What is the N2 range for an assisted air start?

What is the N2 range for an assisted air start?

• A. 0-20%
• B. 0-45%
• C. 30-50%
• D. 50-70%

Answer: (B)

During an assisted air start, external pneumatic air is used to spin the N2 spool from rest up to the point where ignition can occur and the engine becomes self-sustaining. That external assist is active from zero percent N2 up to about mid-range, around 45% N2, where ignition then takes over and the engine continues to run without the starter. So the N2 range for an assisted air start is 0-45%. Ranges above that would indicate operation beyond the assist phase or a transition into self-sustained operation, while the lower end covers starting from a complete standstill.

During an assisted air start, external pneumatic air is used to spin the N2 spool from rest up to the point where ignition can occur and the engine becomes self-sustaining. That external assist is active from zero percent N2 up to about mid-range, around 45% N2, where ignition then takes over and the engine continues to run without the starter. So the N2 range for an assisted air start is 0-45%. Ranges above that would indicate operation beyond the assist phase or a transition into self-sustained operation, while the lower end covers starting from a complete standstill.