namespace JSBSim {
-static const char *IdSrc = "$Id$";
+static const char *IdSrc = "$Id: FGExternalForce.cpp,v 1.11 2011/10/31 14:54:41 bcoconni Exp $";
static const char *IdHdr = ID_EXTERNALFORCE;
//%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
//%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
-FGColumnVector3& FGExternalForce::GetBodyForces(void)
+const FGColumnVector3& FGExternalForce::GetBodyForces(void)
{
if (Magnitude_Function) {
double mag = Magnitude_Function->GetValue();