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 the way fuel flow is metered in an engine using both hydraulic pressure and mechanical linkages inside the fuel control unit. This hybrid approach combines hydraulic signals with mechanical control to adjust how much fuel is delivered to the engine based on throttle input and operating conditions. It’s a characteristic of the fuel control system, not of the oil lubrication, electrical, or a general hydraulic system. So the term applies specifically to the fuel control unit.