diff --git a/aman/sys/aco/RunwayManager.py b/aman/sys/aco/RunwayManager.py
index 6433286..887b7f3 100644
--- a/aman/sys/aco/RunwayManager.py
+++ b/aman/sys/aco/RunwayManager.py
@@ -2,6 +2,7 @@
 
 from datetime import datetime, timedelta
 
+from aman.config.RunwaySequencing import RunwayAssignmentType
 from aman.sys.aco.Configuration import Configuration
 from aman.sys.aco.Constraints import SpacingConstraints
 from aman.sys.aco.Node import Node
@@ -57,15 +58,85 @@ class RunwayManager:
             else:
                 return eta, timedelta(seconds = 0)
 
+    def selectShallShouldMayArrivalRunway(self, node : Node, runways, useETA : bool, earliestArrivalTime : datetime):
+        candidate = None
+        delay = None
+
+        for runway in runways:
+            if True == useETA:
+                reference = node.ArrivalCandidates[runway.Runway.Name].EarliestArrivalTime
+            else:
+                reference = node.ArrivalCandidates[runway.Runway.Name].InitialArrivalTime
+
+            eta, _ = self.calculateEarliestArrivalTime(runway.Runway.Name, node)
+            if None == delay:
+                delay = eta - reference
+                candidate = runway
+            elif delay > (eta - reference):
+                delay = eta- reference
+                candidate = runway
+
+        return candidate
+
+    def executeShallShouldMayAssignment(self, node : Node, useETA : bool, earliestArrivalTime : datetime):
+        shallRunways = []
+        shouldRunways = []
+        mayRunways = []
+
+        for runway in self.Configuration.RunwayConstraints.ActiveArrivalRunways:
+            # test the shall assignments
+            if RunwayAssignmentType.AircraftType in runway.ShallAssignments:
+                if node.Inbound.Report.aircraft.type in runway.ShallAssignments[RunwayAssignmentType.AircraftType]:
+                    shallRunways.append(runway)
+            if RunwayAssignmentType.GateAssignment in runway.ShallAssignments:
+                if node.Inbound.Report.plannedGate in runway.ShallAssignments[RunwayAssignmentType.GateAssignment]:
+                    shallRunways.append(runway)
+
+            # test the should assignments
+            if RunwayAssignmentType.AircraftType in runway.ShouldAssignments:
+                if node.Inbound.Report.aircraft.type in runway.ShouldAssignments[RunwayAssignmentType.AircraftType]:
+                    shouldRunways.append(runway)
+            if RunwayAssignmentType.GateAssignment in runway.ShouldAssignments:
+                if node.Inbound.Report.plannedGate in runway.ShouldAssignments[RunwayAssignmentType.GateAssignment]:
+                    shouldRunways.append(runway)
+
+            if True == useETA:
+                reference = node.ArrivalCandidates[runway.Runway.Name].EarliestArrivalTime
+            else:
+                reference = node.ArrivalCandidates[runway.Runway.Name].InitialArrivalTime
+
+            # test the may assignments
+            if RunwayAssignmentType.AircraftType in runway.MayAssignments:
+                if node.Inbound.Report.aircraft.type in runway.MayAssignments[RunwayAssignmentType.AircraftType]:
+                    eta, _ = self.calculateEarliestArrivalTime(runway.Runway.Name, node, useETA, earliestArrivalTime)
+                    if (eta - reference) <= self.Configuration.MaxDelayMay:
+                        mayRunways.append(runway)
+            if RunwayAssignmentType.GateAssignment in runway.MayAssignments:
+                if node.Inbound.Report.plannedGate in runway.MayAssignments[RunwayAssignmentType.GateAssignment]:
+                    eta, _ = self.calculateEarliestArrivalTime(runway.Runway.Name, node, useETA, earliestArrivalTime)
+                    if (eta - reference) <= self.Configuration.MaxDelayMay:
+                        mayRunways.append(runway)
+
+        runway = self.selectShallShouldMayArrivalRunway(node, shallRunways, useETA, earliestArrivalTime)
+        if None != runway:
+            return [ runway ]
+        runway = self.selectShallShouldMayArrivalRunway(node, shouldRunways, useETA, earliestArrivalTime)
+        if None != runway:
+            return [ runway ]
+        runway = self.selectShallShouldMayArrivalRunway(node, mayRunways, useETA, earliestArrivalTime)
+        if None != runway:
+            return [ runway ]
+
+        return self.Configuration.RunwayConstraints.ActiveArrivalRunways
+
     def selectArrivalRunway(self, node : Node, useETA : bool, earliestArrivalTime : datetime):
         availableRunways = self.Configuration.RunwayConstraints.ActiveArrivalRunways
 
-        #if 1 < len(availableRunways):
-            # TODO filter based on type
-            # TODO filter based on airline
-            # ensure that at least one runway is available
+        if True == self.Configuration.RunwayConstraints.UseShallShouldMay:
+            availableRunways = self.executeShallShouldMayAssignment(node, useETA, earliestArrivalTime)
+        else:
+            availableRunways = self.Configuration.RunwayConstraints.ActiveArrivalRunways
 
-        # fallback to check if we have available runways
         if 0 == len(availableRunways):
             runway = self.Configuration.RunwayConstraints.ActiveArrivalRunways[0]
             return runway, self.calculateEarliestArrivalTime(runway.Runway.Name, node, useETA, earliestArrivalTime)