What is the N2 transient value at 10 seconds?

What is the N2 transient value at 10 seconds?

• A. 108% (10 sec)
• B. 103% (10 sec)
• C. 860 °C (5 sec)
• D. 755 °C max

Answer: (A)

During transients, the permissible N2 value is given as a percentage of the reference N2, showing how far the high-pressure spool can overshoot during a dynamic change. For a 10-second transient, the allowable N2 is 108% of the reference N2. This is the appropriate reading because the question asks for the N2 transient value, which is a speed percentage, not a temperature. The other options present temperatures (860 °C or 755 °C), which relate to EGT or max IT, not the transient N2 limit. Therefore, 108% at 10 seconds is the correct choice.

During transients, the permissible N2 value is given as a percentage of the reference N2, showing how far the high-pressure spool can overshoot during a dynamic change. For a 10-second transient, the allowable N2 is 108% of the reference N2. This is the appropriate reading because the question asks for the N2 transient value, which is a speed percentage, not a temperature. The other options present temperatures (860 °C or 755 °C), which relate to EGT or max IT, not the transient N2 limit. Therefore, 108% at 10 seconds is the correct choice.