diff --git a/src/FDM/JSBSim/FGTank.cpp b/src/FDM/JSBSim/FGTank.cpp
index 83d85744f..664b6b4ce 100644
--- a/src/FDM/JSBSim/FGTank.cpp
+++ b/src/FDM/JSBSim/FGTank.cpp
@@ -54,7 +54,6 @@ CLASS IMPLEMENTATION
 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%*/
 
 FGTank::FGTank(FGConfigFile* AC_cfg)
-    : Contents(-1.0)
 {
   string token;
   
@@ -71,9 +70,8 @@ FGTank::FGTank(FGConfigFile* AC_cfg)
     else if (token == "ZLOC") *AC_cfg >> Z;
     else if (token == "RADIUS") *AC_cfg >> Radius;
     else if (token == "CAPACITY") *AC_cfg >> Capacity;
-    else if (token == "CONTENTS") {
-        if (Contents == -1.0) *AC_cfg >> Contents;
-    } else cerr << "Unknown identifier: " << token << " in tank definition." << endl;
+    else if (token == "CONTENTS") *AC_cfg >> Contents;
+    else cerr << "Unknown identifier: " << token << " in tank definition." << endl;
   }
   
   Selected = true;