diff --git a/src/pmf/Level.php b/src/pmf/Level.php
index 8490acee9..e4c8824fd 100644
--- a/src/pmf/Level.php
+++ b/src/pmf/Level.php
@@ -283,7 +283,7 @@ class PMFLevel extends PMF{
 			return str_repeat("\x00", 8192);
 		}
 		$index = $this->getIndex($X, $Z);
-		if($this->chunks[$index][$Y] === false){
+		if(!isset($this->chunks[$index][$Y]) or $this->chunks[$index][$Y] === false){
 			return str_repeat("\x00", 8192);
 		}
 		return $this->chunks[$index][$Y];