c----------STANDARD ATMOSPHERE density------------------------      
      function rho(h)                                                   
        if(h.lt.36000.) then
          theta=1.0-6.875e-6*h
          rho=0.0023769*theta**4.2561
        else
          rho=0.0023769*0.29709*exp((36000.-h)/20786.)
        endif
      return
      end
                                                                
c----------STANDARD ATMOSPHERE sound speed-------------------      
      function va(h)
        if(h.lt.36000.) then
          va=sqrt(1248273.0-8.56025*h)                                  
        else
          va=sqrt(1248273.-8.56025*36000.)   
        endif
      return
      end