Hi everyone, John here. I had a concerning episode on a recent test flight and would like to know where to start hunting down this issue other than visual inspection. My setup: Skyjib x4xl, Jeti DS-16, Jeti R18 rx, Herk III, KDE 5215xf 435kv 22p, Most recent MK controller, Navi, GPS and external compass. The Herk III firmware is sw103 I2ct,afw1,khz16,adv24 The event: I was test flying my skyjib x4xl without payload when my jeti ds-16 rang out an engine restart error. I watched as motor 4 (top back left) spooled down to a complete stop. Fortunately motor 8 (bottom back left) compensated immediately resulting in no noticeable flight change. I landed the craft easily and shut the motors off. Once settled, I turned the motors back on and all motors except motor 4 spooled up just fine. Motor 4 stuttered then shut off. I then shut the motors off and heard the startup tone from the Herk III. Here is a video of this happening: Visual inspection of all solder points and connections seem fine. I'm not sure where to start looking into this. I'm new to mk so reading the gpx file doesn't help me a great deal. I have attached it if you're interested. The first (15031700) is the most current event and the second (15031302) is another where I found the motor restart error. Questions: 1. Do you seen anything in the gpx file other than the error code that could highlight the source of this problem? 2. Could this be a commutation timing error due to the 22p motors? I have it set at 24 degrees. Any help would be greatly appreciated. Take care, John.