diff --git a/src/FDM/JSBSim/models/propulsion/FGEngine.cpp b/src/FDM/JSBSim/models/propulsion/FGEngine.cpp
index 4f08a4c09..6ef7e2319 100644
--- a/src/FDM/JSBSim/models/propulsion/FGEngine.cpp
+++ b/src/FDM/JSBSim/models/propulsion/FGEngine.cpp
@@ -83,7 +83,7 @@ FGEngine::FGEngine(FGFDMExec* exec, Element* engine_element, int engine_number,
 
   Name = engine_element->GetAttributeValue("name");
 
-  Load(engine_element, PropertyManager, std::to_string(EngineNumber)); // Call ModelFunctions loader
+  Load(engine_element, PropertyManager, to_string(EngineNumber)); // Call ModelFunctions loader
 
 // Find and set engine location
 
@@ -132,7 +132,7 @@ FGEngine::FGEngine(FGFDMExec* exec, Element* engine_element, int engine_number,
   property_name = base_property_name + "/fuel-used-lbs";
   PropertyManager->Tie( property_name.c_str(), this, &FGEngine::GetFuelUsedLbs);
 
-  PostLoad(engine_element, PropertyManager, std::to_string(EngineNumber));
+  PostLoad(engine_element, PropertyManager, to_string(EngineNumber));
 
   Debug(0);
 }