diff --git a/Resources/Scripts/oolite-equipment-control.js b/Resources/Scripts/oolite-equipment-control.js
index 930ad4f9f..a9c20d45d 100644
--- a/Resources/Scripts/oolite-equipment-control.js
+++ b/Resources/Scripts/oolite-equipment-control.js
@@ -159,9 +159,11 @@ this.equipmentAdded = function(equip)
 	var eq_dict = this.$equipmentEnabled;
 	var eqInfo;
 	for (var eqKey in eq_dict) {
-		eqInfo = EquipmentInfo.infoForKey(eqKey);
-		if (eqInfo && eqInfo.incompatibleEquipment && eqInfo.incompatibleEquipment.indexOf(equip) >= 0) {
-			player.ship.removeEquipment(eqKey);
+		if (this.$equipmentEnabled[eqKey]) {
+			eqInfo = EquipmentInfo.infoForKey(eqKey);
+			if (eqInfo && eqInfo.incompatibleEquipment && eqInfo.incompatibleEquipment.indexOf(equip) >= 0) {
+				player.ship.removeEquipment(eqKey);
+			}
 		}
 	}
 	this.$equipmentEnabled[equip] = 1;
@@ -250,4 +252,4 @@ this.$equipmentEnable["EQ_ADVANCED_COMPASS"] = function(info)
 this.$equipmentDisable["EQ_ADVANCED_COMPASS"] = function(info)
 {
 	player.ship.compassType = "OO_COMPASSTYPE_BASIC";
-};
\ No newline at end of file
+};