Nozzle guide vanes (NGVs) at the inlet of the turbine is the first component that comes in contact with the hot gases. Acceleration of hot gases coming from the combustion chamber are done by the convergent shape of vanes. Aim is to get the higher efficiency from turbine by less exhaust gas emission and low fuel consumption. But for higher efficiency engine has to operate at peak temperature. At high temperature nozzle guide vanes can get fails due to thermal stresses induced in it. Leakage or blocking of cooling passages are also the major cause of failure of nozzle guide vanes. The reasons for the thermal failure of NGVs varies the change in temperature. Failure of analysis of NGVs of aero gas turbine engine are discussed.