Which item is located on the engine accessory box and serves as the fuel control unit?

Which item is located on the engine accessory box and serves as the fuel control unit?

• A. HMU (fuel control unit)
• B. PMA
• C. Generator
• D. Air starter

Answer: (A)

In a turbine engine, the device that regulates how much fuel gets to the combustor is the Hydromechanical Unit, or HMU. This fuel control unit sits on the engine’s accessory gearbox, which is where many other components like the hydraulic pump, starter, and generator are mounted. The HMU receives signals from the throttle and engine sensors, uses hydraulic pressure to meter fuel flow precisely, and delivers the correct amount of fuel to the engine to meet the commanded thrust while protecting against overspeed or surge. Other items on the accessory box, such as the PMA (a power source), the generator, and the air starter, perform electrical generation and starting functions rather than fuel regulation.

In a turbine engine, the device that regulates how much fuel gets to the combustor is the Hydromechanical Unit, or HMU. This fuel control unit sits on the engine’s accessory gearbox, which is where many other components like the hydraulic pump, starter, and generator are mounted. The HMU receives signals from the throttle and engine sensors, uses hydraulic pressure to meter fuel flow precisely, and delivers the correct amount of fuel to the engine to meet the commanded thrust while protecting against overspeed or surge. Other items on the accessory box, such as the PMA (a power source), the generator, and the air starter, perform electrical generation and starting functions rather than fuel regulation.