diff --git a/fbw-a380x/src/systems/instruments/src/FCU/Components/NdData.tsx b/fbw-a380x/src/systems/instruments/src/FCU/Components/NdData.tsx
index fe072e8d95f..4431a73502a 100644
--- a/fbw-a380x/src/systems/instruments/src/FCU/Components/NdData.tsx
+++ b/fbw-a380x/src/systems/instruments/src/FCU/Components/NdData.tsx
@@ -3,7 +3,6 @@
 
 import { NavAidMode } from '@flybywiresim/fbw-sdk';
 import {
-  Subject,
   ConsumerSubject,
   DisplayComponent,
   EventBus,
@@ -42,14 +41,7 @@ export class NdData extends DisplayComponent<NdDataProps> {
     NavAidMode.Off,
   );
 
-  private lightsTest = Subject.create(false);
-
-  onAfterRender(_node: VNode): void {
-    this.sub
-      .on('ovhd_ann_lt_test_active')
-      .whenChanged()
-      .handle((v) => this.lightsTest.set(v));
-  }
+  private readonly isLightTestActive = ConsumerSubject.create(this.sub.on('ovhd_ann_lt_test_active'), false);
 
   render(): VNode | null {
     return (
@@ -63,62 +55,62 @@ export class NdData extends DisplayComponent<NdDataProps> {
           <img
             style="position: absolute; top: 0; left: 0"
             width="620px"
-            class={{ hidden: this.lightsTest }}
+            class={{ hidden: this.isLightTestActive }}
             src="/Images/fbw-a380x/fcu/CSTR.png"
           />
           <img
             style="position: absolute; top: 0; left: 890px"
             width="620px"
-            class={{ hidden: this.lightsTest }}
+            class={{ hidden: this.isLightTestActive }}
             src="/Images/fbw-a380x/fcu/WPT.png"
           />
           <img
             style="position: absolute; top: 0; left: 1840px"
             width="620px"
-            class={{ hidden: this.lightsTest }}
+            class={{ hidden: this.isLightTestActive }}
             src="/Images/fbw-a380x/fcu/VORD.png"
           />
           <img
             style="position: absolute; top: 0; left: 2790px"
             width="620px"
-            class={{ hidden: this.lightsTest }}
+            class={{ hidden: this.isLightTestActive }}
             src="/Images/fbw-a380x/fcu/NDB.png"
           />
           <img
             style="position: absolute; top: 0; left: 3740px"
             width="620px"
-            class={{ hidden: this.lightsTest }}
+            class={{ hidden: this.isLightTestActive }}
             src="/Images/fbw-a380x/fcu/ARPT.png"
           />
           {/* LIGHT TESTS */}
           <img
             style="position: absolute; top: 0; left: 0"
             width="620px"
-            class={{ hidden: this.lightsTest.map(SubscribableMapFunctions.not()) }}
+            class={{ hidden: this.isLightTestActive.map(SubscribableMapFunctions.not()) }}
             src="/Images/fbw-a380x/fcu/TEST.png"
           />
           <img
             style="position: absolute; top: 0; left: 890px"
             width="620px"
-            class={{ hidden: this.lightsTest.map(SubscribableMapFunctions.not()) }}
+            class={{ hidden: this.isLightTestActive.map(SubscribableMapFunctions.not()) }}
             src="/Images/fbw-a380x/fcu/TEST.png"
           />
           <img
             style="position: absolute; top: 0; left: 1840px"
             width="620px"
-            class={{ hidden: this.lightsTest.map(SubscribableMapFunctions.not()) }}
+            class={{ hidden: this.isLightTestActive.map(SubscribableMapFunctions.not()) }}
             src="/Images/fbw-a380x/fcu/TEST.png"
           />
           <img
             style="position: absolute; top: 0; left: 2790px"
             width="620px"
-            class={{ hidden: this.lightsTest.map(SubscribableMapFunctions.not()) }}
+            class={{ hidden: this.isLightTestActive.map(SubscribableMapFunctions.not()) }}
             src="/Images/fbw-a380x/fcu/TEST.png"
           />
           <img
             style="position: absolute; top: 0; left: 3740px"
             width="620px"
-            class={{ hidden: this.lightsTest.map(SubscribableMapFunctions.not()) }}
+            class={{ hidden: this.isLightTestActive.map(SubscribableMapFunctions.not()) }}
             src="/Images/fbw-a380x/fcu/TEST.png"
           />
         </div>
@@ -127,62 +119,62 @@ export class NdData extends DisplayComponent<NdDataProps> {
           <img
             style="position: absolute; top: 0; left: 0"
             width="620px"
-            class={{ hidden: this.lightsTest }}
+            class={{ hidden: this.isLightTestActive }}
             src={this.navaidMode1.map((v) => NdData.NAVAID_1_IMAGES[v])}
           />
           <img
             style="position: absolute; top: 0; left: 890px"
             width="620px"
-            class={{ hidden: this.lightsTest }}
+            class={{ hidden: this.isLightTestActive }}
             src="/Images/fbw-a380x/fcu/WX.png"
           />
           <img
             style="position: absolute; top: 0; left: 1840px"
             width="620px"
-            class={{ hidden: this.lightsTest }}
+            class={{ hidden: this.isLightTestActive }}
             src="/Images/fbw-a380x/fcu/TERR.png"
           />
           <img
             style="position: absolute; top: 0; left: 2790px"
             width="620px"
-            class={{ hidden: this.lightsTest }}
+            class={{ hidden: this.isLightTestActive }}
             src="/Images/fbw-a380x/fcu/TRAF.png"
           />
           <img
             style="position: absolute; top: 0; left: 3740px"
             width="620px"
-            class={{ hidden: this.lightsTest }}
+            class={{ hidden: this.isLightTestActive }}
             src={this.navaidMode2.map((v) => NdData.NAVAID_2_IMAGES[v])}
           />
           {/* LIGHT TESTS */}
           <img
             style="position: absolute; top: 0; left: 0"
             width="620px"
-            class={{ hidden: this.lightsTest.map(SubscribableMapFunctions.not()) }}
+            class={{ hidden: this.isLightTestActive.map(SubscribableMapFunctions.not()) }}
             src="/Images/fbw-a380x/fcu/TEST.png"
           />
           <img
             style="position: absolute; top: 0; left: 890px"
             width="620px"
-            class={{ hidden: this.lightsTest.map(SubscribableMapFunctions.not()) }}
+            class={{ hidden: this.isLightTestActive.map(SubscribableMapFunctions.not()) }}
             src="/Images/fbw-a380x/fcu/TEST.png"
           />
           <img
             style="position: absolute; top: 0; left: 1840px"
             width="620px"
-            class={{ hidden: this.lightsTest.map(SubscribableMapFunctions.not()) }}
+            class={{ hidden: this.isLightTestActive.map(SubscribableMapFunctions.not()) }}
             src="/Images/fbw-a380x/fcu/TEST.png"
           />
           <img
             style="position: absolute; top: 0; left: 2790px"
             width="620px"
-            class={{ hidden: this.lightsTest.map(SubscribableMapFunctions.not()) }}
+            class={{ hidden: this.isLightTestActive.map(SubscribableMapFunctions.not()) }}
             src="/Images/fbw-a380x/fcu/TEST.png"
           />
           <img
             style="position: absolute; top: 0; left: 3740px"
             width="620px"
-            class={{ hidden: this.lightsTest.map(SubscribableMapFunctions.not()) }}
+            class={{ hidden: this.isLightTestActive.map(SubscribableMapFunctions.not()) }}
             src="/Images/fbw-a380x/fcu/TEST.png"
           />
         </div>