- Added ultra-light traffic is now a separate traffic class that can have its

own preferential runway support. In future versions, we might want to
condider having a more generic mechanism for this.
- Keep a history of active runway for each class, so that runway assignments
are more consistent after whether updates or time-related schedule changes.

src/Airports/dynamics.cxx

@@ -56,8 +56,8 @@ FGAirportDynamics::FGAirportDynamics(FGAirport* ap) :
   lastUpdate = 0;
   for (int i = 0; i < 10; i++)
      {
-       avWindHeading [i] = 0;
+       //avWindHeading [i] = 0;
-       avWindSpeed   [i] = 0;
+       //avWindSpeed   [i] = 0;
      }
 }
 
@@ -78,8 +78,8 @@ FGAirportDynamics::FGAirportDynamics(const FGAirportDynamics& other) :
   lastUpdate = other.lastUpdate;
   for (int i = 0; i < 10; i++)
     {
-      avWindHeading [i] = other.avWindHeading[i];
+      //avWindHeading [i] = other.avWindHeading[i];
-      avWindSpeed   [i] = other.avWindSpeed  [i];
+      //avWindSpeed   [i] = other.avWindSpeed  [i];
     }
 }
 
@@ -373,57 +373,6 @@ void FGAirportDynamics::getActiveRunway(const string &trafficType, int action, s
 	  
 	  windSpeed = stationweather.get_wind_speed_kt();
 	  windHeading = stationweather.get_wind_from_heading_deg();
-	 //  double averageWindSpeed   = 0;
-// 	  double averageWindHeading = 0;
-// 	  double cosHeading         = 0;
-// 	  double sinHeading         = 0;
-// 	  // Initialize at the beginning of the next day or startup
-// 	  if ((lastUpdate == 0) || (dayStart < lastUpdate))
-// 	    {
-// 	      for (int i = 0; i < 10; i++)
-// 		{
-// 		  avWindHeading [i] = windHeading;
-// 		  avWindSpeed   [i] = windSpeed;
-// 		}
-// 	    }
-// 	  else
-// 	    {
-// 	      if (windSpeed != avWindSpeed[9]) // update if new metar data 
-// 		{
-// 		  // shift the running average
-// 		  for (int i = 0; i < 9 ; i++)
-// 		    {
-// 		      avWindHeading[i] = avWindHeading[i+1];
-// 		      avWindSpeed  [i] = avWindSpeed  [i+1];
-// 		    }
-// 		} 
-// 	      avWindHeading[9] = windHeading;
-// 	      avWindSpeed  [9] = windSpeed;
-// 	    }
-	  
-// 	  for (int i = 0; i < 10; i++)
-// 	    {
-// 	      averageWindSpeed   += avWindSpeed   [i];
-// 	      //averageWindHeading += avWindHeading [i];
-// 	      cosHeading += cos(avWindHeading[i] * SG_DEGREES_TO_RADIANS);
-// 	      sinHeading += sin(avWindHeading[i] * SG_DEGREES_TO_RADIANS);
-// 	    }
-// 	  averageWindSpeed   /= 10;
-// 	  //averageWindHeading /= 10;
-// 	  cosHeading /= 10;
-// 	  sinHeading /= 10;
-// 	  averageWindHeading = atan2(sinHeading, cosHeading) *SG_RADIANS_TO_DEGREES;
-// 	  if (averageWindHeading < 0)
-// 	    averageWindHeading += 360.0;
-// 	  //cerr << "Wind Heading " << windHeading << " average " << averageWindHeading << endl;
-// 	  //cerr << "Wind Speed   " << windSpeed   << " average " << averageWindSpeed   << endl;
-// 	  lastUpdate = dayStart;
-// 	      //if (wind_speed == 0) {
-// 	  //  wind_heading = 270;	 This forces West-facing rwys to be used in no-wind situations
-// 	    // which is consistent with Flightgear's initial setup.
-// 	  //}
-	  
-	  //string rwy_no = globals->get_runways()->search(apt->getId(), int(wind_heading));
 	  string scheduleName;
 	  //cerr << "finding active Runway for" << _ap->getId() << endl;
 	  //cerr << "Nr of seconds since day start << " << dayStart << endl;
@@ -432,7 +381,7 @@ void FGAirportDynamics::getActiveRunway(const string &trafficType, int action, s
 	  //cerr << "A"<< endl;
 	  currSched = rwyPrefs.getSchedule(trafficType.c_str());
 	  if (!(currSched))
-	    return;   
+	    return;
 	  //cerr << "B"<< endl;
 	  scheduleName = currSched->getName(dayStart);
 	  maxTail  = currSched->getTailWind  ();
@@ -446,21 +395,34 @@ void FGAirportDynamics::getActiveRunway(const string &trafficType, int action, s
 	  if (!(currRunwayGroup))
 	    return;
 	  nrActiveRunways = currRunwayGroup->getNrActiveRunways();
-	  //cerr << "Nr of Active Runways = " << nrActiveRunways << endl; 
 
+        // Keep a history of the currently active runways, to ensure
+        // that an already established selection of runways will not
+        // be overridden once a more preferred selection becomes 
+        // available as that can lead to random runway swapping.
+	if (trafficType == "com") {
+          currentlyActive = &comActive;
+        } else if (trafficType == "gen") {
+          currentlyActive = &genActive;
+        } else if (trafficType == "mil") {
+          currentlyActive = &milActive;
+        } else if (trafficType == "ul") {
+          currentlyActive = &ulActive;
+        }
 	  // 
 	  currRunwayGroup->setActive(_ap->getId(), 
 				     windSpeed, 
 				     windHeading, 
 				     maxTail, 
 				     maxCross, 
-				     &currentlyActive); 
+				     currentlyActive); 
 
-	  // Note that I SHOULD keep three lists in memory, one for 
+	  // Note that I SHOULD keep multiple lists in memory, one for 
 	  // general aviation, one for commercial and one for military
 	  // traffic.
-	  currentlyActive.clear();
+	  currentlyActive->clear();
 	  nrActiveRunways = currRunwayGroup->getNrActiveRunways();
+          //cerr << "Choosing runway for " << trafficType << endl;
 	  for (int i = 0; i < nrActiveRunways; i++)
 	    {
 	      type = "unknown"; // initialize to something other than landing or takeoff
@@ -468,16 +430,17 @@ void FGAirportDynamics::getActiveRunway(const string &trafficType, int action, s
 	      if (type == "landing")
 		{
 		  landing.push_back(name);
-		  currentlyActive.push_back(name);
+		  currentlyActive->push_back(name);
 		  //cerr << "Landing " << name << endl; 
 		}
 	      if (type == "takeoff")
 		{
 		  takeoff.push_back(name);
-		  currentlyActive.push_back(name);
+		  currentlyActive->push_back(name);
 		  //cerr << "takeoff " << name << endl;
 		}
 	    }
+          //cerr << endl;
 	}
       if (action == 1) // takeoff 
 	{
@@ -505,8 +468,7 @@ void FGAirportDynamics::getActiveRunway(const string &trafficType, int action, s
 	    {  //fallback
 	       runway = chooseRunwayFallback();
 	    }
-	}
+	} 
-      
       //runway = globals->get_runways()->search(_ap->getId(), int(windHeading));
       //cerr << "Seleceted runway: " << runway << endl;
     }

src/Airports/dynamics.hxx

@@ -50,14 +50,15 @@ private:
   string prevTrafficType;
   stringVec landing;
   stringVec takeoff;
-  stringVec currentlyActive;
+  stringVec milActive, comActive, genActive, ulActive;
+  stringVec *currentlyActive;
 
   // Experimental keep a running average of wind dir and speed to prevent
   // Erratic runway changes. 
   // Note: I should add these to the copy constructor and assigment operator to be
   // constistent
-  double avWindHeading [10];
+  //double avWindHeading [10];
-  double avWindSpeed   [10];
+  //double avWindSpeed   [10];
 
   string chooseRunwayFallback();
 

src/Airports/runwayprefloader.cxx

@@ -114,6 +114,12 @@ void  FGRunwayPreferenceXMLLoader::endElement (const char * name) {
     _pref->setMilTimes(currTimes);
     currTimes.clear();
   }
+  if (!(strcmp(name, "ul"))) { // Military Traffic
+    //cerr << "Setting time table for military traffic" << endl;
+    _pref->setULTimes(currTimes);
+    currTimes.clear();
+  }
+
 
   if (!(strcmp(name, "takeoff"))) {
     //cerr << "Adding takeoff: " << value << endl;

src/Airports/runwayprefs.cxx

@@ -237,7 +237,7 @@ void RunwayGroup::setActive(const string &aptId,
 	    {
 	     
 	      name = rwyList[j].getRwyList(i);
-	      //cerr << "Name of Runway: " << name << endl;
+	      //cerr << "Name of Runway: " << name;
 	      if (globals->get_runways()->search( aptId, 
 						  name, 
 						  &rwy))
@@ -252,21 +252,22 @@ void RunwayGroup::setActive(const string &aptId,
 		  hdgDiff *= ((2*M_PI)/360.0); // convert to radians
 		  crossWind = windSpeed * sin(hdgDiff);
 		  tailWind  = -windSpeed * cos(hdgDiff);
-		  //cerr << "Tailwind : " << tailWind << endl;
+		  //cerr << ". Tailwind : " << tailWind;
-		  //cerr << "Crosswnd : " << crossWind << endl;
+		  //cerr << ". Crosswnd : " << crossWind;
 		  if ((tailWind > maxTail) || (crossWind > maxCross))
 		    {
-		      //cerr << "Invalid : " << endl;
+		      //cerr << ". [Invalid] " << endl;
 		      validSelection = false;
 		   }
 		  else 
 		    {
-		      //cerr << "Valid   : " << endl;;
+		      //cerr << ". [Valid] ";
 		  }
 		}else {
 		SG_LOG( SG_GENERAL, SG_INFO, "Failed to find runway " << name << " at " << aptId );
 		exit(1);
 	      }
+              //cerr << endl;
 	    }
 	  if (validSelection) 
 	    {

src/Airports/runwayprefs.hxx

@@ -135,6 +135,7 @@ private:
   ScheduleTime comTimes; // Commercial Traffic;
   ScheduleTime genTimes; // General Aviation;
   ScheduleTime milTimes; // Military Traffic;
+  ScheduleTime ulTimes;  // Ultralight Traffic
 
   PreferenceList preferences;
   
@@ -157,6 +158,7 @@ public:
   void setMilTimes(ScheduleTime& t) { milTimes = t; };
   void setGenTimes(ScheduleTime& t) { genTimes = t; };
   void setComTimes(ScheduleTime& t) { comTimes = t; };
+  void setULTimes (ScheduleTime& t) { ulTimes  = t; };
 
   void addRunwayGroup(RunwayGroup& g) { preferences.push_back(g); };
 };