AC 3.3.2 Quad Destabilizing

Hi all,
I am running AC 3.3.2 using Pixhawk 1 on my quad after having flown for several weeks, I suddenly started having stability problems randomly. When this happens, the system roll/pitches from 40 degrees to 80 degrees and regains control an instant later losing up to 50 m. I am not sure what the problem is but its worrying to fly with this going on. I have attached a copy of the log that has the problem.

A log of one of the flights is attached.

log

Wow, that’s all sorts of messy.

Check your thrust on Motor3; it looks like it might be an intermittently bad ESC or motor.

Hi, thanks for the reply. I had a feeling it was the ESC but needed a second opinion. I had interchanged the ESC between motor 3 and motor 1 and the problem showed up on motor 1.

Any idea what would cause an ESC to behave like this? Thermal shutdown, Current limiting, intermittent link between ESC and Pixhawk due to bad servo cable (Assuming ESC is good)?

Any idea what would cause an ESC to behave like this? Thermal shutdown,
Current limiting, intermittent link between ESC and Pixhawk due to bad servo
cable (Assuming ESC is good)?

Could be any of those, and lots more besides!

Best to get a couple more of the ESCs - one to put in place of this faulty
one and one so next time it happens you’ve got a part to put in place
immediately!

I have been testing it on the ground with inverted propellers for long durations but the problem hasn’t surfaced. Only seems to show up in air. The ESCs and motors were running hotter than when I run it in air also.