So I just want to share my story and this is actually my fault. On last Saturday my friend ask me to take an aerial photo for new layout on road rc track. I was just from 100 KM away flight before that day. When I was taking off the bird I FORGET TO CALIBRATE THE COMPAS. The bird flew nicely and taking great photo. When time to landing the bird start to fly crazy and almost hit a container as a shop on the track. Luckily the bird still controllable and landed safely. That experience teach me NOT to forget pre check the bird before flight.