If a single engine exhibits abnormal fuel flow during start, what is the immediate action?

• A. Continue the start and monitor for improvement.
• B. Abort the start and follow engine start abort procedures; investigate fuel system for blockage or pump failure.
• C. Switch to the other engine.
• D. Disable the fuel system.

Answer: (B)

When an engine shows abnormal fuel flow during start, the immediate action is to abort the start and follow the engine start abort procedures. Abnormal flow signals a possible fuel system fault, such as a blockage or pump failure, and continuing the start could allow damaged fuel delivery or an unsafe mixture, risking engine damage or a stray fuel/ignition event. Aborting promptly secures the engine, stops fuel flow in a controlled way, and gives you a clear point to investigate the fault before attempting another start.

Investigating the fuel system for blockage or pump failure is the next, logical step after the stop. Look for obstructions in the fuel lines, filters, or injectors, and verify the fuel pumps and their electrical/controls are functioning as required. This approach targets the root cause without exposing the engine to further risk.

Switching to the other engine isn’t the correct immediate action because the issue is with the fuel delivery to the current engine and may affect overall system integrity or power availability. Simply moving to another engine doesn’t address a potential blockage or pump fault and could create new complications. Disabling the fuel system isn’t appropriate either as a first response; you follow the abort procedure to stop safely and then diagnose.