ATA 80 Starting - Bombardier DHC 8-400 (PDF)

BOMBARDIER DHC 8-400 (PWC PW150) ATA 80 - STARTING TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY B1/B2 MAINTENANCE TRAINING MANUAL Issue 6 - January 2023 Page 1 of 16 BOMBARDIER DHC 8-400 (PWC PW150) ENGINE STARTING SYSTEM GENERAL DESCRIPTION The engine start system starts the engines on th...

BOMBARDIER DHC 8-400 (PWC PW150) ATA 80 - STARTING TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY B1/B2 MAINTENANCE TRAINING MANUAL Issue 6 - January 2023 Page 1 of 16 BOMBARDIER DHC 8-400 (PWC PW150) ENGINE STARTING SYSTEM GENERAL DESCRIPTION The engine start system starts the engines on the ground and in the air. The engine control system is powered up when the appropriate airframe 28V DC Essential Bus is selected ON. When powered up, the Full Authority Digital Electronic Control (FADEC) does a series of initialization tests on internal functions and interfaces. If tests are passed, the FADEC begins transmitting data on ARINC 429 and RS 422 serial data buses. Select the ignition switches to the NORM position. An engine start is then initiated by selecting the engine and activating the starter by pressing the engine START switch and moving the Condition Lever from the FUEL OFF to START FEATHER position. The engine start sequence is: • • • • • • Select NORM 1 and/or 2 Set SELECT switch 1 or 2 SELECT segment of START push light comes on Push START START segment of push light comes on At 50% engine speed, the START light goes off TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 80 - STARTING Issue 6 - January 2023 Page 2 of 16 BOMBARDIER DHC 8-400 (PWC PW150) ENGINE STARTING - ENGINE START CONTROL PANEL TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 80 - STARTING Issue 6 - January 2023 Page 3 of 16 BOMBARDIER DHC 8-400 (PWC PW150) ENGINE STARTING SYSTEM SYSTEM DESCRIPTION The movement of the Condition Lever from the FUEL OFF position causes the following to occur: • • • Condition Lever Start/Shutdown micro-switches transition from the closed circuit to the open circuit state (one per channel) resetting the independent NH Over-Speed (O/S) protection circuitry to unlatch any previous O/S trip Wrap-around signals from the Start/Shutdown discretes are input to the FADEC controller, signalling to the software that a start has been commanded When NH is greater than 8% and Condition Lever Angle (CLA) is not in the FUEL OFF position, the FADEC begins metering fuel flow with the metering valve If in flight the FADEC de-energizes the Fuel Metering Unit (FMU) O/S solenoid. On the ground, the FMU O/S solenoid is normally de-energized (open) when the engine is shutdown unless the FMU is determined to be faulty. TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 80 - STARTING Issue 6 - January 2023 Page 4 of 16 BOMBARDIER DHC 8-400 (PWC PW150) ENGINE STARTING - CONDITION LEVER MICROSWITCHES TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 80 - STARTING Issue 6 - January 2023 Page 5 of 16 BOMBARDIER DHC 8-400 (PWC PW150) ENGINE STARTING SYSTEM SYSTEM DESCRIPTION AUTOMATIC ENGINE STARTS ON THE GROUND When the initial engine start is successful, the FADEC controls the starting sequence as follows: • • • • • When the starter has increased the generator speed (NH) to 8%, the FADEC commands ignition On and schedules fuel flow as a function of NH, ambient conditions, and Main Oil Temperature (MOT) Only one of the two ignitors is turned on. If the engine does not light within 8 seconds of fuel flow on, the FADEC turns on both ignitors and logs a fault against the faulty ignitor. Light off of engine is defined as an increase of 20°C Indicated Turbine Temperature (ITT) During run-up to idle, the FADEC switches channels to test the opposite channel When NH is greater than 50%, exciter and ignitors are automatically deenergized The FADEC controls engine run-up to the commanded NH idle speed of 64% NH TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 80 - STARTING Issue 6 - January 2023 Page 6 of 16 BOMBARDIER DHC 8-400 (PWC PW150) ENGINE STARTING - IGNITION SYSTEM ELECTRICAL BLOCK DIAGRAM TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 80 - STARTING Issue 6 - January 2023 Page 7 of 16 BOMBARDIER DHC 8-400 (PWC PW150) ENGINE STARTING SYSTEM SYSTEM DESCRIPTION AUTOMATIC ENGINE STARTS ON THE GROUND CONTINUED During ground starts, the FADEC actively limits the Indicated Turbine Temperature (ITT). This prevents over-temperature due to engine start. The FADEC reduces the fuel flow below the standard start schedule if necessary to prevent an over-temperature. The FADEC automatically aborts the start, and shuts down the engine if any one of these conditions occur: • • • The engine does not light up within 16 seconds of fuel flow on. The FADEC shuts down the fuel to the engine and starts a fault count ITT limit of 920°C is exceeded NH does not reach 50% within 70 seconds i.e. hung or slow start AUTOMATIC STARTS IN FLIGHT In-flight starts are similar to ground starts except for: • • • • Both ignitors are commanded ON during the start The auto-abort features are disabled The FADEC does not actively limit ITT No FADEC channel transfers during the start Flight Mode and Ground Mode starting are determined by: • • If the Calibrated Air Speed (CAS) is greater than 75 kts (139 km/h) then Flight Mode is set In fault conditions when CAS is not available, the WOW Discrete from the Propeller Electronic Control (PEC) determines Ground/Flight Mode Status TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 80 - STARTING Issue 6 - January 2023 Page 8 of 16 BOMBARDIER DHC 8-400 (PWC PW150) ENGINE STARTING - IGNITION SYSTEM ELECTRICAL BLOCK DIAGRAM TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 80 - STARTING Issue 6 - January 2023 Page 9 of 16 BOMBARDIER DHC 8-400 (PWC PW150) ENGINE STARTING SYSTEM SYSTEM DESCRIPTION IGNITION CONTROL DURING STARTS The dual channel ignition system is powered electrically by the aircraft essential busses and activated by the FADEC. The ignition system is configured such that both ignitors can be commanded by each FADEC channel, while maintaining electrical isolation between the FADEC channels and the aircraft essential buses. The ignition selection from the flight compartment is sent to the FADEC on an ARINC 429 bus through the Engine Cockpit Interface Unit (ECIU). The FADEC ignition system has two flight compartment selectable modes of operation: • 1-OFF: The FADEC disables ignition regardless of ground or flight status. • 2-NORM: The FADEC activates ignition during engine starts ground or flight starts. The FADEC commands both ignitors On during flameout and surge accommodation. TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 80 - STARTING Issue 6 - January 2023 Page 10 of 16 BOMBARDIER DHC 8-400 (PWC PW150) ENGINE STARTING - ENGINE START CONTROL PANEL TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 80 - STARTING Issue 6 - January 2023 Page 11 of 16 BOMBARDIER DHC 8-400 (PWC PW150) ENGINE STARTING SYSTEM on GCU pin N. Contacts C1 and C2 close to energize the START light. SYSTEM DESCRIPTION Contacts A1 and A2 close to give a ground signal to the Electrical Power Control Unit (EPCU) which verifies the status of contactor K1, when the system reverts to generator mode. ELECTRICAL OPERATION An output from pin Q of the GCU keeps relay K3 in the energized condition. With the ignition switch set to NORM, the ignition exciter is armed and will start to fire the ignitors when it receives a signal from the FADEC that NH is greater than 8%. The START SELECT switch S1 is a three position switch, spring loaded and lever locked in the centre OFF position. The switch gets 28V DC through a circuit breaker from the left essential bus. When No.1 engine is selected, 28V DC is supplied through switch S1 contacts 4 and 6 to send 28V DC through the normally closed contacts C2 and C3 of relay K1 and diode CR1 to the hold coil of switch S1. The hold coil magnetically holds the START SELECT switch in the No.1 position until the start sequence is complete. Diode CR1 also supplies 28V DC to pin C1 of time delay relay K3. This energizes the amber SELECT light and applies voltage to current limit pin HH of No.1 GCU. This enables the GCU to limit starting current to approximately 400 amps during the start cycle plus 15 seconds after completion. When the starter has accelerated the engine to 8% NH, the FADEC signals the ignition exciter which fires the ignitors to start No.1 engine. When the engine reaches a steady acceleration the FADEC terminates ignition. As the engine becomes self-sustaining, the GCU field current reduces the starter/ generator torque, to keep a positive starting torque. This equates to a steady input current of approximately 400 amps. At 50% NH the speed sensor in the starter, signals the GCU to terminate the output from pin Q. This removes power from the hold coil of START SELECT switch S1. The switch returns to the OFF position and the start light goes off. Power is also removed from pin C1 of time delay relay K3, but because of the time delay, it retains current limiting for a further 15 seconds. The select light then goes off. This is to prevent a high current inrush to the batteries, due to the partial discharge following an engine start. Time delay relay K3 remains energized until the voltage is removed from pin C1. The start select sequence is now complete. The START switch, then armed by S1, supplies 28V DC to the start control pin N of No.1 GCU to energize contactor K1. No.1 starter/generator now starts to rotate the engine. The coil of control relay K1 is also energized. Contacts B1 and B2 close to keep power on K1 coil and to supply a sustaining voltage TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 80 - STARTING Issue 6 - January 2023 Page 12 of 16 BOMBARDIER DHC 8-400 (PWC PW150) ENGINE STARTING - ENGINE START SELECT TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 80 - STARTING Issue 6 - January 2023 Page 13 of 16 BOMBARDIER DHC 8-400 (PWC PW150) ENGINE STARTING - START SWITCH PUSHED TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 80 - STARTING Issue 6 - January 2023 Page 14 of 16 BOMBARDIER DHC 8-400 (PWC PW150) INTENTIONALLY LEFT BLANK TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 80 - STARTING Issue 6 - January 2023 Page 15 of 16 BOMBARDIER DHC 8-400 (PWC PW150) ENGINE STARTING SYSTEM SYSTEM DESCRIPTION IGNITION CONTROL DURING FLAMEOUT AND ENGINE SURGE In addition to controlling the ignitors during starting, the Control System can determine that the engine has suffered a flameout within 1 second rapid decrease of EGT and NH. The FADEC activates the ignition circuitry for both ignitors as soon as the flameout has been detected and will cancel it when the engine has recovered. TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 80 - STARTING Issue 6 - January 2023 Page 16 of 16