diff --git a/ArduSub/AP_Arming_Sub.cpp b/ArduSub/AP_Arming_Sub.cpp
index f60a2b905a..197cab95b9 100644
--- a/ArduSub/AP_Arming_Sub.cpp
+++ b/ArduSub/AP_Arming_Sub.cpp
@@ -155,14 +155,14 @@ bool AP_Arming_Sub::arm(AP_Arming::Method method, bool do_arming_checks)
     return true;
 }
 
-bool AP_Arming_Sub::disarm()
+bool AP_Arming_Sub::disarm(const AP_Arming::Method method)
 {
     // return immediately if we are already disarmed
     if (!sub.motors.armed()) {
         return false;
     }
 
-    if (!AP_Arming::disarm()) {
+    if (!AP_Arming::disarm(method)) {
         return false;
     }
 
diff --git a/ArduSub/AP_Arming_Sub.h b/ArduSub/AP_Arming_Sub.h
index 2fab5503fb..5906b67aa0 100644
--- a/ArduSub/AP_Arming_Sub.h
+++ b/ArduSub/AP_Arming_Sub.h
@@ -15,7 +15,7 @@ public:
     bool pre_arm_checks(bool display_failure) override;
     bool has_disarm_function() const;
 
-    bool disarm() override;
+    bool disarm(AP_Arming::Method method) override;
     bool arm(AP_Arming::Method method, bool do_arming_checks=true) override;
 
 protected:
diff --git a/ArduSub/GCS_Mavlink.cpp b/ArduSub/GCS_Mavlink.cpp
index a180374d20..203296e634 100644
--- a/ArduSub/GCS_Mavlink.cpp
+++ b/ArduSub/GCS_Mavlink.cpp
@@ -794,7 +794,7 @@ void GCS_MAVLINK_Sub::handle_rc_channels_override(const mavlink_message_t &msg)
  */
 MAV_RESULT GCS_MAVLINK_Sub::handle_flight_termination(const mavlink_command_long_t &packet) {
     if (packet.param1 > 0.5f) {
-        sub.arming.disarm();
+        sub.arming.disarm(AP_Arming::Method::TERMINATION);
         return MAV_RESULT_ACCEPTED;
     }
     return MAV_RESULT_FAILED;
diff --git a/ArduSub/control_motordetect.cpp b/ArduSub/control_motordetect.cpp
index 348dba9868..1718de53b4 100644
--- a/ArduSub/control_motordetect.cpp
+++ b/ArduSub/control_motordetect.cpp
@@ -168,7 +168,7 @@ void Sub::motordetect_run()
     }
     case DONE:
         control_mode = prev_control_mode;
-        arming.disarm();
+        arming.disarm(AP_Arming::Method::MOTORDETECTDONE);
         break;
     }
 }
diff --git a/ArduSub/failsafe.cpp b/ArduSub/failsafe.cpp
index 856330f850..701fa9aba3 100644
--- a/ArduSub/failsafe.cpp
+++ b/ArduSub/failsafe.cpp
@@ -92,7 +92,7 @@ void Sub::failsafe_sensors_check()
         // This should always succeed
         if (!set_mode(MANUAL, ModeReason::BAD_DEPTH)) {
             // We should never get here
-            arming.disarm();
+            arming.disarm(AP_Arming::Method::BADFLOWOFCONTROL);
         }
     }
 }
@@ -146,7 +146,7 @@ void Sub::failsafe_ekf_check()
     }
 
     if (g.fs_ekf_action == FS_EKF_ACTION_DISARM) {
-        arming.disarm();
+        arming.disarm(AP_Arming::Method::EKFFAILSAFE);
     }
 }
 
@@ -160,7 +160,7 @@ void Sub::handle_battery_failsafe(const char* type_str, const int8_t action)
             set_mode(SURFACE, ModeReason::BATTERY_FAILSAFE);
             break;
         case Failsafe_Action_Disarm:
-            arming.disarm();
+            arming.disarm(AP_Arming::Method::BATTERYFAILSAFE);
             break;
         case Failsafe_Action_Warn:
         case Failsafe_Action_None:
@@ -194,7 +194,7 @@ void Sub::failsafe_pilot_input_check()
     set_neutral_controls();
 
     if(g.failsafe_pilot_input == FS_PILOT_INPUT_DISARM) {
-        arming.disarm();
+        arming.disarm(AP_Arming::Method::PILOT_INPUT_FAILSAFE);
     }
 #endif
 }
@@ -345,14 +345,14 @@ void Sub::failsafe_gcs_check()
 
     // handle failsafe action
     if (g.failsafe_gcs == FS_GCS_DISARM) {
-        arming.disarm();
+        arming.disarm(AP_Arming::Method::GCSFAILSAFE);
     } else if (g.failsafe_gcs == FS_GCS_HOLD && motors.armed()) {
         if (!set_mode(ALT_HOLD, ModeReason::GCS_FAILSAFE)) {
-            arming.disarm();
+            arming.disarm(AP_Arming::Method::GCS_FAILSAFE_HOLDFAILED);
         }
     } else if (g.failsafe_gcs == FS_GCS_SURFACE && motors.armed()) {
         if (!set_mode(SURFACE, ModeReason::GCS_FAILSAFE)) {
-            arming.disarm();
+            arming.disarm(AP_Arming::Method::GCS_FAILSAFE_SURFACEFAILED);
         }
     }
 }
@@ -411,7 +411,7 @@ void Sub::failsafe_crash_check()
 
     // disarm motors
     if (g.fs_crash_check == FS_CRASH_DISARM) {
-        arming.disarm();
+        arming.disarm(AP_Arming::Method::CRASH);
     }
 }
 
@@ -490,6 +490,6 @@ void Sub::failsafe_terrain_act()
 
     case FS_TERRAIN_DISARM:
     default:
-        arming.disarm();
+        arming.disarm(AP_Arming::Method::TERRAINFAILSAFE);
     }
 }
diff --git a/ArduSub/joystick.cpp b/ArduSub/joystick.cpp
index f1f14b1dee..d9c72d3ac0 100644
--- a/ArduSub/joystick.cpp
+++ b/ArduSub/joystick.cpp
@@ -145,7 +145,7 @@ void Sub::handle_jsbutton_press(uint8_t _button, bool shift, bool held)
     switch (get_button(_button)->function(shift)) {
     case JSButton::button_function_t::k_arm_toggle:
         if (motors.armed()) {
-            arming.disarm();
+            arming.disarm(AP_Arming::Method::MAVLINK);
         } else {
             arming.arm(AP_Arming::Method::MAVLINK);
         }
@@ -154,7 +154,7 @@ void Sub::handle_jsbutton_press(uint8_t _button, bool shift, bool held)
         arming.arm(AP_Arming::Method::MAVLINK);
         break;
     case JSButton::button_function_t::k_disarm:
-        arming.disarm();
+        arming.disarm(AP_Arming::Method::MAVLINK);
         break;
 
     case JSButton::button_function_t::k_mode_manual:
diff --git a/libraries/AP_Arming/AP_Arming.h b/libraries/AP_Arming/AP_Arming.h
index 027655cda1..68bfadaad2 100644
--- a/libraries/AP_Arming/AP_Arming.h
+++ b/libraries/AP_Arming/AP_Arming.h
@@ -66,6 +66,7 @@ public:
         GCS_FAILSAFE_HOLDFAILED = 26, // only disarm uses this...
         TAKEOFFTIMEOUT = 27, // only disarm uses this...
         AUTOLANDED = 28, // only disarm uses this...
+        PILOT_INPUT_FAILSAFE = 29, // only disarm uses this...
     };
 
     enum class Required {