introduce the configuration for the IAF spacing

aman/config/Airport.py

@@ -108,6 +108,13 @@ class Airport:
     def parseConstraints(self, planning):
         self.ArrivalRouteConstraints = {}
 
+        # check if the IAF sequence constraint is defined
+        if 'iafsequence' in planning:
+            self.IafSpacing = float(planning['iafsequence'])
+        else:
+            self.IafSpacing = 10.0
+
+        # parse the arrival constraints
         for key in planning:
             if True == key.startswith('constraints'):
                 star = key.replace('constraints', '').upper()