Which parameter is detected by the turbine engine fuel control unit?

• A. Power lever position
• B. Ambient humidity
• C. Oil viscosity
• D. Coolant temperature

Answer: (B)

The fuel control unit meters fuel to match the pilot’s thrust request, so the signal it relies on most directly is the position of the power lever (throttle). This input tells the FCU how much fuel flow to schedule, which the unit then fine-tunes using engine speed and temperature/pressure readings to achieve the desired thrust while protecting the engine.

Ambient humidity isn’t a standard input for metering fuel in a turbine engine—the FCU relies on air data (like pressure and temperature) to infer air density rather than sensing humidity directly. Oil viscosity and coolant temperature aren’t primary inputs for the fuel metering process in these engines, as lubrication and cooling are handled by separate systems.