diff --git a/flix/parameters.ino b/flix/parameters.ino
index 469a1ba..e58abed 100644
--- a/flix/parameters.ino
+++ b/flix/parameters.ino
@@ -10,6 +10,7 @@ extern float channelZero[16];
 extern float channelMax[16];
 extern float rollChannel, pitchChannel, throttleChannel, yawChannel, armedChannel, modeChannel;
 extern int wifiMode, udpLocalPort, udpRemotePort;
+extern float rcLossTimeout, descendTime;
 
 Preferences storage;
 
@@ -91,6 +92,9 @@ Parameter parameters[] = {
 	{"MAV_SYS_ID", &mavlinkSysId},
 	{"MAV_RATE_SLOW", &telemetrySlow.rate},
 	{"MAV_RATE_FAST", &telemetryFast.rate},
+	// safety
+	{"SF_RC_LOSS_TIME", &rcLossTimeout},
+	{"SF_DESCEND_TIME", &descendTime},
 };
 
 void setupParameters() {
diff --git a/flix/rc.ino b/flix/rc.ino
index 0095d55..f046e5b 100644
--- a/flix/rc.ino
+++ b/flix/rc.ino
@@ -14,7 +14,7 @@ float channelMax[16]; // calibration max values
 
 float controlRoll, controlPitch, controlYaw, controlThrottle; // pilot's inputs, range [-1, 1]
 float controlMode = NAN;
-float controlTime; // time of the last controls update (0 when no RC)
+float controlTime = NAN; // time of the last controls update
 
 // Channels mapping (nan means not assigned):
 float rollChannel = NAN, pitchChannel = NAN, throttleChannel = NAN, yawChannel = NAN, modeChannel = NAN;
diff --git a/flix/safety.ino b/flix/safety.ino
index 35ece02..1d67010 100644
--- a/flix/safety.ino
+++ b/flix/safety.ino
@@ -3,12 +3,12 @@
 
 // Fail-safe functions
 
-#define RC_LOSS_TIMEOUT 1
-#define DESCEND_TIME 10
-
 extern float controlTime;
 extern float controlRoll, controlPitch, controlThrottle, controlYaw;
 
+float rcLossTimeout = 1;
+float descendTime = 10;
+
 void failsafe() {
 	rcLossFailsafe();
 	autoFailsafe();
@@ -16,9 +16,8 @@ void failsafe() {
 
 // RC loss failsafe
 void rcLossFailsafe() {
-	if (controlTime == 0) return; // no RC at all
 	if (!armed) return;
-	if (t - controlTime > RC_LOSS_TIMEOUT) {
+	if (t - controlTime > rcLossTimeout) {
 		descend();
 	}
 }
@@ -27,7 +26,7 @@ void rcLossFailsafe() {
 void descend() {
 	mode = AUTO;
 	attitudeTarget = Quaternion();
-	thrustTarget -= dt / DESCEND_TIME;
+	thrustTarget -= dt / descendTime;
 	if (thrustTarget < 0) {
 		thrustTarget = 0;
 		armed = false;