ATA 72 Engines Maintenance Training Manual January 2023 PDF

BOMBARDIER DHC 8-400 (PWC PW150) ATA 72 - ENGINES TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY B1/B2 MAINTENANCE TRAINING MANUAL Issue 6 - January 2023 Page 1 of 44 BOMBARDIER DHC 8-400 (PWC PW150) ENGINE INTRODUCTION The engine provides motive power to the aircraft and gives air and elect...

BOMBARDIER DHC 8-400 (PWC PW150) ATA 72 - ENGINES TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY B1/B2 MAINTENANCE TRAINING MANUAL Issue 6 - January 2023 Page 1 of 44 BOMBARDIER DHC 8-400 (PWC PW150) ENGINE INTRODUCTION The engine provides motive power to the aircraft and gives air and electrical power to various aircraft systems. The following table describes the engine operating limits: TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 72 - ENGINES Issue 6 - January 2023 Page 2 of 44 BOMBARDIER DHC 8-400 (PWC PW150) ENGINE - OPERATING LIMITS TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 72 - ENGINES Issue 6 - January 2023 Page 3 of 44 BOMBARDIER DHC 8-400 (PWC PW150) ENGINE GENERAL DESCRIPTION The Dash 8 series 400 aircraft is powered by two PW150A turbo-prop engines. The PW150A turboprop engine is a three spool engine with a two section gas generator a low pressure spool and a high pressure spool and a power section. The high pressure (HP) gas generator includes a reduction gearbox. The HP compressor is a centrifugal flow type and the turbine section is axial flow type. This spool rotates at a speed designated Nh. The low pressure (LP) gas generator has both compressor and turbine axial flow sections. This spool rotates at a speed designated NL. The power section is an axial flow type rotating at a speed designated as Npt. This speed is reduced through the reduction gearbox to a propeller shaft rotating at a speed designated as NP. The engine also has a reverse flow annular combustor and a two-stage power turbine. The power turbine provides the drive for the compressors and the Reduction Gearbox (RGB). The RGB reduces the power turbine input speed and increases the torque. Air enters the compressors through the inlet case. The compressors are driven by the LP and HP turbines. Fuel is added to the compressed air in the combustion chamber. The igniters are used for starting but are not required once the fuel/air mixture has ignited. TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 72 - ENGINES Issue 6 - January 2023 Page 4 of 44 BOMBARDIER DHC 8-400 (PWC PW150) ENGINE - IDENTIFICATION OF SECTIONS TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 72 - ENGINES Issue 6 - January 2023 Page 5 of 44 BOMBARDIER DHC 8-400 (PWC PW150) ENGINE SYSTEM DESCRIPTION The engine is started by the starter/generator rotating the HP impeller and the turbine. The drive for this rotation is taken through the accessory gearbox to the driveshaft to rotate the bevel gear splined to the HP impeller. Fuel is sprayed into the combustion chamber, where it is mixed with the incoming air from the compressors. At a predetermined speed, the ignition system switches the igniters on and the air/fuel mixture is ignited. The resultant rearward flow of expanding gases drives the HP and LP turbines, which are connected to the HP and LP compressors. The rotating turbines turn the compressors which draw in more air to mix and burn with the fuel. This creates additional expanding gases which increase the speed of the turbines and compressors until the engine has achieved self-sustaining speed with continuous combustion. The igniters are then switched off and the starter/generator functions as a generator. The flow of expanding gases through the engine also drives the power turbine, which turns the propeller through the gearbox. A further increase in fuel flow to the combustion chamber will increase gas expansion, resulting in an increase in turbine and compressor speed. The HP and power-turbine rotors rotate clockwise. The LP rotor rotates counterclockwise when viewed from the rear. The two engine modules are: • • The reduction gearbox module The turbo-machinery module TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 72 - ENGINES Issue 6 - January 2023 Page 6 of 44 BOMBARDIER DHC 8-400 (PWC PW150) ENGINE - ENGINE CUTAWAY VIEW TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 72 - ENGINES Issue 6 - January 2023 Page 7 of 44 BOMBARDIER DHC 8-400 (PWC PW150) ENGINE - LOCATION OF MODULES AND EXTERNAL COMPONENTS Page 1 TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 72 - ENGINES Issue 6 - January 2023 Page 8 of 44 BOMBARDIER DHC 8-400 (PWC PW150) ENGINE - LOCATION OF MODULES AND EXTERNAL COMPONENTS Page 2 TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 72 - ENGINES Issue 6 - January 2023 Page 9 of 44 BOMBARDIER DHC 8-400 (PWC PW150) ENGINE - LOCATION OF MODULES AND EXTERNAL COMPONENTS Page 3 TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 72 - ENGINES Issue 6 - January 2023 Page 10 of 44 BOMBARDIER DHC 8-400 (PWC PW150) ENGINE - LOCATION OF MODULES AND EXTERNAL COMPONENTS Page 4 TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 72 - ENGINES Issue 6 - January 2023 Page 11 of 44 BOMBARDIER DHC 8-400 (PWC PW150) • • • ENGINE REDUCTION GEARBOX AC generator drive spur gearshaft Hydraulic pump drive spur gearshaft Overspeed-governor drive spur gearshaft GENERAL DESCRIPTION The Reduction Gearbox reduces the input speed from the engine to a suitable speed range for the propeller. The Reduction Gearbox (RGB) module is one of two primary engine modules. The RGB is the reduction stage between the power turbine shaft (input) and the propeller shaft (output). The total reduction ratio is 17.16:1. The RGB reduces the power turbine speed (17,501 rpm) to one suitable for propeller operation (1020 rpm). The RGB has these functions: • • • • • • • Support the propeller Transmit turbomachinery power to propeller Transmit thrust to aircraft structure Drive the RGB mounted accessories, AC generator, overspeed governor and pump, and hydraulic pump Give appropriate reference to torque indicating system Provide attachments for three engine forward mounts Provide housings for AC generator chip detector and RGB chip detector The first stage of the reduction geartrain has a helical input shaft and two first-stage helical gears. The second stage has two helical gearshafts pinion gears and one large helical gearshaft bullgear installed on the propeller shaft. The first-stage gears are connected to the second-stage gearshafts pinion gears through the flexible layshaft couplings. The first-stage gears, the flexible layshaft couplings and the second-stage gearshafts make up the flexible layshafts. The four accessory gears in the reduction gearbox are: • Idler-drive spur gearshaft TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 72 - ENGINES Issue 6 - January 2023 Page 12 of 44 BOMBARDIER DHC 8-400 (PWC PW150) ENGINE - REDUCTION GEARBOX TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 72 - ENGINES Issue 6 - January 2023 Page 13 of 44 BOMBARDIER DHC 8-400 (PWC PW150) ENGINE REDUCTION GEARBOX GENERAL DESCRIPTION CONTINUED The reduction gearbox assembly includes three housings: • • • The front housing The rear housing The diaphragm input-drive housing The accessory drive cover is installed on the top of the back face of the rear housing. The cover has these mounting pads: • • • AC generator Hydraulic pump Overspeed-governor and pump assembly TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 72 - ENGINES Issue 6 - January 2023 Page 14 of 44 BOMBARDIER DHC 8-400 (PWC PW150) ENGINE - REDUCTION GEARBOX REAR DETAIL TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 72 - ENGINES Issue 6 - January 2023 Page 15 of 44 BOMBARDIER DHC 8-400 (PWC PW150) ENGINE REDUCTION GEARBOX SYSTEM DESCRIPTION When the engine turns, the power turbines drive the input shaft clockwise through the PT shaft and the torque shaft. The input shaft engages the first-stage gears. The first-stage gears turn counter-clockwise and the flexible layshaft couplings transmit the power to the second-stage gearshafts pinion gears. The first-stage reduction ratio is 3.92:1. The two second-stage gearshafts pinion gears drive the second-stage spur gearshaft bullgear clockwise, together with the propeller shaft. The second-stage reduction ratio is 4.37:1. The bullgear drives the idler-drive gearshaft and the overspeed-governor gearshaft counter-clockwise. The idler-drive gearshaft drives the alternator-drive gearshaft clockwise. The reduction ratios from the bullgear to the accessory gearshafts are: • • • • The idler-drive gearshaft: 5.62:1 The alternator-drive gearshaft: 15.79:1 The overspeed-governor gearshaft: 5.62:1 The hydraulic pump gearshaft: 6.88:1 A chamber in the rear housing is supplied with engine oil. This auxiliary tank is always full of oil, even when the engine is not in operation. Oil from this tank lubricates the reduction and accessory gears and bearings through oil passages, oil jets and nozzles. The overspeed governor and the propeller control unit uses this oil to operate the pitch-change mechanism of the propeller. The electric feathering-pump mounting pad on the rear housing has oil ports that are connected to this auxiliary oil tank. TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 72 - ENGINES Issue 6 - January 2023 Page 16 of 44 BOMBARDIER DHC 8-400 (PWC PW150) ENGINE - RGB GEARTRAIN TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 72 - ENGINES Issue 6 - January 2023 Page 17 of 44 BOMBARDIER DHC 8-400 (PWC PW150) ENGINE REDUCTION GEARBOX SYSTEM DESCRIPTION CONTINUED REDUCTION GEARBOX GEAR-TRAIN BEARINGS The reduction gearbox gear-train bearings supports the shafts. The input drive shaft is supported by No.8 and No.9 roller bearings. The first stage helical gears are supported by No.11 and No.12 roller bearings. The second stage pinion gears are supported by No.13 and No.14 roller bearings. The propeller shaft is supported by No.19 roller bearing, No.18 ball bearing and No.15 roller bearing. Propeller thrust is transferred by No.18 ball bearing. The idler drive gear shaft is supported by No.27 and No.28 roller bearings. The AC generator drive gear shaft is supported by No.23 and No.26 roller bearings. The overspeed governor drive gear shaft is supported by No.21 and No.22 roller bearings. The hydraulic pump drive gear shaft is supported by No.24 and No.25 roller bearings. TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 72 - ENGINES Issue 6 - January 2023 Page 18 of 44 BOMBARDIER DHC 8-400 (PWC PW150) ENGINE - RGB GEARTRAIN BEARINGS (1) TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 72 - ENGINES Issue 6 - January 2023 Page 19 of 44 BOMBARDIER DHC 8-400 (PWC PW150) ENGINE - RGB GEARTRAIN BEARINGS (2) TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 72 - ENGINES Issue 6 - January 2023 Page 20 of 44 BOMBARDIER DHC 8-400 (PWC PW150) ENGINE - RGB GEARTRAIN BEARINGS (3) TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 72 - ENGINES Issue 6 - January 2023 Page 21 of 44 BOMBARDIER DHC 8-400 (PWC PW150) ENGINE ENGINE AIR INTAKE GENERAL DESCRIPTION The inlet case gives air to the Low Pressure (LP) compressor under all flight conditions with as little turbulence and pressure variation as possible. The front inlet case is the entrance for the air used by the engine. FRONT INLET CASE The front inlet case provides structural connection between the RGB and the turbomachinery. It directs air flow between the inlet duct and the first stage of the LP compressor. The front inlet case also: • • • • Supports the power turbine and low pressure shafts Supports the flexible coupling shaft assembly that transmits power to the RGB Provides sealing for the No.1 bearing cavity Allows oil to pass to bearing cavities The front inlet case is located between the Reduction Gearbox (RGB) and the Low Pressure (LP) compressor case. The inlet case is made of magnesium alloy. Hot oil flows through internal passages in the case. This prevents the formation of ice in the inlet. The Full Authority Digital Electronic Control (FADEC) is mounted on the left side of the case and the fuel flow meter is mounted on the right side. TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 72 - ENGINES Issue 6 - January 2023 Page 22 of 44 BOMBARDIER DHC 8-400 (PWC PW150) ENGINE - ENGINE AIR INTAKE TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 72 - ENGINES Issue 6 - January 2023 Page 23 of 44 BOMBARDIER DHC 8-400 (PWC PW150) ENGINE The gas path is based on an 18:1 pressure ratio. COMPRESSOR SECTION Carbon seals are used in the compressor and other areas of the turbomachinery for sealing the bearing cavities. The Carbon element is replaceable. GENERAL DESCRIPTION Air enters the compressor section from the front inlet case. The compressor section raises the pressure of the incoming air before passing it to the combustion chamber. At the first three stages of compression (LP compression) a series of axial rotors and vane cascades compress, direct, and diffuse the air. The compressors draw air into the engine through the front inlet case. The fourth stage of compression (HP compression) is done by the HP impeller, from there the air goes through the diffuser pipes. Air pressure increases across an axial three stage compressor and a centrifugal impeller. The compressed air is then delivered to the combustion chamber and other systems. The compressed air is used to : • • • • • • Sustain combustion to give the energy necessary to rotate the compressors and power propeller sections Cool the main hot section components Supply bleed air for the aircraft environmental control system air conditioning and de-icing Seal bearing cavities Assist oil scavenging of some bearing cavities Operate the two bleed valves SYSTEM DESCRIPTION The compressor section has two independent compressors: • • Low Pressure (LP) Compressor an axial three stage compressor High Pressure (HP) Compressor a centrifugal impeller Each compressor has a single-stage turbine to make it turn. The axial and centrifugal compressors and the power turbines are attached to coaxially located shafts. The shafts are supported by roller and ball bearings. TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 72 - ENGINES Issue 6 - January 2023 Page 24 of 44 BOMBARDIER DHC 8-400 (PWC PW150) ENGINE - ENGINE SECTIONS TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 72 - ENGINES Issue 6 - January 2023 Page 25 of 44 BOMBARDIER DHC 8-400 (PWC PW150) ENGINE COMPRESSOR SECTION COMPONENT LOCATION AND DESCRIPTION LOW PRESSURE COMPRESSOR The low pressure compressor imparts the initial compression to the incoming air and directs it to the HP compressor. The LP compressor is supported by the damped No.2.5 roller bearing and the No.3 ball bearing. The rotor components are three axial Integrated Blade Rotors (IBR) (1st, 2nd, and 3rd stage) all of titanium alloy. The IBR are designed to be FOD resistant. The drive comes from the 2nd stage IBR integral stub shaft. The shaft rotates the 3rd stage IBR bolted to a flange next to the 2nd stage IBR. The 1st stage IBR is axially retained to the 2nd stage IBR through a tie shaft arrangement. The 1st stage vane assembly is a full vane ring cascade. The 2nd stage vane assembly is similar to the 1st stage. Both the 1st and 2nd stage stators are damped. Facing the 3rd stage stator are the bleed slots P2.2, which bleed up to 15% core flow. The 3rd stage stator assembly is a non-damped double row cascade. This double row cascade slows the air down to provide near zero swirl at the inlet to the Intercompressor Case (ICC) duct. This assembly is split in two halves to permit one piece compressor module assembly and removal. TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 72 - ENGINES Issue 6 - January 2023 Page 26 of 44 BOMBARDIER DHC 8-400 (PWC PW150) ENGINE - LP AXIAL FLOW COMPRESSOR CUTAWAY TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 72 - ENGINES Issue 6 - January 2023 Page 27 of 44 BOMBARDIER DHC 8-400 (PWC PW150) ENGINE COMPRESSOR SECTION COMPONENT LOCATION AND DESCRIPTION CONTINUED INTERCOMPRESSOR CASE The intercompressor case forms a path that allows air to flow from the LP compressor to the HP compressor. The intercompressor case is located between the LP compressor case and the gas generator case. It houses the centrifugal HP compressor and the accessory drive shaft (tower shaft). The titanium intercompressor case casting holds the No.3 and No.4 bearing cavity that supports the LP and HP compressors. The intercompressor case gives support for these components: • • • • • P2.7 Check Valve (for ECS) P2.7 Handling Bleed Valve (HBV) Angle Drive Gearbox Rear Engine Mounts Drain Valve HIGH PRESSURE COMPRESSOR The high pressure compressor completes the compression of the air to the correct pressure ratio. The centrifugal compressor is supported on an integral shaft. The shaft is supported by the upstream side of No.4 ball bearing and the downstream side of the damped No.5 roller bearing. The impeller shroud is a double annulus for the P2.7 and P2.8 bleeds. Cabin bleed is provided by P3 and P2.7 air. TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 72 - ENGINES Issue 6 - January 2023 Page 28 of 44 BOMBARDIER DHC 8-400 (PWC PW150) ENGINE - HP COMPRESSOR DETAIL TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 72 - ENGINES Issue 6 - January 2023 Page 29 of 44 BOMBARDIER DHC 8-400 (PWC PW150) ENGINE COMBUSTION SECTION GENERAL DESCRIPTION The combustion section burns a mixture of fuel and air and delivers the resulting gases to the turbines. Fuel is added to the compressed air in the combustion chamber. The igniters are used for starting but are not required once the fuel/air mixture is lit. The annular reverse flow combustion chamber is contained in the gas generator case. It is located at the rear of the HP compressor and the fish tail diffuser ducts. The major components comprising the combustor are the: • • • • • Outer liner Inner liner Small Exit Duct (SED) Adapter Piston Ring TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 72 - ENGINES Issue 6 - January 2023 Page 30 of 44 BOMBARDIER DHC 8-400 (PWC PW150) ENGINE - ENGINE SECTIONS TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 72 - ENGINES Issue 6 - January 2023 Page 31 of 44 BOMBARDIER DHC 8-400 (PWC PW150) ENGINE COMBUSTION SECTION SYSTEM DESCRIPTION Compressed air from the HP diffuser ducts flows into the Gas Generator Case around the combustion liner. The air flows into the dilution holes and through holes in the machined louvres. Air is used to assist in the fuel atomization, for cooling the liner skin and for combustion. The large exit duct is double skinned, with impingement holes in the outer skin for effective cooling of the inner skin. The inner surface comprises machined louvres. Hot combustion gases flow forward in a three dimensional torroid and are directed rear toward the HP Vane by the combustor outer liner and the Small Exit duct. TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 72 - ENGINES Issue 6 - January 2023 Page 32 of 44 BOMBARDIER DHC 8-400 (PWC PW150) ENGINE - COMBUSTION SECTION TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 72 - ENGINES Issue 6 - January 2023 Page 33 of 44 BOMBARDIER DHC 8-400 (PWC PW150) ENGINE COMBUSTION SECTION COMPONENT LOCATION AND DESCRIPTION COMBUSTOR The combustor provides a contained space in which combustion can occur. It directs the resultant hot, high speed gases to the turbine area. The combustor is made of INCO-625 material, with integral drilled louvres. A thermal barrier coating (plasma spray coating) is applied to all the inside surfaces of the combustor, except for the louvres immediately adjacent to the hole exits. A fuel manifold is mounted around the exterior of the Turbine Support Case. The fuel manifold has: • • Twelve hybrid fuel nozzles each containing a primary air blast A secondary air blast with combustor air swirler Two igniter plug bosses are provided on the gas generator case at the four and seven o’clock positions, with corresponding bosses in the liner. Combustor retention is provided by six combustor retention pins located in the igniter plane. Four of these bosses also permit borescope inspection of the combustor. TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 72 - ENGINES Issue 6 - January 2023 Page 34 of 44 BOMBARDIER DHC 8-400 (PWC PW150) ENGINE - ENGINE COMBUSTOR TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 72 - ENGINES Issue 6 - January 2023 Page 35 of 44 BOMBARDIER DHC 8-400 (PWC PW150) ENGINE The gases then travel across the interturbine vane and impinge on the first stage PT turbine blades. The gases then pass to the PT vane and to the second stage PT turbine. TURBINES GENERAL DESCRIPTION The turbines turn the compressors, the propeller and the engine accessories. The turbines extract kinetic energy from the expanding gases as the gases come from the combustor. The turbines then convert this energy into shaft horsepower to drive the compressors, propeller and the engine accessories. The hot section of the engine has these three turbine stages: • • • Low Pressure (LP) turbine High Pressure (HP) turbine Power Turbines (PT) The LP and HP turbines turn the compressors through their own respective shafts. The power turbines turn the propeller through the power turbine shaft and the reduction gearbox. The LP and HP turbines are installed in the rear of the gas generator case, and the power turbines are installed in the turbine support case. Concentric shafts connect the two-stage power turbine to the gearbox and the single-stage LP and HP turbines to the compressors. The central PT shaft is supported by the No.1 ball, No.2 roller, No.6.5 roller and No.7 roller bearings. The intermediate LP turbine shaft is supported by the No.2.5 roller, No.3 ball and No.6 roller bearings. The HP turbine shaft integral with the impeller is supported by the No.4 ball and No.5 roller bearings. The hot section also has these vane assemblies: • • • • All three turbines turn at independent speeds. At engine start, the starter/generator turns only the HP compressor and HP turbine. The HP turbine rotates clockwise pilot view to a maximum speed of 31150 rpm (100%). HP vane assembly LP vane assembly Inter-turbine vane assembly Power turbine vane assembly Each vane assembly is installed in front of its associated turbine, to direct the hot gases to the turbines and change static pressure into velocity. The LP turbine rotates counter-clockwise to a maximum speed of 27000 rpm (100%). The Power turbine rotates clockwise to a maximum speed of 17501 rpm (100%). SYSTEM DESCRIPTION The hot section of the engine has components downstream of the gas generator. Hot expanding gases leaving the combustion chamber are directed towards the HP turbine blades by the HP turbine ring. After the HP turbine the hot gases are directed towards the LP turbine blades by the LP turbine ring. TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 72 - ENGINES Issue 6 - January 2023 Page 36 of 44 BOMBARDIER DHC 8-400 (PWC PW150) ENGINE - TURBINES TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 72 - ENGINES Issue 6 - January 2023 Page 37 of 44 BOMBARDIER DHC 8-400 (PWC PW150) ENGINE TURBINES COMPONENT LOCATION AND DESCRIPTION HIGH PRESSURE TURBINE (HPT) The high pressure turbine converts the energy in the gas stream into kinetic energy to drive the high pressure compressor. The High Pressure Turbine consists of a nickel alloy disc featuring 41 air cooled blades. The base material for the blades is a single crystal nickel alloy. The blades are secured by fir-tree serrations and two covers. The cooling air is provided through showerhead, tip and platform cooling holes with trailing edge ejection. The HP disc transfers power from the expanding gases to the HP impeller. The disc has two covers that retain the blades axially and minimize cooling air leakage through the fir-tree of the blades. The front cover also increases the air pressure delivered. The cooling air is used to: • • • • Cool the HP blades Ventilate the HP disc bore Purge the downstream side of the rear cover Impinge upon the LP vane inner drum The disc is balanced by eccentric material removal. Both cover plates are detail balanced by concentric material removal. Assembly balancing is achieved by weights mounted on a scalloped flange. TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 72 - ENGINES Issue 6 - January 2023 Page 38 of 44 BOMBARDIER DHC 8-400 (PWC PW150) ENGINE - HP TURBINE TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 72 - ENGINES Issue 6 - January 2023 Page 39 of 44 BOMBARDIER DHC 8-400 (PWC PW150) ENGINE TURBINES COMPONENT LOCATION AND DESCRIPTION CONTINUED LP TURBINE VANE ASSEMBLY The LP vane assembly directs the hot gases to the LP turbine and change static pressure into velocity. The vane stage is made of 28 airfoils, seven segments of four airfoils each, assembled into a squirrel cage outer assembly. The outer support structure is made with large windows to facilitate impingement cooling on the vane segments and for weight saving. The squirrel cage also attenuates the distortion transmitted to the turbine support case to provide better tip clearance control. LP TURBINE The low pressure turbine converts the energy in the gas stream into kinetic energy to drive the low pressure compressor. The LP Turbine is made of nickel alloy. It consists of a disc featuring 41 air-cooled blades. The base material for the blades is a single crystal nickel alloy. The blades are secured by fir-tree serrations and integral rear face disc lugs with a blade retaining cover on the front face. The retaining cover is made with internal fins to pump air for the cooling of the blades. The blades use trailing edge ejection for the cooling air. The disc is straddle mounted on the LP shaft. TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 72 - ENGINES Issue 6 - January 2023 Page 40 of 44 BOMBARDIER DHC 8-400 (PWC PW150) ENGINE - LP TURBINE TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 72 - ENGINES Issue 6 - January 2023 Page 41 of 44 BOMBARDIER DHC 8-400 (PWC PW150) ENGINE Each member of the joint has 36 teeth, allowing for multiple indexing positions, should the need arise. This minimizes disc to disc run out. TURBINES The PT1 disc radial location is aft of the No.6.5 bearing at two spigot locations. COMPONENT LOCATION AND DESCRIPTION CONTINUED Similarly, the PT2 disc location is forward of No.7 bearing, at two spigot locations. Each disc is installed and removed separately. This eases assembly and disassembly of the power turbine section. INTER TURBINE VANE (ITV) ASSEMBLY The ITV assembly acts as the inter turbine duct and the PT1 vane. It also supports the No.6 and No.6.5 bearing housings. The PT2 Vane Assembly comprises 66 hollow airfoils. It is located in the turbine support case, by 11 equally spaced dogs and slots. The inner drum has 11 slots. Cooling is used over the blade shroud to minimize PT1 blade tip clearance impingement. The ITV is attached to the TSC at a flange. The ITV is made of 16 cambered airfoils: two airfoils are thick for oil passage, and 14 airfoils are thin. Cooling flow comes from the intercompressor case P2.7 through an external pipe. The outer drum is cooled by an impingement shield. The air is then passed through the airfoils using a multiple serpentine cooling arrangement. In the event of a LP shaft failure, The ITV is designed to contain the LP rotor axially. Four borescope ports are part of the ITV for gas path component inspection. POWER TURBINES The power turbines extract energy from the hot gases to turn the propeller through a reduction gearbox. The turbines consist of discs with blades. These make up rotor assemblies. A vane assembly is mounted between the rotors. The rotor assemblies consist of 72 un-cooled, shrouded blades secured to a disc through fir-tree serrations and rivets. The first stage blades are single crystal Nickel alloy. The second stage blades are Inconel alloy. The Power Turbines Discs are made of Nickel alloy. A face coupling joint connects the discs. Each of the disc extension arm has a machined integral face coupling. TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 72 - ENGINES Issue 6 - January 2023 Page 42 of 44 BOMBARDIER DHC 8-400 (PWC PW150) ENGINE - POWER TURBINES TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 72 - ENGINES Issue 6 - January 2023 Page 43 of 44 BOMBARDIER DHC 8-400 (PWC PW150) INTENTIONALLY LEFT BLANK TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 72 - ENGINES Issue 6 - January 2023 Page 44 of 44