Glitch Analysis

Greetings forums, please assist with analysis of this glitch. While in auto and about 75% through a mapping mission, my PixHawk powered quad (AC 3.15) experienced an intense pitch & roll glitch, lost altitude and swung about 120deg off heading, but managed to recover and continue the mission, although I did lose my nerve and hit RTL soon after. RTL was uneventful and we executed a safe landing. No damage but a perplexing glitch and one that could easily have led to a crash.

The log file is attached - the glitch occurs at around line 15.135k. It appears as if the first event is a steep drop in channel 1, followed by channel 2, the other channels then swing wildly to compensate. It must have come very close to a flip.

Any thoughts on possible causes? I’ve now done about 5 hours of successful auto flying with this quad so things have been going well.


There is no way to find root cause on this based on the datalog. It was probably a motor or ESC problem, maybe a loss of sync, loose wires, not sure. But the problem was not caused by the Pixhawk. The problem was probably with Motor 3 or 4, most likely 4.

Thanks Rob, for the feedback. I’ve now got about 10hours of autonomous flight with the same quad, and the glitch has occurred once more in that time. It was also recoverable.

Given that there is some uncertainty as to its cause, I will only consider making changes to the motor/ESC combination once I’ve upgraded FW to AC 3.2