ATA 61 Propellers - Bombardier DHC 8-400 (PWC PW150) Jan 2023 PDF

BOMBARDIER DHC 8-400 (PWC PW150) ATA 61 - PROPELLERS TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY B1/B2 MAINTENANCE TRAINING MANUAL Issue 6 - January 2023 Page 1 of 86 BOMBARDIER DHC 8-400 (PWC PW150) PROPELLER SYSTEMS GENERAL DESCRIPTION The propeller converts engine supplied power into u...

BOMBARDIER DHC 8-400 (PWC PW150) ATA 61 - PROPELLERS TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY B1/B2 MAINTENANCE TRAINING MANUAL Issue 6 - January 2023 Page 1 of 86 BOMBARDIER DHC 8-400 (PWC PW150) PROPELLER SYSTEMS GENERAL DESCRIPTION The propeller converts engine supplied power into usable thrust for aircraft propulsion both in-flight and during ground manoeuvres. The aircraft is equipped with two propeller systems, one for each engine. Each system has: • • • • • Dowty CR 408/6-123-F/17 propeller assembly Propeller Electronic Control (PEC) Pitch Control Unit (PCU) Over-speed Governor (OSG) and pump Auxiliary Feather pump The propeller blades are of variable pitch, and are counter weighted to move towards coarse pitch in the event of oil pressure failure. Pitch change is accomplished by metered oil pressure. The oil pressure originates from the related engine and is supplied to a pump which is part of the Over-speed Governor (OSG) installation. The propeller used on the Pratt and Whitney PW150A engine for the De Havilland Dash 8 Series 400 aircraft can be described by its model number as follows: • • • • • • • C - Civil R - Dowty Aerospace Propellers 408 - Aircraft type identification 6 - Number of blades 123 - Blade root end size in mm. F - Flange mounted 17 - Function/Installation characteristics The propeller system incorporates the following subsystems: • • Propeller Propeller Controlling TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 61 - PROPELLERS Issue 6 - January 2023 Page 2 of 86 BOMBARDIER DHC 8-400 (PWC PW150) PROPELLER - PROPELLER ASSEMBLY TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 61 - PROPELLERS Issue 6 - January 2023 Page 3 of 86 BOMBARDIER DHC 8-400 (PWC PW150) PROPELLER SYSTEMS block bracket and sensing the target screws, on the periphery of the slip ring. SYSTEM DESCRIPTION The hydraulic pitch change system can be divided into these sections: The propeller system incorporates a double acting pitch change mechanism that uses high pressure oil to control blade pitch. The propeller control system operates the propeller in these modes and functions: • • • • Constant speed mode Synchrophase mode Beta mode Feather function • • • Pitch Change Unit Beta Tube Assembly Piston and Cylinder Assembly The PCU supplies oil to either of the two sides of the Beta tube assembly that is connected through the reduction gearbox to the propeller. The ported oil is transferred through the Beta tubes to the piston and cylinder assembly. The pressure forces on the piston move the crosshead axially, that in turn moves the blade operating pins to give the requested blade angle. Mode and function control is by the Propeller Electronic Controller (PEC ) that, in turn, controls blade pitch by a servo valve in the PCU. The propeller assembly incorporates counterweights to drive the blades to coarse pitch in the event of loss of oil pressure. The PEC is a digital electronic control unit that incorporates: Over-speed protection for the propeller is controlled by bob-weights in the Overspeed Governor (OSG). The OSG restricts the oil supply to the propeller pitch change mechanism to allow the counterweights to coarsen the blade angle and slow the propeller rotational speed. This occurs at 104% Np (1060 rpm). • • • • • • Propeller speed governing Beta schedule control functions Synchrophasing control Up-trim function Auto-feather function Automatic under-speed protection function The PEC is installed under the spine located at the top forward nacelle, between the two hinged forward doors. Two independent lanes are provided in the PEC for speed governing, synchrophasing and Beta control, with a single auto-feather board. It is possible to feather the propeller at any time using the Auxiliary Feather pump. The pump incorporates a dedicated oil supply within the Reduction Gearbox (RGB). The feather pump will override all other control system demands to produce a fail safe system. The CLA and PLA inputs are from the dual RVDT on each lever in the quadrant. The CLA inputs are provided directly to PEC as analogue signals, with excitation provided by the PEC. The PLA signals are provided to the PEC by the FADEC on an RS422 digital data bus. Propeller speed input is from a Magnetic Pick-up Unit (MPU) installed on the brush TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 61 - PROPELLERS Issue 6 - January 2023 Page 4 of 86 BOMBARDIER DHC 8-400 (PWC PW150) PROPELLER - PROPELLER CONTROL BLOCK DIAGRAM TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 61 - PROPELLERS Issue 6 - January 2023 Page 5 of 86 BOMBARDIER DHC 8-400 (PWC PW150) PROPELLER SYSTEMS SYSTEM DESCRIPTION PROPELLER ASSEMBLY The propeller assembly converts engine supplied power into usable thrust for aircraft propulsion during flight and ground manoeuvres. The six bladed propeller is constant speed, variable pitch, with full feathering and full reverse capabilities. The propeller is installed on the engine reduction gearbox propeller drive flange by 15 threaded studs and nuts. The three location dowels help with the correct propeller installation and transmit some of the drive torque. The blades are installed in a flange mounted aluminium hub. Installed on the hub is a cylinder assembly which houses the pitch change piston. A spinner is attached to the propeller composite back-plate. Pitch change is achieved by a double-acting hydraulic piston in a cylinder installed to the front of the hub. The piston drives a crosshead, installed in the hub, which turns the blades in pitch through off-centre operating pins and bearings installed to each blade root. The propeller assembly incorporates these components: • • • • Propeller Blade Assembly Hub Assembly Back-plate Assembly Spinner Assembly TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 61 - PROPELLERS Issue 6 - January 2023 Page 6 of 86 BOMBARDIER DHC 8-400 (PWC PW150) PROPELLER - PROPELLER ASSEMBLY TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 61 - PROPELLERS Issue 6 - January 2023 Page 7 of 86 BOMBARDIER DHC 8-400 (PWC PW150) PROPELLER SYSTEMS SYSTEM DESCRIPTION PROPELLER BLADES Each propeller blade is an all composite aerofoil construction with a steel outer root sleeve. The aerofoil incorporates a foam core and twin carbon fibre spars with an overall braided carbon/glass fibre shell. A polyurethane spray coat for erosion protection is applied to the complete blade surface. A nickel leading edge guard is installed for blade erosion protection. A heater element to de-ice 70% of the blade radius is installed on the blade leading edge. The operating pins on the base of each blade engage between the faces of the crosshead, to give blade pitch rotation. TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 61 - PROPELLERS Issue 6 - January 2023 Page 8 of 86 BOMBARDIER DHC 8-400 (PWC PW150) PROPELLER - PROPELLER BLADE ASSEMBLY TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 61 - PROPELLERS Issue 6 - January 2023 Page 9 of 86 BOMBARDIER DHC 8-400 (PWC PW150) PROPELLER SYSTEMS SYSTEM DESCRIPTION PROPELLER BLADE TO HUB ATTACHMENT Each blade is supported by a pair of blade root bearings. The inner bearing is an angular contact ball race whose balls are inserted in the hub through a hole blanked off, after assembly, by a plug. The outer bearing is a taper roller race. A blade secondary retention cable is fed into a circumferential groove in each blade port, between the hub and outer bearing track. A snap ring is installed around the base of each blade root. In the event of the balls of the lower blade bearing totally disintegrating, tangential movement of the blade is limited by the snap ring being baulked by the blade secondary retention cable. TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 61 - PROPELLERS Issue 6 - January 2023 Page 10 of 86 BOMBARDIER DHC 8-400 (PWC PW150) PROPELLER - BLADE TO HUB ATTACHMENT TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 61 - PROPELLERS Issue 6 - January 2023 Page 11 of 86 BOMBARDIER DHC 8-400 (PWC PW150) PROPELLER SYSTEMS SYSTEM DESCRIPTION HUB ASSEMBLY The hub assembly incorporates a one piece aluminium hub, with 15 integral steel mounting studs with self-locking nuts and 3 equally spaced location/drive dowels. To prevent fretting at the shaft to propeller interface, a composite shim is installed on the flange. The shaft dowel holes are also lined with composite material. A back-plate constructed of carbon fibre composite, and attached to the hub forms the aerodynamic interface between the spinner and engine nacelle. The back-plate incorporates holes for balancing bolts and washers. A slip-ring is used to transfer electrical power for blade de-icing. The slip ring is installed directly onto the back-plate and incorporates an aluminium alloy housing with three bronze rings in a plastic moulding. The target screws that supply propeller speed and phase angle feedback are located on the external diameter of the slip-ring. TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 61 - PROPELLERS Issue 6 - January 2023 Page 12 of 86 BOMBARDIER DHC 8-400 (PWC PW150) PROPELLER - PROPELLER ATTACHMENT AND BACKPLATE ASSEMBLY TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 61 - PROPELLERS Issue 6 - January 2023 Page 13 of 86 BOMBARDIER DHC 8-400 (PWC PW150) PROPELLER SYSTEMS SYSTEM DESCRIPTION SPINNER ASSEMBLY The spinner is of composite construction and gives an aerodynamic fairing over the front end of the propeller. The spinner is attached to the propeller back-plate with 12 quick release fasteners. A centralizing/support diaphragm on the pitch change cylinder makes sure that the spinner runs concentrically, when rotating with the propeller. The spinner is dynamically balanced as an assembly, during manufacture/repair, by the addition of rubber balancing pads. TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 61 - PROPELLERS Issue 6 - January 2023 Page 14 of 86 BOMBARDIER DHC 8-400 (PWC PW150) PROPELLER - PROPELLER SPINNER TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 61 - PROPELLERS Issue 6 - January 2023 Page 15 of 86 BOMBARDIER DHC 8-400 (PWC PW150) PROPELLER SYSTEMS PROPELLER CONTROLLING SYSTEM GENERAL DESCRIPTION The purpose of the propeller control system is to modulate blade angle or pitch, to achieve the necessary propeller rpm (Np) and blade pitch (Beta) control. The propeller control system also feathers the propeller. The purpose of the power levers is to control the propeller pitch Beta control), the condition levers are used to set Np and to feather the propellers. The Propeller Electronic Controller (PEC) supplies the current to the servovalve drive, through a dual line hydromechanical actuation system, to change the blade pitch. TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 61 - PROPELLERS Issue 6 - January 2023 Page 16 of 86 BOMBARDIER DHC 8-400 (PWC PW150) PROPELLER - PROPELLER CONTROL BLOCK DIAGRAM TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 61 - PROPELLERS Issue 6 - January 2023 Page 17 of 86 BOMBARDIER DHC 8-400 (PWC PW150) PROPELLER SYSTEMS PROPELLER CONTROLLING SYSTEM GENERAL DESCRIPTION CONTINUED The main modes of propeller operation for control during flight and on the ground are: • • • • Constant Speed Mode Power Lever between above Flight Idle and MAX Power Beta Control Mode Power Lever between above Flight Idle to below Disc Reverse speed control mode Power lever between below Disc and Max Reverse Synchrophase control mode slave propeller The propeller control system incorporates these units: • • • • • • • Propeller Electronic Control Unit Beta Tube Assembly Magnetic Pick-up Unit Pitch Control Unit Over-speed Governor - High pressure Pump Feathering Pump Propeller Control Panel TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 61 - PROPELLERS Issue 6 - January 2023 Page 18 of 86 BOMBARDIER DHC 8-400 (PWC PW150) PROPELLER - PROPELLER CONTROL LOOP LOGIC TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 61 - PROPELLERS Issue 6 - January 2023 Page 19 of 86 BOMBARDIER DHC 8-400 (PWC PW150) PROPELLER SYSTEMS SYSTEM OPERATION BETA CONTROL The purpose of the Beta control system is to control propeller pitch in the Betamode where propeller pitch is a function of Power Lever Angle (PLA). In this mode the system operates in closed loop blade angle control. The measured blade pitch is determined from the Beta Feedback Transducer (BFT) output signal and the required blade angle, is determined from a schedule against Power Lever Angle (PLA). The system limits the pitch change rate in order to match the rate of change of torque absorption of the propeller to the rate of change of engine torque. This reduces propeller over-speed and under-speeds during power lever transients. The rate limit is based on blade pitch and direction of blade pitch change. Movement of the PLA into the region between Flight Idle (FI) and Ground Idle (GI) at high airspeeds or high power can cause potentially high over-speed. This is because the blade angle is close to flat pitch and is absorbing power from the air-stream windmilling. A blade angle biasing device is included within beta control that drives the blades fine towards GI in the event of a large over-speed. The blade angle biasing is deactivated when PLA is moved above FI or below GI. During Beta Control, the Propeller Electronic Control (PEC) directs the servovalve to meter oil into the fine or coarse pitch chamber to achieve the required blade angle. The blade angle is set by the dual Power Lever Angle (PLA) Rotary Variable Differential Transformer (RVDT), located on the power lever quadrant. The PEC receives PLA signals through the Full Authority Digital Electronic Control (FADEC). TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 61 - PROPELLERS Issue 6 - January 2023 Page 20 of 86 BOMBARDIER DHC 8-400 (PWC PW150) PROPELLER - GROUND BETA MODE TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 61 - PROPELLERS Issue 6 - January 2023 Page 21 of 86 BOMBARDIER DHC 8-400 (PWC PW150) PROPELLER SYSTEMS This disables the OSG. SYSTEM OPERATION Failure of the GBEV spool to move to its in-flight position causing loss of over-speed protection can be proved by doing an OSG test. BETA CONTROL CONTINUED When the power lever is in the beta range, propeller speed is usually governed by the FADEC and engine fuel system at 660 rpm. The position of the ports in the PCU/Beta tubes make sure that fine pitch in the inflight constant speed mode is limited to a blade angle of 16°. This hydraulic cut-off of oil pressure is specified as the hydraulic flight fine stop interlock. The flight fine stop keeps a minimum pitch consistent with positive counterweight effort driving towards coarse pitch, to make sure the OSG is effective throughout the in-flight pitch range. A soft flight fine stop at approximately 16.5° is programmed into the PEC. This stop makes sure the blade angle does not drop below 16.5° while the power lever is at, or above flight idle in flight. This is specified as a software flight fine stop. A detent on the power lever quadrant stops unintentional movement of the lever below flight idle during flight. A power lever switch which closes below a PLA of 33°, energizes the Ground Beta Enable Solenoid (GBES), if the blade angle is less than a predetermined minimum and the aircraft is on the ground. When the GBES is energized, a pilot valve vents the chamber at the end of the Ground Beta Enable Valve spool (GBEV) to drain. The spring at the other end moves to its ground position. Fine pitch oil pressure then enters another chamber in the PCU, which allows for ground beta blade angles down to reverse. Also with the GBEV in the ground position, the HP supply from the OSG is isolated and the second stage of the servo valve is supplied directly by the HP pump. TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 61 - PROPELLERS Issue 6 - January 2023 Page 22 of 86 BOMBARDIER DHC 8-400 (PWC PW150) PROPELLER - BETA SCHEDULE TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 61 - PROPELLERS Issue 6 - January 2023 Page 23 of 86 BOMBARDIER DHC 8-400 (PWC PW150) PROPELLER SYSTEMS The flyweights are held in a carrier which is driven round with the high pressure pump by the Propeller Reduction Gearbox (PRG). SYSTEM OPERATION FORWARD SPEED CONTROL The purpose of the Forward Speed Control system is to control the propeller in the constant speeding mode. In this mode the system operates in closed loop propeller RPM control. Propeller Rpm (Np) is calculated from the propeller Magnetic Pickup Unit (MPU) output by timing a complete revolution. Three discrete speeds 850 rpm, 900 rpm and 1020 rpm can be selected from CLA. Changes in forward speed request, NPREQ, are passed through a small first order lag to give a smooth speed response. In the event of the PLA being moved into the over-travel position, NPREQ is set to 1020 rpm. this speed is latched until the CLA is moved to the 1020 rpm position, or the start/feather position. If the servo valve sticks at the fine pitch selection, Np will increase to approximately 1060 rpm. The OSG spool will then isolate the propeller control system from the high pressure oil supply. Np will decrease due to propeller counterweight action. The OSG will then reconnect the high pressure oil supply and a stable governing condition at 1060 rpm will be quickly achieved. The OSG spool spring is located in a cylinder, on a piston, that is connected to the high pressure oil supply, through a solenoid operated pilot valve. The solenoid is energized by the PROP O/SPEED GOVERNOR TEST switch on the pilot side console. A Weight-On-Wheels (WOW) input to the PEC prevents test operation during flight. The FADEC controls fuel flow to the engine to protect the engine and propeller from high torque conditions that would result from an inadvertent propeller feather. During in-flight constant speeding operation, the Propeller Electronic Control Unit (PEC) directs the servovalve to meter high pressure oil into the propeller fine pitch chamber. This is to balance the coarse seeking moment applied to the blades, so that the propeller stays at the selected speed (Np). If there is a loss of high pressure oil supply, the blades will auto-coarsen to a safe high pitch under-speeding condition, to give low wind-milling drag. For under-speeding conditions, other than loss of oil pressure or servovalve failure, high pressure oil is sent to the fine pitch chamber to restore propeller speed. If the Np is greater that the demanded speed, the servovalve will send the oil pressure to the coarse pitch chamber to reduce propeller speed. Constant speed mode is entered when propeller speed reaches 850 rpm, 900 rpm or 1020 rpm, depending on the condition lever selection. High pressure oil for constant speeding flows through the Over-speed Governor (OSG) before it reaches the servovalve. A spool in the OSG is held at either end by the opposing forces of a spring and the toes of a pair of flyweights. TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 61 - PROPELLERS Issue 6 - January 2023 Page 24 of 86 BOMBARDIER DHC 8-400 (PWC PW150) PROPELLER - STEADY STATE CONSTANT SPEED CONTROL TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 61 - PROPELLERS Issue 6 - January 2023 Page 25 of 86 BOMBARDIER DHC 8-400 (PWC PW150) PROPELLER SYSTEMS SYSTEM OPERATION SYNCHROPHASE CONTROL The purpose of the Synchrophase control is to control the propellers to within a set RPM of each other and to control the phase, to reduce noise and vibration. In this mode the system operates in closed loop propeller speed and propeller phase control. Synchrophasing acts to reduce cabin noise by ensuring that the relative position, or phase difference, between the slave and master propellers is controlled to a demanded angle. The phase angle is calculated by timing the differences between master and slave propeller MPU signals over a complete revolution. The phase demand is determined from either the CLA position, or the output from the Active Noise Vibration System (ANVS). TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 61 - PROPELLERS Issue 6 - January 2023 Page 26 of 86 BOMBARDIER DHC 8-400 (PWC PW150) PROPELLER - PEC CONTROL MODE TRANSITIONS INCLUDING SYNCHROPHASE TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 61 - PROPELLERS Issue 6 - January 2023 Page 27 of 86 BOMBARDIER DHC 8-400 (PWC PW150) PROPELLER SYSTEMS SYSTEM OPERATION ROUTINE FEATHER The purpose of the Routine Feather mode is to feather the propeller on routine engine shutdowns. Routine feather is set when the condition lever is moved to either the START/FEATHER or FUEL OFF detent. A routine feather signal commands the PEC to drive the servovalve towards coarse pitch. TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 61 - PROPELLERS Issue 6 - January 2023 Page 28 of 86 BOMBARDIER DHC 8-400 (PWC PW150) PROPELLER - NORMAL FEATHER TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 61 - PROPELLERS Issue 6 - January 2023 Page 29 of 86 BOMBARDIER DHC 8-400 (PWC PW150) PROPELLER SYSTEMS SYSTEM OPERATION REVERSE SPEED CONTROL The purpose of the Reverse Speed control is to control the propeller speed in reverse to a maximum of 950 rpm. In this mode the system operates in closed loop propeller RPM control, maintaining the propeller speed at 950 rpm. The FADEC schedules fuel based on a power schedule versus PLA, with a maximum limit of 1500 SHP. At low airspeeds it is possible that the propeller could reach the maximum reverse stop, the Np is then controlled by the engine over-speed governor. TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 61 - PROPELLERS Issue 6 - January 2023 Page 30 of 86 BOMBARDIER DHC 8-400 (PWC PW150) PROPELLER - MAXIMUM REVERSE TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 61 - PROPELLERS Issue 6 - January 2023 Page 31 of 86 BOMBARDIER DHC 8-400 (PWC PW150) PROPELLER SYSTEMS SYSTEM OPERATION AUTOMATIC UNDER-SPEED PROTECTION CIRCUIT (AUPC) The purpose of AUPC is to protect the aircraft from lack of thrust caused by a common software problem in both PECs. This function is implemented by hardware which is independent of the PEC control lane software. The function is incorporated to protect against a common software error in both powerplant PEC controllers. This would result in a drive coarse signal on both propellers and loss of thrust. An under-speed condition detected on both Npt sensors causes a drive fine signal to be generated and the Np will increase. The propeller speed increase will be arrested by the Over-speed Governor (OSG). This function overrides the authority of the control lane software but is, in turn, overridden by the autofeather function. The AUPC is armed as follows: • • • PLA is above FI CLA above Start/Feather Autofeather or manual feather not demanded for >0.5 seconds AUPC is activated as follows: • Propeller speed is <80% and torque is >50% for >1 second AUPC is disarmed as follows: • • • PLA moved below FI CLA moved to Start/Feather Autofeather or manual feather demanded The AUPC function is tested during Autofeather Test. TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 61 - PROPELLERS Issue 6 - January 2023 Page 32 of 86 BOMBARDIER DHC 8-400 (PWC PW150) PROPELLER - AUPC LOGIC TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 61 - PROPELLERS Issue 6 - January 2023 Page 33 of 86 BOMBARDIER DHC 8-400 (PWC PW150) PROPELLER SYSTEMS At this point the A/F ARM indication is removed from the ED. SYSTEM OPERATION AUTOMATIC TAKE-OFF THRUST CONTROL SYSTEM The purpose of the ATTCS is to give the necessary protection against engine failure during the critical part of the take-off roll. The Automatic Take-Off Thrust Control System (ATTCS) causes an uptrim of the remote powerplant and an auto-feather on the failed powerplant. Any erroneous feather of the local propeller will cause an uptrim of the remote powerplant. The ATTCS incorporates two sub-systems: • • Autofeather Uptrim AUTOFEATHER The purpose of the Autofeather system is to prevent both powerplants autofeathering simultaneously. The autofeather function is implemented in PEC hardware and includes cross-wing communication with the remote PEC. Two torque signals are needed to show less than 25% torque for three seconds before the system autofeathers. The autofeather function is armed by moving the PLA to above 60° and by having local and remote torques above 50% and pressing the AUTOFEATHER SELECT switch. When both powerplants are armed, an A/F ARM indication is shown on the Engine Display (ED). Autofeather is disarmed by either de-selecting the AUTOFEATHER SELECT switch, or moving both PLA below 60°. An autofeather will cause the PEC to: • • Output a servovalve drive coarse signal Energize the auxiliary pump relay TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 61 - PROPELLERS Issue 6 - January 2023 Page 34 of 86 BOMBARDIER DHC 8-400 (PWC PW150) PROPELLER - AUTOFEATHER STATE TRANSITIONS TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 61 - PROPELLERS Issue 6 - January 2023 Page 35 of 86 BOMBARDIER DHC 8-400 (PWC PW150) PROPELLER SYSTEMS SYSTEM OPERATION AUTO FEATHER CONTINUED When the propeller is auto-feathered, the system can only be disarmed by deselecting the AUTOFEATHER SELECT switch. A detected failure in the ATTCS results in the system inhibiting the A/F ARM indication. TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 61 - PROPELLERS Issue 6 - January 2023 Page 36 of 86 BOMBARDIER DHC 8-400 (PWC PW150) PROPELLER - AUTOFEATHER MODE TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 61 - PROPELLERS Issue 6 - January 2023 Page 37 of 86 BOMBARDIER DHC 8-400 (PWC PW150) PROPELLER SYSTEMS SYSTEM OPERATION AUTO FEATHER CONTINUED UP-TRIM The purpose of the Uptrim system is to uptrim the local engine by 10%, when signalled to do so by the remote PEC. The uptrim function is implemented in the PEC hardware, with cross-wing communication from the local PEC to the remote FADEC. Uptrim is armed by moving both PLA above 60° and having remote torque high (Q) for >2 seconds. Uptrim is disarmed by moving either PLA below 60° or by autofeather of the remote powerplant. When the system is armed an uptrim will occur if: • • • Both torque signals drop below 25% or Both torque sensors show a speed of less than 800 rpm or Autofeather active An uptrim will cause the PEC to command the FADEC to change from the Normal Take-Off Power (NTOP) schedule, to the Maximum Take-Off Power schedule. An UPTRIM message will appear on the ED. TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 61 - PROPELLERS Issue 6 - January 2023 Page 38 of 86 BOMBARDIER DHC 8-400 (PWC PW150) PROPELLER - UPTRIM FOR LOW NP OR LOW TORQUE TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 61 - PROPELLERS Issue 6 - January 2023 Page 39 of 86 BOMBARDIER DHC 8-400 (PWC PW150) PROPELLER SYSTEMS SYSTEM OPERATION ALTERNATE FEATHER The purpose of the Alternate Feather system is to give an independent means to feather the propeller of a failed engine. Alternate feather is set when the condition lever is moved to the START/FEATHER or FUEL OFF position and the applicable ALT FTHR switch-light, on the PROPELLER CONTROL panel is pushed. The auxiliary pump runs for a maximum of 30 seconds and supplies pressure to enable the Back Up Feather Valve and drive the propeller to coarse pitch. The electrical circuit for the alternate feather mode incorporates a switch installed on the condition lever. The switch closes at, or below the START/FEATHER position, to ensure that the flight crew must select normal feather before selecting alternate feather. The alternate feather function gives an independent method to feather the propeller and will override the authority of the PEC control lanes. TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 61 - PROPELLERS Issue 6 - January 2023 Page 40 of 86 BOMBARDIER DHC 8-400 (PWC PW150) PROPELLER - PROPELLER CONTROL PANEL TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 61 - PROPELLERS Issue 6 - January 2023 Page 41 of 86 BOMBARDIER DHC 8-400 (PWC PW150) PROPELLER SYSTEMS SYSTEM OPERATION MAINTENANCE UNFEATHER On the ground, a static propeller can be un-feathered by selecting the applicable MAINTENANCE UNFEATHER switch on the Maintenance Panel to ON. This energizes the auxiliary pump and the un-feather solenoid, scheduling oil pressure to the servo valve. The PEC controls the servovalve output to drive the propeller towards fine pitch if all of the following are true: • • • There is no propeller rotation Maintenance mode is selected Weight-On-Wheels input signals are detected TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 61 - PROPELLERS Issue 6 - January 2023 Page 42 of 86 BOMBARDIER DHC 8-400 (PWC PW150) INTENTIONALLY LEFT BLANK TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 61 - PROPELLERS Issue 6 - January 2023 Page 43 of 86 BOMBARDIER DHC 8-400 (PWC PW150) PROPELLER SYSTEMS COMPONENT LOCATION AND DESCRIPTION BETA TUBE ASSEMBLY The purpose of the beta tube assembly is to transfer fine and coarse pitch oil pressure from the Pitch Control Unit to the propeller pitch change mechanism. The Beta Feedback transducer installed at the back of beta tube assembly monitors the blade pitch angle for beta control. TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 61 - PROPELLERS Issue 6 - January 2023 Page 44 of 86 BOMBARDIER DHC 8-400 (PWC PW150) PROPELLER - BETA TUBE ASSEMBLY AND BETA FEEDBACK TRANSDUCER TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 61 - PROPELLERS Issue 6 - January 2023 Page 45 of 86 BOMBARDIER DHC 8-400 (PWC PW150) PROPELLER SYSTEMS COMPONENT LOCATION AND DESCRIPTION BETA TUBE ASSEMBLY CONTINUED The assembly is attached to the front of the crosshead assembly by means of an adjustable screw thread and splined locking collar. The adjustment permits setting of the assembly within the BFT to achieve full range of feedback. TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 61 - PROPELLERS Issue 6 - January 2023 Page 46 of 86 BOMBARDIER DHC 8-400 (PWC PW150) PROPELLER - BETA TUBE ASSEMBLY TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 61 - PROPELLERS Issue 6 - January 2023 Page 47 of 86 BOMBARDIER DHC 8-400 (PWC PW150) PROPELLER SYSTEMS COMPONENT LOCATION AND DESCRIPTION MAGNETIC PICKUP UNIT (MPU) The purpose of the MPU is to signal PEC for the NP and phase of the propeller. The speed and phase of the propeller is sensed by a Magnetic Pickup Unit and a set of 7 targets on the de-icing slip-ring. Six targets give speed signalling/phase inputs and one acts as a master reference for balancing purposes. The MPU is a dual channel device located on the front of the reduction gearbox. TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 61 - PROPELLERS Issue 6 - January 2023 Page 48 of 86 BOMBARDIER DHC 8-400 (PWC PW150) PROPELLER - MAGNETIC PICK UP UNIT TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 61 - PROPELLERS Issue 6 - January 2023 Page 49 of 86 BOMBARDIER DHC 8-400 (PWC PW150) PROPELLER SYSTEMS COMPONENT LOCATION AND DESCRIPTION PITCH CONTROL UNIT (PCU) The purpose of the PCU is to control the flow of oil pressure to the fine and coarse pitch sides of the propeller pitch change mechanism. The PCU modulates high pressure oil supplied by the Over-speed Governor (OSG) using a servovalve. The servovalve receives electrical signals from the PEC and directs oil pressure through a transfer sleeve and beta tubes, to the coarse/fine sides of the propeller pitch change piston. The PCU incorporates these components: • • • • • Servovalve Ground Beta Enable Solenoid Valve Un-feather valve Back up Feather Valve Beta Feedback Transducer The PCU rear case gives the interface with the beta feedback transducer (BFT). The Ground Beta Enable Solenoid Valve (GBEV), the Un-feather Solenoid Valve, the servovalve, and the Beta Feedback Transducer (BFT), are line replaceable units. The PCU is located on the rear face of the reduction gearbox and is attached to a bolted on adaptor on the gearbox by a V-band clamp. TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 61 - PROPELLERS Issue 6 - January 2023 Page 50 of 86 BOMBARDIER DHC 8-400 (PWC PW150) PROPELLER - PITCH CONTROL UNIT TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 61 - PROPELLERS Issue 6 - January 2023 Page 51 of 86 BOMBARDIER DHC 8-400 (PWC PW150) PROPELLER SYSTEMS A drive fine would be arrested by the OSG and a drive coarse, at higher power, by the AUPC. COMPONENT LOCATION AND DESCRIPTION PITCH CONTROL UNIT (PCU) CONTINUED SERVO VALVE The purpose of the servovalve is to control the flow of oil, to control blade pitch. The servovalve is a two stage nozzle flapper design that is used to control blade pitch in all control modes. The torque motor drive on the first stage incorporates two coils, line connected to each PEC lane. Opening the valve schedules high pressure oil to one line, while venting the other line to drain. The valve is biased such that the propeller is driven towards coarse pitch in the event of an interruption of the electrical drive signal from PEC. The propeller will then move towards feather. This coarse pitch bias was chosen because total loss of electrical power will cause the fuel supply to the engine to be shut off, so it is appropriate in this condition to feather the propeller to minimize windmilling drag. In the total absence of hydraulic supply to the servo valve, or loss of hydraulic supply to the second stage only, the propeller will be influenced by the blade forces. During flight the counterweight effort will drive the propeller coarse, on the ground the final pitch will be indeterminate, due to the variable nature of the blade forces at low blade angles. In the absence of hydraulic supply to the first stage of the servo valve, blade angle selection will be indeterminate as there is no mechanical bias to the second stage spool. TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 61 - PROPELLERS Issue 6 - January 2023 Page 52 of 86 BOMBARDIER DHC 8-400 (PWC PW150) PROPELLER - SERVOVALVE TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 61 - PROPELLERS Issue 6 - January 2023 Page 53 of 86 BOMBARDIER DHC 8-400 (PWC PW150) PROPELLER SYSTEMS COMPONENT LOCATION AND DESCRIPTION PITCH CONTROL UNIT (PCU) CONTINUED GROUND BETA ENABLE SOLENOID VALVE (GBEV) The purpose of the GBEV is to stop the propeller entering the ground range during flight. The Ground Beta Enable Valve is controlled by the Ground Beta Enable Solenoid. When energized it vents the enable valve end chamber to drain letting spring pressure move the valve from the flight position into the ground position. In the flight position solenoid de-energized, the ground fine chamber in the PCU is vented to drain. This stops the propeller being driven below the flight fine stop, which is set just below flight idle pitch. The OSG is connected into the hydraulic system with the valve in this position. In the ground position solenoid energized, the ground fine chamber is connected to the fine pitch oil line. This lets the propeller be driven into the ground blade pitch range. The OSG is isolated from the system to prevent potential coarse pitch hang ups during selection of maximum reverse after touchdown, or full power from the reverse position. The engine fuel control system gives overspeed protection with the valve in this position. For maintenance feathering and unfeathering, where there is no propeller rotation and no output from the high pressure pump, a spring in the Ground Beta Enable Valve makes sure that the valve is in the ground position. The GBEV is installed in the PCU. TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 61 - PROPELLERS Issue 6 - January 2023 Page 54 of 86 BOMBARDIER DHC 8-400 (PWC PW150) PROPELLER - GROUND BETA ENABLE VALVE AND SOLENOID (Shown in flight position) TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 61 - PROPELLERS Issue 6 - January 2023 Page 55 of 86 BOMBARDIER DHC 8-400 (PWC PW150) PROPELLER SYSTEMS COMPONENT LOCATION AND DESCRIPTION PITCH CONTROL UNIT (PCU) CONTINUED UNFEATHER VALVE AND SOLENOID The purpose of the Unfeather Valve and Solenoid is to direct oil from the auxiliary pump to the PCU servovalve. The valve is enabled when the unfeather solenoid and auxiliary pump are energized. The unfeather solenoid is activated by a maintenance switch, and is monitored by the PEC, although PEC incorporates no control over the valve. TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 61 - PROPELLERS Issue 6 - January 2023 Page 56 of 86 BOMBARDIER DHC 8-400 (PWC PW150) PROPELLER - UNFEATHER VALVE AND SOLENOID TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 61 - PROPELLERS Issue 6 - January 2023 Page 57 of 86 BOMBARDIER DHC 8-400 (PWC PW150) PROPELLER SYSTEMS The single wound solenoid is energized by operating the OSG Test Switch on the pilot side console. An interlock to prevent operation in flight is provided by the WOW input to a low side switch in the PEC. COMPONENT LOCATION AND DESCRIPTION OVERSPEED GOVERNOR AND HIGH PRESSURE PUMP (OSG) This provides a low-side switching from the local secondary 28V DC bus to ground through the OSG reset solenoid and the OSG Test Switch. The purpose of the OSG is to: The switching logic occurs in PEC control lanes that signal a transistor, on the Autofeather module to ground the OSG reset circuit. • • Increase the pressure of engine supplied oil, to a pressure suitable for propeller actuation Control the supply of oil to the propeller during flight The cylinder is then vented to drain so that the piston bottoms under spring force. The resultant lower spring load on the OSG governor spool causes the OSG to isolate HP supply at the lower 860 rpm ± 10 rpm. If an overspeed occurs, at approximately 1040 rpm, the oil supply to the second stage of the PCU servo valve will be vented to drain. This lets the propeller move towards coarse pitch by action of the blade counterweights, reducing Np. The unit incorporates a reset solenoid which sets the governor to a lower value, approximately 860 rpm, when doing functional checks. The OSG incorporates a gear pump and fly weight governor driven by the reduction gearbox. The governor controls the position of a spring loaded spool. When an overspeed condition occurs the spool will move against the spring, to vent the PCU supply line to drain. The unit is a two piece aluminium constructed body housing the gear pump case and governor/spool. The governor/spool body houses the reset solenoid valve and a pressure relief valve which limits pump maximum output pressure to 1100 psi (758.4 kPa). The OSG and pump are attached to the reduction gearbox by four studs and nuts. Correct installation is assured by one dowel. A bonded seal plate provides sealing against the gearbox casing for four oil ports. The OSG spool spring is installed on a piston in a cylinder that is normally connected to high pressure oil through a solenoid operated pilot valve. TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 61 - PROPELLERS Issue 6 - January 2023 Page 58 of 86 BOMBARDIER DHC 8-400 (PWC PW150) PROPELLER - PROPELLER OVERSPEED GOVERNOR AND PUMP TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 61 - PROPELLERS Issue 6 - January 2023 Page 59 of 86 BOMBARDIER DHC 8-400 (PWC PW150) PROPELLER SYSTEMS COMPONENT LOCATION AND DESCRIPTION FEATHERING PUMP The purpose of the feathering pump is to feather the propeller independently of the normal control system and achieves full feather zero windmilling The pump supplies backup oil pressure if the engine supply is not available. It gets its oil supply independently from a reserved chamber in the reduction gearbox. When energized, the pump supplies oil pressure to the PCU, which will feather the propeller blades. The pump is energized during: • • • Autofeather Alternate feather Maintenance feather/unfeather The unit incorporates a gear pump and 28V DC electric motor. The electric drive to the pump incorporates a run time (30 seconds) protection relay to prevent damage to the unit. The pump incorporates an aluminium body that contains a gear pump and a reduction gearbox, a filter, filter bypass valve, and a pressure relief valve. The pump is located on the rear case of the reduction gearbox and is attached by four studs and nuts. Two oil transfer bobbins and “O” ring seals give the sealing for the supply and outlets ports of the pump. TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 61 - PROPELLERS Issue 6 - January 2023 Page 60 of 86 BOMBARDIER DHC 8-400 (PWC PW150) PROPELLER - ALTERNATE FEATHER PUMP TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 61 - PROPELLERS Issue 6 - January 2023 Page 61 of 86 BOMBARDIER DHC 8-400 (PWC PW150) PROPELLER SYSTEMS COMPONENT LOCATION AND DESCRIPTION PROPELLER ELECTRONIC CONTROL UNIT (PEC) The purpose of the PEC is to control propeller pitch by controlling the servo valve. The Propeller Electronic Control (PEC) is a dual lane control device that supplies the servovalve drive current, to drive two motor coils in the servovalve. A number of failure conditions will cause the propeller to go into coarse pitch automatically. The coarse pitch bias was chosen because, total loss of electrical power will cause fuel supply to the engine to be shut off, so it is appropriate in this condition to feather the propeller. The failure conditions are: • • • Total loss of electrical power Loss of output from both PEC control lanes Failure of both servovalve torque motor coils The PEC is installed in the forward nacelle of each engine, on the spine between the forward and mid frames. Anti-vibration mounts are used at all mounting points, and all connectors point vertically downwards. The Propeller Electronic Controller (PEC) controls the various modes of the propeller system. The modes are: • • • • • • • Speed control Beta control Reverse thrust speed control Autofeather Engine uptrim command Synchrophasing AUPC TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 61 - PROPELLERS Issue 6 - January 2023 Page 62 of 86 BOMBARDIER DHC 8-400 (PWC PW150) PROPELLER - PEC FUNCTIONAL CONNECTIONS TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 61 - PROPELLERS Issue 6 - January 2023 Page 63 of 86 BOMBARDIER DHC 8-400 (PWC PW150) PROPELLER SYSTEMS The PEC continuously monitors itself and connected equipment for failures. COMPONENT LOCATION AND DESCRIPTION Fault codes are sent to the FADEC and can be shown on the Audio Radio Control and Display Unit (ARCDU) or the Engine Display (ED). PROPELLER ELECTRONIC CONTROL UNIT (PEC) CONTINUED Detected faults can be advisory or cautionary. The PEC also does numerous BITE and pilot initiated tests and incorporates comprehensive fault management software. These faults will normally be annunciated on request to the maintenance crew only and are not displayed to the pilots. The unit incorporates two control lanes, one active and one on standby, with automatic transfer to the standby lane in the event of a fault. For faults that are considered non-dispatchable a POWERPLANT message will be shown on the ED. An autofeather module is also installed, and is independent of engine control (FADEC) and control lane modules in the PEC. Lane is changed with WOW signal and NP into feather. Cautionary faults need pilot action. PEC cautionary faults will cause either the #1 or #2 PEC caution light, or absence of the A/F ARM indication when it should be indicated. The PEC does these functions: • • • • • • • • • • • • Control mode and Control function selection Servovalve control Ground Beta Enable and Overspeed Governor reset solenoid control Unfeather solenoid monitoring Low pitch indication Fault management Fault detection Fault accommodation Fault storage Fault annunciation Automatic under-speed protection circuit (AUPC) Automatic Takeoff Thrust Control System PEC output is isolated when both lanes are faulty or all electrical power is lost. Primary source of PEC power is the engine Permanent Magnet Alternator (PMA) rectified by the FADEC. During starting, or for PMA failure, the PEC is supplied by the essential buses. TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 61 - PROPELLERS Issue 6 - January 2023 Page 64 of 86 BOMBARDIER DHC 8-400 (PWC PW150) PROPELLER - PEC ELECTRICAL SUPPLIES TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 61 - PROPELLERS Issue 6 - January 2023 Page 65 of 86 BOMBARDIER DHC 8-400 (PWC PW150) PROPELLER SYSTEMS CONTROLS AND INDICATIONS The propeller control and indication system incorporates: • • Propeller RPM display Propeller ground range lights PROPELLER RPM DISPLAY Propeller RPM is shown on the Engine Display (ED). TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 61 - PROPELLERS Issue 6 - January 2023 Page 66 of 86 BOMBARDIER DHC 8-400 (PWC PW150) PROPELLER - ENGINE DISPLAY (ED) TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 61 - PROPELLERS Issue 6 - January 2023 Page 67 of 86 BOMBARDIER DHC 8-400 (PWC PW150) PROPELLER SYSTEMS CONTROLS AND INDICATIONS PROPELLER GROUND RANGE LIGHTS Propeller ground range lights on the left glare-shield panel show when the blade angles are in the ground operating range. The purpose of the propeller ground range lights is to indicate the propeller blade angles are 10° and below. The lights are controlled by the associated PEC that receives blade angle information from the Beta Feedback transducer. TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 61 - PROPELLERS Issue 6 - January 2023 Page 68 of 86 BOMBARDIER DHC 8-400 (PWC PW150) PROPELLER - PROPELLER GROUND RANGE LIGHTS TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 61 - PROPELLERS Issue 6 - January 2023 Page 69 of 86 BOMBARDIER DHC 8-400 (PWC PW150) PROPELLER SYSTEMS CONTROLS AND INDICATIONS PEC CAUTION LIGHTS The appropriate PEC caution light, installed on the Caution and Warning Panel, will come on in the event of: • • • • • • • • • • Automatic Under-speed Protection Circuit (AUPC) active PCU servo valve current demand and feedback disagree PCU servo valve current power up BIT failure PLA invalid PLA beta switch stuck OPEN Ground Beta Enable Solenoid (GBES) stuck OPEN or CLOSED Magnetic Pickup Unit (MPU) signal out of range HIGH MPU signal disagrees with Npt A and Npt B Beta out of range Beta unreliable in beta range TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 61 - PROPELLERS Issue 6 - January 2023 Page 70 of 86 BOMBARDIER DHC 8-400 (PWC PW150) PROPELLER - PEC CAUTION LIGHTS TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 61 - PROPELLERS Issue 6 - January 2023 Page 71 of 86 BOMBARDIER DHC 8-400 (PWC PW150) PROPELLER SYSTEMS INTERFACES Serial data bus links are used to exchange information between the PEC and the Full Authority Digital Electronic Controller (FADEC). The serial bus links also send maintenance data to the aircraft monitoring system, through FADEC and the Engine Monitoring Unit (EMU). TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 61 - PROPELLERS Issue 6 - January 2023 Page 72 of 86 BOMBARDIER DHC 8-400 (PWC PW150) WORD RANGE OR BITS Beta ± 90° Untrimmed Beta ± 90° CLA -11° to +110° Np 0 to 1530 rpm PEC S/N 6 characters PEC P/N 19 characters Phase angle ± 90° Demanded phase ± 90° Disc 1 WOW - Cancel Npt Gov - A/F Q Low - PLA High - FADEC Power Not Available - A/F Test in Progress Disc 2 A/F Test Status - OSG Test Abort - OSG test in Progress - OSG Test Status - AUPC Test in Progress - AUPC Test Status Disc 3 AUPC Test Abort - BFT Trim in Progress - BFT Trim Status - BFT Trim Abort - A/F Arm Indication - A/F Select Indication - Slave PEC Disc 4 Maintenance Mode - Low Beta Indication - Manual Feather Indication - Manual Unfeather Indication - PEC Caution Indication - OSG Test Request Discrete - Lane (Channel) Active Indication Disc 5 Np Reference = 1020 rpm - Np Reference = 900 rpm - Np Reference = 850 rpm - Np Reference = Feather - Short Term TLD - Long Term TLD - (Short Term + Long Term = No Dispatch) - PLA Beta Switch Indication Disc 6 FADEC Communication Fail - A/F Indication Fail (PEC Detected Engine Failure) - A/F Feather Indication (PEC detected Autofeather) Maintenance 1 1-499 (from PEC RAM) Maintenance 2 1-499 (from PEC NVM) PROPELLER - RS422 Data Bus - PEC to FADEC TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 61 - PROPELLERS Issue 6 - January 2023 Page 73 of 86 BOMBARDIER DHC 8-400 (PWC PW150) WORD RANGE or BITS PLA -9° to 109° CAS 30 to 420 knots T 1.5 -7°C to 100°C Pamb 1.675 to 18.275 psia Qbias ± 298.74 ft lbs Qgain 0.9 to 1.1:1 Q -50% to 260% Disc 1 MaintenanceMode - PMA Power - RDC TOP Decrease - Rigging Trim - Remote Uptrim Confirmed - Active Noise Selected (not enabled in wiring) Disc 2 No PEC Communication - FADEC Synchronized with PEC - RDC Np PROPELLER - RS422 DATA BUS - FADEC TO PEC TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 61 - PROPELLERS Issue 6 - January 2023 Page 74 of 86 BOMBARDIER DHC 8-400 (PWC PW150) INTENTIONALLY LEFT BLANK TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 61 - PROPELLERS Issue 6 - January 2023 Page 75 of 86 BOMBARDIER DHC 8-400 (PWC PW150) PROPELLER SYSTEMS SYSTEM TESTS OVERSPEED GOVERNOR TEST To conduct an overspeed governor test the following conditions are set: • • • • • • • • • Power Levers - Flight Idle Condition levers - Max 1020 rpm Control Lock - Off OSG Test Switch - Test Power levers - Slowly advance to 20% Torque Check prop governs to 860 rpm ± 10 rpm Observe OSG TEST PASS appears on ED Power levers - Disc OSG Test Switch - Release TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 61 - PROPELLERS Issue 6 - January 2023 Page 76 of 86 BOMBARDIER DHC 8-400 (PWC PW150) PROPELLER - PROPELLER OSG TEST SWITCH TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 61 - PROPELLERS Issue 6 - January 2023 Page 77 of 86 BOMBARDIER DHC 8-400 (PWC PW150) PROPELLER SYSTEMS SYSTEM TESTS CONTINUED AUTO FEATHER TEST To conduct an autofeather test the following conditions are set: • • • • • • • • • • • • • • Condition Levers - Start/Feather or Fuel Off Power Levers - Disc A/F Select Switch - Confirm Selection on ED Observe the following on ED A/F Select A/F Test in Progress Uptrim NTOP changes to MTOP Torque bug ratings increase by 10%. #1 and #2 ALT FTHR advisory lights come on momentarily A/F Test Pass MTOP changes to NTOP Torque bug ratings decrease by 10% Autofeather Select Switch - Push TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 61 - PROPELLERS Issue 6 - January 2023 Page 78 of 86 BOMBARDIER DHC 8-400 (PWC PW150) PROPELLER - PROPELLER CONTROL PANEL TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 61 - PROPELLERS Issue 6 - January 2023 Page 79 of 86 BOMBARDIER DHC 8-400 (PWC PW150) • • PROPELLER SYSTEMS POWERPLANT RIGGING/TRIMMING • CONDITION LEVER ANGLE • Set PLA to FLIGHT IDLE and CLA to 850 rpm positions Put the FADEC/PEC in maintenance mode. Maintenance Panel MAINT DISC ON Hold the Maintenance Panel RIG TRIM switch ON for approximately 5 seconds Confirm on ARCDU page that a trimmed value of 35° is shown for both channels Although CLA is an analogue (variable voltage ratio) input to the PEC, the signal is treated as switched input for each position. Therefore there is no requirement to rig CLA. Correct tolerances are achieved when the quadrant RVDT are set up on the bench in accordance with the CMM. The PEC can verify that the CLA signal is in tolerance as follows: • • • • Set PLA to FLIGHT IDLE and CLA to 850 rpm positions Put FADEC/PEC in maintenance mode Maintenance Panel MAINT DISC on Hold the Maintenance Panel RIG TRIM switch on for approximately 5 seconds Confirm on the CDS that there are no CLA associated faults The requirements for this check are also satisfied during FADEC rig trim. POWER LEVER ANGLE The FADEC is rigged/trimmed at flight idle to match PLA RVDT input to the FADEC software. System tolerances then ensure that sensed PLA is consistent between the two engines throughout the PLA range. Both FADEC may be done together if required. The procedure is: • • Put the CDS in maintenance mode. Maintenance Panel CDS GND MAINT switch ON. ARCDU MAINT pushbutton ON Select PLA TRIM page on the ARCDU TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 61 - PROPELLERS Issue 6 - January 2023 Page 80 of 86 BOMBARDIER DHC 8-400 (PWC PW150) PROPELLER - PLA TRIM TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 61 - PROPELLERS Issue 6 - January 2023 Page 81 of 86 BOMBARDIER DHC 8-400 (PWC PW150) PROPELLER SYSTEMS The procedure for hydraulically setting flight fine pitch is: • • • • PROPELLER RIGGING/TRIMMING The propeller system is rigged/trimmed at FLIGHT IDLE to: • • • Position the Beta tube assembly within the Beta Feedback Transducer so that the signal remains within range throughout the reverse and Beta schedules Ensure that the propeller blade angle is correct at this condition, flight fine pitch, for aircraft in flight handling Match PLA RVDT input to the PEC software for Beta scheduling Set PLA to FLIGHT IDLE Select MAINT DISC ON Select UNFEATHER until blade pitch stops moving Confirm by inspection of the flight fine pitch marking on blade #1 that the propeller is at flight fine If any part of the hydro-mechanical propeller system incorporates been disturbed, then the mechanical set-up of the Beta tubes and blade angle incorporates to be accomplished before trimming the PEC. If only the PEC incorporates been replaced, then the feathering pump is used to drive the propeller to flight fine pitch and PEC trimming is done at this condition. The procedure to position the Beta tube assembly is: • • • Remove the cover from the cylinder Bat the blades to reverse pitch so that the end of the Beta tube protrudes from the cylinder Turn the assembly in, or out, until the distance between the end face of the tube assembly and the end face of the locking collar spring loaded outwards is 0.275 inch The procedure for setting the flight fine pitch is: • • • With the cylinder cover removed, bat the blades until the distance between the piston retaining nut outer surface and the cylinder end cover face equals the BETA CAL dimension marked on the cylinder OR Pre-set the Beta Cal tool to the marked dimension, install the tool in place of the cover and using the feathering pump, drive the propeller fine, until it stops moving. This indicates that the piston nut incorporates contacted the tool TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 61 - PROPELLERS Issue 6 - January 2023 Page 82 of 86 BOMBARDIER DHC 8-400 (PWC PW150) PROPELLER - SETTING FLIGHT FINE PITCH TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 61 - PROPELLERS Issue 6 - January 2023 Page 83 of 86 BOMBARDIER DHC 8-400 (PWC PW150) PROPELLER SYSTEMS PROPELLER RIGGING/TRIMMING CONTINUED The procedure for trimming the PEC is: • • • • • • • • Set the propeller to flight fine pitch as previously described Set PLA for the PEC to be trimmed to FLIGHT IDLE, ensure the other PLA is at DISC Set CLA for the PEC to be trimmed to 1020 rpm, ensure the other CLA is at FUEL OFF Put the CDS in Maintenance Mode - Maintenance Panel CDS GND MAINT switch ON, ARCDU MAINT pushbutton ON Select PROPELLER PITCH TRIM page on ARCDU Put the FADEC/PEC in maintenance mode - Maintenance Panel MAINT DISC ON Hold the Maintenance Panel RIG TRIM switch ON for approximately 15 seconds Confirm on the ARCDU page that COMPLETE, with a trimmed value of 16° or 17° is shown for both channels TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 61 - PROPELLERS Issue 6 - January 2023 Page 84 of 86 BOMBARDIER DHC 8-400 (PWC PW150) PROPELLER - PROPELLER BLADE PITCH TRIM TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 61 - PROPELLERS Issue 6 - January 2023 Page 85 of 86 BOMBARDIER DHC 8-400 (PWC PW150) PROPELLER SYSTEMS PROPELLER RIGGING/TRIMMING CONTINUED PEC TORQUE TRIM The torque signal trim values for offset and gain from the engine characterization plug are used by the PEC to calibrate the torque signals for UPTRIM and AUTOFEATHER functions. The values are stored in PEC NVM. The NVM torque trim values may be updated as follows: • • • • Ensure both PLA are set to DISC. This avoids activating any other rig/trim functions Ensure AUTOFEATHER switch is selected OFF Put the FADEC/PEC in maintenance mode. Maintenance Panel MAINT DISC ON Hold the Maintenance Panel RIG TRIM switch ON for approximately 5 seconds TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 61 - PROPELLERS Issue 6 - January 2023 Page 86 of 86