Preflight Checker only checks your drone before taking off. It is isolated with flight application, so it does not affect any flight.
Preflight Checker is totally free. The team behind it is more than happy to make a contribution to the safety of drones.
Preflight Checker is the first one worldwide to provide professional security checking for all DJI drones. Our professional engineers, with years of flight experience, check every API of DJI drone's sensors and dive deep into each item detail that would affect the flight, making sure it's simple and reliable.