What are the equation linking static air temperature with true airspeed & altitude? If I want to calculate static air temperature (OAT), but I'm only given an altitude and a true airspeed. Is there such an equation that relates these principles together. I've had a look at wikipedia and to calculate OAT, the total air temperature is required. Problem is, I don't have a Mach number to solve the equation. Is there another way to solve this problem
Provided that your calculations take place for a standard day, below 11 km altitude the Outside Air Temperature is simply a linear function of altitude. From the wikipedia article for Standard Atmosphere:



So OAT = 15 - 1.98 * Altitude, with OAT in °C and Altitude in 1,000 ft. Airspeed data is superfluous.