diff --git a/ArduPlane/navigation.pde b/ArduPlane/navigation.pde
index bdbc5fa0cf..e4846c9ace 100644
--- a/ArduPlane/navigation.pde
+++ b/ArduPlane/navigation.pde
@@ -182,7 +182,7 @@ static void update_fbwb_speed_height(void)
     
     change_target_altitude(g.flybywire_climb_rate * elevator_input * delta_us_fast_loop * 0.0001f);
     
-    if (elevator_input == 0.0f && last_elevator_input != 0.0f) {
+    if (AP_Math::is_zero(elevator_input) && !AP_Math::is_zero(last_elevator_input)) {
         // the user has just released the elevator, lock in
         // the current altitude
         set_target_altitude_current();
diff --git a/ArduPlane/takeoff.pde b/ArduPlane/takeoff.pde
index 2baf8632f4..47f14f3392 100644
--- a/ArduPlane/takeoff.pde
+++ b/ArduPlane/takeoff.pde
@@ -37,7 +37,7 @@ static bool auto_takeoff_check(void)
 
     // Check for launch acceleration or timer started. NOTE: relies on TECS 50Hz processing
     if (!launchTimerStarted &&
-        g.takeoff_throttle_min_accel != 0.0f &&
+        !AP_Math::is_zero(g.takeoff_throttle_min_accel) &&
         SpdHgt_Controller->get_VXdot() < g.takeoff_throttle_min_accel) {
         goto no_launch;
     }
@@ -65,7 +65,7 @@ static bool auto_takeoff_check(void)
     }
 
     // Check ground speed and time delay
-    if (((gps.ground_speed() > g.takeoff_throttle_min_speed || g.takeoff_throttle_min_speed == 0.0f)) &&
+    if (((gps.ground_speed() > g.takeoff_throttle_min_speed || AP_Math::is_zero(g.takeoff_throttle_min_speed))) &&
         ((now - last_tkoff_arm_time) >= wait_time_ms)) {
         gcs_send_text_fmt(PSTR("Triggered AUTO, GPSspd = %.1f"), gps.ground_speed());
         launchTimerStarted = false;