1. ECU / HMU / POU slide presentation ECU LOCKOUT discussion CW2 Scott Paul Rogers

2. ECU….. WHAT’S IT DO? Trims the HMU NG governor through the tq motor within acceptable engine limits to maintain isochronous NP governing. This can be overridden ONLY by TGT limiting. Exchanges tq signals to provide automatic load sharing for multi-engine use. Provides signal to the POU for NP overspeed protection 106+- 1% Provides cockpit signals, NP, TGT, TQ

3. ECU FUNCTIONS, OR CHECK RIDE ANSWERS ? Np reference from cockpit Overspeed signal to POU (redundant power,TQ SIGNAL) TGT limiting, 837-849 Signals to cockpit, TQ, TGT, Np History recorder signal Isochronous NP governing(will maintain ref.) Torque load sharing

4. HMU DESCRIPTION Mounted on the aft center of the AGB Receives filtered fuel through cored passages in the AGB High pressure vane type pump. Max 832 PSI

5. HMU FUNCTIONS High P ressure Fuel pumping Fuel Flow M etering C ollective pitch compensation (LDS) A cceleration/deceleration flow limiting N g limiting (Governing & shutdown) V ariable geometry positioning E CU lockout via the PAS T orque motor servo to trim NG governor O pens Vapor vent for HMU priming

6. POU DESCRIPTION The Pressurizing and overspeed unit is mounted on the aft, left hand side of the AGB 3 outlets. Start fuel manifold, main fuel manifold, and overboard drain (+bypass during overspeed) 3 inlets. Fuel through AGB core, P3 air, overspeed signal

7. POU FUNCTIONS Sequences fuel to start fuel manifold (2) 17? Sequences fuel to main fuel manifold (12) 23? Purges start fuel manifold and nozzles during start, and main fuel manifold and nozzles during shutdown Provides NP overspeed protection when activated from the ECU overspeed circuit

8. We have discussed the functions of the ECU / HMU / POU Let’s now address ECU Lockout Definition of lockout? Caution?

9. The term LOCKOUT is defined as manual control of engine RPM while bypassing 700 ECU When an engine is controlled with ENG POWER CONT lever in LOCKOUT, engine response is much faster and TGT limiting system is inoperative. Care must be taken not to exceed TGT limits and keeping % RPM R and % RPM 1 and 2 in operating range.