use the best initial ITA

aman/sys/aco/Node.py

@@ -183,6 +183,8 @@ class Node:
 
                 self.PredictedCoordinate = prediction
 
+        setInitialArrivalTime = None == self.Inbound.InitialArrivalTime
+
         # calculate the timings for the different arrival runways
         for identifier in sequencingConfig.ActiveArrivalRunways:
             star = Node.findArrivalRoute(self.Inbound.Report.initialApproachFix, identifier.Runway, navData)
@@ -212,5 +214,6 @@ class Node:
                                                                              ttl = ttl, latest = latest, route = arrivalRoute,
                                                                              trackmiles = trackmiles)
 
-                if None == self.Inbound.InitialArrivalTime:
-                    self.Inbound.InitialArrivalTime = self.ArrivalCandidates[identifier.Runway.Name].InitialArrivalTime
+                ita = self.ArrivalCandidates[identifier.Runway.Name].InitialArrivalTime
+                if True == setInitialArrivalTime and (None == self.Inbound.InitialArrivalTime or ita < self.Inbound.InitialArrivalTime):
+                    self.Inbound.InitialArrivalTime = ita