According to the result of trial flights of Cw - 1002 and - 5 airoplans, theperformances of these two products are compared and analyzed- The new opinion of obtaining rnethod ofthe air temperature during flight is proposed. Using the general formula of time constant provided inthis paper,the delay correction may be done for the air recovery temperature measured,the coefficient ofrestitution at any condition may be evaluated by interpolation method and the air instantaneoustemperature may be evaluated at last. It is suggested that the coefficient of restitution of air temperaturetranducer is calibrated by Reynalds analogue criterion.