Crash Analysis Help

Hi All,

Been a few years since I used ArduCopter and the Log files have moved a long way since I last used them

Hoping someone can check my theory about crash on 2nd flight of new quad.

Few details.

Spider 700 V Frame
3508-700kv Motors
30Amp Esc’s
15x5.5 Carbon Props
4s -8000mAh 10C Battery
Pixhawk 3.4

This was just second flight after I had tweaked the PID’s down a little, Hovered at about 30% throttle. Nice and stable, if a little twitchy (not run autotune yet).

It was all going fine for about 4 mins, had used Alt Hold, held 4-5 feet very well. Switched to loiter, seems very stable, little drift but no toilet bowling of sorts.

Then all of a sudden quad fliped over and crashed. before I was able to hit stabilise, anyway, only damage 1x prop. So was lucky.

Now I have looked at the log best I can but cant seem to see anything strange myself, you can see where the quad flips and then hits the deck. But not sure if im reading it right.

I am therefore suspecting mechanical failure of some kind. It was almost as if the front right prop just shut down. Maybe issue with ESC or motor… I checked the temps straight after Motor was 28dec C, ESC was 45C. Not overly hot at all!

Anyway, if anyone can give me pointers before i try again would be very gratefu. Maybe im missing something in the log.


Link to the log file 4mb so cant upload it directly.

It looks like GPS drift because the flight controller commanded the pitch and roll. I did not see a large change in GPS position but there was a little movement at the point of the crash.

Flying in your back yard with GPS is not a good idea.


Also the logs show you are running 3.3.3.


not mutch to contribute, but there are a lot of unusual spikes in the data. Just check:

Maybe it is a power/short circuit issue?

Best regards,


Thanks for reply.

Ill try and dig a bit deeper, mainly for my own benefit of learning, into the GPS position, and the commanded pitch and roll

Whilst I accept there as a bit of drift, there wasnt a big jump and the copter snap rolled into the ground in under a second with a very rapid roll. Not a general drift into anything. Isnt there a parameter that would limit the pitch/roll angle when in loiter? Thought it was 45 deg.

Mine flipped over almost 120deg into the ground.

Anyway, im not an expert so will try and understand the logs a bit more.

Yeap, Think I am 3.3

Should I update to latest??

Thanks for the tip on the spikes will def check them out before next flight.

You are in 3.3.3, so I’ve changed the category.

As has been said your log has some weird spikes. I can see that roll didn’t match the desired roll:

This means that it wasn’t the flight controller that commanded the unexpected roll. I’m not the best looking at the log to understand why this happened but I would say that it can be some kind of mechanical failure.