diff --git a/ArduCopter/control_modes.pde b/ArduCopter/control_modes.pde
index 93ca383c09..6d9f8b33e7 100644
--- a/ArduCopter/control_modes.pde
+++ b/ArduCopter/control_modes.pde
@@ -109,6 +109,7 @@ static void init_aux_switches()
         case AUX_SWITCH_ACRO_TRAINER:
         case AUX_SWITCH_EPM:
         case AUX_SWITCH_SPRAYER:
+        case AUX_SWITCH_EKF:
             do_aux_switch_function(g.ch7_option, ap.CH7_flag);
             break;
     }
@@ -122,6 +123,7 @@ static void init_aux_switches()
         case AUX_SWITCH_ACRO_TRAINER:
         case AUX_SWITCH_EPM:
         case AUX_SWITCH_SPRAYER:
+        case AUX_SWITCH_EKF:
             do_aux_switch_function(g.ch8_option, ap.CH8_flag);
             break;
     }
@@ -371,6 +373,13 @@ static void do_aux_switch_function(int8_t ch_function, uint8_t ch_flag)
                 }
             }
             break;
+
+#if AP_AHRS_NAVEKF_AVAILABLE
+    case AUX_SWITCH_EKF:
+        ahrs.set_ekf_use(ch_flag==AUX_SWITCH_HIGH);
+        break;
+#endif
+        
     }
 }
 
diff --git a/ArduCopter/defines.h b/ArduCopter/defines.h
index b7dcb0e3a5..97a7e42230 100644
--- a/ArduCopter/defines.h
+++ b/ArduCopter/defines.h
@@ -52,6 +52,7 @@
 #define AUX_SWITCH_AUTOTUNE         17      // auto tune
 #define AUX_SWITCH_LAND             18      // change to LAND flight mode
 #define AUX_SWITCH_EPM              19      // Operate the EPM cargo gripper low=off, middle=neutral, high=on
+#define AUX_SWITCH_EKF              20      // Enable NavEKF
 
 // values used by the ap.ch7_opt and ap.ch8_opt flags
 #define AUX_SWITCH_LOW              0       // indicates auxiliar switch is in the low position (pwm <1200)