How a Fight Starts
Three separate triggers — no shared mechanism.
01
Player-ordered attack — clicking attack on an enemy stack, or a map point for artillery and bombers.
02
Automatic proximity engagement — checked once per real second: if two enemy stacks (or two patrolling enemy aircraft) drift within each other's weapons range while at war, combat starts with no click needed. This is why units parked near an active front spontaneously start shooting.
03
Radar lock — a radar or AWACS lock on an enemy aircraft can trigger SAM fire on its own, independent of the other two triggers.