diff --git a/APMrover2/GCS_Mavlink.pde b/APMrover2/GCS_Mavlink.pde
index a3b25145a9..99cfe6a0de 100644
--- a/APMrover2/GCS_Mavlink.pde
+++ b/APMrover2/GCS_Mavlink.pde
@@ -869,7 +869,7 @@ void GCS_MAVLINK::handleMessage(mavlink_message_t* msg)
                 break;
 
             case MAV_CMD_PREFLIGHT_CALIBRATION:
-                if (AP_Math::is_equal(packet.param1,1.0f)) {
+                if (is_equal(packet.param1,1.0f)) {
                     ins.init_gyro();
                     if (ins.gyro_calibrated_ok_all()) {
                         ahrs.reset_gyro_drift();
@@ -877,13 +877,13 @@ void GCS_MAVLINK::handleMessage(mavlink_message_t* msg)
                     } else {
                         result = MAV_RESULT_FAILED;
                     }
-                } else if (AP_Math::is_equal(packet.param3,1.0f)) {
+                } else if (is_equal(packet.param3,1.0f)) {
                     init_barometer();
                     result = MAV_RESULT_ACCEPTED;
-                } else if (AP_Math::is_equal(packet.param4,1.0f)) {
+                } else if (is_equal(packet.param4,1.0f)) {
                     trim_radio();
                     result = MAV_RESULT_ACCEPTED;
-                } else if (AP_Math::is_equal(packet.param5,1.0f)) {
+                } else if (is_equal(packet.param5,1.0f)) {
                     float trim_roll, trim_pitch;
                     AP_InertialSensor_UserInteract_MAVLink interact(this);
                     if (g.skip_gyro_cal) {
@@ -905,12 +905,12 @@ void GCS_MAVLINK::handleMessage(mavlink_message_t* msg)
                 break;
 
             case MAV_CMD_PREFLIGHT_SET_SENSOR_OFFSETS:
-                if (AP_Math::is_equal(packet.param1,2.0f)) {
+                if (is_equal(packet.param1,2.0f)) {
                     // save first compass's offsets
                     compass.set_and_save_offsets(0, packet.param2, packet.param3, packet.param4);
                     result = MAV_RESULT_ACCEPTED;
                 }
-                if (AP_Math::is_equal(packet.param1,5.0f)) {
+                if (is_equal(packet.param1,5.0f)) {
                     // save secondary compass's offsets
                     compass.set_and_save_offsets(1, packet.param2, packet.param3, packet.param4);
                     result = MAV_RESULT_ACCEPTED;
@@ -967,15 +967,15 @@ void GCS_MAVLINK::handleMessage(mavlink_message_t* msg)
             break;
 
         case MAV_CMD_PREFLIGHT_REBOOT_SHUTDOWN:
-            if (AP_Math::is_equal(packet.param1,1.0f) || AP_Math::is_equal(packet.param1,3.0f)) {
+            if (is_equal(packet.param1,1.0f) || is_equal(packet.param1,3.0f)) {
                 // when packet.param1 == 3 we reboot to hold in bootloader
-                hal.scheduler->reboot(AP_Math::is_equal(packet.param1,3.0f));
+                hal.scheduler->reboot(is_equal(packet.param1,3.0f));
                 result = MAV_RESULT_ACCEPTED;
             }
             break;
 
         case MAV_CMD_REQUEST_AUTOPILOT_CAPABILITIES: {
-            if (AP_Math::is_equal(packet.param1,1.0f)) {
+            if (is_equal(packet.param1,1.0f)) {
                 gcs[chan-MAVLINK_COMM_0].send_autopilot_version();
                 result = MAV_RESULT_ACCEPTED;
             }
diff --git a/APMrover2/Log.pde b/APMrover2/Log.pde
index e64ffb2cbb..932880eca0 100644
--- a/APMrover2/Log.pde
+++ b/APMrover2/Log.pde
@@ -337,7 +337,7 @@ struct PACKED log_Sonar {
 static void Log_Write_Sonar()
 {
     uint16_t turn_time = 0;
-    if (!AP_Math::is_zero(obstacle.turn_angle)) {
+    if (!is_zero(obstacle.turn_angle)) {
         turn_time = hal.scheduler->millis() - obstacle.detected_time_ms;
     }
     struct log_Sonar pkt = {
diff --git a/APMrover2/Steering.pde b/APMrover2/Steering.pde
index f62c406cda..08fdb167e3 100644
--- a/APMrover2/Steering.pde
+++ b/APMrover2/Steering.pde
@@ -40,7 +40,7 @@ static bool auto_check_trigger(void)
         return true;
     }
 
-    if (g.auto_trigger_pin == -1 && AP_Math::is_zero(g.auto_kickstart)) {
+    if (g.auto_trigger_pin == -1 && is_zero(g.auto_kickstart)) {
         // no trigger configured - let's go!
         auto_triggered = true;
         return true;
@@ -52,7 +52,7 @@ static bool auto_check_trigger(void)
         return true;            
     }
 
-    if (!AP_Math::is_zero(g.auto_kickstart)) {
+    if (!is_zero(g.auto_kickstart)) {
         float xaccel = ins.get_accel().x;
         if (xaccel >= g.auto_kickstart) {
             gcs_send_text_fmt(PSTR("Triggered AUTO xaccel=%.1f"), (double)xaccel);
diff --git a/APMrover2/test.pde b/APMrover2/test.pde
index 1e48c1d1c0..0fea8aba4a 100644
--- a/APMrover2/test.pde
+++ b/APMrover2/test.pde
@@ -480,7 +480,7 @@ test_sonar(uint8_t argc, const Menu::arg *argv)
     
         float dist_cm = sonar.distance_cm(0);
         float voltage = sonar.voltage_mv(0);
-        if (AP_Math::is_zero(sonar_dist_cm_min)) {
+        if (is_zero(sonar_dist_cm_min)) {
             sonar_dist_cm_min = dist_cm;
             voltage_min = voltage;
         }
@@ -491,7 +491,7 @@ test_sonar(uint8_t argc, const Menu::arg *argv)
 
         dist_cm = sonar.distance_cm(1);
         voltage = sonar.voltage_mv(1);
-        if (AP_Math::is_zero(sonar2_dist_cm_min)) {
+        if (is_zero(sonar2_dist_cm_min)) {
             sonar2_dist_cm_min = dist_cm;
             voltage2_min = voltage;
         }