In a turbine engine with a starter-generator, which action occurs when the start switch is moved to START?

• A. The generator field relay is closed, connecting the voltage regulator to the starter-generator.
• B. The engine is automatically connected to external power.
• C. The starter relay closes and actuates the ignition exciter.
• D. The bus is disconnected from the generator.

Answer: (C)

Moving to START energizes the starter circuit and primes the ignition system. The starter relay closes, engaging the starter motor to spin the turbine, and the ignition exciter is actuated so ignition can occur as soon as fuel starts to burn. This combination is what gets the engine turning and ready to ignite. The other actions described don’t happen at the instant you select START: external power isn’t automatically applied, the generator field/voltage regulator connection isn’t established yet, and the bus isn’t being intentionally disconnected by this action.