diff --git a/ArduCopter/AP_Arming.cpp b/ArduCopter/AP_Arming.cpp
index 6839e2390e..292ee288f8 100644
--- a/ArduCopter/AP_Arming.cpp
+++ b/ArduCopter/AP_Arming.cpp
@@ -318,8 +318,8 @@ bool AP_Arming_Copter::motor_checks(bool display_failure)
         // check we have an ESC present for every SERVOx_FUNCTION = motorx
         // find and report first missing ESC, extra ESCs are OK
         AP_ToshibaCAN *tcan = AP_ToshibaCAN::get_tcan(tcan_index);
-        const uint16_t motors_mask = copter.motors->get_motor_mask();
-        const uint16_t esc_mask = tcan->get_present_mask();
+        const uint32_t motors_mask = copter.motors->get_motor_mask();
+        const uint32_t esc_mask = tcan->get_present_mask();
         uint8_t escs_missing = 0;
         uint8_t first_missing = 0;
         for (uint8_t i = 0; i < 16; i++) {
diff --git a/ArduCopter/afs_copter.cpp b/ArduCopter/afs_copter.cpp
index 2eb2c1db14..9f669eee8c 100644
--- a/ArduCopter/afs_copter.cpp
+++ b/ArduCopter/afs_copter.cpp
@@ -45,7 +45,7 @@ void AP_AdvancedFailsafe_Copter::setup_IO_failsafe(void)
 
 #if FRAME_CONFIG != HELI_FRAME
     // setup AP_Motors outputs for failsafe
-    uint16_t mask = copter.motors->get_motor_mask();
+    uint32_t mask = copter.motors->get_motor_mask();
     hal.rcout->set_failsafe_pwm(mask, copter.motors->get_pwm_output_min());
 #endif
 }