It is anticipated that future jet fuels will be required to handle a thermal stress of approximately 900 degrees F ( 480 degrees C). Such an environment presents many challenges in providing fuels with the necessary thermal oxidative and pyrolytic stability. We report single-tube flow reactor data which suggests that addition of 100 ppm of dicyclohexylphenyl phosphine ( DCP) to an air saturated JP-8, followed by stressing up to similar to 675 degrees C, provides significant improvement in both thermal oxidative and pyrolytic stability. In addition, we present our current mechanistic understanding of how DCP might stabilize jet fuels under these extreme conditions. Finally, this work required us to reformulate the electron- transfer- initiated oxygenation ( ETIO) mechanism proposed to explain the reaction of DCP with molecular oxygen.