diff --git a/MechJeb2/MechJebModuleNodeExecutor.cs b/MechJeb2/MechJebModuleNodeExecutor.cs
index 5466633e..b5d94868 100644
--- a/MechJeb2/MechJebModuleNodeExecutor.cs
+++ b/MechJeb2/MechJebModuleNodeExecutor.cs
@@ -88,8 +88,8 @@ public void Abort()
             Core.Warp.MinimumWarp();
             Core.Thrust.ThrustOff();
             Users.Clear();
-            _dvLeft = 0;
-            State   = States.IDLE;
+            _dvLeft   = 0;
+            State     = States.IDLE;
         }
 
         protected override void OnModuleEnabled()
@@ -119,15 +119,11 @@ public enum States { WARPALIGN, LEAD, BURN, IDLE }
         private        double   _ignitionUT;
         private static bool     _isLoadedPrincipia => VesselState.isLoadedPrincipia;
         private        bool     _hasNodes          => Vessel.patchedConicSolver.maneuverNodes.Count > 0;
-        private        double   _ullageUntil;
 
         public override void Drive(FlightCtrlState s) => DoRCS(s);
 
         private void DoRCS(FlightCtrlState s)
         {
-            // seconds to continue to apply RCS after ullage has settled to VeryStable
-            const double MIN_RCS_TIME = 0.50;
-
             if (State == States.BURN && RCSOnly)
             {
                 Vessel.ActionGroups.SetGroup(KSPActionGroup.RCS, true);
@@ -141,12 +137,6 @@ private void DoRCS(FlightCtrlState s)
             if (!Core.Thrust.AutoRCSUllaging)
                 return;
 
-            if (VesselState.lowestUllage >= 1.0 && VesselState.time > _ullageUntil)
-                return;
-
-            if (VesselState.lowestUllage < 1.0)
-                _ullageUntil = VesselState.time + MIN_RCS_TIME;
-
             if (!Vessel.hasEnabledRCSModules())
                 return;
 
diff --git a/MechJeb2/MechJebModuleThrustController.cs b/MechJeb2/MechJebModuleThrustController.cs
index c73a118b..b4688da3 100644
--- a/MechJeb2/MechJebModuleThrustController.cs
+++ b/MechJeb2/MechJebModuleThrustController.cs
@@ -225,8 +225,6 @@ public enum LimitMode
 
         private bool _tmodeChanged;
 
-        private double _ullageUntil;
-
         private PIDController _pid;
 
         public  float LastThrottle;
@@ -875,26 +873,22 @@ private static void MaxThrust(double[] x, ref double func, double[] grad, object
         /// <param name="s"></param>
         private void ProcessUllage(FlightCtrlState s)
         {
-            // seconds to continue to apply RCS after ullage has settled to VeryStable
-            const double MIN_RCS_TIME = 0.50;
-            // seconds after VeryStable to wait before applying throttle
-            const double IGNITION_DELAY = 0.10;
-
             if (!AutoRCSUllaging || s.mainThrottle <= 0F || ThrottleLimit <= 0F)
                 return;
 
             if (!Vessel.hasEnabledRCSModules())
                 return;
 
-            if (VesselState.lowestUllage >= 1.0 && VesselState.time > _ullageUntil)
-                return;
+            bool stableUllage = VesselState.lowestUllage >= 1.0;
 
-            if (VesselState.lowestUllage < 1.0)
-                _ullageUntil = VesselState.time + MIN_RCS_TIME;
+            // ullage may dramatically drop below stable (by as much as to 0.76 in a single tick) so
+            // we cannot "detect" low ullage and compensate, but must apply RCS until thrust has come
+            // up sufficiently.
+            if (stableUllage && VesselState.thrustCurrent > VesselState.rcsThrustAvailable.Up )
+                return;
 
             // limit the throttle only if we aren't already burning (don't waste ignitions)
-            // also apply RCS for IGNITION_DELAY seconds above VeryStable point.
-            if (LastThrottle <= 0 && _ullageUntil - VesselState.time < MIN_RCS_TIME - IGNITION_DELAY)
+            if (LastThrottle <= 0 && !stableUllage)
                 SetTempLimit(0.0F, LimitMode.AUTO_RCS_ULLAGE);
 
             if (!Vessel.ActionGroups[KSPActionGroup.RCS])