Crazy Behavior/Crash in Stabilize Mode

Hi. I’m relatively new to the whole APM copter scene. I have a quadcopter with an APM 2.6 on it that I’d love to get flying autonomously, but at the moment I can’t even get it to fly in stabilize.

This morning I got the props in the mail, so I decided to take it out for a test flight. Armed with no pre-arm alerts, no compass interference, GPS works fine, calibrated accelerometer. I got it in the air and it worked amazingly for about 15 or 30 seconds, when it suddenly became really slow in responding to my controls. Then, it flew off in a big arc very fast, almost hitting the house and some trees. I killed the throttle but it took about 3 seconds to respond.

Luckily, no severe damage. Broke a piece of wood that holds up the GPS/compass and snapped a prop, but I have extra of both. I’d really like to figure out why this happened, because I’m scared to fly it autonomously if it can’t even handle stabilize.

I’ve uploaded the log and attached it. I tried looking through it, but I’m not really sure what to look for. Thanks for any advice!