What is a compressor stall and its effect?

What is a compressor stall and its effect?

• A. Flow disruption in the compressor causing loss of surge margin; results in rough running, possible flameout.
• B. A sudden drop in fuel pressure causing engine flameout.
• C. A stall of the aircraft due to loss of lift.
• D. Electrical failure in the engine control unit.

Answer: (A)

A compressor stall is a disruption of the smooth airflow through the engine’s compressor stages. When the flow becomes unstable, the compressor loses its ability to maintain a stable pressure ratio, moving toward surge. This unstable flow causes the engine to run roughly and can lead to a flameout if the unstable conditions extend into the combustor, since the fuel-air mixture and pressure oscillate rather than staying steady. The phrase “loss of surge margin” means the engine is closer to surging, a more severe instability that can escalate if conditions don’t stabilize. The other descriptions don’t fit because they describe different problems: a sudden drop in fuel pressure is a fuel system/combustion issue, not an airflow stall in the compressor; a stall of the aircraft due to loss of lift is an aerodynamic flight issue; and electrical failure in the engine control unit is an electrical fault, not an airflow-related compressor stall.

A compressor stall is a disruption of the smooth airflow through the engine’s compressor stages. When the flow becomes unstable, the compressor loses its ability to maintain a stable pressure ratio, moving toward surge. This unstable flow causes the engine to run roughly and can lead to a flameout if the unstable conditions extend into the combustor, since the fuel-air mixture and pressure oscillate rather than staying steady. The phrase “loss of surge margin” means the engine is closer to surging, a more severe instability that can escalate if conditions don’t stabilize.

The other descriptions don’t fit because they describe different problems: a sudden drop in fuel pressure is a fuel system/combustion issue, not an airflow stall in the compressor; a stall of the aircraft due to loss of lift is an aerodynamic flight issue; and electrical failure in the engine control unit is an electrical fault, not an airflow-related compressor stall.