[etc]

package {
    public class A {

        public function A() {
            super();
            this.arr = new Array(1,2,3,4);
        }

        public var arr:Array;
    }
}

package {
    public class B {

        public function B(arr:Array) {
            super();
            trace(arr);
        }
    }
}

new B((new A()).arr);