diff --git a/ArduCopter/AP_State.pde b/ArduCopter/AP_State.pde
index 4913d411bf..9f70263a61 100644
--- a/ArduCopter/AP_State.pde
+++ b/ArduCopter/AP_State.pde
@@ -153,3 +153,9 @@ void set_using_interlock(bool b)
     }
 }
 
+void set_motor_estop(bool b)
+{
+    if(ap.motor_estop != b) {
+        ap.motor_estop = b;
+    }
+}
\ No newline at end of file
diff --git a/ArduCopter/ArduCopter.pde b/ArduCopter/ArduCopter.pde
index 95a0e6468f..cb79a6fe7c 100644
--- a/ArduCopter/ArduCopter.pde
+++ b/ArduCopter/ArduCopter.pde
@@ -359,6 +359,7 @@ static union {
         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
     };
     uint32_t value;
 } ap;
diff --git a/ArduCopter/Parameters.pde b/ArduCopter/Parameters.pde
index 507a34a3a0..a4e190aba4 100644
--- a/ArduCopter/Parameters.pde
+++ b/ArduCopter/Parameters.pde
@@ -379,42 +379,42 @@ const AP_Param::Info var_info[] PROGMEM = {
     // @Param: CH7_OPT
     // @DisplayName: Channel 7 option
     // @Description: Select which function if performed when CH7 is above 1800 pwm
-    // @Values: 0:Do Nothing, 2:Flip, 3:Simple Mode, 4:RTL, 5:Save Trim, 7:Save WP, 8:Multi Mode, 9:Camera Trigger, 10:RangeFinder, 11:Fence, 12:ResetToArmedYaw, 13:Super Simple Mode, 14:Acro Trainer, 16:Auto, 17:AutoTune, 18:Land, 19:EPM, 21:Parachute Enable, 22:Parachute Release, 23:Parachute 3pos, 24:Auto Mission Reset, 25:AttCon Feed Forward, 26:AttCon Accel Limits, 27:Retract Mount, 28:Relay On/Off, 29:Landing Gear, 30:Lost Copter Sound
+    // @Values: 0:Do Nothing, 2:Flip, 3:Simple Mode, 4:RTL, 5:Save Trim, 7:Save WP, 8:Multi Mode, 9:Camera Trigger, 10:RangeFinder, 11:Fence, 12:ResetToArmedYaw, 13:Super Simple Mode, 14:Acro Trainer, 16:Auto, 17:AutoTune, 18:Land, 19:EPM, 21:Parachute Enable, 22:Parachute Release, 23:Parachute 3pos, 24:Auto Mission Reset, 25:AttCon Feed Forward, 26:AttCon Accel Limits, 27:Retract Mount, 28:Relay On/Off, 29:Landing Gear, 30:Lost Copter Sound, 31:E-Stop, 32:Motor Interlock
     // @User: Standard
     GSCALAR(ch7_option, "CH7_OPT",                  AUXSW_DO_NOTHING),
 
     // @Param: CH8_OPT
     // @DisplayName: Channel 8 option
     // @Description: Select which function if performed when CH8 is above 1800 pwm
-    // @Values: 0:Do Nothing, 2:Flip, 3:Simple Mode, 4:RTL, 5:Save Trim, 7:Save WP, 8:Multi Mode, 9:Camera Trigger, 10:RangeFinder, 11:Fence, 12:ResetToArmedYaw, 13:Super Simple Mode, 14:Acro Trainer, 16:Auto, 17:AutoTune, 18:Land, 19:EPM, 21:Parachute Enable, 22:Parachute Release, 23:Parachute 3pos, 24:Auto Mission Reset, 25:AttCon Feed Forward, 26:AttCon Accel Limits, 27:Retract Mount, 28:Relay On/Off, 29:Landing Gear, 30:Lost Copter Sound
+    // @Values: 0:Do Nothing, 2:Flip, 3:Simple Mode, 4:RTL, 5:Save Trim, 7:Save WP, 8:Multi Mode, 9:Camera Trigger, 10:RangeFinder, 11:Fence, 12:ResetToArmedYaw, 13:Super Simple Mode, 14:Acro Trainer, 16:Auto, 17:AutoTune, 18:Land, 19:EPM, 21:Parachute Enable, 22:Parachute Release, 23:Parachute 3pos, 24:Auto Mission Reset, 25:AttCon Feed Forward, 26:AttCon Accel Limits, 27:Retract Mount, 28:Relay On/Off, 29:Landing Gear, 30:Lost Copter Sound, 31:E-Stop, 32:Motor Interlock
     // @User: Standard
     GSCALAR(ch8_option, "CH8_OPT",                  AUXSW_DO_NOTHING),
 
     // @Param: CH9_OPT
     // @DisplayName: Channel 9 option
     // @Description: Select which function if performed when CH9 is above 1800 pwm
-    // @Values: 0:Do Nothing, 2:Flip, 3:Simple Mode, 4:RTL, 5:Save Trim, 7:Save WP, 8:Multi Mode, 9:Camera Trigger, 10:RangeFinder, 11:Fence, 12:ResetToArmedYaw, 13:Super Simple Mode, 14:Acro Trainer, 16:Auto, 17:AutoTune, 18:Land, 19:EPM, 21:Parachute Enable, 22:Parachute Release, 23:Parachute 3pos, 24:Auto Mission Reset, 25:AttCon Feed Forward, 26:AttCon Accel Limits, 27:Retract Mount, 28:Relay On/Off, 29:Landing Gear, 30:Lost Copter Sound
+    // @Values: 0:Do Nothing, 2:Flip, 3:Simple Mode, 4:RTL, 5:Save Trim, 7:Save WP, 8:Multi Mode, 9:Camera Trigger, 10:RangeFinder, 11:Fence, 12:ResetToArmedYaw, 13:Super Simple Mode, 14:Acro Trainer, 16:Auto, 17:AutoTune, 18:Land, 19:EPM, 21:Parachute Enable, 22:Parachute Release, 23:Parachute 3pos, 24:Auto Mission Reset, 25:AttCon Feed Forward, 26:AttCon Accel Limits, 27:Retract Mount, 28:Relay On/Off, 29:Landing Gear, 30:Lost Copter Sound, 31:E-Stop, 32:Motor Interlock
     // @User: Standard
     GSCALAR(ch9_option, "CH9_OPT",                  AUXSW_DO_NOTHING),
 
     // @Param: CH10_OPT
     // @DisplayName: Channel 10 option
     // @Description: Select which function if performed when CH10 is above 1800 pwm
-    // @Values: 0:Do Nothing, 2:Flip, 3:Simple Mode, 4:RTL, 5:Save Trim, 7:Save WP, 8:Multi Mode, 9:Camera Trigger, 10:RangeFinder, 11:Fence, 12:ResetToArmedYaw, 13:Super Simple Mode, 14:Acro Trainer, 16:Auto, 17:AutoTune, 18:Land, 19:EPM, 21:Parachute Enable, 22:Parachute Release, 23:Parachute 3pos, 24:Auto Mission Reset, 25:AttCon Feed Forward, 26:AttCon Accel Limits, 27:Retract Mount, 28:Relay On/Off, 29:Landing Gear, 30:Lost Copter Sound
+    // @Values: 0:Do Nothing, 2:Flip, 3:Simple Mode, 4:RTL, 5:Save Trim, 7:Save WP, 8:Multi Mode, 9:Camera Trigger, 10:RangeFinder, 11:Fence, 12:ResetToArmedYaw, 13:Super Simple Mode, 14:Acro Trainer, 16:Auto, 17:AutoTune, 18:Land, 19:EPM, 21:Parachute Enable, 22:Parachute Release, 23:Parachute 3pos, 24:Auto Mission Reset, 25:AttCon Feed Forward, 26:AttCon Accel Limits, 27:Retract Mount, 28:Relay On/Off, 29:Landing Gear, 30:Lost Copter Sound, 31:E-Stop, 32:Motor Interlock
     // @User: Standard
     GSCALAR(ch10_option, "CH10_OPT",                AUXSW_DO_NOTHING),
 
     // @Param: CH11_OPT
     // @DisplayName: Channel 11 option
     // @Description: Select which function if performed when CH11 is above 1800 pwm
-    // @Values: 0:Do Nothing, 2:Flip, 3:Simple Mode, 4:RTL, 5:Save Trim, 7:Save WP, 8:Multi Mode, 9:Camera Trigger, 10:RangeFinder, 11:Fence, 12:ResetToArmedYaw, 13:Super Simple Mode, 14:Acro Trainer, 16:Auto, 17:AutoTune, 18:Land, 19:EPM, 21:Parachute Enable, 22:Parachute Release, 23:Parachute 3pos, 24:Auto Mission Reset, 25:AttCon Feed Forward, 26:AttCon Accel Limits, 27:Retract Mount, 28:Relay On/Off, 29:Landing Gear, 30:Lost Copter Sound
+    // @Values: 0:Do Nothing, 2:Flip, 3:Simple Mode, 4:RTL, 5:Save Trim, 7:Save WP, 8:Multi Mode, 9:Camera Trigger, 10:RangeFinder, 11:Fence, 12:ResetToArmedYaw, 13:Super Simple Mode, 14:Acro Trainer, 16:Auto, 17:AutoTune, 18:Land, 19:EPM, 21:Parachute Enable, 22:Parachute Release, 23:Parachute 3pos, 24:Auto Mission Reset, 25:AttCon Feed Forward, 26:AttCon Accel Limits, 27:Retract Mount, 28:Relay On/Off, 29:Landing Gear, 30:Lost Copter Sound, 31:E-Stop, 32:Motor Interlock
     // @User: Standard
     GSCALAR(ch11_option, "CH11_OPT",                AUXSW_DO_NOTHING),
 
     // @Param: CH12_OPT
     // @DisplayName: Channel 12 option
     // @Description: Select which function if performed when CH12 is above 1800 pwm
-    // @Values: 0:Do Nothing, 2:Flip, 3:Simple Mode, 4:RTL, 5:Save Trim, 7:Save WP, 8:Multi Mode, 9:Camera Trigger, 10:RangeFinder, 11:Fence, 12:ResetToArmedYaw, 13:Super Simple Mode, 14:Acro Trainer, 16:Auto, 17:AutoTune, 18:Land, 19:EPM, 21:Parachute Enable, 22:Parachute Release, 23:Parachute 3pos, 24:Auto Mission Reset, 25:AttCon Feed Forward, 26:AttCon Accel Limits, 27:Retract Mount, 28:Relay On/Off, 29:Landing Gear, 30:Lost Copter Sound
+    // @Values: 0:Do Nothing, 2:Flip, 3:Simple Mode, 4:RTL, 5:Save Trim, 7:Save WP, 8:Multi Mode, 9:Camera Trigger, 10:RangeFinder, 11:Fence, 12:ResetToArmedYaw, 13:Super Simple Mode, 14:Acro Trainer, 16:Auto, 17:AutoTune, 18:Land, 19:EPM, 21:Parachute Enable, 22:Parachute Release, 23:Parachute 3pos, 24:Auto Mission Reset, 25:AttCon Feed Forward, 26:AttCon Accel Limits, 27:Retract Mount, 28:Relay On/Off, 29:Landing Gear, 30:Lost Copter Sound, 31:E-Stop, 32:Motor Interlock
     // @User: Standard
     GSCALAR(ch12_option, "CH12_OPT",                AUXSW_DO_NOTHING),
 
diff --git a/ArduCopter/defines.h b/ArduCopter/defines.h
index 2088dd0333..e3d6217cf1 100644
--- a/ArduCopter/defines.h
+++ b/ArduCopter/defines.h
@@ -66,6 +66,7 @@ enum aux_sw_func {
     AUXSW_RELAY,                   // Relay pin on/off (only supports first relay)
     AUXSW_LANDING_GEAR,            // Landing gear controller
     AUXSW_LOST_COPTER_SOUND,       // Play lost copter sound
+    AUXSW_MOTOR_ESTOP,             // Emergency Stop Switch
     AUXSW_MOTOR_INTERLOCK,         // Motor On/Off switch
 };
 
diff --git a/ArduCopter/motors.pde b/ArduCopter/motors.pde
index e6bb84275a..3a3ef600ae 100644
--- a/ArduCopter/motors.pde
+++ b/ArduCopter/motors.pde
@@ -167,6 +167,17 @@ static bool init_arm_motors(bool arming_from_gcs)
         return false;
     }
 
+    // if we are not E-Stop switch option, force Estop false to ensure motors
+    // can run normally
+    if (!check_if_auxsw_mode_used(AUXSW_MOTOR_ESTOP)){
+        set_motor_estop(false);
+    // if we are using motor Estop switch, it must not be in Estop position
+    } else if (check_if_auxsw_mode_used(AUXSW_MOTOR_ESTOP) && ap.motor_estop){
+        gcs_send_text_P(SEVERITY_HIGH,PSTR("Arm: Motor Emergency Stopped"));
+        AP_Notify::flags.armed = false;
+        return false;
+    }
+
     // enable gps velocity based centrefugal force compensation
     ahrs.set_correct_centrifugal(true);
     hal.util->set_soft_armed(true);
@@ -228,6 +239,15 @@ static bool pre_arm_checks(bool display_failure)
         return false;
     }
 
+    // if we are using Motor E-Stop aux switch, check it is not enabled 
+    // and warn if it is
+    if (check_if_auxsw_mode_used(AUXSW_MOTOR_ESTOP) && ap.motor_estop){
+        if (display_failure) {
+            gcs_send_text_P(SEVERITY_HIGH,PSTR("PreArm: Motor Emergency Stopped"));
+        }
+        return false;
+    }
+
     // exit immediately if we've already successfully performed the pre-arm check
     if (ap.pre_arm_check) {
         // run gps checks because results may change and affect LED colour
@@ -757,8 +777,11 @@ static void motors_output()
             // true means motors run, false motors don't run
             motors.set_interlock(ap.motor_interlock);
         } else {
-            // if not using interlock switch, force interlock true
-            motors.set_interlock(true);
+            // 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
+            // invert motor_estop status for motors to run.
+            motors.set_interlock(!ap.motor_estop);
         }
         motors.output();
     }
diff --git a/ArduCopter/switches.pde b/ArduCopter/switches.pde
index b13d60c06c..99b8ca13e1 100644
--- a/ArduCopter/switches.pde
+++ b/ArduCopter/switches.pde
@@ -227,6 +227,8 @@ static void init_aux_switch_function(int8_t ch_option, uint8_t ch_flag)
         case AUXSW_ATTCON_ACCEL_LIM:
         case AUXSW_RELAY:
         case AUXSW_LANDING_GEAR:
+        case AUXSW_MOTOR_ESTOP:
+        case AUXSW_MOTOR_INTERLOCK:
             do_aux_switch_function(ch_option, ch_flag);
             break;
     }
@@ -533,7 +535,12 @@ static void do_aux_switch_function(int8_t ch_function, uint8_t ch_flag)
                 landinggear.set_cmd_mode(LandingGear_Retract);
                 break;
         }
-        break;    
+        break;
+
+      case AUXSW_MOTOR_ESTOP:
+        // Turn on E-Stop logic when channel is high
+        set_motor_estop(ch_flag == AUX_SWITCH_HIGH);
+        break;
 
     case AUXSW_LOST_COPTER_SOUND:
         switch (ch_flag) {