Need help! My first build crashed at test flight


I’m fairly new to the drone world and just finished my first build and sadly enough it crashed at it’s maiden voyage. At first everything seemed ok but just before I wanted to land it after the first test flight it suddenly started to pitch backwards a few times and before I knew what was going on it backflipped into the grass…
I’m in the process of rebuilding the drone but I really would like to know what went wrong before I attempt to make a second test flight and get the same problem. I analyzed the logs but being new at this haven’t got that much experience in this field. It looks like the gps glitched in the last few seconds and hopping from one side of the field to the other. Could this be the reason of the sudden crash? Could somebody help me analyze this log and prevent the drone from crashing again?

I’ve build a Tarot 650 Sport
Flightcontroller: Pixhawk
Esc: 40a hobbywing
Motors: 4008 380kv tarot
Prop: Tarot 1555

It also looks like the desired pitch and actual pitch are off although they are following the same line.
In the end I tried to flip the switch for the RTL function in a rookie attempt to save it. At the moment of impact the battery disconnected so the log ends there. Also when I got home I tried to connect the pixhawk to mission planner but when I plugged in the usb I got several beeps and a solid red light. After a few times this problem solved itself and I could download the logs but it did make me think that maybe the flight controller itself has got problems or maybe the gps and that caused the crash?
Hope somebody can help me analyze this log and tell me what really went wrong so I can try preventing it from crashing again.


Try uploading the log again.
That link you provided is invalid when I click it.

If it went opposite to what you want it to, sounds like you have the pitch normal which is wrong.
Pitch needs to be reversed from what you see in Mission Planner.
IE push stick forward, bar moves down…pull stick back, bar goes up.

Think of an airplane - pull back on the stick to pitch up - move towards you.

Program that flight mode where you know where it is at.
Have all other flight modes set to Stabilize.

Once you get comfortable with those two modes, add another and so on.

Thanks I edited it and the link now works like it should. I had the drone in Loiter mode when it crashed. It backflipped all by itself so no rookie pilot error:P altough maybe could have saved it by going back to stabalize mode but it all happened in a split second…

If it back flipped in flight, not takeoff, then it is a mechanical/ electrical failure in the rear motors.

Once you go above 13" props it can happen with some setups and standard PID’s, especially if you are overpowered or under loaded (testing with no payload, as we do)

This might be useful
It was for me.