Coverage depends on ground receiver reception and is not a complete picture of traffic.
The hex code is the aircraft's ICAO 24-bit address, broadcast by its ADS-B transponder. It is the key used to match live position reports to this registration.
An in-flight collision with birds.
The pilot's poor judgment in conducting the flight in the existing high gusting wind conditions. A factor associated with the accident was the operator allowing/dispatching the accident flight in the prevailing weather conditions, and the icy ramp/taxi area.
The pilot's inadequate preflight of the airplane by failing to ensure that all the airplane's doors were properly closed. A factor associated with the accident is an open door.