Crash in auto mode. Dataflash differ from telemetry

Two weeks ago I was doing a survey with my plane and when I activated the auto mode the plane didn’t follow the programmed waypoints and ended up crashing.

I have a Hobbistar 60 with a Pixhawk running plane 3.1.1. I have flown this setup for about two years now (most of the time in auto mode) and never had any problems. I have a preflight checklist that I follow everytime and one of the things I do is to read the waypoints from the Pixhawk just after writing them to be shure everything onboard is according to what is supposed to do.

I tookoff in manual mode (hand-launched) and shortly after, activated the auto mode. The plane headed to the wrong direction and was not climbing as expected. I kind of froze and didn’t manage to do anything before the plane crashed into a hill nearby.

Fortunatly I recover the crashed plane with the Pixhawk and all electronics intact so I managed to get onboard logs from the flight. When I checked the logs I could see the plane had programed an old mission wich was the one it was trying to follow. Then I check the telemetry logs and, strange as it sounds, it shows me the correct mission. Never show (or never saw, at least) any error when writing the mission to the Pixhawk and that seems to be in accordance with what telemetry shows me.

So, the dataflash shows a wrong mission but the telemetry shows the correct one.

I’m attaching both logs, telemetry and dataflash, so maybe someone could help mefind ou t what happened (dataflash is quite big because it kept loging until we found the plane so I had to split it up).

Thanks a lot.

Hi. It looks like you didn’t upload the new mission. Normally when you upload a mission the first thing we see in the tlog is to clear any current mission. It looks like:
MISSION_CLEAR_ALL {target_system : 1, target_component : 1}

Your tlog doesn’t have that anywhere so it looks like your new mission wasn’t uploaded.

The other thing is your as your running older ArduPlane it doesn’t support dataflashing logging before being armed so I can’t tell if you tried to upload the new mission on your dataflash log. I can see however that it does startup with the old mission loaded.

Thanks, Grant.