Quadplane unstable in loiter (Crash, BIN attached)

I have a Swan K1 converted to Ardupilot 4.2 on a MATEK F765Wing. I have been tuning and getting everything dialed in but one issue that has finally led to a crash is unstable loiter in fixed wing. About half the time it will enter a loiter fine (as an auto mission or just switching to loiter from cruise etc). The other half of the time it will become very unstable and basically wobble towards the ground. So, I tried adjusting the max bank angle, increased the default loiter radius etc hoping to get rid of this issue. In this flight I ran autotune in fixed wing mode and it completed fine. So I went back to cruise mode then tried loiter again to see if it was any better. It did a death dive towards the ground and burned in. I tried switching back to cruise to save it as I have before but it was too late. Can anyone take a look at the bin file and see if anything jumps out as the case of this instability? I did see a couple EV EKF Yaw Reset messages but nothing looks bad in reference to the compass and it didn’t come up during the crash. I also see an EKF Lane Switch but it wasn’t at the same time as the crash. Still researching what the error means exactly. Thanks for any help.


Were you able to find the cause. I’m also getting this EKF YAW RESET error and Aircraft going uncontrollable. Trying to figure out. Even changed the compass location. Still getting the error

Unfortunately no. I was unable to find a definitive answer to the EKF yaw reset message. It is either too cryptic or too NOOB to warrant an answer. I ended up changing to an f405 wing, adding dual compass/gps/baros and so far haven’t had another crash. I do get that error at times still however. I have tried the compassmot cal but can not get it to start (on 3 different systems none the less). On all my vtols, even with my latest build of A zmo with a cube orange, I have found that taking off in loiter causes unstable flight but instead taking off in q_stabilize and the switching to loiter seems better. Maybe it gives the compass time to settle.

I had a minitalon with matek 765 and had 3 reboots mild flight but was lucky enough not to crash. I ended trashing the 765 and going back to 405 wing. Doing a search in web you will find reports about the 765 rebooting mild flight.