diff --git a/src/Instrumentation/HUD/HUD_label.cxx b/src/Instrumentation/HUD/HUD_label.cxx
index 3b83c9f58..98a6a1df0 100644
--- a/src/Instrumentation/HUD/HUD_label.cxx
+++ b/src/Instrumentation/HUD/HUD_label.cxx
@@ -80,7 +80,7 @@ HUD::Label::Label(HUD *hud, const SGPropertyNode *n, float x, float y) :
 
 void HUD::Label::draw(void)
 {
-    if (!(_mode == NONE || _input.isValid() && blink()))
+    if (!(_mode == NONE || (_input.isValid() && blink())))
         return;
 
     if (_box) {
diff --git a/src/Instrumentation/HUD/HUD_ladder.cxx b/src/Instrumentation/HUD/HUD_ladder.cxx
index 9fe331493..75b2e3afc 100644
--- a/src/Instrumentation/HUD/HUD_ladder.cxx
+++ b/src/Instrumentation/HUD/HUD_ladder.cxx
@@ -478,9 +478,9 @@ void HUD::Ladder::draw(void)
             else if (i == -90 && _nadir)
                 draw_nadir(0.0, y);
 
-            if (_zenith && i > 85 || i > 90)
+            if ((_zenith && i > 85) || i > 90)
                 continue;
-            if (_nadir && i < -85 || i < -90)
+            if ((_nadir && i < -85) || i < -90)
                 continue;
 
             lo.x = -half_span;
diff --git a/src/Instrumentation/HUD/HUD_runway.cxx b/src/Instrumentation/HUD/HUD_runway.cxx
index 5c788e949..8eb443c36 100644
--- a/src/Instrumentation/HUD/HUD_runway.cxx
+++ b/src/Instrumentation/HUD/HUD_runway.cxx
@@ -183,7 +183,7 @@ void HUD::Runway::get_rwy_points(sgdVec3 *_points3d)
     double alt = current_aircraft.fdm_state->get_Runway_altitude() * SG_FEET_TO_METER;
     double length = _runway->lengthM() * 0.5;
     double width = _runway->widthM() * 0.5;
-    double frontLat, frontLon, backLat, backLon,az, tempLat, tempLon;
+    double frontLat = 0.0, frontLon = 0.0, backLat = 0.0, backLon = 0.0, az = 0.0, tempLat = 0.0, tempLon = 0.0;
 
     geo_direct_wgs_84(alt, _runway->latitude(), _runway->longitude(), _runway->headingDeg(), length, &backLat, &backLon, &az);
     sgGeodToCart(backLat * SG_DEGREES_TO_RADIANS, backLon * SG_DEGREES_TO_RADIANS, alt, _points3d[4]);
diff --git a/src/Instrumentation/HUD/HUD_tape.cxx b/src/Instrumentation/HUD/HUD_tape.cxx
index 5e73dfc1b..02fb76f15 100644
--- a/src/Instrumentation/HUD/HUD_tape.cxx
+++ b/src/Instrumentation/HUD/HUD_tape.cxx
@@ -243,11 +243,12 @@ void HUD::Tape::draw_vertical(float value)
     for (int i = 0; ; i++) {
         float v = vstart + i * _minor_divs;
 
-        if (!_modulo)
+        if (!_modulo) {
             if (v < _input.min())
                 continue;
             else if (v > _input.max())
                 break;
+        }
 
         float y = _y + (v - vmin) * factor();
 
@@ -335,8 +336,8 @@ void HUD::Tape::draw_vertical(float value)
                     continue;
 
                 if (_label_gap == 0.0
-                        || b < _center_y - _label_gap && t < _center_y - _label_gap
-                        || b > _center_y + _label_gap && t > _center_y + _label_gap) {
+                        || (b < _center_y - _label_gap && t < _center_y - _label_gap)
+                        || (b > _center_y + _label_gap && t > _center_y + _label_gap)) {
                     draw_text(x, y, s);
                 }
             }
@@ -451,11 +452,12 @@ void HUD::Tape::draw_horizontal(float value)
     for (int i = 0; ; i++) {
         float v = vstart + i * _minor_divs;
 
-        if (!_modulo)
+        if (!_modulo) {
             if (v < _input.min())
                 continue;
             else if (v > _input.max())
                 break;
+        }
 
         float x = _x + (v - vmin) * factor();
 
@@ -520,8 +522,8 @@ void HUD::Tape::draw_horizontal(float value)
                     continue;
 
                 if (_label_gap == 0.0
-                        || l < _center_x - _label_gap && r < _center_x - _label_gap
-                        || l > _center_x + _label_gap && r > _center_x + _label_gap) {
+                        || (l < _center_x - _label_gap && r < _center_x - _label_gap)
+                        || (l > _center_x + _label_gap && r > _center_x + _label_gap)) {
                     draw_text(x, y, s);
                 }
             }