Take off failure

ArduPlane Plane 3.3
1

Today we launched a plane that has been working perfectly fine for many flights and on launching it, power was only at 70% and the plane did not climb as expected. I will load the .tlog shortly, but, unfortunately the data flash logs can’t be downloaded off the pixhawk for some reason.

Only changes since the last flight was adding a LIDAR lite, but it was reporting correct altitudes and should have no effect on launching.

My belief for the failure is actually a mission planner issue. After the plane hit the ground (damage to the airframe was minimal but an ESC burned up from the prop hitting the ground with power) I went to the flight planner and saw the drop down menu to select “absolute, relative or terrain” was blank. I have a feeling of this box glitches and is blank it defaults to absolute altitude and it caused the plane to try and go from an absolute altitude of over 2000 meters down to 150 actual.

Is there any way to verify the desired absolute altitude of the waypoints using .tlogs only?

I will post the logs soon to see if you guys see something different.

Thank you

2

Here’s the .tlog

3

I was incorrect in thinking the altitude type was incorrect. I am now stumped as to why the launch went wrong?

Any help would be greatly appreciated.

4

The other strange thing is the Distance to WP1 when Auto is selected shows over 8700 meters. No point in the entire flight is that far away and WP1 is the take off command.

Any idea’s why it could be reading that?

5

Something definetly went wrong. I took the SD Card out of the pixhawk to see if I could extract the logs that way.

Here’s the files that were created that day. Very little information on them for some reason.

Completely stumped, any help would be greatly appreciated.

6

The only thing I can think of is the pixhawk itself glitched as it did not even properly write the log files.

Nothing else seems to make sense. I redownloaded the waypoint file and everything looks correct and also set it to “auto” and it responded properly this time.

Very very strange.

7

Ok, one more discovery. The pixhawk was being powered off the servo rail as one of the wires for the main power supply came loose.

I guess it’s been flying like this for a little while, so I don’t think thta is the direct cause of this issue, but maybe voltage fluctuations caused it to glitch?

8

I got the plane all back together and powered it up. It seems that the LIDAR Lite can glitch sometimes and cause this problem. It seems to interfere with the GPS some how and the altitude bounces all over the place.

I reset the power on the lidar lite and everything was fine.

Has anyone else has issues with the LIDAR Lite? I am thinking this may have been the cause of the crash now. Maybe it really does need the capacitor?

9

I am going to hook the LIDAR Lite up through the servo rail and see if that fixes the issues. I have a feeling that the servo rail is a better option than the I2C even with the newer versions of the LIDAR Lite