Well, a tie black squadron, a Sabre interceptor or a Green A can equip pilot upgrade card. But not supposed elite crews as E generic, or Tie Defender. And a PS 3 a wing pilot can equip one, but not a PS 4 x wing pilot.
I cant see a reason. And I am curious about the why? Tie interceptors are superb ships. Y wings not. And a generic PS 4 tie can equip those, and a PS 4 Y not. Why?