diff --git a/ArduCopter/GCS_Mavlink.cpp b/ArduCopter/GCS_Mavlink.cpp
index 853a463c91..32602be04a 100644
--- a/ArduCopter/GCS_Mavlink.cpp
+++ b/ArduCopter/GCS_Mavlink.cpp
@@ -278,7 +278,7 @@ NOINLINE void Copter::send_extended_status1(mavlink_channel_t chan)
 
 #if FRSKY_TELEM_ENABLED == ENABLED
     // give mask of error flags to Frsky_Telemetry
-    uint32_t sensors_error_flags = !control_sensors_health & control_sensors_enabled & control_sensors_present;
+    uint32_t sensors_error_flags = (~control_sensors_health) & control_sensors_enabled & control_sensors_present;
     frsky_telemetry.update_sensor_status_flags(sensors_error_flags);
 #endif