Log review help

Can anyone help me figure out why the plane decided to nose dive when switched into auto mode?

Plane was bungie launched in manual mode since we decided against using the auto take off, then switched to auto, then it tried nose diving to the ground. Luckily we switched to manual and landed but I don’t know why it didn’t want to fly in auto.

Here’s the link:

dropbox.com/s/zvv2q5cg7rfvu … .tlog?dl=0

Did you do a test on the ground with the plane in Stabilize mode and see that it responded appropriately to changes in pitch and roll? That is, when you tilt the nose up does the plane respond with down elevator? Often times it needs to be reversed in APM so that it responds correctly. From your description that’s what it sounds like.

Yes, all preflight checks were done. This was also not the first flight with this plane and it had quite a few successful flights. It is a commercial grade plane and all preflight procedures were completed.

Dataflash logs have more details and would prove more useful for analysis. Are you able to send those?

Thanks, Grant.

I unfortunately don’t have access to that at the moment. I should within the next 2 weeks, however, and will post it to see if there is anymore information there.

Thank you for the help!

Here is the .rlog file. Maybe you can see more with this? We are still clueless as to what happened.

dropbox.com/s/uzih4jfaxc7f9 … .rlog?dl=0

Interestingly the tlog is recording your flight altitude of the plane in ABS (above sea level) i.e. over 2500m however your waypoints are set in REL - 180m - so my guess is when you set AUTO the plane is trying to go 180m ABS hence its diving. I haven’t been able to confirm this so you will need to test my theory.
What GCS do you use? How did you configure it to use ABS? Most people use REL but perhaps you have a need for ABS which is fine - you just need to be consistent I think.
I like your airfield by the way - the cows don’t mind the planes flying around?
Thanks, Grant.

Thank you,

That is most certainly a good explanation. I am using mission planner and we use REL due to extreme mountainous conditions throughout the area. I checked the elevation map before launch and it did not show any errors. What is the best mode to use for mountainous conditions where we want the plane to remain at the altitude AGL?

Terrain mode is nice, but, we chose not to use it since it doesn’t show the values of altitude change, however, I do not understand why the REL altitude would change to ASL? Isn’t it supposed to maintain relative to ground level?

Maybe the terrain data is not accurate for this area?

Thank you for the help!

Verify height was used. The weird thing is I programmed it exactly the same the previous time that we flew and it worked perfect. Is it just a glitch?

Would there be anyway for someone to program in a warning, or a “preflight” button into the flight plan page to do a quick logical test for things like this. EI, compare the elevation data with your flight plan, ensure there is no altitude changes beyond set limits, and any other major potential errors with the mission?

Just a quick sanity check before sending it off to the aircraft for the mission?

If I knew how to write code I would work on the pull request myself, but, unfortunately I do not possess that skill set as of right now.

With code we can do anything - its just a matter of priorities :wink:
Can you post a tlog of your successful flight please so I can have a look?
Actually, I really need the dataflash log (.bin) as well please.
Thanks, Grant.


Any successful flight with this aircraft? Or is there one in particular you would want to see?

Sorry for the delay

Any successful flight is fine.

Thanks, Grant.


Here’s a couple files. Not exactly sure which is the correct ones but they should all be successful flights.

dropbox.com/s/chemuivfk4s1y … 5.zip?dl=0

Thanks for that. Looks ok. Glad your plane is working well now.

Thanks, Grant.

Thank you, I appreciate the help.