TBS Discovery pitches back


When flying my TBS Discovery forward, particularly into the wind, it will pitch back violently once I let off the stick (for example, if I let the stick spring back to neutral). As it pitches back it abruptly flies backwards and down - looking as if it will crash. If it is high enough in the air it catches itself and self levels. It does not exhibit this behavior if flying backwards, nor on the roll axis.

I am using a Pixhawk with AC 3.1.5. The model is setup as a V-Frame. PID gains set via APM AutoTune. Trims set with APM Save Trim procedure and flies stable/responsive otherwise.

It also exhibits a “twitch” when switching between Stabilize and Loiter and/or Alt Hold. It also is very scary when using GPS waypoints in Guided or Auto as it will pitch when reaching each waypoint.

I have seen references to others having similar issues but have not seen any resolutions.

Any support would be appreciated. Thanks.


How about providing tlogs and/or data flash logs to help troubleshoot your issue.

Thank you for your fast response. I was not subscribed so I did not see your reply until now.

I am not sure which log file corresponds to my latest ‘incident’. One of these logs corresponds to a flight in which I induced the behavior which resulted in the quad flying violently backwards and then crashing as a result. I hope they are helpful. I apologize for not being able to pinpoint the exact log as I am very new to this.

I did notice that there were errors reported when viewing in the graphs in amp planner. I said that two of the logs had a handful of corrupted lines.


I’m not sure if all the tlogs uploaded as it seemed to time out so I’m adding the other two that I have from that session.

I filmed a brief clip of the behavior. I can be found here: youtu.be/Goyjg-vFXWY

Also, I am attaching a new data flash log from a session that reproduced the issue.

I hope someone can help me.

Thank you.


Bump… Dumb question: Is this the only channel for support for The Pixhawk?

Did you ever figure this out? I looked at your video and somebody recommended pushing your battery in further. I’m having a similar situation and my battery is centered on my symmetrical X quad.