If you pay close attention to the aircraft trail, you’ll notice that it will suddenly disappear when the aircraft makes contact with the ground.
The aircraft trail is the dots seen behind an aircraft. It represents 100 seconds, 5 seconds for each dot shown, 20 dots.
Trails are awesome for radar you just have to give it a try and stick to it for a few sessions. You’ll hate at first but then you start to appreciate it. They can be toggled on and off by clicking the gear icon then click ‘Hide Aircraft Trails’.