but soft, due to low battery, upon arriving to landing spot within 3 minutes, there was a deer that was hovering over the craft, (video shows 2 in area and 1 nudging craft) and lightly nudged Mavic with uncertainty of what it was, seen from deep in the grass video recording, Mavic was still powered and filming, but it was a very light tap, hardly moved??
These are 2 stills of where she landed and how thick and deep it was....
View attachment 78501

View attachment 78502

Just to clarify - in the flight under discussion the aircraft did not, at any point, enter ATTI mode, despite the compass errors. The unusual attitude excursions were likely due to the yaw errors. I doubt that there was a physical cause for that behavior.