IMU redundancy switch occurs when it switches to the 2nd IMU because of errors with the primary one.
You can observe this by holding your tablet close to the drone while looking at the IMU status screen. The electromagnetic interference from the tablet will trigger it. Move the tablet away and...
Battery is used warming up, preflight checks, hovering, climbing, flight may be meandering, basically lots of reasons. But the most important one would be wind. The bird doesn't how it will be affected by the wind flying back.
Does anyone know why Airmap lists every school in the surrounding area? I haven't seen that on any other app including the FAA app.
I don't remember exactly what the message was but it lists them. I didn't know that schools were of any relevance to drone flights.