FAA Powerplant Written Practice Test

What indicates a "hung" start in a turbine engine?

1. The engine fails to ignite

2. The engine fails to reach idle rpm

3. The engine runs roughly

4. The engine experiences a surge

The correct answer is: The engine fails to reach idle rpm

A "hung" start in a turbine engine is characterized by the scenario where the engine fails to reach idle RPM after the start sequence is initiated. This condition occurs when the engine rotates at a speed that is slower than expected due to insufficient fuel flow, pressure issues, or mechanical problems. In a typical start, a turbine engine should accelerate through the start sequence and reach idle RPM steadily. If it stalls or fails to increase its RPM adequately but is still producing some evidence of ignition, this indicates that the start process was not successful, leading to the designation of a "hung" start. Recognizing this condition is crucial for pilots and maintenance personnel, as it may require intervention to prevent potential damage to the engine and ensure safe operation. Other situations, such as a complete failure to ignite or experiencing engine surges, might indicate different types of issues with the engine, but they do not specifically define a "hung" start condition.