FAA Powerplant Written Practice Test

During engine operation, what is the consequence of insufficient fuel flow?

1. Higher efficiency

2. Engine stalling or failure

3. Enhanced performance

4. Improved fuel burn

The correct answer is: Engine stalling or failure

Insufficient fuel flow during engine operation can lead to engine stalling or failure due to the inability of the engine to maintain the necessary fuel-air mixture for proper combustion. An engine requires a specific amount of fuel to mix with air in order to produce the energy needed to operate effectively. If the fuel flow is inadequate, this balance is disrupted, which can cause the engine to lose power, run roughly, or ultimately stall. Stalling occurs when the engine's power output is insufficient to maintain its operational demands, often leading to a significant reduction in performance. In the absence of a proper fuel supply, combustion may not occur effectively, resulting in what is known as a lean mixture, which can cause operational issues. Furthermore, in extreme cases, continued operation with insufficient fuel can lead to engine failure due to overheating or mechanical damage resulting from abnormal combustion conditions.