On the function call "Call Enemy_Air_Parts_Spawn" add an parameter and give it the value: Enemys_Air_test.UID
This becomes your Parameter 0 to the function.
So in your function On "Enemy_Air_Parts_Spawn" add the condition to pick that instance:
Choose your Enemy_Air_Test Family/Object and "Pick by Unique ID" (in the 'misc' section).
Your Unique ID is going to be the parameter you passed. You can access it by putting the value Function.Param(0).