Which statement best describes the cause of gas path erosion?

• A. Ingestion of large water droplets
• B. Ingestion of sand, dirt, dust, and other fine airborne contaminants
• C. Aerodynamic heating of the inlet
• D. Corrosion from humidity in the inlet

Answer: (C)

Gas path erosion is caused by abrasive wear from solid particles carried in the intake air that are ingested and accelerated through the engine, striking blades and vanes at high speed and gradually removing material. The particles—sand, dirt, dust, and other fine contaminants—act like an abrasive sandpaper on metal surfaces, creating pits and grooves that propagate erosion and degrade performance. This mechanical wear is distinct from thermal or chemical damage: aerodynamic heating affects temperature and stresses, while humidity-driven corrosion is a chemical process. Water droplets can cause other damage modes but not the abrasive wear that defines erosion. Reducing inlet particle concentration with proper filtration and separation helps prevent this erosion.