General Electric T-700 Engine Overview Presented by CW2 Keith Koca UH-60 IPC Class 99-06

Objective Develop Student Instructor Pilot’s understanding of the T-700 Engine and it’s related components. The Student Instructor will utilize fundamentals of instruction (FOI) from the IP handbook for the class. The Student Instructor will utilize the Guided Discussion method of teaching.

Topics of Discussion General Engine Components, and Engine Modules Engine Alternator Electrical Control Unit (ECU) Hydromechanical Unit (HMU) Pressurizing and Overspeed Unit (POU) Np Overspeed Protection Engine/Inlet Anti-ice System

T-700 General Engine Components, and Engine Modules Students will identify engine components Students will identify engine sections I.E. Power Turbine Section, Hot Section. Refer to Engine Overhead Projections.

Engine Alternator Location It supplies AC power to engine components and a signal to a Signal Data Converter (SDC) to represent a cockpit instrument indication. Provides 3 windings: NG signal, Power to the DEC, and Power to the ignition exciters.

Engine Alternator What will happen if the Ng signal is interrupted? What will happen with a complete alternator failure? What will happen if the ignition power from the alternator is lost?

Digital Engine Control (DEC) 7 Functions: Acronym S - C - O - R - E I - T

Electrical Control Unit (ECU) S - Signals to the History Recorder. C - Cockpit Indications: Np, TGT, TRQ O - Overspeed Protection: 106%NP R - Reference Signal, NP set by pilot using the incr/dec switch on either collective. Can be set 96 to 100 %. E - Engine Torque Matching - Q1, Q2 signal, lower torque engine matches higher torque engine up to 103 % Np.

Electrical Control Unit (ECU) I - Isochronous Np Governing: ECU will maintain a constant reference Np speed set by the pilot. Isochronous means: “Equal in duration”. T - TGT Limiting: 837 - 849 degrees C, the ECU will send a signal to the HMU Torque Motor to reduce to fuel flow to the engine.

Electrical Control Unit (ECU) Emergency Procedures -Decreasing RPM R -Increasing RPM R -% RPM Increasing/Decreasing Oscillation -%TRQ Split Between Engines 1 - 2

Hydromechanical Unit (HMU) 9 Functions Acronym N - P - M T - O C - A - V - E

Hydromechanical Unit (HMU) N - Ng Limiting: Limits Max Trq Avail during low temperatures (OAT). P - Pumps Fuel: High pressure for precise fuel spray pattern, approx. 832 PSI Operating, Ref. GE 700 Training Guide. M- Meters fuel flow to the POU in response to PAS pos., LDS pos., ECU, T2, P3, and NG.

Hydromechanical Unit (HMU) T - Torque motor to trim engine Ng output. O - Overtravel of the PAS to allow fuel system priming.

Hydromechanical Unit (HMU) C - Collective pitch compensation through LDS. A - Acceleration and deceleration fuel flow limiting. V - Variable geometry positioning. Positions IGV’s and variable stator vanes. E - ECU inoperative: PAS Override to manually control engine.

Hydromechanical Unit (HMU) Emergency Procedures: - Increasing % RPM R - Engine Compressor Stall

Pressurizing and Overspeed Unit (POU) Sequences start fuel to primer nozzles for engine starting. Purges fuel from primer nozzles after starting to keep fuel from coking inside nozzles. P3 air purges primer nozzles. Sequences main fuel to fuel injectors for starting acceleration and engine operation.

Pressurizing and Overspeed Unit (POU) Purges main fuel manifold after shutdown. -Residual combustion chamber pressures (P3) forces the fuel in the injectors and manifold back through the unit and out the overboard drain line.

Pressurizing and Overspeed Unit (POU) Np Overspeed Protection: -POU reduces fuel to the engine during engine overspeed, 106% Np, when the overspeed system is tripped by the ECU. - In the event of an alternator failure Np overspeed protection is still available, due to redundant electrical power provided to the ECU for Overspeed protection.

Pressurizing and Overspeed Unit (POU) Emergency Procedures - Increasing % RPM R

Engine Anti-ice System Two Engine Anti-ice Systems: - Bleed air (stage 5 Compressor air) routed to the swirl frame and front frame for front of engine anti-icing. Another branch of anti-icing air is utilized to heat the IGV’s. - Hot engine oil passing within the scroll vanes also prevents icing.

Engine Anti-ice System When the anti-ice valve is open, the ENG ANTI-ICE advisory light will be illuminated. In the event of electrical failure, the anti-ice valve will open allowing engine anti-ice protection.

Engine Inlet Anti-ice System Stage 5 compressor bleed air is directly routed to the Engine Inlet Anti-ice Modulating Valve. With the Engine Anti-ice switch in the on position and OAT below 4 deg. C, the modulating valve will open and provide anti-ice protection to the engine inlet. -Note: 4 - 13 deg. C the modulating valve may or may not open.

Engine Inlet Anti-ice System Inlet anti-icing will turn on if DC primary bus power loss occurs. Valve is electrically held closed. -Temperature must still be below 4 deg. C for valve to open. ENG INLET ANTI-ICE ON advisory light will illuminate when inlet fairing temperature reaches 93 deg. C.

Engine/Inlet Anti-ice System Emergency Procedures -Single/Dual Engine failure Warning - Engine HIT Check Caution - Engine FOD, 2 Cautions, chapter 2/8

Summary/Review General Engine Components, and Engine Modules Engine Alternator Electrical Control Unit (ECU) Hydromechanical Unit (HMU) Pressurizing and Overspeed Unit (POU) Np Overspeed Protection Engine/Inlet Anti-ice System

T-700 Engine QUESTIONS?