diff --git a/simgear/misc/zfstream.cxx b/simgear/misc/zfstream.cxx
index b5755625..38a16ff2 100644
--- a/simgear/misc/zfstream.cxx
+++ b/simgear/misc/zfstream.cxx
@@ -237,7 +237,7 @@ char
 gzfilebuf::allocate()
 {
     obuf_size = page_size / sizeof(char);
-    obuffer = new char [ibuf_size];
+    obuffer = new char [obuf_size];
     return 0;
 }
 
diff --git a/simgear/misc/zfstream.hxx b/simgear/misc/zfstream.hxx
index 635397a7..5b391d20 100644
--- a/simgear/misc/zfstream.hxx
+++ b/simgear/misc/zfstream.hxx
@@ -102,7 +102,7 @@ protected:
     virtual int_type overflow( int_type c = parent::traits_type::eof() );
     bool    out_waiting();
     char*   base() {return obuffer;}
-    int     blen() {return ibuf_size;}
+    int     blen() {return obuf_size;}
     char    allocate();
 
 private: