src/ATC/ATCmgr.cxx

   1 // ATCmgr.cxx - Implementation of FGATCMgr - a global Flightgear ATC manager.
   2 //
   3 // Written by David Luff, started February 2002.
   4 //
   5 // Copyright (C) 2002  David C Luff - david.luff@nottingham.ac.uk
   6 //
   7 // This program is free software; you can redistribute it and/or
   8 // modify it under the terms of the GNU General Public License as
   9 // published by the Free Software Foundation; either version 2 of the
  10 // License, or (at your option) any later version.
  11 //
  12 // This program is distributed in the hope that it will be useful, but
  13 // WITHOUT ANY WARRANTY; without even the implied warranty of
  14 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  15 // General Public License for more details.
  16 //
  17 // You should have received a copy of the GNU General Public License
  18 // along with this program; if not, write to the Free Software
  19 // Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  20
  21 //#include <Time/event.hxx>
  22
  23 #include <simgear/misc/sg_path.hxx>
  24 #include <simgear/debug/logstream.hxx>
  25 #include <Airports/simple.hxx>
  26
  27 #include "ATCmgr.hxx"
  28 #include "commlist.hxx"
  29 #include "ATCdisplay.hxx"
  30 #include "ATCDialog.hxx"
  31 #include "ATCutils.hxx"
  32
  33 /*
  34 // periodic radio station search wrapper
  35 static void fgATCSearch( void ) {
  36         globals->get_ATC_mgr()->Search();
  37 }
  38 */ //This wouldn't compile - including Time/event.hxx breaks it :-(
  39
  40 AirportATC::AirportATC() :
  41     lon(0.0),
  42     lat(0.0),
  43     elev(0.0),
  44     atis_freq(0.0),
  45     atis_active(false),
  46     tower_freq(0.0),
  47     tower_active(false),
  48     ground_freq(0.0),
  49     ground_active(false),
  50     set_by_AI(false),
  51         numAI(0)
  52 {
  53     set_by_comm[0] = false;
  54         set_by_comm[1] = false;
  55 }
  56
  57 FGATCMgr::FGATCMgr() {
  58         comm_ident[0] = "";
  59         comm_ident[1] = "";
  60         last_comm_ident[0] = "";
  61         last_comm_ident[1] = "";
  62         approach_ident = "";
  63         last_in_range = false;
  64         comm_type[0] = INVALID;
  65         comm_type[1] = INVALID;
  66         comm_atc_ptr[0] = NULL;
  67         comm_atc_ptr[1] = NULL;
  68         comm_valid[0] = false;
  69         comm_valid[1] = false;
  70 }
  71
  72 FGATCMgr::~FGATCMgr() {
  73         delete v1;
  74 }
  75
  76 void FGATCMgr::bind() {
  77 }
  78
  79 void FGATCMgr::unbind() {
  80 }
  81
  82 void FGATCMgr::init() {
  83         comm_node[0] = fgGetNode("/radios/comm[0]/frequencies/selected-mhz", true);
  84         comm_node[1] = fgGetNode("/radios/comm[1]/frequencies/selected-mhz", true);
  85         lon_node = fgGetNode("/position/longitude-deg", true);
  86         lat_node = fgGetNode("/position/latitude-deg", true);
  87         elev_node = fgGetNode("/position/altitude-ft", true);
  88         atc_list_itr = atc_list.begin();
  89
  90         // Search for connected ATC stations once per 0.8 seconds or so
  91         // global_events.Register( "fgATCSearch()", fgATCSearch,
  92         //                  fgEVENT::FG_EVENT_READY, 800);
  93         // For some reason the above doesn't compile - including Time/event.hxx stops compilation.
  94
  95         // Initialise the frequency search map
  96     current_commlist = new FGCommList;
  97     SGPath p_comm( globals->get_fg_root() );
  98     current_commlist->init( p_comm );
  99
 100 #ifdef ENABLE_AUDIO_SUPPORT
 101         // Load all available voices.
 102         // For now we'll do one hardwired one
 103
 104         v1 = new FGATCVoice;
 105         voiceOK = v1->LoadVoice("default");
 106         voice = true;
 107
 108         /* I've loaded the voice even if /sim/sound/audible is false
 109         *  since I know no way of forcing load of the voice if the user
 110         *  subsequently switches /sim/sound/audible to true. */
 111 #else
 112         voice = false;
 113 #endif
 114
 115         // Initialise the ATC Dialogs
 116         //cout << "Initing Transmissions..." << endl;
 117     SG_LOG(SG_ATC, SG_INFO, "  ATC Transmissions");
 118     current_transmissionlist = new FGTransmissionList;
 119     SGPath p_transmission( globals->get_fg_root() );
 120     p_transmission.append( "ATC/default.transmissions" );
 121     current_transmissionlist->init( p_transmission );
 122         //cout << "Done Transmissions" << endl;
 123
 124     SG_LOG(SG_ATC, SG_INFO, "  ATC Dialog System");
 125     current_atcdialog = new FGATCDialog;
 126     current_atcdialog->Init();
 127
 128         ATCDialogInit();
 129
 130         // DCL - testing
 131         //current_atcdialog->add_entry( "EGNX", "Request vectoring for approach", "Request Vectors" );
 132         //current_atcdialog->add_entry( "EGNX", "Mayday, Mayday", "Declare Emergency" );
 133 }
 134
 135 void FGATCMgr::update(double dt) {
 136         //cout << "Entering update..." << endl;
 137         //Traverse the list of active stations.
 138         //Only update one class per update step to avoid the whole ATC system having to calculate between frames.
 139         //Eventually we should only update every so many steps.
 140         //cout << "In FGATCMgr::update - atc_list.size = " << atc_list.size() << '\n';
 141         if(atc_list.size()) {
 142                 if(atc_list_itr == atc_list.end()) {
 143                         atc_list_itr = atc_list.begin();
 144                 }
 145                 //cout << "Updating " << (*atc_list_itr)->get_ident() << ' ' << (*atc_list_itr)->GetType() << '\n';
 146                 //cout << "Freq = " << (*atc_list_itr)->get_freq() << '\n';
 147                 (*atc_list_itr)->Update(dt * atc_list.size());
 148                 //cout << "Done ATC update..." << endl;
 149                 ++atc_list_itr;
 150         }
 151
 152         // Search the tuned frequencies every now and then - this should be done with the event scheduler
 153         static int i = 0;
 154         if(i == 7) {
 155                 //cout << "About to AreaSearch()" << endl;
 156                 AreaSearch();
 157         }
 158         if(i == 15) {
 159                 //cout << "About to search(1)" << endl;
 160                 FreqSearch(1);
 161         }
 162         if(i == 30) {
 163                 //cout << "About to search(2)" << endl;
 164                 FreqSearch(2);
 165                 i = 0;
 166         }
 167         ++i;
 168
 169         //cout << "comm1 type = " << comm_type[0] << '\n';
 170         //cout << "Leaving update..." << endl;
 171 }
 172
 173
 174 // Returns frequency in KHz - should I alter this to return in MHz?
 175 unsigned short int FGATCMgr::GetFrequency(string ident, atc_type tp) {
 176         ATCData test;
 177         bool ok = current_commlist->FindByCode(ident, test, tp);
 178         return(ok ? test.freq : 0);
 179 }
 180
 181
 182 // Register the fact that the AI system wants to activate an airport
 183 // Might need more sophistication in this in the future - eg registration by aircraft call-sign.
 184 bool FGATCMgr::AIRegisterAirport(string ident) {
 185         SG_LOG(SG_ATC, SG_BULK, "AI registered airport " << ident << " with the ATC system");
 186         if(airport_atc_map.find(ident) != airport_atc_map.end()) {
 187                 airport_atc_map[ident]->set_by_AI = true;
 188                 airport_atc_map[ident]->numAI++;
 189                 return(true);
 190         } else {
 191                 FGAirport ap;
 192                 if(dclFindAirportID(ident, &ap)) {
 193                         //cout << "ident = " << ident << '\n';
 194                         AirportATC *a = new AirportATC;
 195                         // I'm not entirely sure that this AirportATC structure business is actually needed - it just duplicates what we can find out anyway!
 196                         a->lon = ap.longitude;
 197                         a->lat = ap.latitude;
 198                         a->elev = ap.elevation;
 199                         a->atis_freq = GetFrequency(ident, ATIS);
 200                         //cout << "ATIS freq = " << a->atis_freq << '\n';
 201                         a->atis_active = false;
 202                         a->tower_freq = GetFrequency(ident, TOWER);
 203                         //cout << "Tower freq = " << a->tower_freq << '\n';
 204                         a->tower_active = false;
 205                         a->ground_freq = GetFrequency(ident, GROUND);
 206                         //cout << "Ground freq = " << a->ground_freq << '\n';
 207                         a->ground_active = false;
 208                         // TODO - some airports will have a tower/ground frequency but be inactive overnight.
 209                         a->set_by_AI = true;
 210                         a->numAI = 1;
 211                         airport_atc_map[ident] = a;
 212                         return(true);
 213                 }
 214         }
 215         return(false);
 216 }
 217
 218
 219 // Register the fact that the comm radio is tuned to an airport
 220 // Channel is zero based
 221 bool FGATCMgr::CommRegisterAirport(string ident, int chan) {
 222         SG_LOG(SG_ATC, SG_BULK, "Comm channel " << chan << " registered airport " << ident);
 223         if(airport_atc_map.find(ident) != airport_atc_map.end()) {
 224                 //cout << "IN MAP - flagging set by comm..." << endl;
 225                 if(chan == 0) {
 226                         airport_atc_map[ident]->set_by_comm[0] = true;
 227                 } else if(chan == 1) {
 228                         airport_atc_map[ident]->set_by_comm[1] = true;
 229                 } else {
 230                         SG_LOG(SG_ATC, SG_ALERT, "COMM CHANNEL NOT 0 OR 1 IN FGATCMGR!");
 231                         // Just register both and accept the fact that this ATC will probably never get removed!
 232                         airport_atc_map[ident]->set_by_comm[0] = true;
 233                         airport_atc_map[ident]->set_by_comm[1] = true;
 234                 }
 235                 return(true);
 236         } else {
 237                 //cout << "NOT IN MAP - creating new..." << endl;
 238                 FGAirport ap;
 239                 if(dclFindAirportID(ident, &ap)) {
 240                         AirportATC *a = new AirportATC;
 241                         // I'm not entirely sure that this AirportATC structure business is actually needed - it just duplicates what we can find out anyway!
 242                         a->lon = ap.longitude;
 243                         a->lat = ap.latitude;
 244                         a->elev = ap.elevation;
 245                         a->atis_freq = GetFrequency(ident, ATIS);
 246                         a->atis_active = false;
 247                         a->tower_freq = GetFrequency(ident, TOWER);
 248                         a->tower_active = false;
 249                         a->ground_freq = GetFrequency(ident, GROUND);
 250                         a->ground_active = false;
 251                         // TODO - some airports will have a tower/ground frequency but be inactive overnight.
 252                         a->set_by_AI = false;
 253                         a->numAI = 0;
 254                         if(chan == 0) {
 255                                 a->set_by_comm[0] = true;
 256                         } else if(chan == 1) {
 257                                 a->set_by_comm[1] = true;
 258                         } else {
 259                                 SG_LOG(SG_ATC, SG_ALERT, "COMM CHANNEL NOT 1 OR 2 IN FGATCMGR!");
 260                                 // Just register both and accept the fact that this ATC will probably never get removed!
 261                                 a->set_by_comm[0] = true;
 262                                 a->set_by_comm[1] = true;
 263                         }
 264                         airport_atc_map[ident] = a;
 265                         return(true);
 266                 }
 267         }
 268         return(false);
 269 }
 270
 271
 272 // Remove from list only if not needed by the AI system or the other comm channel
 273 // Note that chan is zero based.
 274 void FGATCMgr::CommRemoveFromList(const char* id, atc_type tp, int chan) {
 275         SG_LOG(SG_ATC, SG_BULK, "CommRemoveFromList called for airport " << id << " by channel " << chan);
 276         if(airport_atc_map.find((string)id) != airport_atc_map.end()) {
 277                 AirportATC* a = airport_atc_map[(string)id];
 278                 //cout << "In CommRemoveFromList, a->ground_freq = " << a->ground_freq << endl;
 279                 if(a->set_by_AI) {
 280                         // Don't remove
 281                         FGATC* aptr = GetATCPointer((string)id, tp);
 282                         switch(chan) {
 283                         case 0:
 284                                 //cout << "chan 1\n";
 285                                 a->set_by_comm[0] = false;
 286                                 if(!a->set_by_comm[1]) {
 287                                         //cout << "not set by comm2\n";
 288                                         if(aptr != NULL) {
 289                                                 //cout << "Got pointer\n";
 290                                                 aptr->SetNoDisplay();
 291                                                 //cout << "Setting no display...\n";
 292                                         } else {
 293                                                 //cout << "Not got pointer\n";
 294                                         }
 295                                 }
 296                                 break;
 297                         case 1:
 298                                 a->set_by_comm[1] = false;
 299                                 if(!a->set_by_comm[0]) {
 300                                         if(aptr != NULL) {
 301                                                 aptr->SetNoDisplay();
 302                                                 //cout << "Setting no display...\n";
 303                                         }
 304                                 }
 305                                 break;
 306                         }
 307                         airport_atc_map[(string)id] = a;
 308                         return;
 309                 } else {
 310                         switch(chan) {
 311                         case 0:
 312                                 a->set_by_comm[0] = false;
 313                                 // Remove only if not also set by the other comm channel
 314                                 if(!a->set_by_comm[1]) {
 315                                         RemoveFromList(id, tp);
 316                                 }
 317                                 break;
 318                         case 1:
 319                                 a->set_by_comm[1] = false;
 320                                 if(!a->set_by_comm[0]) {
 321                                         RemoveFromList(id, tp);
 322                                 }
 323                                 break;
 324                         }
 325                 }
 326         }
 327 }
 328
 329
 330 // Remove from list - should only be called from above or similar
 331 // This function *will* remove it from the list regardless of who else might want it.
 332 void FGATCMgr::RemoveFromList(const char* id, atc_type tp) {
 333         //cout << "Requested type = " << tp << '\n';
 334         //cout << "id = " << id << '\n';
 335         atc_list_itr = atc_list.begin();
 336         while(atc_list_itr != atc_list.end()) {
 337                 //cout << "type = " << (*atc_list_itr)->GetType() << '\n';
 338                 //cout << "Ident = " << (*atc_list_itr)->get_ident() << '\n';
 339                 if( (!strcmp((*atc_list_itr)->get_ident(), id))
 340                         && ((*atc_list_itr)->GetType() == tp) ) {
 341                                 //Before removing it stop it transmitting!!
 342                                 //cout << "OBLITERATING FROM LIST!!!\n";
 343                                 (*atc_list_itr)->SetNoDisplay();
 344                                 (*atc_list_itr)->Update(0.00833);
 345                                 delete (*atc_list_itr);
 346                                 atc_list_itr = atc_list.erase(atc_list_itr);
 347                                 break;
 348                         }  // Note that that can upset where we are in the list but that doesn't really matter
 349                 ++atc_list_itr;
 350         }
 351 }
 352
 353
 354 // Find in list - return a currently active ATC pointer given ICAO code and type
 355 // Return NULL if the given service is not in the list
 356 // - *** THE CALLING FUNCTION MUST CHECK FOR THIS ***
 357 FGATC* FGATCMgr::FindInList(const char* id, atc_type tp) {
 358         atc_list_itr = atc_list.begin();
 359         while(atc_list_itr != atc_list.end()) {
 360                 if( (!strcmp((*atc_list_itr)->get_ident(), id))
 361                 && ((*atc_list_itr)->GetType() == tp) ) {
 362                         return(*atc_list_itr);
 363                 }       // Note that that can upset where we are in the list but that shouldn't really matter
 364                 ++atc_list_itr;
 365         }
 366         // If we get here it's not in the list
 367         return(NULL);
 368 }
 369
 370 // Returns true if the airport is found in the map
 371 bool FGATCMgr::GetAirportATCDetails(string icao, AirportATC* a) {
 372         if(airport_atc_map.find(icao) != airport_atc_map.end()) {
 373                 *a = *airport_atc_map[icao];
 374                 return(true);
 375         } else {
 376                 return(false);
 377         }
 378 }
 379
 380
 381 // Return a pointer to a given sort of ATC at a given airport and activate if necessary
 382 // Returns NULL if service doesn't exist - calling function should check for this.
 383 // We really ought to make this private and call it from the CommRegisterAirport / AIRegisterAirport functions
 384 // - at the moment all these GetATC... functions exposed are just too complicated.
 385 FGATC* FGATCMgr::GetATCPointer(string icao, atc_type type) {
 386         if(airport_atc_map.find(icao) == airport_atc_map.end()) {
 387                 return NULL;
 388         }
 389         AirportATC *a = airport_atc_map[icao];
 390         //cout << "a->lon = " << a->lon << '\n';
 391         //cout << "a->elev = " << a->elev << '\n';
 392         //cout << "a->tower_freq = " << a->tower_freq << '\n';
 393         switch(type) {
 394         case TOWER:
 395                 if(a->tower_active) {
 396                         // Get the pointer from the list
 397                         return(FindInList(icao.c_str(), type));
 398                 } else {
 399                         ATCData data;
 400                         if(current_commlist->FindByFreq(a->lon, a->lat, a->elev, a->tower_freq, &data, TOWER)) {
 401                                 FGTower* t = new FGTower;
 402                                 t->SetData(&data);
 403                                 atc_list.push_back(t);
 404                                 a->tower_active = true;
 405                                 airport_atc_map[icao] = a;
 406                                 t->Init();
 407                                 return(t);
 408                         } else {
 409                                 SG_LOG(SG_ATC, SG_ALERT, "ERROR - tower that should exist in FGATCMgr::GetATCPointer for airport " << icao << " not found");
 410                         }
 411                 }
 412                 break;
 413         case APPROACH:
 414                 break;
 415         case ATIS:
 416                 SG_LOG(SG_ATC, SG_ALERT, "ERROR - ATIS station should not be requested from FGATCMgr::GetATCPointer");
 417                 break;
 418         case GROUND:
 419                 //cout << "IN CASE GROUND" << endl;
 420                 if(a->ground_active) {
 421                         // Get the pointer from the list
 422                         return(FindInList(icao.c_str(), type));
 423                 } else {
 424                         ATCData data;
 425                         if(current_commlist->FindByFreq(a->lon, a->lat, a->elev, a->ground_freq, &data, GROUND)) {
 426                                 FGGround* g = new FGGround;
 427                                 g->SetData(&data);
 428                                 atc_list.push_back(g);
 429                                 a->ground_active = true;
 430                                 airport_atc_map[icao] = a;
 431                                 g->Init();
 432                                 return(g);
 433                         } else {
 434                                 SG_LOG(SG_ATC, SG_ALERT, "ERROR - ground control that should exist in FGATCMgr::GetATCPointer for airport " << icao << " not found");
 435                         }
 436                 }
 437                 break;
 438                 case INVALID:
 439                 break;
 440                 case ENROUTE:
 441                 break;
 442                 case DEPARTURE:
 443                 break;
 444         }
 445
 446         SG_LOG(SG_ATC, SG_ALERT, "ERROR IN FGATCMgr - reached end of GetATCPointer");
 447
 448         return(NULL);
 449 }
 450
 451 // Return a pointer to an appropriate voice for a given type of ATC
 452 // creating the voice if necessary - ie. make sure exactly one copy
 453 // of every voice in use exists in memory.
 454 //
 455 // TODO - in the future this will get more complex and dole out country/airport
 456 // specific voices, and possible make sure that the same voice doesn't get used
 457 // at different airports in quick succession if a large enough selection are available.
 458 FGATCVoice* FGATCMgr::GetVoicePointer(atc_type type) {
 459         // TODO - implement me better - maintain a list of loaded voices and other voices!!
 460         if(voice) {
 461                 switch(type) {
 462                 case ATIS:
 463                         if(voiceOK) {
 464                                 return(v1);
 465                         }
 466                 case TOWER:
 467                         return(NULL);
 468                 case APPROACH:
 469                         return(NULL);
 470                 case GROUND:
 471                         return(NULL);
 472                 default:
 473                         return(NULL);
 474                 }
 475                 return(NULL);
 476         } else {
 477                 return(NULL);
 478         }
 479 }
 480
 481 // Display a dialog box with options relevant to the currently tuned ATC service.
 482 void FGATCMgr::doPopupDialog() {
 483         ATCDoDialog(comm_type[0]);      // FIXME - currently hardwired to comm1
 484 }
 485
 486 // Search for ATC stations by frequency
 487 void FGATCMgr::FreqSearch(int channel) {
 488         int chan = channel - 1;         // Convert to zero-based for the arrays
 489
 490         ATCData data;
 491         double freq = comm_node[chan]->getDoubleValue();
 492         lon = lon_node->getDoubleValue();
 493         lat = lat_node->getDoubleValue();
 494         elev = elev_node->getDoubleValue() * SG_FEET_TO_METER;
 495
 496         // Query the data store and get the closest match if any
 497         if(current_commlist->FindByFreq(lon, lat, elev, freq, &data)) {
 498                 // We have a match
 499                 // What's the logic?
 500                 // If this channel not previously valid then easy - add ATC to list
 501                 // If this channel was valid then - Have we tuned to a different service?
 502                 // If so - de-register one and add the other
 503                 if(comm_valid[chan]) {
 504                         if((comm_ident[chan] == data.ident) && (comm_type[chan] == data.type)) {
 505                                 // Then we're still tuned into the same service so do nought and return
 506                                 return;
 507                         } else {
 508                                 // Something's changed - either the location or the service type
 509                                 // We need to feed the channel in so we're not removing it if we're also tuned in on the other channel
 510                                 CommRemoveFromList(comm_ident[chan], comm_type[chan], chan);
 511                         }
 512                 }
 513                 // At this point we can assume that we need to add the service.
 514                 comm_ident[chan] = (data.ident).c_str();
 515                 comm_type[chan] = data.type;
 516                 comm_x[chan] = (double)data.x;
 517                 comm_y[chan] = (double)data.y;
 518                 comm_z[chan] = (double)data.z;
 519                 comm_lon[chan] = (double)data.lon;
 520                 comm_lat[chan] = (double)data.lat;
 521                 comm_elev[chan] = (double)data.elev;
 522                 comm_valid[chan] = true;
 523
 524                 // This was a switch-case statement but the compiler didn't like the new variable creation with it.
 525                 if(comm_type[chan] == ATIS) {
 526                         CommRegisterAirport(comm_ident[chan], chan);
 527                         FGATC* app = FindInList(comm_ident[chan], TOWER);
 528                         if(app != NULL) {
 529                                 // The station is already in the ATC list
 530                                 //cout << "In list - flagging SetDisplay..." << endl;
 531                                 app->SetDisplay();
 532                         } else {
 533                                 // Generate the station and put in the ATC list
 534                                 //cout << "Not in list - generating..." << endl;
 535                                 FGATIS* a = new FGATIS;
 536                                 a->SetData(&data);
 537                                 comm_atc_ptr[chan] = a;
 538                                 a->SetDisplay();
 539                                 //a->Init();
 540                                 atc_list.push_back(a);
 541                         }
 542                 } else if (comm_type[chan] == TOWER) {
 543                         CommRegisterAirport(comm_ident[chan], chan);
 544                         //cout << "Done (TOWER)" << endl;
 545                         FGATC* app = FindInList(comm_ident[chan], TOWER);
 546                         if(app != NULL) {
 547                                 // The station is already in the ATC list
 548                                 //cout << "In list - flagging SetDisplay..." << endl;
 549                                 app->SetDisplay();
 550                         } else {
 551                                 // Generate the station and put in the ATC list
 552                                 //cout << "Not in list - generating..." << endl;
 553                                 FGTower* t = new FGTower;
 554                                 t->SetData(&data);
 555                                 comm_atc_ptr[chan] = t;
 556                                 t->SetDisplay();
 557                                 t->Init();
 558                                 atc_list.push_back(t);
 559                         }
 560                 }  else if (comm_type[chan] == GROUND) {
 561                         CommRegisterAirport(comm_ident[chan], chan);
 562                         //cout << "Done (GROUND)" << endl;
 563                         FGATC* app = FindInList(comm_ident[chan], GROUND);
 564                         if(app != NULL) {
 565                                 // The station is already in the ATC list
 566                                 app->SetDisplay();
 567                         } else {
 568                                 // Generate the station and put in the ATC list
 569                                 FGGround* g = new FGGround;
 570                                 g->SetData(&data);
 571                                 comm_atc_ptr[chan] = g;
 572                                 g->SetDisplay();
 573                                 g->Init();
 574                                 atc_list.push_back(g);
 575                         }
 576                 } else if (comm_type[chan] == APPROACH) {
 577                         // We have to be a bit more carefull here since approaches are also searched by area
 578                         CommRegisterAirport(comm_ident[chan], chan);
 579                         //cout << "Done (APPROACH)" << endl;
 580                         FGATC* app = FindInList(comm_ident[chan], APPROACH);
 581                         if(app != NULL) {
 582                                 // The station is already in the ATC list
 583                                 app->AddPlane("Player");
 584                                 app->SetDisplay();
 585                                 comm_atc_ptr[chan] = app;
 586                         } else {
 587                                 // Generate the station and put in the ATC list
 588                                 FGApproach* a = new FGApproach;
 589                                 a->SetData(&data);
 590                                 a->AddPlane("Player");
 591                                 atc_list.push_back(a);
 592                                 comm_atc_ptr[chan] = a;
 593                         }
 594                 }
 595         } else {
 596                 if(comm_valid[chan]) {
 597                         if(comm_type[chan] != APPROACH) {
 598                                 // Currently approaches are removed by Alexander's out-of-range mechanism
 599                                 CommRemoveFromList(comm_ident[chan], comm_type[chan], chan);
 600                         }
 601                         // Note that we *don't* call SetNoDisplay() here because the other comm channel
 602                         // might be tuned into the same station - this is handled by CommRemoveFromList(...)
 603                         comm_type[chan] = INVALID;
 604                         comm_atc_ptr[chan] = NULL;
 605                         comm_valid[chan] = false;
 606                 }
 607         }
 608 }
 609
 610
 611 // Search ATC stations by area in order that we appear 'on the radar'
 612 void FGATCMgr::AreaSearch() {
 613         // Search for Approach stations
 614         comm_list_type approaches;
 615         comm_list_iterator app_itr;
 616
 617         lon = lon_node->getDoubleValue();
 618         lat = lat_node->getDoubleValue();
 619         elev = elev_node->getDoubleValue() * SG_FEET_TO_METER;
 620
 621         // search stations in range
 622         int num_app = current_commlist->FindByPos(lon, lat, elev, 100.0, &approaches, APPROACH);
 623         if (num_app != 0) {
 624                 //cout << num_app << " approaches found in radiostack search !!!!" << endl;
 625
 626                 for(app_itr = approaches.begin(); app_itr != approaches.end(); app_itr++) {
 627
 628                         FGATC* app = FindInList((app_itr->ident).c_str(), app_itr->type);
 629                         if(app != NULL) {
 630                                 // The station is already in the ATC list
 631                                 app->AddPlane("Player");
 632                                 //app->Update();
 633                         } else {
 634                                 // Generate the station and put in the ATC list
 635                                 FGApproach* a = new FGApproach;
 636                                 a->SetData(&(*app_itr));
 637                                 a->AddPlane("Player");
 638                                 //a->Update();
 639                                 atc_list.push_back(a);
 640                         }
 641                 }
 642         }
 643
 644         // remove planes which are out of range
 645         // TODO - I'm not entirely sure that this belongs here.
 646         atc_list_itr = atc_list.begin();
 647         while(atc_list_itr != atc_list.end()) {
 648                 if((*atc_list_itr)->GetType() == APPROACH ) {
 649                         int np = (*atc_list_itr)->RemovePlane();
 650                         // if approach has no planes left remove it from ATC list
 651                         if ( np == 0) {
 652                                 (*atc_list_itr)->SetNoDisplay();
 653                                 (*atc_list_itr)->Update(0.00833);
 654                                 delete (*atc_list_itr);
 655                                 atc_list_itr = atc_list.erase(atc_list_itr);
 656                                 break;     // the other stations will be checked next time
 657                         }
 658                 }
 659                 ++atc_list_itr;
 660         }
 661 }