ENGINE FUEL AND CONTROL - ENGINE CONTROL - HMU - FUNCTIONAL DESCRIPTION ALL General The electronic engine control (EEC) sends control signals to servo system in the hydromechanical unit (HMU). The electro-hydraulic servo valves (EHSVs) in the HMU change these signals to hydraulic fuel pressure for these components: Fuel metering valve (FMV) Transient bleed valve (TBV) High pressure turbine active clearance control (HPTACC) valve Low pressure turbine active clearance control (LPTACC) valve Variable bleed valves (VBV) Variable stator vanes (VSV). AAL ALL P, 3AR-3AY, 3BA-3BH, 3BJ-3BN, 3BP, 3BR-3BY, 3CA-3CH, 3CJ-3CN, 3CP, 3CR-3CY, 3DA-3DH, 3DJ-3ZZ PRE SB CFM56-7B 73-44 The EEC also sends a signal to the burner staging valve (BSV) solenoid in the HMU. This valve supplies servo fuel to open and close the BSV. The high pressure shutoff valve (HPSOV) and mechanical overspeed governor are also in the HMU. The start lever and the fire handle control the HPSOV independent of the EEC. When closed this valve stops fuel flow to the combustor. The mechanical overspeed governor makes sure the N2 rotor does not turn too fast.
HMMMMMMMM, sounds right to me.....
