1) With a lock , the angle of the target apears on the hud - 180 deg. for a head on - and on the radar screen below the target, in this case indicating 0 degr. for a head on, which can be confusing. Why is this difference in the symbology between hud - hdd ? (is there a difference between intercept and aspect angle in general?)
2) Also, with a lock , an arrow extends from the targets marker, indicating his direction, but this line has not always the same lenght. What is the arrow's length indicating ? ( perhaps closure speed ? grater closure speed = larger arrow? is the lenght varying according the selected radar range? )
3) also , at the bottom of the screen there is a big arrow, pointing always at the 12' position and indicating our heading. What is the operational use of this indication? Perhaps, the pilot should put this line in a 90 deg. angle to the big intercept line , to achieve a notch?