What temperature condition requires the engine start to be aborted?

The requirement to abort an engine start under specific temperature conditions is critical for ensuring the safety and integrity of the engine system. A hot start occurs when the engine's turbine inlet temperature (ITT) exceeds 1,000 ºC during the starting procedure. This situation indicates that the engine is overheating, which can lead to severe damage, including turbine blade deformation or failure.

When the ITT exceeds this threshold, it is a clear sign that the engine is not properly igniting the fuel-air mixture or that there is another malfunction causing excessive heat. Aborting the start in this scenario is necessary to protect engine components and avoid catastrophic failure.

In the context of the other options, while a hung start (where N1 stops increasing) or a cold start (where ITT does not rise) may indicate problems, they do not necessarily require immediate abort unless they are accompanied by other alarming symptoms. The scenario of ITT exceeding the critical threshold is the most severe and requires action to prevent damage. Thus, the condition of a hot start with ITT exceeding 1,000 ºC unequivocally necessitates aborting the engine start.