diff --git a/02_telemetry_bridge/src/mode_mavlink.cpp b/02_telemetry_bridge/src/mode_mavlink.cpp
index 2d4730b..62dcda8 100644
--- a/02_telemetry_bridge/src/mode_mavlink.cpp
+++ b/02_telemetry_bridge/src/mode_mavlink.cpp
@@ -36,6 +36,13 @@ static uint8_t  c_lq = 0;                 // link quality %
 
 static uint32_t tHB = 0, tSYS = 0, tGPS = 0, tATT = 0, tHUD = 0, tBAT = 0, tRADIO = 0;
 
+// Staleness: se non arrivano frame validi entro TELEM_TIMEOUT_MS, smettiamo
+// di spacciare per "vivi" gli ultimi valori in cache. Continuiamo a emettere
+// l'HEARTBEAT (il link verso il GCS resta), ma con stato CRITICAL e GPS senza
+// fix, cosi' il GCS segnala "telemetria persa" invece di un aereo congelato.
+static uint32_t lastFrameMs = 0;
+static const uint32_t TELEM_TIMEOUT_MS = 2000;
+
 static uint8_t  mbuf[MAVLINK_MAX_PACKET_LEN];
 static mavlink_message_t mmsg;
 
@@ -76,10 +83,12 @@ static void mav_onFrame(const uint8_t* buf, uint16_t len) {
             break;
         default: break;
     }
+    if (id) lastFrameMs = millis();                       // frame valido ricevuto
 }
 
 static void mav_tick() {
     uint32_t now = millis();
+    bool stale = (lastFrameMs == 0) || (now - lastFrameMs > TELEM_TIMEOUT_MS);
 
     if (now - tATT >= 100) {                 // ATTITUDE 10 Hz
         tATT = now;
@@ -91,7 +100,8 @@ static void mav_tick() {
     if (now - tGPS >= 200) {                  // GPS_RAW_INT 5 Hz
         tGPS = now;
         bool hasPos = (c_lat != 0) || (c_lon != 0);
-        uint8_t fix = (c_sats >= 5 && hasPos) ? GPS_FIX_TYPE_3D_FIX
+        uint8_t fix = stale ? GPS_FIX_TYPE_NO_FIX
+                    : (c_sats >= 5 && hasPos) ? GPS_FIX_TYPE_3D_FIX
                     : (c_sats > 0 ? GPS_FIX_TYPE_2D_FIX : GPS_FIX_TYPE_NO_FIX);
         mavlink_msg_gps_raw_int_pack(SYSID, COMPID, &mmsg,
             (uint64_t)now * 1000ULL, fix, c_lat, c_lon, c_alt_m * 1000,
@@ -156,7 +166,8 @@ static void mav_tick() {
     if (now - tHB >= 1000) {                  // HEARTBEAT 1 Hz
         tHB = now;
         mavlink_msg_heartbeat_pack(SYSID, COMPID, &mmsg,
-            MAV_TYPE_FIXED_WING, MAV_AUTOPILOT_GENERIC, 0, 0, MAV_STATE_ACTIVE);
+            MAV_TYPE_FIXED_WING, MAV_AUTOPILOT_GENERIC, 0, 0,
+            stale ? MAV_STATE_CRITICAL : MAV_STATE_ACTIVE);
         sendMsg();
     }
 }