Animating a Movie clip with code

Dear All thank you for your time and patience.

I am trying to animate a sky moving up as it playing fwd, I am using a simple time line tween to animate the Mc of the sky but have tried various ways to move the clip up or down, to simulate an aircraft climbing or descending.

I tried using the set interval to call the the function and a for loop

both say in console "y is not defined "when I run the animation.

The only way can get it to work is a tick function but when i try to clear the event lisetner with "clear interval(interval name)"for the Ticker nothing happens.

this.mystop_btn.addEventListener("click", fl_ClickToGoToAndPlayFromFrame.bind(this));

function fl_ClickToGoToAndPlayFromFrame(){

    this.mysky_mc.gotoAndPlay(1)
skyup()

}

function skyup(){
	
	for(var i= 0; i< 100; i ++){
	this.mysky_mc.y-=1
		console.log(y)
}
}

this.addEventListener("tick", fl_AnimateHorizontally.bind(this));

function fl_AnimateHorizontally()
{
	
	this.mysky_mc.y-=1
	
		console.log(this.mysky_mc.x)

		console.log("test3")
		
	

	}

I am doing something wrong, but not sure what it is looked at many articles but cant seem to find the info anywhere.

Best Regards

Peter