To prevent a drone down from sky, may I know if there is a way to check or tell if the battery, motor, esc, propellers is failing thus no fly and repair it before fly.
It's always good to visually inspect your Phantom before flying. For example, check if the props are cracked anywhere, ensure the motors turn freely, etc. If you always do the same checks before flying, you should be able to easily tell when something is out of the norm.