What is the maximum ITT limit for engine start?

What is the maximum ITT limit for engine start?

• A. 450 C
• B. 400 C
• C. 500 C
• D. 475 C

Answer: (A)

Inter-Turbine Temperature (ITT) is the temperature limit used to protect the turbine during the start transient. During start, fuel is introduced and the engine begins to spool, but cooling and airflow are still developing, which can push turbine components toward thermal stress. To prevent damage, there is a maximum ITT that must not be exceeded during start. The typical maximum ITT for engine start in this context is 450 C. If ITT approaches that limit, fuel flow is reduced or the start is aborted to keep temperatures from climbing further. After the engine reaches a stable state and moves into normal operation, higher ITT limits apply. The other values (400 C, 500 C, 475 C) do not reflect the standard start limit used here; they would either be unnecessarily restrictive or unsafe for the start sequence.

Inter-Turbine Temperature (ITT) is the temperature limit used to protect the turbine during the start transient. During start, fuel is introduced and the engine begins to spool, but cooling and airflow are still developing, which can push turbine components toward thermal stress. To prevent damage, there is a maximum ITT that must not be exceeded during start. The typical maximum ITT for engine start in this context is 450 C. If ITT approaches that limit, fuel flow is reduced or the start is aborted to keep temperatures from climbing further. After the engine reaches a stable state and moves into normal operation, higher ITT limits apply. The other values (400 C, 500 C, 475 C) do not reflect the standard start limit used here; they would either be unnecessarily restrictive or unsafe for the start sequence.