During the manual start, the master switch is turned ON ________.

During the manual start, the master switch is turned ON ________.

• A. Before starting
• B. When N2 RPM reaches maximum motoring (minimum 20%) and other starting indications are normal
• C. After engine is stable
• D. When N2 is at idle

Answer: (B)

The start sequence is to use the starter to spin the engine (motoring) until the N2 speed reaches a safe minimum, then energize the engine systems to light off. Turning the engine master ON when N2 has reached about 20% and other starting indications are normal ensures the starter is actually turning the compressor and that the conditions are right for a stable start. At this point, fuel and ignition can be commanded by the start system, allowing a smooth transition from motoring to a self-sustained run. If you switch the master on too early, fuel could be supplied while the rotor isn’t at a safe speed, risking a hung start or compressor surge. If you wait until after the engine is already running or at idle, you miss the proper sequencing and the start procedure isn’t followed correctly.

The start sequence is to use the starter to spin the engine (motoring) until the N2 speed reaches a safe minimum, then energize the engine systems to light off. Turning the engine master ON when N2 has reached about 20% and other starting indications are normal ensures the starter is actually turning the compressor and that the conditions are right for a stable start. At this point, fuel and ignition can be commanded by the start system, allowing a smooth transition from motoring to a self-sustained run. If you switch the master on too early, fuel could be supplied while the rotor isn’t at a safe speed, risking a hung start or compressor surge. If you wait until after the engine is already running or at idle, you miss the proper sequencing and the start procedure isn’t followed correctly.