diff --git a/Nasal/fuel.nas b/Nasal/fuel.nas
index d4cba1ce..b41b179e 100644
--- a/Nasal/fuel.nas
+++ b/Nasal/fuel.nas
@@ -6,6 +6,10 @@
 #############
 
 var fuel_init = func {
+	setprop("/systems/fuel/gravityfeedL", 0);
+	setprop("/systems/fuel/gravityfeedR", 0);
+	setprop("/systems/fuel/gravityfeedL-output", 0);
+	setprop("/systems/fuel/gravityfeedR-output", 0);
 	setprop("/controls/fuel/x-feed", 0);
 	setprop("/controls/fuel/tank2pump1", 0);
 	setprop("/controls/fuel/tank2pump2", 0);
@@ -40,15 +44,37 @@ var master_fuel = func {
 	var xfeed = getprop("/systems/fuel/x-feed");
 	var ac1 = getprop("/systems/electrical/bus/ac1");
 	var ac2 = getprop("/systems/electrical/bus/ac2");
+	var gravityfeedL = getprop("/systems/fuel/gravityfeedL");
+	var gravityfeedR = getprop("/systems/fuel/gravityfeedR");
+	var gload = getprop("/accelerations/pilot-gdamped");
+	
+	if (gload >= 0.7 and gravityfeedL) {
+		setprop("/systems/fuel/gravityfeedL-output", 1);
+	} else {
+		setprop("/systems/fuel/gravityfeedL-output", 0);
+	}
+	
+	if (gload >= 0.7 and gravityfeedR) {
+		setprop("/systems/fuel/gravityfeedR-output", 1);
+	} else {
+		setprop("/systems/fuel/gravityfeedR-output", 0);
+	}
+	
+	var gravityfeedL_output = getprop("/systems/fuel/gravityfeedL-output");
+	var gravityfeedR_output = getprop("/systems/fuel/gravityfeedR-output");
 	
 	if ((ac1 >= 110 or ac2 >= 110) and tank2pump1_sw) {
 		setprop("/systems/fuel/tank[2]/feed0", 1);
+	} else if (gravityfeedL_output) {
+		setprop("/systems/fuel/tank[2]/feed0", 1);
 	} else {
 		setprop("/systems/fuel/tank[2]/feed0", 0);
 	}
 	
 	if ((ac1 >= 110 or ac2 >= 110) and tank2pump2_sw) {
 		setprop("/systems/fuel/tank[2]/feed1", 1);
+	} else if (gravityfeedL_output) {
+		setprop("/systems/fuel/tank[2]/feed1", 1);
 	} else {
 		setprop("/systems/fuel/tank[2]/feed1", 0);
 	}
@@ -67,12 +93,16 @@ var master_fuel = func {
 	
 	if ((ac1 >= 110 or ac2 >= 110) and tank4pump1_sw) {
 		setprop("/systems/fuel/tank[4]/feed0", 1);
+	} else if (gravityfeedR_output) {
+		setprop("/systems/fuel/tank[2]/feed0", 1);
 	} else {
 		setprop("/systems/fuel/tank[4]/feed0", 0);
 	}
 	
 	if ((ac1 >= 110 or ac2 >= 110) and tank4pump2_sw) {
 		setprop("/systems/fuel/tank[4]/feed1", 1);
+	} else if (gravityfeedR_output) {
+		setprop("/systems/fuel/tank[2]/feed1", 1);
 	} else {
 		setprop("/systems/fuel/tank[4]/feed1", 0);
 	}
@@ -90,7 +120,22 @@ var master_fuel = func {
 	var tank4feed0 = getprop("/systems/fuel/tank[4]/feed0");
 	var tank4feed1 = getprop("/systems/fuel/tank[4]/feed1");
 	
-	if ((getprop("/fdm/jsbsim/propulsion/tank[3]/contents-lbs") >= 50) and tank3feed0 and tank3feed1) {
+	if (((ac1 >= 110 or ac2 >= 110) and tank2pump1_sw and tank2pump1_sw)) {
+		setprop("/systems/fuel/gravityfeedL", 0);
+	} else {
+		setprop("/systems/fuel/gravityfeedL", 1);
+	}
+	
+	if (((ac1 >= 110 or ac2 >= 110) and tank4pump1_sw and tank4pump1_sw)) {
+		setprop("/systems/fuel/gravityfeedR", 0);
+	} else {
+		setprop("/systems/fuel/gravityfeedR", 1);
+	}
+	
+	var gravityfeedL = getprop("/systems/fuel/gravityfeedL");
+	var gravityfeedR = getprop("/systems/fuel/gravityfeedR");
+	
+	if ((getprop("/fdm/jsbsim/propulsion/tank[3]/contents-lbs") >= 50) and tank3feed0 and tank3feed1 and !gravityfeedL and !gravityfeedR) {
 		setprop("/systems/fuel/only-use-ctr-tank", 1);
 	} else {
 		setprop("/systems/fuel/only-use-ctr-tank", 0);