diff --git a/libraries/AP_NavEKF3/AP_NavEKF3_core.cpp b/libraries/AP_NavEKF3/AP_NavEKF3_core.cpp
index 1abdb4202f..9924fa2808 100644
--- a/libraries/AP_NavEKF3/AP_NavEKF3_core.cpp
+++ b/libraries/AP_NavEKF3/AP_NavEKF3_core.cpp
@@ -466,8 +466,8 @@ bool NavEKF3_core::InitialiseFilterBootstrap(void)
     // If we are a plane and don't have GPS lock then don't initialise
     if (assume_zero_sideslip() && dal.gps().status(preferred_gps) < AP_DAL_GPS::GPS_OK_FIX_3D) {
         dal.snprintf(prearm_fail_string,
-                         sizeof(prearm_fail_string),
-                         "EKF3 init failure: No GPS lock");
+                     sizeof(prearm_fail_string),
+                     "EKF3 init failure: No GPS lock");
         statesInitialised = false;
         return false;
     }