diff --git a/Nasal/engines-common.nas b/Nasal/engines-common.nas
index f0d3a6df..685e3fc3 100644
--- a/Nasal/engines-common.nas
+++ b/Nasal/engines-common.nas
@@ -65,7 +65,7 @@ setlistener("/controls/APU/master", func {
 		apu_egt_check.stop();
 		apu_egt2_check.stop();
 		apu_stop();
-	} else if (getprop("/controls/APU/master") = 1) {
+	} else if (getprop("/controls/APU/master") == 1) {
 		apuBleedChk.stop();
 		setprop("/systems/apu/bleed-counting", 0);
 	}