diff --git a/libraries/SITL/SIM_Frame.cpp b/libraries/SITL/SIM_Frame.cpp
index d5435047f9..c3f2fba101 100644
--- a/libraries/SITL/SIM_Frame.cpp
+++ b/libraries/SITL/SIM_Frame.cpp
@@ -338,15 +338,15 @@ void Frame::load_frame_params(const char *model_json)
     } else {
         IGNORE_RETURN(asprintf(&fname, "@ROMFS/models/%s", model_json));
         if (AP::FS().stat(model_json, &st) != 0) {
-            AP_HAL::panic("%s failed to load\n", model_json);
+            AP_HAL::panic("%s failed to load", model_json);
         }
     }
     if (fname == nullptr) {
-        AP_HAL::panic("%s failed to load\n", model_json);
+        AP_HAL::panic("%s failed to load", model_json);
     }
     AP_JSON::value *obj = AP_JSON::load_json(model_json);
     if (obj == nullptr) {
-        AP_HAL::panic("%s failed to load\n", model_json);
+        AP_HAL::panic("%s failed to load", model_json);
     }
 
     enum class VarType {
diff --git a/libraries/SITL/SIM_JSON_Master.cpp b/libraries/SITL/SIM_JSON_Master.cpp
index 9b8c3b5906..a6b92591d4 100644
--- a/libraries/SITL/SIM_JSON_Master.cpp
+++ b/libraries/SITL/SIM_JSON_Master.cpp
@@ -37,15 +37,15 @@ void JSON_Master::init(const int32_t num_slaves)
         uint16_t port = 9002 + 10 * i;
 
         if (!list->sock_in.reuseaddress()) {
-            AP_HAL::panic("JSON master: socket reuseaddress failed on port: %d - %s\n", port, strerror(errno));
+            AP_HAL::panic("JSON master: socket reuseaddress failed on port: %d - %s", port, strerror(errno));
         }
 
         if (!list->sock_in.bind("127.0.0.1", port)) {
-            AP_HAL::panic("JSON master: socket reuseaddress failed on port: %d - %s\n", port, strerror(errno));
+            AP_HAL::panic("JSON master: socket reuseaddress failed on port: %d - %s", port, strerror(errno));
         }
 
         if (!list->sock_in.set_blocking(false)) {
-            AP_HAL::panic( "JSON master: socket set_blocking(false) failed on port: %d - %s\n", port, strerror(errno));
+            AP_HAL::panic( "JSON master: socket set_blocking(false) failed on port: %d - %s", port, strerror(errno));
         }
 
         printf("Slave %u: listening on %u\n", list->instance, port);
diff --git a/libraries/SITL/SIM_XPlane.cpp b/libraries/SITL/SIM_XPlane.cpp
index 3633bb4b1a..e9c147c633 100644
--- a/libraries/SITL/SIM_XPlane.cpp
+++ b/libraries/SITL/SIM_XPlane.cpp
@@ -116,7 +116,7 @@ XPlane::XPlane(const char *frame_str) :
 #endif
 
     if (!load_dref_map(XPLANE_JSON)) {
-        AP_HAL::panic("%s failed to load\n", XPLANE_JSON);
+        AP_HAL::panic("%s failed to load", XPLANE_JSON);
     }
 }