A series of compounds were examined to determine which structural aspects were necessary to effectively block the catalytic activity of soluble copper that promotes thermal deposition from jet fuel during JFTOT testing. The results indicated that salicylidene compounds such as that currently used as a metal-deactivating additive are the most effective, with the copper coordinated with both the nitrogen and oxygen atoms. The significance of the thermal stability of the copper complex of the metal-deactivator additive was revealed through thermal-desorption mass spectrometry and XPS examination of copper-rich JFTOT tube deposits generated at high temperatures. Through JFTOT testing with heater tubes constructed from a variety of alloys, the impact of alloy composition on thermal deposition from jet fuel was demonstrated. These findings were used to construct a hypothesis that is consistent with the appearance of MDA induction periods in accelerated turbulent flow fuel tests.