diff --git a/master/master/config.h b/master/master/config.h
--- a/master/master/config.h
+++ b/master/master/config.h
@@ -29,6 +29,13 @@
 
 #define HEATER_THRESHOLD 60
 
+// Touchdown buzzer settings
+#define BUZZER_RATE 3000
+#define BUZZER_DURATION 1
+
+#define BUZZER_FAILSAFE_DURATION 600000
+#define BUZZER_TRIGGER_MINDURATION 1
+#define BUZZER_TRIGGER_MAXALTITUDE 1
 
 // --------------------------------------------------------------------------
 // Error Codes config (led.c, used throughout code)
diff --git a/master/master/lib/led.c b/master/master/lib/led.c
--- a/master/master/lib/led.c
+++ b/master/master/lib/led.c
@@ -43,7 +43,7 @@ void led_power_toggle()
 // Turn the specified LED on
 void led_on(uint8_t led) 
 {
-	if(blackout && led != LED_ERROR)
+	if(blackout && led != LED_ERROR && led != LED_BUZZ)
 	{
 		return;
 	}		
@@ -58,7 +58,7 @@ void led_off(uint8_t led)
 
 void led_toggle(uint8_t led)
 {
-	if(blackout && led != LED_ERROR)
+	if(blackout && led != LED_ERROR && led != LED_BUZZ)
 	{
 		return;
 	}
diff --git a/master/master/lib/sensordata.c b/master/master/lib/sensordata.c
--- a/master/master/lib/sensordata.c
+++ b/master/master/lib/sensordata.c
@@ -204,4 +204,45 @@ void sensordata_logvalues()
 		snprintf(logbuf + strlen(logbuf),CSV_LOGLINE_SIZE-strlen(logbuf),"\r\n");
 		logger_log(logbuf);
 	}
+}
+
+bool isTouchdown = false;
+bool sensordata_isTouchdown()
+{
+	return isTouchdown;
+}
+
+int32_t sensordata_getSensorValue(uint8_t sensorID) 
+{
+	// Loop through all slaves
+	for(int i=0; i<MAX_NUM_SLAVES; i++)
+	{
+		uint32_t val = sensordata_get(i, sensorID);
+		if(val != -2111111111) {
+			return val;
+		}
+	}		
+	return -2111111111;
+}
+
+void sensordata_checkTouchdown()
+{
+	// If we have reached touchdown, never get out of this state
+	if(isTouchdown)
+	{
+		return;
+	}
+	
+	if(time_millis() > BUZZER_FAILSAFE_DURATION)
+	{
+		isTouchdown = true;
+	}
+	else
+	{
+		int32_t altitude = sensordata_getSensorValue(SENSOR_ALTITUDE);
+		if(altitude != -2111111111 && altitude < BUZZER_TRIGGER_MAXALTITUDE && time_millis() > BUZZER_TRIGGER_MINDURATION)
+		{
+			isTouchdown = true;
+		}			
+	}
 }
\ No newline at end of file
diff --git a/master/master/lib/sensordata.h b/master/master/lib/sensordata.h
--- a/master/master/lib/sensordata.h
+++ b/master/master/lib/sensordata.h
@@ -21,5 +21,7 @@ void sensordata_set(uint8_t nodeID, uint
 int32_t sensordata_get(uint8_t nodeID, uint8_t type);
 char* slavesensors_getAPRScomment();
 void sensordata_logvalues();
+bool sensordata_isTouchdown();
+void sensordata_checkTouchdown();
 
 #endif /* SENSORDATA_H_ */
\ No newline at end of file
diff --git a/master/master/master.c b/master/master/master.c
--- a/master/master/master.c
+++ b/master/master/master.c
@@ -64,6 +64,7 @@ int main(void)
 	uint32_t lastLog = 0;
 	uint32_t lastLedCycle = 0;
 	uint32_t lastDataReq = 0;
+	uint32_t lastBuzz = 0;
 	
 	// Result of last parser run
 	int parseResult = PARSERESULT_NODATA;
@@ -73,7 +74,6 @@ int main(void)
 	
 	while(1)
     {
-		
 		// Periodic: LED execution indicator
 		if(time_millis() - lastLedCycle > LEDCYCLE_RATE) 
 		{
@@ -113,11 +113,20 @@ int main(void)
 			lastLog = time_millis();
 		}		
 		
+		// Periodic: Buzzer
+		if(time_millis() - lastBuzz > BUZZER_RATE) {
+			if(sensordata_isTouchdown())
+			{
+				led_on(LED_BUZZ);
+				_delay_ms(BUZZER_DURATION);
+				led_off(LED_BUZZ);
+			}			
+			lastBuzz = time_millis();
+		}
 		
 		// Periodic: Data Request
 		if(time_millis() - lastDataReq > DATAREQUEST_RATE)  
 		{
-			
 			// Start getting values for next transmission
 			if(slavesensors_isrequesting())
 			{
@@ -135,6 +144,10 @@ int main(void)
 		// Periodic: APRS transmission
 		if(time_millis() - lastAprsBroadcast > APRS_TRANSMIT_PERIOD) 
 		{
+			// Check for touchdown
+			sensordata_checkTouchdown();
+			
+			// LED blackout
 			#ifdef BLACKOUT_ENABLE
 			led_blackout();
 			#endif