diff --git a/S-75/Nasal/fire-control.nas b/S-75/Nasal/fire-control.nas
index a329620..d6189a6 100644
--- a/S-75/Nasal/fire-control.nas
+++ b/S-75/Nasal/fire-control.nas
@@ -61,7 +61,16 @@ var isInEngagementEnvelope = func (target_radial_airspeed, target_ground_distanc
 	return 1;
 }
 
-var midflight = nil;
+var midflight = func (struct) {
+	if (struct.guidance == "semi-radar") {
+		# This makes the SAM system keep lock on target when missile in-flight and no longer tracking the target.
+		# Usage is to make the RWR lock sound go off in targets cockpit.
+		thread.lock(mutexLock);
+		semi_active_track = struct.callsign;
+		thread.unlock(mutexLock);
+	}
+	return {};
+};
 
 
 ##########################################################################
diff --git a/SA-6/Nasal/fire-control.nas b/SA-6/Nasal/fire-control.nas
index ed28c8f..024013b 100644
--- a/SA-6/Nasal/fire-control.nas
+++ b/SA-6/Nasal/fire-control.nas
@@ -61,7 +61,16 @@ var isInEngagementEnvelope = func (target_radial_airspeed, target_ground_distanc
 	return 1;
 }
 
-var midflight = nil;
+var midflight = func (struct) {
+	if (struct.guidance == "semi-radar") {
+		# This makes the SAM system keep lock on target when missile in-flight and no longer tracking the target.
+		# Usage is to make the RWR lock sound go off in targets cockpit.
+		thread.lock(mutexLock);
+		semi_active_track = struct.callsign;
+		thread.unlock(mutexLock);
+	}
+	return {};
+};
 
 
 ##########################################################################