diff --git a/ArduCopter/AP_State.pde b/ArduCopter/AP_State.pde
index 9f70263a61..8eec59d8be 100644
--- a/ArduCopter/AP_State.pde
+++ b/ArduCopter/AP_State.pde
@@ -139,13 +139,6 @@ void set_pre_arm_rc_check(bool b)
     }
 }
 
-void set_motor_interlock(bool b)
-{
-    if(ap.motor_interlock != b) {
-        ap.motor_interlock = b;
-    }
-}
-
 void set_using_interlock(bool b)
 {
     if(ap.using_interlock != b) {
diff --git a/ArduCopter/ArduCopter.pde b/ArduCopter/ArduCopter.pde
index 48c2f289de..9358443a3d 100644
--- a/ArduCopter/ArduCopter.pde
+++ b/ArduCopter/ArduCopter.pde
@@ -357,9 +357,8 @@ static union {
         uint8_t system_time_set     : 1; // 28      // true if the system time has been set from the GPS
         uint8_t gps_base_pos_set    : 1; // 29      // true when the gps base position has been set (used for RTK gps only)
         enum HomeState home_state   : 2; // 30,31   // home status (unset, set, locked)
-        uint8_t motor_interlock     : 1; // 32      // motor interlock status, final control for motors on/off
-        uint8_t using_interlock     : 1; // 33      // aux switch motor interlock function is in use
-        uint8_t motor_estop         : 1; // 34      // motor estop switch, shuts off motors when enabled
+        uint8_t using_interlock     : 1; // 32      // aux switch motor interlock function is in use
+        uint8_t motor_estop         : 1; // 33      // motor estop switch, shuts off motors when enabled
     };
     uint32_t value;
 } ap;
diff --git a/ArduCopter/motors.pde b/ArduCopter/motors.pde
index ea4aa4ab18..5cf1962511 100644
--- a/ArduCopter/motors.pde
+++ b/ArduCopter/motors.pde
@@ -84,7 +84,7 @@ static void auto_disarm_check()
 
     // allow auto disarm in manual flight modes or Loiter/AltHold if we're landed
     // always allow auto disarm if using interlock switch or motors are E-stopped
-    if (mode_has_manual_throttle(control_mode) || ap.land_complete || (ap.using_interlock && !ap.motor_interlock) || ap.motor_estop) {
+    if (mode_has_manual_throttle(control_mode) || ap.land_complete || (ap.using_interlock && !motors.get_interlock()) || ap.motor_estop) {
         auto_disarming_counter++;
 
         // use a shorter delay if using throttle interlock switch or E-stop, because it is less
@@ -173,8 +173,8 @@ static bool init_arm_motors(bool arming_from_gcs)
     // check if we are using motor interlock control on an aux switch
     set_using_interlock(check_if_auxsw_mode_used(AUXSW_MOTOR_INTERLOCK));
 
-    // if we are using motor interlock switch and it's disabled, fail to arm
-    if (ap.using_interlock && ap.motor_interlock){
+    // if we are using motor interlock switch and it's enabled, fail to arm
+    if (ap.using_interlock && motors.get_interlock()){
         gcs_send_text_P(SEVERITY_HIGH,PSTR("Arm: Motor Interlock Enabled"));
         AP_Notify::flags.armed = false;
         return false;
@@ -245,7 +245,7 @@ static bool pre_arm_checks(bool display_failure)
     // otherwise exit immediately.  This check to be repeated, 
     // as state can change at any time.
     set_using_interlock(check_if_auxsw_mode_used(AUXSW_MOTOR_INTERLOCK));
-    if (ap.using_interlock && ap.motor_interlock){
+    if (ap.using_interlock && motors.get_interlock()){
         if (display_failure) {
             gcs_send_text_P(SEVERITY_HIGH,PSTR("PreArm: Motor Interlock Enabled"));
         }
@@ -741,9 +741,6 @@ static void init_disarm_motors()
     gcs_send_text_P(SEVERITY_HIGH, PSTR("DISARMING MOTORS"));
 #endif
 
-    // always force Motor Interlock to false
-    set_motor_interlock(false);
-
     // send disarm command to motors
     motors.armed(false);
 
@@ -785,11 +782,7 @@ static void motors_output()
     if (ap.motor_test) {
         motor_test_output();
     } else {
-        if (ap.using_interlock){
-            // pass in motor interlock status to motors class
-            // true means motors run, false motors don't run
-            motors.set_interlock(ap.motor_interlock);
-        } else {
+        if (!ap.using_interlock){
             // if not using interlock switch, set according to E-Stop status
             // where E-Stop is forced false during arming if E-Stop switch
             // is not used. Interlock enabled means motors run, so we must
diff --git a/ArduCopter/radio.pde b/ArduCopter/radio.pde
index 64f3cefec3..f0d3042f2a 100644
--- a/ArduCopter/radio.pde
+++ b/ArduCopter/radio.pde
@@ -184,7 +184,7 @@ static void set_throttle_zero_flag(int16_t throttle_control)
     // if not using throttle interlock and non-zero throttle and not E-stopped,
     // or using motor interlock and it's enabled, then motors are running, 
     // and we are flying. Immediately set as non-zero
-    if ((!ap.using_interlock && (throttle_control > 0) && !ap.motor_estop) || (ap.using_interlock && ap.motor_interlock)) {
+    if ((!ap.using_interlock && (throttle_control > 0) && !ap.motor_estop) || (ap.using_interlock && motors.get_interlock())) {
         last_nonzero_throttle_ms = tnow_ms;
         ap.throttle_zero = false;
     } else if (tnow_ms - last_nonzero_throttle_ms > THROTTLE_ZERO_DEBOUNCE_TIME_MS) {
diff --git a/ArduCopter/switches.pde b/ArduCopter/switches.pde
index 99b8ca13e1..de0c3e235e 100644
--- a/ArduCopter/switches.pde
+++ b/ArduCopter/switches.pde
@@ -556,7 +556,7 @@ static void do_aux_switch_function(int8_t ch_function, uint8_t ch_flag)
     case AUXSW_MOTOR_INTERLOCK:
         // Turn on when above LOW, because channel will also be used for speed
         // control signal in tradheli
-        set_motor_interlock(ch_flag == AUX_SWITCH_HIGH || ch_flag == AUX_SWITCH_MIDDLE);
+        motors.set_interlock(ch_flag == AUX_SWITCH_HIGH || ch_flag == AUX_SWITCH_MIDDLE);
         break;
                 
     }