If this caution is displayed on the CAD it means that the ___________ oil is contaminated by ___________ particles.

• A. Main Transmission; Metallic
• B. Tail Rotor; Metallic
• C. Main Transmission; Nonmetallic
• D. Engine oil; Metallic

Answer: (A)

The main idea here is that metallic particles in the main transmission oil point to wear inside the main transmission itself. When the CAD shows a caution about the main transmission oil being contaminated by metallic particles, it means metal particles are shedding from metal components such as gears or bearings inside that transmission. This is a serious indication because it signals internal wear that could lead to gear failure or loss of drive if not addressed. The other scenarios don’t fit: contamination in the tail rotor or engine oil would involve different systems, and contamination by nonmetallic particles doesn’t reflect metal wear typical of these cautions.