What occurs during a hot start in a turbine engine?

During a hot start in a turbine engine, the engine experiences a surge in exhaust gas temperature (EGT) exceeding established limits, typically because there's an inappropriate or excessive fuel flow into the combustion chamber without sufficient airflow to support combustion. This situation can occur during the starting sequence when the engine does not achieve the necessary RPM and airflow to ignite the fuel, resulting in a buildup of unburned fuel.

As the fuel continues to inject into the combustion chamber, the EGT can continue to rise, potentially leading to damaging conditions if corrective measures are not taken promptly. The occurrence of a hot start generally indicates that the engine is heating up too quickly and indicates a risk of component damage due to the high temperatures being reached during an attempted start. This phenomenon highlights the importance of monitoring engine parameters in order to respond effectively during the start process.

Other outcomes like failure to ignite despite fuel flow or unexpected shutdowns are related to different types of starting issues but do not specifically align with the characteristic rise in EGT associated with a hot start.