I may have also spoken too soon. Last week I took a flight, and while flying forward, no yaw or roll, and relatively close range, no obstructions, I had a complete signal loss for 11 seconds. The AC initiated a RTH. Once I regained a signal, I tried to cancel RTH three times, all unsuccessfully, it just kept on coming home. About 8 seconds later, a yaw error occurred, and it just sat there in ATTI mode. I was finally able to take control of it at this point and continue traveling back, and eventually, it switched back to P-GPS. 2nd flight, while moving from hovering to forward flight, 8 seconds later, it again received a yaw error and switched to ATTI mode. This was hundreds of feet of altitude, I don't know where magnetic interference would occur. Had I not been able to reconnect during the 1st flight, I would be out looking for the downed Spark. I fly fine in ATTI mode, but my worry is losing the signal and getting a yaw error at the same time. This also puts a damper on Litchi missions that are close to or beyond RC range. After some searching the forums, yaw errors seem to be a problem with the Spark.