Actionscript - randomly drop from moving plane MC

Question

I wasn't quite sure how to describe my problem in the subject. I have a plane MC and a crate MC. The plane only flies along the y axis from the bottom of the screen to top. Along the way I want it to randomly drop the crate MC. My code is below. The problem is that the crates spontaneously keep spawning and not near the plane.

function movePlane():void
{
    var tempY:Number;
    var tempX:Number;
    var tempCrate:MovieClip;
    var tempPlane:MovieClip;

    for (var j:int =planes.length-1; j>=0; j--)
    {
        tempPlane = planes[j];
        tempPlane.y +=  tempPlane.planeSpeed;
        tempCrate = new Crate();
        tempY = Math.floor(Math.random() * tempPlane.y);
        tempX = Math.floor(Math.random() * tempPlane.x);
    }
    tempCrate.y = tempY;
    tempCrate.x = tempX;

    addChild(tempCrate);
}

Answer 1

Edited answer:

To make a crate drop on each plane once you can create this behavior by creating a timer on each plane with a random time value. Like this:

function addRandomCreation():void{
    var animationTime:Number = 5000; //The time the planes will be animating in ms 

    for(var i:int = 0; i < planes.length; i++){
        var planeTimer:Timer = new Timer(Math.round(animationTime * Math.random()));
        planeTimer.addEventListener(TimerEvent.TIMER, timerComplete(i));
        planeTimer.start();
    }
}

function timerComplete(planeID:int):function{
    return function(event:TimerEvent):void{
        event.target.stop();
        event.target.removeEventListener(event.type, arguments.callee);

        var tempCrate:MovieClip = new Crate();
        tempY = Math.round(Math.random() * planes[planeID].y);
        tempCrate.y = tempY;
        tempCrate.x = planes[planeID].x;
        addChild(tempCrate);        
    }
}

Edited answer:

This will create a crate on the same x axis as the plane it's being created by.

function movePlane():void
{
    var tempY:Number;
    var tempX:Number;
    var tempCrate:MovieClip;
    var tempPlane:MovieClip;

    for (var j:int =planes.length-1; j>=0; j--)
    {
        tempPlane = planes[j];
        tempPlane.y +=  tempPlane.planeSpeed;
        tempCrate = new Crate();
        tempY = Math.floor(Math.random() * tempPlane.y);
        tempCrate.y = tempY;
        tempCrate.x = tempPlane.x;
        addChild(tempCrate);
    }
}

You have have to use addChild each time you create a new Crate otherwise it will just create a lot of crates which only the last one will be added to the stage. To do this you have to move the addChild into the loop.

function movePlane():void
{
    var tempY:Number;
    var tempX:Number;
    var tempCrate:MovieClip;
    var tempPlane:MovieClip;

    for (var j:int =planes.length-1; j>=0; j--)
    {
        tempPlane = planes[j];
        tempPlane.y +=  tempPlane.planeSpeed;
        tempCrate = new Crate();
        tempY = Math.floor(Math.random() * tempPlane.y);
        tempX = Math.floor(Math.random() * tempPlane.x);
        tempCrate.y = tempY;
        tempCrate.x = tempX;
        addChild(tempCrate);
    }
}