On the flight line, most of the damage to the compressor section comes from which source?

• A. Bird strikes
• B. Operational vibration
• C. Foreign Object Damage
• D. Thermal distortion

Answer: (C)

Damage to the compressor on the flight line is most often caused by foreign object damage. The compressor blades and vanes operate at very high speeds with very tight clearances, so any object that enters the inlet—such as loose hardware, tools, rags, gravel, or other debris—can strike a blade, nick tips, or upset the aerodynamics. That kind of impact can quickly lead to pitting, cracks, loss of efficiency, or an unbalance that propagates damage. Bird strikes fall under this same category because they are debris in the inlet, but the broad idea—foreign object damage—covers all such ingestion events. Operational vibration is a normal condition that can contribute to wear over time but doesn’t account for the majority of compressor damage seen on the flight line. Thermal distortion results from overheating and is not the typical source of compressor damage in this setting.

Good ramp practices—keeping the area clean, using covers and inlet screens, and ensuring tools and materials aren’t left around—help prevent this kind of damage.