What characterizes a hot start during engine ignition?

A hot start during engine ignition is characterized by an excessive rise in interstage turbine temperature (ITT) as the engine attempts to start. Specifically, if the ITT rate of increase surpasses 1000 °C, it indicates that the combustion process is not starting properly and excessive heat is being generated. This can lead to potentially damaging thermal stresses on the engine components.

The other choices highlight conditions that do not align with a hot start scenario. For instance, an ITT remaining below 871 °C would suggest that the engine is starting normally or coolly. Meanwhile, no increase in ITT or a normal ITT observed signifies that the engine is functioning correctly without excessive temperatures, which contradicts the criteria for a hot start. Thus, monitoring the ITT's behavior is crucial in determining the health of the engine during ignition attempts, making the identification of an ITT rate of increase exceeding 1000 °C a critical factor for diagnosing a hot start.