diff --git a/src/Sound/fg_fx.cxx b/src/Sound/fg_fx.cxx
index c5fa6ae5e..66c06d5d8 100644
--- a/src/Sound/fg_fx.cxx
+++ b/src/Sound/fg_fx.cxx
@@ -75,6 +75,8 @@ FGFX::FGFX ( const std::string &refname, SGPropertyNode *props ) :
         _avionics = _smgr->find("avionics", true);
         _avionics->tie_to_listener();
     }
+    else
+        _avionics = NULL;
 }
 
 void FGFX::unbind()
@@ -174,7 +176,7 @@ FGFX::update (double dt)
 
       
     if ( _enabled->getBoolValue() ) {
-        if ( _avionics_enabled->getBoolValue())
+        if ( _avionics && _avionics_enabled->getBoolValue())
         {
             if (_avionics_ext->getBoolValue() || _internal->getBoolValue()) {
                 // avionics sound is enabled