A commercial Jet-A aviation fuel, POSF-2827, was treated with an antifouling additive package, DuPont Jet Fuel Additive No. 5 (JFA-5), at a concentration of 12 mg/L. Fouling of heated stainless-steel (304) tubes from the neat and treated fuels was studied over the temperature range 155-390 degrees C using a single-pass heat exchanger and at 185 degrees C in flask tests. The rate of autoxidation in the treated fuel was slowed over the temperature range 1.55-225 degrees C, but total surface fouling evaluated after 100% conversion of dissolved oxygen was not reduced. Significant reduction (factor of 2-3) in surface fouling was observed at the higher temperatures, 255 and 300 degrees C. This improvement was traced to one component of the package, namely, a metal deactivator present at 2 mg/L. Additive packages such as JFA-5 which contain antioxidant, dispersant, and-in particular-metal-deactivator components may reduce Jet-A fuel fouling in certain temperature regimes.