ATA 76 Engine Controls (Bombardier DHC 8-400) January 2023 PDF

BOMBARDIER DHC 8-400 (PWC PW150) ATA 76 - ENGINE CONTROLS TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY B1/B2 MAINTENANCE TRAINING MANUAL Issue 6 - January 2023 Page 1 of 32 BOMBARDIER DHC 8-400 (PWC PW150) ENGINE CONTROL SYSTEM GENERAL DESCRIPTION The engine controls provide power manageme...

BOMBARDIER DHC 8-400 (PWC PW150) ATA 76 - ENGINE CONTROLS TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY B1/B2 MAINTENANCE TRAINING MANUAL Issue 6 - January 2023 Page 1 of 32 BOMBARDIER DHC 8-400 (PWC PW150) ENGINE CONTROL SYSTEM GENERAL DESCRIPTION The engine controls provide power management and propeller control. The emergency shutdown controls engine shutdown in an emergency situation. The engines are controlled by the power and condition levers. The power levers are identified as 1 and 2. The condition levers are also identified as 1 and 2. Emergency shutdown stops the flow of fuel to the engine. At the same time, the flow of hydraulic fluid to the engine-installed hydraulic pump is stopped. POWER LEVERS The power levers send control signals to the Full Authority Digital Electronic Controls (FADEC) to control the turbomachinery sections of the engines, in the forward and reverse ranges. The power levers also send control signals to the Propeller Electronic Controls (PEC) to control propeller blade angles in the beta range. CONDITION LEVERS Each condition lever sends signals to a PEC. Each PEC controls: • • Propeller feather and unfeather Propeller speeds Each condition lever also sends signals to a FADEC to switch fuel on and off. TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 76 - ENGINE CONTROLS Issue 6 - January 2023 Page 2 of 32 BOMBARDIER DHC 8-400 (PWC PW150) ENGINE CONTROLS - POWER AND CONDITION LEVERS DETAIL TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 76 - ENGINE CONTROLS Issue 6 - January 2023 Page 3 of 32 BOMBARDIER DHC 8-400 (PWC PW150) ENGINE CONTROL SYSTEM SYSTEM OPERATION COMPONENT LOCATION AND DESCRIPTION PULL FUEL/HYD OFF HANDLE The PULL FUEL/HYD OFF handle is used to initiate an emergency shutdown of the engine. When the handle is pulled, the fuel emergency shut off valve is energized to the closed position. This shuts down the engine by shutting off the fuel supply. The FMU is also de-energized. Pulling these handles also energizes the emergency hydraulic shutoff valve to the closed position. This shuts off the hydraulic fluid supply to the EDP (Engine Driven Pump). TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 76 - ENGINE CONTROLS Issue 6 - January 2023 Page 4 of 32 BOMBARDIER DHC 8-400 (PWC PW150) ENGINE CONTROLS - POWER CONTROL GENERAL, FIRE PROTECTION PANEL TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 76 - ENGINE CONTROLS Issue 6 - January 2023 Page 5 of 32 BOMBARDIER DHC 8-400 (PWC PW150) ENGINE CONTROL SYSTEM SYSTEM OPERATION POWER CONTROLS The FADEC and the PEC get electrical signals from the Rotary Variable Differential Transducers (RVDT) and the micro switches of the power lever and condition lever. GENERAL DESCRIPTION These electrical signals are computed by the FADEC and PEC. The powerplant control system provides power management and propeller control. The propulsion control system is not a complete system by itself. It gives these inputs and outputs to several systems. The function of this system is to give: • • • • Connection between the Engine Control Panel and Full Authority Digital Electronic Controls (FADEC) through the ECIU Bleed valve selection signals from the Environmental Control System (ECS) panel to the FADEC through the ECIU Power lever position to the FADEC Condition lever position to the PEC and the FADEC • • • Beta lockout warning Propeller Ground Beta Enable Roll spoiler Lift Dump Cabin Pressure Control System Autofeather and Uptrim PLA high Oil Cooler Ejector Valve Power Lever Angle (PLA) Condition Lever Angle (CLA) Operating mode A flight idle gate for the power levers prevents inadvertent selection of engine ground beta and reverse operation. Lift stops for the condition lever prevent inadvertent selection of propeller feather and fuel shutoff. A Beta Lockout warning tone is generated by the aural warning system when the: • • • The system also gives these power lever position discretes: • • • • • • The FADEC and PEC electronically control the engine and propeller as set by the selected: Radio altimeter output is more than 20 ft (6.1 m) PLA is at flight idle or lower Power lever trigger is lifted The system also gives these condition lever discretes: • • • Engine Shutdown Switch Hydraulic Pump Caution Light Alternate Feather Lockout The Engine Cockpit Interface Unit (ECIU) converts discrete analogue inputs into digital outputs for insertion into the data stream on an ARINC 429 bus. TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 76 - ENGINE CONTROLS Issue 6 - January 2023 Page 6 of 32 BOMBARDIER DHC 8-400 (PWC PW150) ENGINE CONTROLS - POWER AND CONDITION LEVERS LOCATION TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 76 - ENGINE CONTROLS Issue 6 - January 2023 Page 7 of 32 BOMBARDIER DHC 8-400 (PWC PW150) ENGINE CONTROL SYSTEM It is not possible to raise the release lever until the power lever is at the flight idle gate. POWER CONTROLS A warning tone is generated if the trigger is lifted during flight. SYSTEM OPERATION Each lever has an overtravel margin beyond the RATING detent 95° to 100° PLA, to let the pilot select 25% extra power for emergency operation only. COMPONENT LOCATION AND DESCRIPTION DISC 20° PLA POWER LEVER QUADRANT With the power lever in the DISC detent the engine will supply minimum power. The power and condition lever quadrant has the power levers, condition levers, flap lever, control lock lever, park/emergency brake lever and elevator trim indication. Power lever movement is limited by fixed stops at both ends of the quadrant. With the power lever at or below 5° the engine will supply a maximum of 1500 Shaft horsepower (1119kW). A friction knob for both power levers is located in the centre console below the power levers. Turning the knob in the FRICTION INCREASE direction progressively increases friction and prevents movement. The friction load can be reduced by turning the knob in the opposite direction. Each lever has these settings: • • • • MAX REVERSE 0° TO 5° PLA RATING rated power detent FLIGHT IDLE detent and gate DISC detent MAX REVERSE detent and stop A CONTROL LOCK handle is located forward of the power levers. When the handle is in the ON position the power levers cannot be advanced to the take off position. RATING (80° ± 2 PLA) With the power lever in the RATING or rated power detent, the engine will deliver the horsepower demanded by the rating selections. The rating is selected by the Condition Lever Angle (CLA) or by the rating select switches on the engine control panel. FLIGHT IDLE (35° PLA) The flight idle gate lets the power lever in the forward direction toward the rated power detent. As the lever is moved rearward towards reverse it meets a gate at the flight idle setting. To move the lever past the fight idle detent, the release lever must be pulled. TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 76 - ENGINE CONTROLS Issue 6 - January 2023 Page 8 of 32 BOMBARDIER DHC 8-400 (PWC PW150) ENGINE CONTROLS - POWER AND CONDITION LEVERS DETAIL TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 76 - ENGINE CONTROLS Issue 6 - January 2023 Page 9 of 32 BOMBARDIER DHC 8-400 (PWC PW150) ENGINE CONTROL SYSTEM POWER CONTROLS SYSTEM OPERATION COMPONENT LOCATION AND DESCRIPTION POWER LEVER QUADRANT CONTINUED Each power lever drives two identical RVDT on a common shaft, one for each FADEC channel. The FADEC provides the excitation for the RVDT. Power lever position is represented by a proportional AC voltage at the FADEC. Four micro-switches are operated by the power lever, one at each of these positions: • • • • PLA at 33° Flight idle -2° position - low PLA. Ground Beta Enable Switch for propeller control in Discing and Reverse PLA at 47° Flight idle +12° position - low PLA. Spoiler Lift Dump Switch armed PLA at 60° or above high PLA input for Autofeather Arming system PLA at 60° or above high PLA for pre-pressurization function in Cabin Pressure Control System (2 PLA only) TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 76 - ENGINE CONTROLS Issue 6 - January 2023 Page 10 of 32 BOMBARDIER DHC 8-400 (PWC PW150) ENGINE CONTROLS - POWER LEVER RVDT AND MICRO-SWITCHES SCHEMATIC TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 76 - ENGINE CONTROLS Issue 6 - January 2023 Page 11 of 32 BOMBARDIER DHC 8-400 (PWC PW150) ENGINE CONTROL SYSTEM MIN 850 POWER CONTROLS With the CLA in this position and the PLA in the RATING detent, Maximum Cruise Power (MCR) at 850 Np is demanded. SYSTEM OPERATION START FEATHER COMPONENT LOCATION AND DESCRIPTION With the CLA in this position, the propeller is in the feathered condition. CONDITION LEVER QUADRANT FUEL OFF The condition levers are installed in the pilots’ control pedestal, to the right of the power levers. Each condition lever has five distinct settings in the console slot. The positions are marked on the quadrant to indicate: With the CLA in this position, fuel to the engine is cut off. As the lever is moved rearward toward the FUEL OFF position it meets a gate at the MIN position. The condition lever knob must be lifted to remove the gate to let the lever move past it. There is another gate at the START FEATHER position. The condition lever knob must be lifted to let the lever reach the FUEL OFF position. The two gates permit forward movement of the lever without lifting the lever knob. Lever movement at FUEL OFF is limited by a fixed stop at the rear of the quadrant. • • • Propeller control range Engine start and propeller setting Fuel shutoff position The condition lever detents are: • • • • • A friction brake knob for both condition levers, is located in the centre console, below the levers. Rotating the knob in the FRICTION INCREASE direction progressively increases friction. The friction is decreased by turning the knob in the opposite direction. MAX (1020) 900 rpm MIN (850) START FEATHER FUEL OFF Each condition lever drives two identical RVDT on a common shaft. Both RVDT send Condition Lever Angle (CLA) signals to the PEC. Four switches are operated by each condition lever at these positions: MAX 1020 • With the CLA in this position and the PLA in the RATING detent, Normal Take Off Power (NTOP) at 1020 Np is demanded. • 900 RPM • With the CLA in this position and the PLA in the RATING detent, Maximum Climb Power (MCL) at 900 Np is demanded. TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY • CLA at 15° or below - Engine Start/Shutdown Switch send fuel off signals to the FADEC Channel A CLA at 15° or below - Engine Start/Shutdown Switch send fuel off signals to the FADEC Channel B CLA at 15° or below - Engine Hydraulic Pump Caution Switch, ensures light on when propeller feathered CLA at 40° or above - high CLA inhibits alternate feather function through Alternate Feather Lockout Switch ATA 76 - ENGINE CONTROLS Issue 6 - January 2023 Page 12 of 32 BOMBARDIER DHC 8-400 (PWC PW150) ENGINE CONTROLS - CONDITION LEVER RVDT AND MICRO-SWITCHES SCHEMATIC TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 76 - ENGINE CONTROLS Issue 6 - January 2023 Page 13 of 32 BOMBARDIER DHC 8-400 (PWC PW150) ENGINE CONTROL SYSTEM POWER CONTROLS SYSTEM OPERATION COMPONENT LOCATION AND DESCRIPTION ENGINE CONTROL PANEL The engine control panel provides alternate power rating selections. The engine control panel is located on the centre console, forward of the power and condition levers. The panel has: • • • • • • Maximum Take Off Power (MTOP ) switch Reduced propeller RPM (RDC Np) switch Maximum Climb Power (MCL) switch Maximum Cruise Power (MCR) switch Reduced Power Take Off (RDC TOP) DEC and RESET switches EVENT MARKER switch Push-button and switch-light selections are transmitted as momentary discretes to the Engine Cockpit Interface Unit (ECIU). The ECIU converts the discretes to ARINC 429 labels and transmits them to the FADEC. The selected rating stays latched until another selection is made on the CLA, pushbutton or switch-light. TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 76 - ENGINE CONTROLS Issue 6 - January 2023 Page 14 of 32 BOMBARDIER DHC 8-400 (PWC PW150) ENGINE CONTROLS - ENGINE CONTROL PANEL TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 76 - ENGINE CONTROLS Issue 6 - January 2023 Page 15 of 32 BOMBARDIER DHC 8-400 (PWC PW150) ENGINE CONTROL SYSTEM MCL SWITCH POWER CONTROLS The MCL switch changes the engine rating to MCL at 850 rpm if: • • SYSTEM OPERATION MCR is selected to the CLA at MIN 850 rpm position PLA is in the RATING detent COMPONENT LOCATION AND DESCRIPTION MCR SWITCH ENGINE CONTROL PANEL CONTINUED The MCR switch changes the engine rating to MCR at 900 rpm if the MCL is CLA at 900 rpm. MTOP SWITCH (OPTIONAL) REDUCED TAKE OFF PUSH-BUTTON SWITCH The MTOP switch selects maximum take off power if: • • The DEC button reduces NTOP by 2% - maximum of 10%. Pressing the RESET button resets NTOP. CLA is at 1020 rpm PLA is at the RATING detent EVENT MARKER SWITCH RDC NP SWITCH (OPTIONAL) The RDC Np switch selects reduced Np for noise reduction during landing using logic in the FADEC. For reduced Np during landing, these conditions apply: • • • Instructs the EMU to record a 3 minutes snapshot and a trace 2 minutes before, 1 minute after the selection) CLA at 850 rpm PLA at less than 60° Aircraft in the air Operating the Reduced Np switch-light will latch Np at 850 rpm and the Engine Display (ED) will show REDUCED NP. Subsequent movement of CLA to MAX selects NTOP for landing, but Np remains at 850 rpm unless: • • • The switch-light is pushed again MTOP rating is achieved PLA increases above 65° TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 76 - ENGINE CONTROLS Issue 6 - January 2023 Page 16 of 32 BOMBARDIER DHC 8-400 (PWC PW150) ENGINE CONTROLS - ENGINE CONTROL PANEL TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 76 - ENGINE CONTROLS Issue 6 - January 2023 Page 17 of 32 BOMBARDIER DHC 8-400 (PWC PW150) ENGINE CONTROL SYSTEM POWER CONTROLS SYSTEM OPERATION COMPONENT LOCATION AND DESCRIPTION PROPELLER CONTROL PANEL The propeller control panel provides autofeather and alternate feather selection. The propeller control panel is located on the centre console forward of the power and condition levers. The panel has the two guarded alternate feather push-buttons and one autofeather push-button. #1 AND #2 ALT FTHR SWITCHES Initiates propeller feather of the selected engine. AUTOFEATHER SWITCH Select the automatic propeller feathering system. TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 76 - ENGINE CONTROLS Issue 6 - January 2023 Page 18 of 32 BOMBARDIER DHC 8-400 (PWC PW150) ENGINE CONTROLS - PROPELLER CONTROL PANEL TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 76 - ENGINE CONTROLS Issue 6 - January 2023 Page 19 of 32 BOMBARDIER DHC 8-400 (PWC PW150) ENGINE CONTROL SYSTEM INTERFACES ENGINE COCKPIT INTERFACE UNIT INTRODUCTION The engine cockpit interface unit is a signal conditioning interface between the FADEC and aircraft systems. TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 76 - ENGINE CONTROLS Issue 6 - January 2023 Page 20 of 32 BOMBARDIER DHC 8-400 (PWC PW150) ENGINE CONTROL SYSTEM INTERFACES ENGINE COCKPIT INTERFACE UNIT CONTINUED DESCRIPTION The Engine Cockpit Interface Unit (ECIU) is installed vertically with anti-vibration mounts on the pilot circuit breaker console lower shelf. The ECIU provides: • • • • Connection between the Engine Control Panel and both FADEC Connection between the FADEC and the Caution Warning Panel for the engine oil pressure, engine fuel pressure and fuel filter bypass lights Output drivers to the FADEC for the oil cooler flap door actuator and the engine oil cooler ejector Isolated data exchange between engine 1 FADEC and engine 2 FADEC for sharing T 1.8 temperature value to equalize rated power Connections to the both FADEC are through ARINC 429 data busses. All other connections are discrete signals. The ECIU sends and receives ARINC 429 data from both FADEC. All flight compartment discretes connected to the ECIU are converted into ARINC data and inserted into the data stream when the correct gap in the stream is detected. FADEC channel A of engine #1 communicates with FADEC channel B of engine #2, through ECIU channel A. FADEC channel B of engine #1 communicates with FADEC channel A of engine #2, through ECIU channel B. TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 76 - ENGINE CONTROLS Issue 6 - January 2023 Page 21 of 32 BOMBARDIER DHC 8-400 (PWC PW150) • ENGINE CONTROL SYSTEM The signals from the Environmental Control Panel are: INTERFACES • • • • • ENGINE COCKPIT INTERFACE UNIT CONTINUED INPUT/OUTPUT SIGNALS The warning lights outputs from the ECIU are: • • ECS BLEED 1 ECS BLEED 2 ECS MIN ECS NORM ECS MAX Ignition Panel inputs are: #1 ENG OIL PRESS #2 ENG OIL PRESS • • • • The caution lights outputs from the ECIU are: • • • • RDC TOP RESET #1 ENG FUEL PRESS #2 ENG FUEL PRESS #1 FUEL FLTR BYPASS #2 FUEL FLTR BYPASS IGN OFF engine #1 IGN NORM engine #1 IGN OFF engine #2 IGN NORM engine #2 Maintenance Panel inputs are: • • MAINT TEST RIGGING TRIM The discrete outputs from the ECIU are: • • • • • • #1 engine Flap Door Actuator A #1 engine Flap Door Actuator B #2 engine Flap Door Actuator A #2 engine Flap Door Actuator B #1 engine Oil Cooler Ejector #2 engine Oil Cooler Ejector Flight compartment discrete signals are processed by both ECIU channels to improve the availability of the signals. The signals from the Engine Control Panel are: • • • • • MTOP MCL MCR RDC NP RDC TOP DEC TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 76 - ENGINE CONTROLS Issue 6 - January 2023 Page 22 of 32 BOMBARDIER DHC 8-400 (PWC PW150) ENGINE CONTROLS - ECIU INTERFACES TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 76 - ENGINE CONTROLS Issue 6 - January 2023 Page 23 of 32 BOMBARDIER DHC 8-400 (PWC PW150) ENGINE CONTROL SYSTEM EMERGENCY SHUTDOWN GENERAL DESCRIPTION The emergency shutdown system provides a quick and safe method to shutdown engine fuel and hydraulic fluid flow in an emergency. NOTE: The description that follows gives the operation of the components for the emergency shutdown of the No.1 engine. The No.2 engine emergency shutdown components and their operation are the same. TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 76 - ENGINE CONTROLS Issue 6 - January 2023 Page 24 of 32 BOMBARDIER DHC 8-400 (PWC PW150) ENGINE CONTROL SYSTEM EMERGENCY SHUTDOWN GENERAL DESCRIPTION CONTINUED Emergency shutdown stops the flow of fuel to the engine. At the same time, the flow of hydraulic fluid to the engine-installed hydraulic pump is stopped. The components that follow are supplied for each engine: • • • • • • • A PULL FUEL OFF handle for each engine A fuel emergency shutoff valve for each engine A hydraulic emergency shutoff valve for each engine Relays Circuit protection Position indication Fuel shutoff valve (FMU) Operation of the PULL FUEL/HYD OFF handle closes the fuel emergency shutoff valve and the hydraulic shutoff valve for that engine. It also closes a dedicated fuel shutoff solenoid valve at the Fuel Metering Unit. TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 76 - ENGINE CONTROLS Issue 6 - January 2023 Page 25 of 32 BOMBARDIER DHC 8-400 (PWC PW150) ENGINE CONTROL SYSTEM EMERGENCY SHUTDOWN COMPONENT LOCATION AND DESCRIPTION PULL FUEL/HYD OFF HANDLE The PULL FUEL/HYD OFF handle forms part of the engine fire indication system and closes the fuel and hydraulic emergency shutoff valves. The PULL FUEL/HYD OFF handles are on the fire protection panel in the flight compartment. There are red lights in the handles. They come on if fire is detected. The handles are operated manually. Pulling the handle completes the circuits that close the emergency fuel and hydraulic shutoff valves. When the PULL FUEL/HYD OFF handle is pulled, limit switches in the handle are closed. This energizes the valve close circuits. The valves go to the CLOSED position. With the valves CLOSED, limit switches in each valve are operated. One limit switch removes electrical power to the close side of the valve motor. The other limit switch arms the valve OPEN circuits. With the PULL FUEL/HYD OFF handle pulled, fire extinguishing circuits are armed. With the PULL FUEL/HYD OFF handle in the normal position: • • • Fire extinguishing circuits are disarmed The fuel valve closed lights go out The valves move to the open position Limit switches in each valve are operated at the valve OPEN position as follows: • • One limit switch to shutdown the valve motor The other limit switch to arm the valve close circuits TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 76 - ENGINE CONTROLS Issue 6 - January 2023 Page 26 of 32 BOMBARDIER DHC 8-400 (PWC PW150) ENGINE CONTROL SYSTEM EMERGENCY SHUTDOWN COMPONENT LOCATION AND DESCRIPTION EMERGENCY FUEL SHUTOFF VALVE The emergency fuel shutoff valve shuts off the fuel supply to the engine in the event of an emergency. The emergency shutoff valves are located on the main wing rear spar. There is a valve on each wing, one for each engine. With the 28V DC essential buses and the batteries energized, relays 2822-K1 and 2822-K2 energize. With the PULL FUEL/HYD OFF handles in the normal (pushed-in) position, the valves are open. 28V DC power from the battery bus is supplied through the normally closed contacts in the handles to the valve open circuits in the related fuel and hydraulic shutoff valves. The electrically energized valves are each supplied with a mechanical position indicator. Limit switches in the valves control valve motor start/stop operation. The valves are assembled with thermal relief protection. The valves are connected electrically to limit switches in the related PULL FUEL/HYD OFF handle. This completes the valve open and close circuits. The circuit for each valve is energized from the 28V DC battery bus. Through a 7.5A circuit breaker. The close circuit of the emergency fuel shutoff valve gets a 28V DC supply from the close circuit of the related hydraulic emergency shutoff valve through a blocking diode when the hydraulic valve close circuit energizes. TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 76 - ENGINE CONTROLS Issue 6 - January 2023 Page 27 of 32 BOMBARDIER DHC 8-400 (PWC PW150) ENGINE CONTROL SYSTEM EMERGENCY SHUTDOWN COMPONENT LOCATION AND DESCRIPTION EMERGENCY HYDRAULIC SHUTOFF VALVE The emergency hydraulic shutoff valve closes off the hydraulic fluid supply to the engine in the event of an emergency. The emergency hydraulic shutoff valves are located in each nacelle one for the each engine. With the 28V DC essential buses and the batteries energized, relays 2822K1 and 2822-K2 energize. With the PULL FUEL/HYD OFF handles in the normal (pushed-in) position, the valves are closed. 28V DC power from the battery bus is supplied through the NC contacts in the handles. 28V DC is supplied to the valve open circuits in the related fuel and hydraulic shutoff valves. The electrically-powered valves are each supplied with a mechanical position indicator. Limit switches in the valves control valve motor start/stop operation. The valves are connected electrically to limit switches in the related PULL FUEL/HYD OFF handle. The circuit for each valve is energized from the 28V DC battery bus through a 7.5A circuit breaker. The close circuit of the emergency hydraulic shutoff valve gets a 28V DC supply to the close circuit of the related hydraulic emergency shutoff valve through a 28V DC battery bus when the PULL FUEL/HYD OFF handle is pulled. RELAYS The relays are electrically energized from the 28V DC essential buses. Relay K1 is energized through the left DC essential bus, and relay K2, through the right DC essential bus. The relays, on relay panel No.1, are connected to the fuel valve light circuits. TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 76 - ENGINE CONTROLS Issue 6 - January 2023 Page 28 of 32 BOMBARDIER DHC 8-400 (PWC PW150) ENGINE CONTROLS - EMERGENCY SHUTDOWN ELECTRICAL SCHEMATIC TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 76 - ENGINE CONTROLS Issue 6 - January 2023 Page 29 of 32 BOMBARDIER DHC 8-400 (PWC PW150) ENGINE CONTROL SYSTEM The mechanical position indicator shows the valve position, between CLOSED and OPEN. CONTROLS AND INDICATIONS CIRCUIT PROTECTION POSITION INDICATION The relays are protected by the 5 A REFUEL/DEFUEL TNK 1 (L4) and REFUEL/ DEFUEL TNK 2 (F4) circuit breakers on the left and right essential bus circuit breaker panels. DESCRIPTION The position indication system indicates the positions of the fuel and hydraulic emergency shutoff valves. They are located on the Fire Protection Panel in the flight compartment. Fuel valve position is shown by: • • FUEL VALVE CLOSED light white FUEL VALVE OPEN light(green The No.1 engine fuel emergency shutoff valve is protected by the FUEL SOV ENG 1 (K2) circuit breaker. No.1 engine hydraulic shutoff valve is protected by the FUEL & HYD SOV ENG 1 (H2) circuit breaker. These circuit breakers are on the 28V DC right essential panel. The electrical circuit is through the advisory lights dim and test box. The valve position indicator lights come on if the buses are electrically energized (BATTERY MASTER switch ON). When the fuel valves get to the open position, the FUEL VALVE OPEN lights come on. This is shown by the movement of the visual indicator pencil lever on each valve. With power removed from the aircraft buses, BATTERY MASTER switch OFF relays 2822-K1 and 2822-K2 do not get electrical power. The isolation relays 2822-K1, and 2822-K2 isolate the valve position lights circuits from the battery power. This is done when electrical power is removed from the aircraft buses. The No.2 engine fuel emergency shutoff valve is protected by the FUEL SOV ENG 2 (L2) circuit breaker. The hydraulic emergency shutoff valves give a visual indication of valve position. The indication is with the mechanical position indicator installed on the valve. The mechanical position indicator shows the valve position (between CLOSED and OPEN). No.2 engine hydraulic shutoff valve is protected by the FUEL & HYD SOV ENG 2 (J2) circuit breaker. These circuit breakers are on the 28V DC right essential panel. The fuel emergency shutoff valves are electrically connected to the valve OPEN and to the valve CLOSED indicator lights. The fuel emergency shutoff valves also give a visual indication of valve position with a mechanical position pencil lever indicator, installed on the valve. When the circuits are not energized, you can manually operate the indicators on the fuel valves to the CLOSED, or to the OPEN position. TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 76 - ENGINE CONTROLS Issue 6 - January 2023 Page 30 of 32 BOMBARDIER DHC 8-400 (PWC PW150) ENGINE CONTROLS - FIRE PROTECTION PANEL TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 76 - ENGINE CONTROLS Issue 6 - January 2023 Page 31 of 32 BOMBARDIER DHC 8-400 (PWC PW150) INTENTIONALLY LEFT BLANK TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 76 - ENGINE CONTROLS Issue 6 - January 2023 Page 32 of 32