diff --git a/Nasal/FMGC/FMGC-b.nas b/Nasal/FMGC/FMGC-b.nas
index e30a4a72..76acb10f 100644
--- a/Nasal/FMGC/FMGC-b.nas
+++ b/Nasal/FMGC/FMGC-b.nas
@@ -1043,6 +1043,17 @@ setlistener(pts.Systems.Navigation.ADR.Output.overspeed, func(v) {
 	}
 }, 0, 0);
 
+setlistener(pts.Systems.Navigation.ADR.Output.underspeed, func(v) {
+	if (v.getBoolValue() and !Output.ap1.getBoolValue() and !Output.ap2.getBoolValue() and Output.athr.getBoolValue() and Modes.PFD.FMA.pitchMode.getValue() == "OP DES" and Modes.PFD.FMA.throttle.getValue() == "THR IDLE") {
+		Input.fd1.setValue(0);
+		Input.fd2.setValue(0);
+		ecam.aural[5].setBoolValue(0);
+		settimer(func() {
+			ecam.aural[5].setBoolValue(1);
+		}, 0.15);
+	}
+}, 0, 0);
+
 
 setlistener("/sim/signals/fdm-initialized", func {
 	ITAF.init();
diff --git a/Nasal/Libraries/property-tree-setup.nas b/Nasal/Libraries/property-tree-setup.nas
index d3d99167..85b13d6d 100644
--- a/Nasal/Libraries/property-tree-setup.nas
+++ b/Nasal/Libraries/property-tree-setup.nas
@@ -282,6 +282,7 @@ var Systems = {
 		ADR: {
 			Output: {
 				overspeed: props.globals.getNode("/systems/navigation/adr/output/overspeed"),
+				underspeed: props.globals.getNode("/systems/navigation/adr/output/underspeed"),
 			},
 		},
 	},
diff --git a/Systems/a320-adr.xml b/Systems/a320-adr.xml
index b1ef10f0..1946e513 100644
--- a/Systems/a320-adr.xml
+++ b/Systems/a320-adr.xml
@@ -736,6 +736,33 @@
 			</function>
 		</fcs_function>
 		
+		<switch name="/systems/navigation/adr/computation/underspeed-difference">
+			<default value="2"/>
+			<test logic="OR" value="19">
+				/controls/flight/speedbrake eq 1.0
+			</test>
+		</switch>
+		
+		<fcs_function name="/systems/navigation/adr/computation/underspeed">
+			<function>
+				<ifthen>
+					<lt>
+						<max>
+							<property>/systems/navigation/adr/output/cas-1</property>
+							<property>/systems/navigation/adr/output/cas-2</property>
+							<property>/systems/navigation/adr/output/cas-3</property>
+						</max>
+						<difference>
+							<property>/FMGC/internal/vls-min</property>
+							<property>/systems/navigation/adr/computation/underspeed-difference</property>
+						</difference>
+					</lt>
+					<value>1</value>
+					<value>0</value>
+				</ifthen>
+			</function>
+		</fcs_function>
+		
 	</channel>
 	
 	<channel name="ADR Output" execrate="2"> <!-- todo - need lowpass? -->
@@ -905,6 +932,11 @@
 			<gain>/systems/navigation/adr/any-adr-on</gain>
 		</pure_gain>
 		
+		<pure_gain name="/systems/navigation/adr/output/underspeed">
+			<input>/systems/navigation/adr/computation/underspeed</input>
+			<gain>/systems/navigation/adr/any-adr-on</gain>
+		</pure_gain>
+		
 		<pure_gain name="/instrumentation/radar-altimeter[0]/radar-altitude-ft-corrected">
 			<input>/instrumentation/radar-altimeter[0]/radar-altitude-ft</input>
 			<gain>1</gain>