diff --git a/src/ATCDCL/atis.cxx b/src/ATCDCL/atis.cxx
index c637640fd..3cdfa806f 100644
--- a/src/ATCDCL/atis.cxx
+++ b/src/ATCDCL/atis.cxx
@@ -1025,14 +1025,6 @@ bool FGATIS::search(double dt)
     RangeFilter rangeFilter(aircraftPos );
     CommStation* sta = CommStation::findByFreq(freqKhz, aircraftPos, &rangeFilter );
     SetStation(sta);
-    if (sta && sta->airport())
-    {
-        SG_LOG(SG_ATC, SG_DEBUG, "FGATIS " << _name << ": " << sta->airport()->name());
-    }
-    else
-    {
-        SG_LOG(SG_ATC, SG_DEBUG, "FGATIS " << _name << ": no station.");
-    }
 
     return true;
 }
diff --git a/src/Instrumentation/tacan.cxx b/src/Instrumentation/tacan.cxx
index ee8022bf1..07c2d617b 100644
--- a/src/Instrumentation/tacan.cxx
+++ b/src/Instrumentation/tacan.cxx
@@ -40,7 +40,6 @@ adjust_range (double transmitter_elevation_ft, double aircraft_altitude_ft,
     else if (range_nm < 20.0)
         range_nm = 20.0;
     double rand = sg_random();
-    SG_LOG( SG_INSTR, SG_DEBUG, " tacan range " << range_nm << " max range " << max_range_nm);
     return range_nm + (range_nm * rand * rand);
 }
 
@@ -136,7 +135,6 @@ TACAN::update (double delta_time_sec)
         _distance_node->setDoubleValue(0);
         _speed_node->setDoubleValue(0);
         _time_node->setDoubleValue(0);
-        SG_LOG( SG_INSTR, SG_DEBUG, "skip tacan" );
         return;
     }
 
@@ -153,8 +151,6 @@ TACAN::update (double delta_time_sec)
     double mobile_bearing = 0;
     double mobile_distance = 0;
 
-    SG_LOG( SG_INSTR, SG_DEBUG, "mobile_name " << _mobile_name);
-    SG_LOG( SG_INSTR, SG_DEBUG, "mobile_valid " << _mobile_valid);
     geo_inverse_wgs_84(pos, _mobilePos,
                        &mobile_bearing, &mobile_az2, &mobile_distance);
 
@@ -170,8 +166,6 @@ TACAN::update (double delta_time_sec)
 
     //select the nearer
     if ( mobile_distance <= distance && _mobile_valid) {
-        SG_LOG( SG_INSTR, SG_DEBUG, "mobile_distance_m " << mobile_distance);
-        SG_LOG( SG_INSTR, SG_DEBUG, "distance_m " << distance);
         bearing = mobile_bearing;
         distance = mobile_distance;
         _transmitter_pos.setElevationFt(_mobilePos.getElevationFt());
@@ -200,15 +194,10 @@ TACAN::update (double delta_time_sec)
 
     double horiz_offset = bearing;
 
-    SG_LOG( SG_INSTR, SG_DEBUG, "distance_nm " << distance_nm << " bearing "
-            << bearing << " horiz_offset " << horiz_offset);
-
     // calculate values for radar display
     double y_shift = distance_nm * cos( horiz_offset * SG_DEGREES_TO_RADIANS);
     double x_shift = distance_nm * sin( horiz_offset * SG_DEGREES_TO_RADIANS);
 
-    SG_LOG( SG_INSTR, SG_DEBUG, "y_shift " << y_shift  << " x_shift " << x_shift);
-
     double rotation = 0;
 
     double range_nm = adjust_range(_transmitter_pos.getElevationFt(),
@@ -269,15 +258,12 @@ TACAN::search (double frequency_mhz,const SGGeod& pos)
     int number, i;
     _mobile_valid = false;
 
-    SG_LOG( SG_INSTR, SG_DEBUG, "tacan freq " << frequency_mhz );
-
     // reset search time
     _time_before_search_sec = 1.0;
 
     //try any carriers first
     FGNavRecord *mobile_tacan = FGNavList::findByFreq( frequency_mhz, FGNavList::carrierFilter() );
     bool freq_valid = (mobile_tacan != NULL);
-    SG_LOG( SG_INSTR, SG_DEBUG, "mobile freqency valid " << freq_valid );
 
     if ( freq_valid ) {
 
@@ -288,15 +274,11 @@ TACAN::search (double frequency_mhz,const SGGeod& pos)
 
         number = carrier.size();
 
-        SG_LOG( SG_INSTR, SG_DEBUG, "carrier " << number );
         for ( i = 0; i < number; ++i ) {
             string str2 ( carrier[i]->getStringValue("name", ""));
-            SG_LOG( SG_INSTR, SG_DEBUG, "carrier name " << str2 );
 
-            SG_LOG( SG_INSTR, SG_DEBUG, "strings 1 " << str1 << " 2 " << str2 );
             string::size_type loc1= str1.find( str2, 0 );
             if ( loc1 != string::npos && str2 != "" ) {
-                SG_LOG( SG_INSTR, SG_DEBUG, " string found" );
                 _mobilePos = SGGeod::fromDegFt(
                              carrier[i]->getDoubleValue("position/longitude-deg"),
                              carrier[i]->getDoubleValue("position/latitude-deg"),
@@ -306,34 +288,23 @@ TACAN::search (double frequency_mhz,const SGGeod& pos)
                 _mobile_name = mobile_tacan->name();
                 _mobile_ident = mobile_tacan->get_trans_ident();
                 _mobile_valid = true;
-                SG_LOG( SG_INSTR, SG_DEBUG, " carrier transmitter valid " << _mobile_valid );
                 break;
             } else {
                 _mobile_valid = false;
-                SG_LOG( SG_INSTR, SG_DEBUG, " carrier transmitter invalid " << _mobile_valid );
             }
         }
 
         //try any AI tankers second
-
         if ( !_mobile_valid) {
-            SG_LOG( SG_INSTR, SG_DEBUG, "tanker transmitter valid start " << _mobile_valid );
-
         SGPropertyNode * branch = fgGetNode("ai/models", true);
         vector<SGPropertyNode_ptr> tanker = branch->getChildren("tanker");
 
         number = tanker.size();
 
-        SG_LOG( SG_INSTR, SG_DEBUG, "tanker number " << number );
-
         for ( i = 0; i < number; ++i ) {
             string str4 ( tanker[i]->getStringValue("callsign", ""));
-            SG_LOG( SG_INSTR, SG_DEBUG, "tanker callsign " << str4 );
-
-            SG_LOG( SG_INSTR, SG_DEBUG, "strings 1 " << str1 << " 4 " << str4 );
             string::size_type loc1= str1.find( str4, 0 );
             if ( loc1 != string::npos && str4 != "" ) {
-                SG_LOG( SG_INSTR, SG_DEBUG, " string found" );
                 _mobilePos = SGGeod::fromDegFt(
                                              tanker[i]->getDoubleValue("position/longitude-deg"),
                                              tanker[i]->getDoubleValue("position/latitude-deg"),
@@ -345,11 +316,9 @@ TACAN::search (double frequency_mhz,const SGGeod& pos)
                 _mobile_name = mobile_tacan->name();
                 _mobile_ident = mobile_tacan->get_trans_ident();
                 _mobile_valid = true;
-                SG_LOG( SG_INSTR, SG_DEBUG, " tanker transmitter valid " << _mobile_valid );
                 break;
             } else {
                 _mobile_valid = false;
-                SG_LOG( SG_INSTR, SG_DEBUG, " tanker transmitter invalid " << _mobile_valid );
             }
         }
     }
@@ -357,24 +326,16 @@ TACAN::search (double frequency_mhz,const SGGeod& pos)
     //try any mp tankers third, if we haven't found the tanker in the ai aircraft
 
     if ( !_mobile_valid ) {
-        SG_LOG( SG_INSTR, SG_DEBUG, " mp tanker transmitter valid start " << _mobile_valid );
-
         SGPropertyNode * branch = fgGetNode("ai/models", true);
         vector<SGPropertyNode_ptr> mp_tanker = branch->getChildren("multiplayer");
 
         number = mp_tanker.size();
 
-        SG_LOG( SG_INSTR, SG_DEBUG, " mp tanker number " << number );
-
         if ( number > 0 ) {	  // don't do this if there are no MP aircraft
             for ( i = 0; i < number; ++i ) {
                 string str6 ( mp_tanker[i]->getStringValue("callsign", ""));
-                SG_LOG( SG_INSTR, SG_DEBUG, "mp tanker callsign " << str6 );
-
-                SG_LOG( SG_INSTR, SG_DEBUG, "strings 1 " << str1 << " 5 " << str6 );
                 string::size_type loc1= str1.find( str6, 0 );
                 if ( loc1 != string::npos && str6 != "" ) {
-                    SG_LOG( SG_INSTR, SG_DEBUG, " string found" );
                   _mobilePos = SGGeod::fromDegFt(
                                                  mp_tanker[i]->getDoubleValue("position/longitude-deg"),
                                                  mp_tanker[i]->getDoubleValue("position/latitude-deg"),
@@ -386,21 +347,15 @@ TACAN::search (double frequency_mhz,const SGGeod& pos)
                     _mobile_name = mobile_tacan->name();
                     _mobile_ident = mobile_tacan->get_trans_ident();
                     _mobile_valid = true;
-
-                    SG_LOG( SG_INSTR, SG_DEBUG, " mp tanker transmitter valid " << _mobile_valid );
-                    SG_LOG( SG_INSTR, SG_DEBUG, " mp tanker name " << _mobile_name);
-                    SG_LOG( SG_INSTR, SG_DEBUG, " mp range " << _mobile_range_nm);
                     break;
                 } else {
                     _mobile_valid = false;
-                    SG_LOG( SG_INSTR, SG_DEBUG, " mp tanker transmitter invalid " << _mobile_valid );
-                    }
+                }
                 }
             }
         }
     } else {
         _mobile_valid = false;
-        SG_LOG( SG_INSTR, SG_DEBUG, " mobile transmitter invalid " << _mobile_valid );
     }
 
     // try the TACAN/VORTAC list next
@@ -409,7 +364,6 @@ TACAN::search (double frequency_mhz,const SGGeod& pos)
     _transmitter_valid = (tacan != NULL);
 
     if ( _transmitter_valid ) {
-        SG_LOG( SG_INSTR, SG_DEBUG, "transmitter valid " << _transmitter_valid );
 
         _transmitter_pos = tacan->geod();
         _transmitter_range_nm = tacan->get_range();
@@ -418,12 +372,6 @@ TACAN::search (double frequency_mhz,const SGGeod& pos)
         _name_node->setStringValue(_transmitter_name.c_str());
         _transmitter_ident = tacan->get_trans_ident();
         _ident_node->setStringValue(_transmitter_ident.c_str());
-
-        SG_LOG( SG_INSTR, SG_DEBUG, "name " << _transmitter_name);
-        SG_LOG( SG_INSTR, SG_DEBUG, _transmitter_pos);
-
-    } else {
-        SG_LOG( SG_INSTR, SG_DEBUG, "transmitter invalid " << _transmitter_valid );
     }
 }
 
diff --git a/src/Scenery/tilecache.cxx b/src/Scenery/tilecache.cxx
index bdec44d3b..d82d2e304 100644
--- a/src/Scenery/tilecache.cxx
+++ b/src/Scenery/tilecache.cxx
@@ -154,7 +154,6 @@ void TileCache::clear_cache() {
 
     for ( ; current != end; ++current ) {
         long index = current->first;
-        SG_LOG( SG_TERRAIN, SG_DEBUG, "clearing " << index );
         TileEntry *e = current->second;
         if ( e->is_loaded() ) {
             e->tile_bucket.make_bad();
diff --git a/src/Scenery/tileentry.cxx b/src/Scenery/tileentry.cxx
index a901f6dfa..31d14c713 100644
--- a/src/Scenery/tileentry.cxx
+++ b/src/Scenery/tileentry.cxx
@@ -101,8 +101,6 @@ TileEntry::addToSceneGraph(osg::Group *terrain_branch)
 void
 TileEntry::removeFromSceneGraph()
 {
-    SG_LOG( SG_TERRAIN, SG_DEBUG, "disconnecting TileEntry nodes" );
-
     if (! is_loaded()) {
         SG_LOG( SG_TERRAIN, SG_DEBUG, "removing a not-fully loaded tile!" );
     } else {
diff --git a/src/Time/light.cxx b/src/Time/light.cxx
index 5cdf21c33..43e44744c 100644
--- a/src/Time/light.cxx
+++ b/src/Time/light.cxx
@@ -212,8 +212,6 @@ void FGLight::update_sky_color () {
     const SGVec4f base_sky_color( 0.31, 0.43, 0.69, 1.0 );
     const SGVec4f base_fog_color( 0.63, 0.72, 0.88, 1.0 );
 
-    SG_LOG( SG_EVENT, SG_DEBUG, "Updating light parameters." );
-
     // calculate lighting parameters based on sun's relative angle to
     // local up
     float av = _humidity->getFloatValue() * 45;
@@ -221,7 +219,6 @@ void FGLight::update_sky_color () {
     float visibility_inv = (45000.0 - av)/45000.0;
 
     float deg = _sun_angle * SGD_RADIANS_TO_DEGREES;
-    SG_LOG( SG_EVENT, SG_DEBUG, "  Sun angle = " << deg );
 
     if (_saturation < 0.0) _saturation = 0.0;
     else if (_saturation > 1.0) _saturation = 1.0;
@@ -240,10 +237,6 @@ void FGLight::update_sky_color () {
     specular *= _saturation;
     sky_brightness *= _saturation;
 
-    SG_LOG( SG_EVENT, SG_DEBUG,
-            "  ambient = " << ambient << "  diffuse = " << diffuse
-            << "  specular = " << specular << "  sky = " << sky_brightness );
-
     // sky_brightness = 0.15;  // used to force a dark sky (when testing)
 
     /** fog color */
@@ -393,8 +386,6 @@ void FGLight::update_adj_fog_color () {
 void FGLight::updateSunPos()
 {
     SGTime *t = globals->get_time_params();
-    SG_LOG( SG_EVENT, SG_DEBUG, "  Updating Sun position" );
-    SG_LOG( SG_EVENT, SG_DEBUG, "  Gst = " << t->getGst() );
 
     fgSunPositionGST(t->getGst(), &_sun_lon, &_sun_lat);
 
@@ -406,11 +397,6 @@ void FGLight::updateSunPos()
     SGVec3d sunpos = SGVec3d::fromGeoc(SGGeoc::fromRadM(_sun_lon, _sun_lat,
                                                           SGGeodesy::EQURAD));
 
-    SG_LOG( SG_EVENT, SG_DEBUG, "    t->cur_time = " << t->get_cur_time() );
-    SG_LOG( SG_EVENT, SG_DEBUG,
-            "    Sun Geocentric lat = " << _sun_lat
-            << " Geodcentric lat = " << _sun_lat );
-
     // update the sun light vector
     _sun_vec = SGVec4f(toVec3f(normalize(sunpos)), 0);
     _sun_vec_inv = - _sun_vec;
@@ -430,9 +416,6 @@ void FGLight::updateSunPos()
     double signedPI = (_sun_angle < 0.0) ? -SGD_PI : SGD_PI;
     _sun_angle = fmod(_sun_angle+signedPI, SGD_2PI) - signedPI;
 
-    SG_LOG( SG_EVENT, SG_DEBUG, "sun angle relative to current location = "
-            << get_sun_angle() );
-
     // Get direction to the sun in the local frame.
     SGVec3d local_sun_vec = hlOr.transform(nsun);