diff --git a/ArduCopter/ArduCopter.pde b/ArduCopter/ArduCopter.pde
index 5fc4d2e6e9..687ad0eb40 100644
--- a/ArduCopter/ArduCopter.pde
+++ b/ArduCopter/ArduCopter.pde
@@ -1083,7 +1083,7 @@ static void ten_hz_logging_loop()
     if (g.log_bitmask & MASK_LOG_RCOUT) {
         DataFlash.Log_Write_RCOUT();
     }
-    if (g.log_bitmask & MASK_LOG_NTUN && mode_requires_GPS(control_mode)) {
+    if ((g.log_bitmask & MASK_LOG_NTUN) && mode_requires_GPS(control_mode)) {
         Log_Write_Nav_Tuning();
     }
 }