samana, для вас:
Код AS3:
private var timeline:TimelineLite;
...
timeline = new TimelineLite( { onComplete:repeatAnim } );
timeline.append(TweenLite.to(obj, .3, { y:5 } ));
timeline.append(TweenLite.to(obj, .3, { y:0 } ));
...
private function repeatAnim():void {
timeline.restart();
}