the PCFS is an advancement in ATSP, the PCFS protects the projectile from other projectiles, meaning that they are the last thing to be hit. this "system" works in the same ways as an f-22's arnament, all of the arnament is hidden under the walls of the fueslage. plus, even if this 'system' doesnt work, it still looks cool, even with the test plane i used here. it can also be used in the standard edition of Simple Planes, or any version of SP as long as it has rotators, pylons, detachers and wings. the projectiles are also changed so that they fly straight and not spin while in flight, which helps alot on the accuracy. -BlueWhiskyYT