Final answer:
The maximum EGT for engine start is around 477°C (891°F). The percentage of N2 at which this limit applies depends on the engine's design.
Step-by-step explanation:
The maximum Exhaust Gas Temperature (EGT) for engine start varies depending on the specific engine and its design. However, a common maximum EGT limit for engine start is around 477°C (891°F)^[1^].
The percentage of N2 (Nitrogen) at which this limit applies depends on the engine's design and manufacturer specifications. Without specific information about the engine in question, it is difficult to determine the exact percentage of N2 at which the EGT limit applies.