Regardless of whether the automatic or manual start procedure is used, when will the ignition automatically shut off?

Regardless of whether the automatic or manual start procedure is used, when will the ignition automatically shut off?

• A. When the N2 RPM reaches 60%
• B. When the N2 RPM reaches 55%
• C. When the N1 RPM reaches 50%
• D. After 15 seconds

Answer: (B)

Ignition during start is used to help the flame light off, then it is automatically cut off when the gas generator speed reaches a specific threshold. For the A320, that threshold is about 55% N2. Once N2 hits roughly 55%, the ignition system is switched off automatically so the engine can continue to accelerate with normal fuel control and without spark. The decision is based on the N2 speed (gas generator speed), not on N1 or on a fixed time delay, which is why the 55% N2 point is the correct cutoff.

Ignition during start is used to help the flame light off, then it is automatically cut off when the gas generator speed reaches a specific threshold. For the A320, that threshold is about 55% N2. Once N2 hits roughly 55%, the ignition system is switched off automatically so the engine can continue to accelerate with normal fuel control and without spark. The decision is based on the N2 speed (gas generator speed), not on N1 or on a fixed time delay, which is why the 55% N2 point is the correct cutoff.