Which statement describes the engine self-sustain condition?

• A. When the engine accelerates without starter motor assistance
• B. When the engine requires continued starter operation
• C. When the engine rpm is at idle
• D. When the fuel pump is disengaged

Answer: (A)

Self-sustain means the engine can keep running on its own after the starter is removed, once it has reached a speed and fuel/air conditions that allow continuous combustion and rotation.

The statement describing self-sustain is when the engine accelerates without any assistance from the starter motor. That shows the engine has reached the point where ignition, combustion, and compressor flow can maintain rotation without external starting power. It’s not yet self-sustaining if the starter must remain engaged, and idle speed isn’t specifically about sustaining operation without the starter. Cutting fuel supply would also stop the engine, so disengaging the fuel pump isn’t related to self-sustain.