What indicates a hot start?

A hot start occurs when there is an excessively high temperature during the engine start phase, particularly indicated by the Interstage Turbine Temperature (ITT). The correct choice, which highlights a high or rapidly rising ITT, clearly identifies the engine’s temperature spike, which can potentially lead to damage if it exceeds safe limits. During a hot start, the engine is failing to ignite properly and is building excessive temperature in the combustion chamber while the fuel continues to flow.

The mention of lower N1 and lower Np supports the indication of a hot start because, in such situations, the engine does not achieve the expected performance levels due to the abnormal temperature rise. Typically, in a hot start scenario, you would expect the ITT to rise sharply compared to normal indications, further leading to concerns about engine safety and operational integrity.

Other options do not adequately represent the conditions associated with a hot start. For example, slow rising ITT would suggest a more controlled or normal start-up. No ITT indication alongside lower N1 might indicate a failure to start or an unrelated issue, but not necessarily a hot start. Low oil pressure and rapid decay of ITT would imply a different set of problems, such as an engine stall rather than a hot start.