diff --git a/ArduCopter/commands_logic.cpp b/ArduCopter/commands_logic.cpp
index f2b8e47a20..2e6da19730 100644
--- a/ArduCopter/commands_logic.cpp
+++ b/ArduCopter/commands_logic.cpp
@@ -752,7 +752,7 @@ bool Copter::verify_payload_place()
         // we have a valid calibration.  Hopefully.
         nav_payload_place.hover_throttle_level = current_throttle_level;
         const float hover_throttle_delta = fabsf(nav_payload_place.hover_throttle_level - motors.get_throttle_hover());
-        gcs_send_text_fmt(MAV_SEVERITY_INFO, "hover throttle delta: %f", hover_throttle_delta);
+        gcs_send_text_fmt(MAV_SEVERITY_INFO, "hover throttle delta: %f", static_cast<double>(hover_throttle_delta));
         nav_payload_place.state = PayloadPlaceStateType_Descending_Start;
         // fall through
     };