diff --git a/libraries/AP_L1_Control/AP_L1_Control.cpp b/libraries/AP_L1_Control/AP_L1_Control.cpp
index 9f4847a8c3..9199e3ba0b 100644
--- a/libraries/AP_L1_Control/AP_L1_Control.cpp
+++ b/libraries/AP_L1_Control/AP_L1_Control.cpp
@@ -1,4 +1,4 @@
-// -*- tab-width: 4; Mode: C++; c-basic-offset: 4; indent-tabs-mode: t -*-
+// -*- tab-width: 4; Mode: C++; c-basic-offset: 4; indent-tabs-mode: nil -*-
 
 #include "AP_L1_Control.h"
 
diff --git a/libraries/AP_L1_Control/AP_L1_Control.h b/libraries/AP_L1_Control/AP_L1_Control.h
index 4535bedb61..4e45d31b37 100644
--- a/libraries/AP_L1_Control/AP_L1_Control.h
+++ b/libraries/AP_L1_Control/AP_L1_Control.h
@@ -1,4 +1,4 @@
-// -*- tab-width: 4; Mode: C++; c-basic-offset: 4; indent-tabs-mode: t -*-
+// -*- tab-width: 4; Mode: C++; c-basic-offset: 4; indent-tabs-mode: nil -*-
 
 /// @file    AP_L1_Control.h
 /// @brief   L1 Control algorithm. This is a instance of an