Hydro-mechanical control is a term used to describe control within which system?

• A. Fuel control unit
• B. Oil lubrication system
• C. Electrical system
• D. Hydraulic system

Answer: (A)

Hydro-mechanical control describes regulating fuel flow by using both hydraulic pressure and mechanical linkages. This combination is implemented in the fuel control unit, where hydraulic signals and mechanical inputs work together to meter the correct amount of fuel to the engine. That’s why the concept fits the fuel control unit: it’s about how fuel delivery is controlled, not about oil lubrication, the electrical system, or the hydraulic power system itself. The other options involve different parts of the engine where lubrication, electricity, or hydraulic power operate, but not the hydro-mechanical metering of fuel.