ios app crash after download due to low memory in ipad 1

air 3.7

ios 6.3  

     //download button click:

               ...

                        loader.dataFormat = URLLoaderDataFormat.BINARY;

                        loader.load(selectedContent.fileurl);

                        loader.addEventListener(ProgressEvent.PROGRESS, downloadProgress);

                        loader.addEventListener(Event.COMPLETE, downloadComplete);

               ...

private function downloadComplete(event:Event):void

        {

            var fileName:String = "z" + downloadContent.loid.toString() + ".zip"; // new String(downloadContent.fileurl).split("/").pop();

            //call the saveLocally function; loader.data has the bytes of the loaded resource

            saveLocally("zip/" + fileName, loader.data);

            loadingText.text = lang.getWord("player.mobile.downloadFinished");

            loader.close();

            loader == null;

            try

            {

                unzipFile("zip/" + fileName);

            }

            catch (err:Error)

            {

                loadingText.visible = false;

                downloadContent = null;

                UI.hideActivityIndicator();

                Warn(lang.getWord("player.mobile.downloadError"));

                refreshList();

            }

        }