diff --git a/simgear/misc/sgstream.cxx b/simgear/misc/sgstream.cxx
index 59f756d5..9a1dd95b 100644
--- a/simgear/misc/sgstream.cxx
+++ b/simgear/misc/sgstream.cxx
@@ -43,10 +43,11 @@ sg_gzifstream::sg_gzifstream()
 //
 // Open a possibly gzipped file for reading.
 //
-sg_gzifstream::sg_gzifstream( const SGPath& name, ios_openmode io_mode )
+sg_gzifstream::sg_gzifstream( const SGPath& name, ios_openmode io_mode,
+  bool use_exact_name )
     : istream(&gzbuf)
 {
-    this->open( name, io_mode );
+    this->open( name, io_mode, use_exact_name );
 }
 
 //-----------------------------------------------------------------------------
@@ -62,17 +63,20 @@ sg_gzifstream::sg_gzifstream( int fd, ios_openmode io_mode )
 //-----------------------------------------------------------------------------
 //
 // Open a possibly gzipped file for reading.
-// If the initial open fails and the filename has a ".gz" extension then
-// remove the extension and try again.
-// If the initial open fails and the filename doesn't have a ".gz" extension
-// then append ".gz" and try again.
+// If 'use_exact_name' is true, just try to open the indicated file, nothing
+// else. Otherwise:
+//   - if the initial open fails and the filename has a ".gz" extension, then
+//     remove it and try again;
+//   - if the initial open fails and the filename doesn't have a ".gz"
+//     extension, then append ".gz" and try again.
 //
 void
-sg_gzifstream::open( const SGPath& name, ios_openmode io_mode )
+sg_gzifstream::open( const SGPath& name, ios_openmode io_mode,
+                     bool use_exact_name )
 {
     std::string s = name.utf8Str();
     gzbuf.open( s.c_str(), io_mode );
-    if ( ! gzbuf.is_open() )
+    if ( ! (gzbuf.is_open() || use_exact_name) )
     {
         if ( s.substr( s.length() - 3, 3 ) == ".gz" )
         {
diff --git a/simgear/misc/sgstream.hxx b/simgear/misc/sgstream.hxx
index edd6fd43..66fc8cbd 100644
--- a/simgear/misc/sgstream.hxx
+++ b/simgear/misc/sgstream.hxx
@@ -54,13 +54,15 @@ public:
     sg_gzifstream();
 
     /**
-     * Constructor that attempt to open a file with and without
-     * ".gz" extension.
+     * Constructor that attempts to open a file.
      * @param name name of file
      * @param io_mode file open mode(s) "or'd" together
+     * @param use_exact_name if false, try to add or remove a ".gz" extension
+     *                       in case the indicated file can't be opened
      */
     sg_gzifstream( const SGPath& name,
-		   ios_openmode io_mode = ios_in | ios_binary );
+		   ios_openmode io_mode = ios_in | ios_binary,
+                   bool use_exact_name = false );
 
     /**
      * Constructor that attaches itself to an existing file descriptor.
@@ -70,12 +72,15 @@ public:
     sg_gzifstream( int fd, ios_openmode io_mode = ios_in|ios_binary );
 
     /**
-     * Attempt to open a file with and without ".gz" extension.
+     * Attempt to open a file.
      * @param name name of file
      * @param io_mode file open mode(s) "or'd" together
+     * @param use_exact_name if false, try to add or remove a ".gz" extension
+     *                       in case the indicated file can't be opened
      */
     void open( const SGPath& name,
-	       ios_openmode io_mode = ios_in|ios_binary );
+	       ios_openmode io_mode = ios_in|ios_binary,
+               bool use_exact_name = false );
 
     /**
      * Attach to an existing file descriptor.