diff --git a/public_html/planeObject.js b/public_html/planeObject.js
index 6e81ffd..39e3c4d 100644
--- a/public_html/planeObject.js
+++ b/public_html/planeObject.js
@@ -337,7 +337,7 @@ PlaneObject.prototype.getAltitudeColor = function(altitude) {
                 h = ColorByAlt.unknown.h;
                 s = ColorByAlt.unknown.s;
                 l = ColorByAlt.unknown.l;
-        } else if (this.altitude === "ground") {
+        } else if (altitude === "ground") {
                 h = ColorByAlt.ground.h;
                 s = ColorByAlt.ground.s;
                 l = ColorByAlt.ground.l;