diff --git a/core/resources/l10n/messages.properties b/core/resources/l10n/messages.properties
index 4b1c2b4b8..46a969ff4 100644
--- a/core/resources/l10n/messages.properties
+++ b/core/resources/l10n/messages.properties
@@ -1827,6 +1827,7 @@ Warning.ZERO_LENGTH_BODY = Zero length bodies may not result in accurate simulat
 Warning.ZERO_RADIUS_BODY = Zero length bodies may not result in accurate simulations.
 Warning.TUBE_SEPARATION = Space between tube fins may not result in accurate simulations.
 Warning.TUBE_OVERLAP = Overlapping tube fins may not result in accurate simulations.
+Warning.SEPARATION_ORDER = Stages separated in an unreasonable order
 
 ! Scale dialog
 ScaleDialog.lbl.scaleRocket = Entire rocket
diff --git a/core/src/net/sf/openrocket/aerodynamics/Warning.java b/core/src/net/sf/openrocket/aerodynamics/Warning.java
index b48a35a5e..803073948 100644
--- a/core/src/net/sf/openrocket/aerodynamics/Warning.java
+++ b/core/src/net/sf/openrocket/aerodynamics/Warning.java
@@ -396,4 +396,6 @@ public abstract class Warning {
 
 	public static final Warning TUBE_SEPARATION = new Other(trans.get("Warning.TUBE_SEPARATION"));
 	public static final Warning TUBE_OVERLAP = new Other(trans.get("Warning.TUBE_OVERLAP"));
+
+	public static final Warning SEPARATION_ORDER = new Other(trans.get("Warning.SEPARATION_ORDER"));
 }
diff --git a/core/src/net/sf/openrocket/simulation/BasicEventSimulationEngine.java b/core/src/net/sf/openrocket/simulation/BasicEventSimulationEngine.java
index 5212790b8..ecb4ae5cb 100644
--- a/core/src/net/sf/openrocket/simulation/BasicEventSimulationEngine.java
+++ b/core/src/net/sf/openrocket/simulation/BasicEventSimulationEngine.java
@@ -444,6 +444,18 @@ public class BasicEventSimulationEngine implements SimulationEngine {
 					// Record the event.
 					currentStatus.getFlightData().addEvent(event);
 
+					// If I've got something other than one active stage below the separation point,
+					// flag a warning
+					int numActiveBelow = 0;
+					for (int i = stageNumber; i < currentStatus.getConfiguration().getStageCount(); i++) {
+						if (currentStatus.getConfiguration().isStageActive(i)) {
+							numActiveBelow++;
+						}
+					}
+					if (numActiveBelow != 1) {
+						currentStatus.getWarnings().add(Warning.SEPARATION_ORDER);
+					}
+
 					// Create a new simulation branch for the booster
 					SimulationStatus boosterStatus = new SimulationStatus(currentStatus);