The Fuel Control Unit (FCU) regulates the precise volume of fuel delivered to the combustion chamber of a jet or turboshaft engine. It continuously calculates the required fuel flow based on throttle position, compressor speed, altitude, and air temperature. While newer aircraft integrate this function into digital engine controls, many legacy and helicopter engines still rely on highly complex hydro-mechanical FCUs to prevent flameouts and compressor stalls.
Heard on the job
We've a sluggish throttle response on number two, so we're pulling the FCU for a bench test.
Insider tip
Hydro-mechanical FCUs are packed with intricate cams, springs, and flyweights, earning them a reputation among mechanics as a watchmaker's nightmare.