pw127 maintenance manual chapter 72-00

7/24/2019 PW127 Maintenance Manual chapter 72-00

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CHAPTERSECTION PAGE DATE

LEP 1 Jan 24/20062 Jan 24/20063 Jan 24/20064 Jan 24/20065 Jan 24/20066 Jan 24/20067 Jan 24/20068 Jan 24/2006

Contents 1 Jan 24/20062 Jan 24/2006

3 Jan 24/20064 Jan 24/20065 Jan 24/20066 Jan 24/20067 Jan 24/20068 Jan 24/20069 Jan 24/2006

10 Jan 24/200611 Jan 24/200612 blank Jan 24/2006

72-00-00

Description andOperation

1 Nov 04/2005

2 Nov 04/20053 Nov 04/20054 Nov 04/20055 Nov 04/20056 Nov 04/20057 Nov 04/20058 Nov 04/20059 Nov 04/2005

10 Nov 04/200511 Nov 04/200512 Nov 04/200513 Nov 04/200514 Nov 04/200515 Nov 04/200516 Nov 04/200517 Nov 04/200518 Nov 04/200519 Nov 04/2005


20 Nov 04/200521 Nov 04/200522 Nov 04/200523 Nov 04/200524 Nov 04/200525 Nov 04/200526 Nov 04/200527 Nov 04/200528 Nov 04/200529 Nov 04/200530 Nov 04/2005

31 Nov 04/200532 Nov 04/200533 Nov 04/200534 Nov 04/200535 Nov 04/200536 Nov 04/200537 Nov 04/200538 Nov 04/200539 Nov 04/200540 Nov 04/200541 Nov 04/200542 Nov 04/2005

43 Nov 04/200544 Nov 04/200545 Nov 04/200546 Nov 04/200547 Nov 04/200548 Nov 04/200549 Nov 04/200550 Nov 04/200551 Nov 04/200552 Nov 04/200553 Nov 04/200554 Nov 04/200555 Nov 04/200556 Nov 04/200557 Nov 04/200558 Nov 04/200559 Nov 04/200560 Nov 04/2005

PRATT & WHITNEY CANADAMAINTENANCE MANUAL

MANUAL PART NO. 3045542

LIST OF EFFECTIVE PAGES

Page 1

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84 Nov 04/2005

72-00-00Fault Isolation

101 Sep 03/99102 blank Sep 03/99

72-00-00MaintenancePractices

201 Nov 04/2005202 Nov 04/2005203 Nov 04/2005204 Nov 04/2005205 Nov 04/2005206 Nov 04/2005207 Nov 04/2005208 Nov 04/2005209 Nov 04/2005210 Nov 04/2005211 Nov 04/2005212 Nov 04/2005213 Nov 04/2005




237 Nov 04/2005238 Nov 04/2005239 Nov 04/2005240 Nov 04/2005241 Nov 04/2005242 Nov 04/2005243 Nov 04/2005244 Nov 04/2005245 Nov 04/2005246 Nov 04/2005247 Nov 04/2005248 Nov 04/2005249 Nov 04/2005250 Nov 04/2005250 A deleted250 B deleted251 Nov 04/2005252 Nov 04/2005




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253 Nov 04/2005254 Nov 04/2005255 Nov 04/2005256 blank Nov 04/2005

72-00-00Servicing

301 May 02/2003302 May 02/2003303 May 02/2003304 May 02/2003305 May 02/2003306 May 02/2003

307 May 02/2003308 May 02/2003309 May 02/2003310 May 02/2003311 May 02/2003312 May 02/2003313 May 02/2003314 May 02/2003315 May 02/2003316 May 02/2003317 May 02/2003318 May 02/2003

319 May 02/2003320 May 02/2003321 May 02/2003322 May 02/2003323 May 02/2003324 Mar 11/2005325 May 02/2003326 May 02/2003327 May 02/2003328 May 02/2003329 May 02/2003330 May 02/2003331 May 02/2003332 May 02/2003333 May 02/2003334 May 02/2003335 May 02/2003336 May 02/2003


337 May 02/2003338 May 02/2003339 May 02/2003340 May 02/2003341 May 02/2003342 blank May 02/2003

72-00-00Removal/Installation

401 Mar 11/2005402 Mar 11/2005403 Mar 11/2005404 Mar 11/2005

405 Mar 11/2005406 Mar 11/2005407 Mar 11/2005408 Mar 11/2005409 Mar 11/2005410 blank Mar 11/2005

72-00-00Adjustment/Test

501 Mar 09/2001502 Mar 01/2002503 Jul 13/2001504 Mar 09/2001505 Jul 13/2001

506 Jul 13/2001507 Mar 01/2002508 Mar 01/2002509 Mar 01/2002510 Jul 13/2001511 Mar 01/2002512 Mar 01/2002512 A Jul 13/2001512 B blank Jul 13/2001513 Mar 01/2002514 Jan 16/2004515 Mar 09/2001516 blank Mar 09/2001517 Mar 09/2001518 blank Mar 09/2001519 Mar 09/2001520 blank Mar 09/2001521 Mar 09/2001




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522 blank Mar 09/2001523 Mar 09/2001524 blank Mar 09/2001525 Jan 16/2004526 Mar 09/2001

72-00-00InspectionCheck

601 Jan 24/2006602 Jan 24/2006603 Jan 24/2006604 Jan 24/2006605 Jan 24/2006

606 Jan 24/2006607 Jan 24/2006608 Jan 24/2006609 Jan 24/2006610 Jan 24/2006611 Jan 24/2006612 Jan 24/2006613 Jan 24/2006614 Jan 24/2006615 Jan 24/2006616 Jan 24/2006617 Jan 24/2006

618 Jan 24/2006619 Jan 24/2006620 Jan 24/2006621 Jan 24/2006622 Jan 24/2006623 Jan 24/2006624 Jan 24/2006625 Jan 24/2006626 Jan 24/2006627 Jan 24/2006628 Jan 24/2006629 Jan 24/2006630 Jan 24/2006631 Jan 24/2006632 Jan 24/2006632 A Jan 24/2006632 B Jan 24/2006632 C Jan 24/2006


632 D Jan 24/2006632 E Jan 24/2006632 F Jan 24/2006632 G Jan 24/2006632 H Jan 24/2006632 I Jan 24/2006632 J Jan 24/2006632 K Jan 24/2006632 L Jan 24/2006632 M Jan 24/2006632 N Jan 24/2006

632 O Jan 24/2006632 P Jan 24/2006632 Q Jan 24/2006632 R Jan 24/2006633 Jan 24/2006634 Jan 24/2006635 Jan 24/2006636 Jan 24/2006637 Jan 24/2006638 Jan 24/2006639 Jan 24/2006640 Jan 24/2006

640 A deleted640 B deleted640 C deleted640 D deleted640 E deleted640 F deleted640 G deleted640 H deleted640 I deleted640 J deleted641 Jan 24/2006642 Jan 24/2006643 Jan 24/2006644 Jan 24/2006645 Jan 24/2006646 Jan 24/2006647 Jan 24/2006648 Jan 24/2006




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648 A deleted648 B deleted648 C deleted648 D deleted648 E deleted648 F deleted648 G deleted648 H deleted648 I deleted648 J deleted648 K deleted

648 L deleted648 M deleted648 N deleted648 O deleted648 P deleted648 Q deleted648 R deleted648 S deleted648 T deleted649 Jan 24/2006650 Jan 24/2006651 Jan 24/2006

652 Jan 24/2006653 Jan 24/2006654 Jan 24/2006655 Jan 24/2006656 Jan 24/2006657 Jan 24/2006658 Jan 24/2006659 Jan 24/2006660 Jan 24/2006661 Jan 24/2006662 Jan 24/2006663 Jan 24/2006664 Jan 24/2006665 Jan 24/2006666 Jan 24/2006667 Jan 24/2006668 Jan 24/2006669 Jan 24/2006


670 Jan 24/2006671 Jan 24/2006672 Jan 24/2006673 Jan 24/2006674 Jan 24/2006675 Jan 24/2006676 Jan 24/2006677 Jan 24/2006678 Jan 24/2006679 Jan 24/2006680 Jan 24/2006

681 Jan 24/2006682 Jan 24/2006683 Jan 24/2006684 Jan 24/2006685 Jan 24/2006686 Jan 24/2006687 Jan 24/2006688 Jan 24/2006689 Jan 24/2006690 Jan 24/2006691 Jan 24/2006692 Jan 24/2006

72-00-00Cleaning/Painting

701 Jan 24/2006702 Jan 24/2006703 Jan 24/2006704 Jan 24/2006705 Jan 24/2006706 Jan 24/2006707 Jan 24/2006708 Jan 24/2006709 Jan 24/2006710 Jan 24/2006711 Jan 24/2006712 Jan 24/2006713 Jan 24/2006714 Jan 24/2006715 Jan 24/2006716 Jan 24/2006717 Jan 24/2006




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718 Jan 24/2006719 Jan 24/2006720 Jan 24/2006721 Jan 24/2006722 Jan 24/2006723 Jan 24/2006724 Jan 24/2006725 Jan 24/2006726 Jan 24/2006

72-00-00

ApprovedRepairs

801 Mar 01/2002

802 Mar 01/2002803 Mar 01/2002804 Mar 01/2002805 Mar 01/2002806 Mar 01/2002807 Mar 01/2002808 Mar 01/2002809 Mar 01/2002810 Jan 16/2004811 Jan 16/2004812 blank Mar 01/2002










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171 Nov 04/2005172 Nov 04/2005


101 Oct 20/2000102 Sep 03/99103 Oct 20/2000104 Oct 20/2000105 Sep 03/99106 Sep 03/99107 Sep 03/99108 blank Sep 03/99109 Sep 03/99

110 blank Sep 03/99111 Sep 03/99112 Sep 03/99113 Sep 03/99114 Sep 03/99115 Sep 03/99116 Sep 03/99117 Sep 03/99118 Sep 03/99119 Sep 03/99120 Sep 03/99121 Sep 03/99122 Sep 03/99123 Sep 03/99124 Sep 03/99125 Sep 03/99126 Sep 03/99127 Sep 03/99


128 Sep 03/99129 Sep 03/99130 Sep 03/99131 Sep 03/99132 Sep 03/99133 Sep 03/99134 Sep 03/99135 Sep 03/99136 Sep 03/99137 Sep 03/99138 Sep 03/99

139 Sep 03/99140 Sep 03/99141 Sep 03/99142 Sep 03/99143 Sep 03/99144 Sep 03/99145 Sep 03/99146 Sep 03/99147 Sep 03/99148 Sep 03/99149 Sep 03/99150 Sep 03/99

151 Sep 03/99152 Sep 03/99153 Sep 03/99154 Sep 03/99155 Sep 03/99156 Sep 03/99157 Sep 03/99158 Sep 03/99159 Sep 03/99160 Sep 03/99161 Sep 03/99162 Sep 03/99163 Sep 03/99164 Sep 03/99165 Sep 03/99166 Sep 03/99167 Sep 03/99168 Sep 03/99




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ENGINE - DESCRIPTION AND OPERATION 72-00-00

1. General 12. Description 1

A. Reduction Gearbox 1

B. Turbomachinery 9

C. Accessory Drives 11

D. Identification of Engine Bearings, Flanges and Stations 13

E. Oil System 19

F. Fuel and Control System 26

G. Propeller Control System 46

H. Inlet Temperature and Torque Sensing Systems 48

I. Ignition System 48

J. Performance Indicating System 51

K. Air System 53

3. Operation (A summary of the functions previously described) 64

4. Engine - Approved Fuels 64

A. Use of Approved Fuels 64

B. High Temperature Stability 71

C. Quality 71

D. Additives 71

E. Acceptable Fuels (Unrestricted Use) 75

F. Acceptable Fuels (Restricted Use) 77G. Alternate/Emergency Fuels 78

5. Engine - Approved Lubricating Oils 78

A. General 78

B. Approved Oils 79

TABLE OF CONTENTSSUBJECT PAGE



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ENGINE - DESCRIPTION AND OPERATION (Contd) 72-00-00

C. Dupont Oil Blue Dye (PWC05-026) 80

D. Oil Drain Period 80

E. Oil Analysis 83

ENGINE - FAULT ISOLATION 72-00-00

1. General 101

2. Consumable Materials 101

3. Special Tools 101

4. Fixtures, Equipment and Supplier Tools 101

5. Fault Isolation Chart Locations 101

ENGINE - MAINTENANCE PRACTICES 72-00-00

1. General 201




5. Standard Torques 202

6. Torque Wrenches 203

A. General 203

B. Standard Torque Wrenches and Extensions 203

C. Power Torque Wrenches 205

7. General Torque Recommendations 206

A. Oil Lubricated Parts 206

B. Self-locking Nuts and Helical Coil Inserts 206

C. Castellated Nuts 207

D. Standard and Stepped Studs 207

E. Tube Nuts 207




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ENGINE - MAINTENANCE PRACTICES (Contd) 72-00-00

8. Locking 207

A. General 207

B. Keywashers 207

C. Lockwire 210

D. Retaining Rings 212

9. Marking of Parts 212

A. General 212

B. Permanent Marking 217

C. Temporary Marking 217

10. Lubrication 219

A. General 219

11. Tube-to-Boss Elbows, Elbow Adapters, Elbow Assemblies, Teesand Tee Assemblies 219

A. Removal 219

B. Installation 219

12. Straight Nipples or Adapters, Bulkhead Couplings and TubeConnector Nipples 221

A. Installation 221

13. Wiring Harness Connectors 221

A. General 221

B. Installation Procedure 221

14. Inspection 225A. General 225

B. Inspection Procedures 225

C. Inspection Terms 226

D. Inspection Gages 226






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ENGINE - MAINTENANCE PRACTICES (Contd) 72-00-00

E. Magnetic Particle Inspection 231

F. Fluorescent Penetrant Inspection 231

G. Inspection of Fuel, Oil and Air Filters 232

15. Cleaning 232

A. General 232

B. Precautions 232

16. Bearings 233

17. Debris Analysis and Material Specifications 233

A. General 233

B. Filter Patch Check Debris Inspection/Analysis 233

C. Chip and Flake Analysis 234

D. Material Specifications 235

E. Laboratories 250

ENGINE - SERVICING 72-00-00

1. General 301




5. Removal/Installation 302

A. Preparation of Shipping Container for Service or Storage 302

B. Removal of Engine from Shipping Container 302

C. Installation of Engine in Shipping Container 303

D. Removal of Reduction Gearbox from Shipping Container 308

E. Installation of Reduction Gearbox in Shipping Container 313

F. Removal of Turbomachinery from Shipping Container 314






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ENGINE - SERVICING (Contd) 72-00-00

G. Installation of Turbomachinery in Shipping Container 319

6. Preservation/Depreservation 320

A. General Engine Storage/Preservation Procedure 320

B. Oil System Preservation 323

C. Fuel System 324

D. Accessories 325

E. Desiccant and Humidity Indicator Reactivation 326

F. Depreservation (Engine) 326

G. Depreservation (Accessories) 329

7. Shipping 329

A. General 329

B. Shipping Method 331

8. Oil Draining 332

A. Main Oil Tank and/or RGB 332

9. Chip Collector - Replacement 333

A. Procedure 333

10. Oil System Flushing and Filling 335

A. Procedure 335

11. Oil System Filling 337

A. Oil Filling Procedure 337

B. Replenishing Empty Oil System 338

12. Oil Level Check and Top-up 339

A. General Oil Level Check 339

B. Top-up 339






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ENGINE - SERVICING (Contd) 72-00-00

13. Oil Consumption Trend Monitoring 340

A. General 340

B. Procedure 340

ENGINE - REMOVAL/INSTALLATION 72-00-00

1. General 401




5. Removal 402

A. Engine from Airframe 402

B. Engine from Stand (PWC34200) 402

6. Installation 403

A. Engine in Airframe 403

B. Engine in Stand (PWC34200) 409

ENGINE - ADJUSTMENT/TEST 72-00-00

1. General 501




5. Engine Ground Running Operating Limits 501

6. Engine/Component Replacement Test Requirements 501

7. Overtorque and Overtemperature Limits 502

8. Starting 503

A. Prestart 503

B. Wet Motoring 503






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ENGINE - ADJUSTMENT/TEST (Contd) 72-00-00

C. Dry Motoring (to purge engine of fuel after wet motoring run orin the event of fire occurring in the engine after starting orpermit a compressor wash to be carried out.) 504

D. Start 504

9. Shutdown 507

A. Procedure 507

10. Checks 507

A. Oil Pressure 507

B. Leak Check 508

C. Ground IDLE - NH GOVERNING 508

D. Flight IDLE - NH GOVERNING 508

E. Flight IDLE/MIN NP GOVERNING 508

F. REVERSE/MIN. and MAX NP Governing 508

G. Maximum Forward Governing (T.O.P or ITT/T6 Limit) 509

H. EEC Manual Reversion 509

I. Autofeather and Uptrim (both engines running) 509

J. Power Assurance Check 512

K. Acceleration Check 514

ENGINE - INSPECTION/CHECK 72-00-00

1. General 601


3. Special Tools 6014. Fixtures, Equipment and Supplier Tools 601

5. Periodic Inspection 602

6. Rotor Components - Service Life 602

7. Engines with Defects Outside Specified Limits 602






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ENGINE - INSPECTION/CHECK (Contd) 72-00-00

8. Low Pressure and High Pressure Impellers - Foreign ObjectDamage 603

A. LP Impeller 603

B. HP Impeller 609

9. Borescope Inspection 616

A. General 616

B. Side-viewing Adapter 616

C. Light Source 617

D. Camera 617

E. Guide Tubes 619

F. Troubleshooting 619

G. Low Pressure Impeller 620

H. High Pressure Impeller 623

I. Fuel Pump and Oil Pump Drive Bevel Gears 623

J. Accessory Drive Bevel Gears (Towershaft) 625

K. Starter-generator Drive Gear 625

L. Intercompressor Case Air Plenum 627

M. No. 5 Bearing Cavity 629

N. Combustion Chamber Liner Assembly, HP Turbine Vane RingSegments and HP Turbine Blades 631

O. LP Turbine Blades and Stator Assembly 632C

P. Power Turbine Stator Assembly and First-stage Blades 632EQ. No. 6 and 7 Bearing Vent Transfer Tube. 632H

R. Second-stage Power Turbine Blades and Vane Ring 632H

S. RGB First-stage Helical and Input Shaft Gears 632I

T. RGB Second-stage Gears (Bull Gear and Layshaft Pinions) 632M






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ENGINE - INSPECTION/CHECK (Contd) 72-00-00

10. Hot Section Component Borescope Inspection Criteria 632R

A. General 632R

B. CombustionChamber (Small Exit Duct, Inner and Outer LinerAssemblies) 632R

C. High Pressure (HP) Turbine Vane Segments 643

D. HP Turbine Blades 646

E. HP Turbine Shroud Segment 654

F. LP Turbine Stator . 678

G. LP Turbine Blades 678

H. First- and Second-stage Power Turbine Vanes 681

I. First- and Second-stage Power Turbine (PT) Blades 685

11. Gear Teeth Inspection 685

A. Acceptable Conditions 685

B. Non-acceptable Conditions 688

12. Cracks in Turbine Support Case Inner Wall 688

13. Cracks in Gas Generator Case Firewall Support Ring 689

A. Visual Inspection 689

ENGINE - CLEANING/PAINTING 72-00-00

1. General 701




5. Engine Cleaning 702

A. External Wash 702

B. Compressor Wash 702






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ENGINE - CLEANING/PAINTING (Contd) 72-00-00

C. Turbine Wash 719

ENGINE - APPROVED REPAIRS 72-00-00

1. General 801




5. Helical Coil Insert Replacement 802

A. General 802

B. Procedure (same size insert replacement) 802

C. Procedure (oversize insert replacement) 802

6. Keensert Insert Replacement 803

A. Procedure 803

7. Stud Replacement 806

A. Procedure 806

8. Stud Hole Repair 808

A. Procedure 808

9. Anodic Film Repair of Aluminum 808

A. Procedure 808

10. Chromate Surface Repair of Magnesium 809

A. General 809

B. Procedure 810

11. Jacking Insert Replacement 811

A. Procedure 811


1. General 101






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ENGINE - FAULT ISOLATION (Contd) 72-00-01




5. Fault Isolation Fault Index 101


1. General 101




5. Electronic Fuel Control System 101

A. Procedures 101

6. Servicing Connectors with Aircraft Electrical Power On 103

A. Procedure 103

7. Fault Isolation Fault Index 104

8. Fault Isolation Steps 106




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ENGINE - DESCRIPTION AND OPERATION

1. General (Ref. Figs. 1 and 2)

The PW127H turboprop engine has two centrifugal impellers driven by independent axial

turbines, a reverse flow annular combustor and a two-stage power turbine which provides thedrive for the reduction gearbox. The engine has two modules: a reduction gearbox moduleand a turbomachinery module. The modules are joined to form a rigid unit. Provision is madefor the installation of airframe equipment on the engines.

2. Description

A. Reduction Gearbox (Ref. Figs. 3, 4 and 5)

The reduction gearbox has an accessory drive cover and three housings: the fronthousing, the rear housing and the input housing (which together make up the housingset). Reduction is accomplished by a two-stage geartrain.

(1) Front Housing

The front housing holds the front roller bearings for the two second-stagegearshafts and the propeller shaft, and the ball thrust bearing for the propellershaft. The propeller shaft seal is under a cover on the front housing.

In front of each gearshaft are mounting pads. A propeller brake is fitted to the leftpad. These pads are provided with seal drains blanked off with flight closures.

The propeller brake (Ref. Fig. 5) is a hydromechanical type actuated by solenoidvalves which are energized by an airframe-mounted control unit which controls thebraking and unbraking sequences. The brake is used to immobilize the propellerwhen the engine is running and providing electricity and compressor air for off-engine

use. Push buttons on each solenoid valve allow manual operation of the brakerelease system during maintenance or when an electrical failure has occurred.

A mounting pad is provided on the right side of the front housing to accommodatean electric feathering pump. The pad has oil ports that are connected to aninternal oil tank which is part of the rear housing.

The data plate of the reduction gearbox module is attached to the left side of thefront housing.

At the one and eleven oclock positions on the front housing flange are two liftingbrackets.

(2) Rear Housing

The rear housing carries the second-stage reduction gear and drive pinions,propeller shaft rear roller bearing, second-stage reduction gear rear roller bearings,front roller bearing of the input shaft and the front roller bearings of both first-stagehelical gears.



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NP PULSE PICKUPPROBE

ENGINE FRONTMOUNTING PAD

TORQUE MOUNTING PAD

AMBIENT PRESSURETRANSDUCER

TOTAL INLETPRESSURE TRANSDUCER

OIL INLET(FROM REMOTEOIL COOLER)

OIL PRESSUREREGULATING VALVE

T6 BUSBARS

FUEL INLET

OIL PRESSUREFILTER IMPENDINGBYPASS INDICATOR

OIL PRESSUREFILTER

ENGINE ELECTRONICCONTROL

TORQUE SENSORGEARBOX DATA PLATE

CHIP DETECTOR

MOUNTING PAD

MECHANICALFUEL CONTROL UNIT

FUEL PUMPOUTLET FILTER

LOW OIL PRESSURESWITCH

MAIN OIL PRESSURESENSOR

OIL LEVEL INDICATOR

C61309B

Typical EngineFigure 1 (Sheet 1 of 2)





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REAR ENGINEMOUNTING PAD

ACCESSORY GEARBOXBREATHER TUBE


TORQUEMOUNTING PAD

TORQUE SENSOR

IGNITION EXCITER

AIR INLET

IGNITION HARNESS

REDUCTION GEARBOXSCAVENGE OIL FILTER

OIL OUTLET(TO REMOTEOIL COOLER)OIL PUMP

PACK

NO. 6 & 7 BEARINGSCAVENGE PIPE

FUEL PUMPINLET FILTER

GEARBOX OILPRESSURE PIPE


ELECTRIC FEATHERINGPUMP MOUNTING PAD

OIL TO FUEL

T6 TRIM RESISTOR

OIL SCAVENGE FILTERIMPENDING BYPASS INDICATOR

IGNITER PLUG

HIGH PRESSURE ROTOR (NH)PULSE PICKUP PROBE

STARTER MOUNTING PAD

TOTAL INLETTEMPERATURE SENSOR

PRESSURIZING AIR SUPPLY PIPE

ENGINE DATA PLATEHEATER

C61311A

Typical EngineFigure 1 (Sheet 2)





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P0/T0

PRESSURE/TEMPERATURE STATIONS

P1/T1 P1.5/T1.5 P1.8/T1.8 P2/T2

FLANGES A B

BEARINGS 1 2

DC

C11121D_1

Bearings, Flanges and StationsFigure 2 (Sheet 1 of 2)





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P2.5/T2.5

P3/T3

P4/T4

P5/T5

P6/T6 P7/T7 P8/T8

E

3 4

F

5

K

6 7

C11121D_2

Bearings, Flanges and StationsFigure 2 (Sheet 2)





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ENGINEMOUNTING PAD

DATA PLATE

TORQUEMOUNT

CHIP DETECTORAND STRAINER

GEARSHAFTCOVERS

PROPELLER SHAFTSEAL DRAIN

REAR HOUSING

LIFTING BRACKETS

FRONT HOUSING

PROPELLER SHAFT

PROPELLER SHAFTFLANGE

FEATHERING PUMPMOUNT PAD

TORQUE MOUNT

ENGINE MOUNTINGPAD

INPUT DRIVEHOUSING

ACCESSORYDRIVE COVER

TOP MOUNTINGPAD

C38713

Reduction Gearbox - 34 ViewFigure 3





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REDUCTION GEARBOXREAR HOUSING

OVERSPEED GOVERNORDRIVE GEARSHAFT

135 TOOTH SECONDSTAGE SPUR GEAR

PROPELLER SHAFT


REDUCTION GEARBOXFRONT HOUSING

FIRST STAGEHELICAL GEAR

HELICAL INPUTGEARSHAFT

INTERGRATEDDRIVE GENERATOR

PROPELLER SHAFTFRONT ROLLERBEARING

IDLER DRIVESPUR GEARSHAFT

PROPELLERSHAFT SEAL

PROPELLERMOUNTING FLANGE

FIRST STAGEHELICAL GEAR


PROPELLERBRAKE COUPLING

GEARSHAFT

C69157

Reduction GeartrainFigure 4





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PROPELLER BRAKE

SOLENOID VALVES

MANUAL CONTROL

C38712

Propeller Brake and Propeller Brake Control - 3/4 ViewFigure 5





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The front engine three main mounting pads are located as follows: two on eitherside of the housing, and the third at the top center. Torque mounts are located at the5 and 7 oclock positions on the housing.

The accessory drive cover is mounted on the top rear face.

The propeller (NP) pulse pickup probe is installed in a mounting pad at the11 oclock position.

On the bottom right side is a pad for the chip detector and oil strainer. Another chipdetector and strainer are installed on the upper left side.

The propeller valve module is mounted on a pad behind, and driven by, thepropeller shaft.

(3) Input Drive Housing

The input drive housing carries the rear roller bearings of the input driveshaft and

both layshafts.

Two torque sensors are mounted on pads located opposite one another on thehorizontal centerline of the input drive housing.

(4) Accessory Drives

The overspeed governor/pump assembly is mounted on the right pad and driven bythe 135-tooth second-stage gear. An oil cooled integrated drive generator (IDG)is mounted on the left pad and is driven by the idler gear, which is also driven by the135-tooth second-stage gear.

B. Turbomachinery

The turbomachinery consists of four sections, contained in six casings (Ref. Fig. 6). Thecasings are bolted together at flanges (Ref. Fig. 2).

(1) Air Inlet Section

The air inlet section consists of the front inlet case and the rear inlet case boltedtogether at flange C.

The front inlet case has the engine electronic control (EEC) and autofeather unit(AFU) mounted on the left side, and the fuel-cooled oil cooler, ignition exciters andturbomachinery data plate on the right side. An access plate is on its top surface.The forward flange of the front inlet case has two integral lifting brackets and isconnected to the RGB at flange B.

The rear inlet case joins the front case to the low pressure (LP) diffuser case atflange D. The case contains two bearings (No. 1 and 2) and seals for the powerturbine shaft. Mounting pads are provided for accessories. The engine oil tank formspart of the casing.





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OIL TANKGAS GENERATOR CASEINTERCOMPRESSOR CASE

FRONT INLET CASE

TURBINE

SUPPORTFUEL MANIFOLD& NOZZLES

DIFFUSEREXITDUCTS L.P. DIFFUSER CASE

REAR INLET CASE

INLET SECTIONTURBINE SECTIONCOMPRESSOR

COMBUSTIONSECTION

SECTION

CASE

C69158A

TurbomachineryFigure 6





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(2) Compressor Section

The compressor section comprises the low pressure (LP) and high pressure (HP)independent centrifugal impellers. These are contained within the LP diffuser case(flange D to E) and the intercompressor case (flange E to F) and the front of the

gas generator case (flange F to K).

Diffuser pipes connect the diffuser case, which contains the LP impeller, to theintercompressor case. Two ball bearings (No. 3 and 4) are housed in theintercompressor case. The No. 5 roller bearing is contained in the gas generatorcase.

A lifting bracket is located at the twelve oclock position on flange K of the gasgenerator case.

A Y-adapter and non-return valve are located at the 12 oclock position on theintercompressor case to supply low pressure air for use in the environment controlsystem of the aircraft.

(3) Combustion Section

The annular reverse-flow combustion chamber is contained in the gas generatorcase. The fuel manifold is mounted around the exterior of the gas generator case,with spray nozzles which protrude into the combustion chamber liner. Twoigniter plug bosses are provided on the gas generator case, with correspondingbosses in the liner. The gas generator case incorporates an air bleed pad throughwhich P3 air is supplied for off-engine use at low power and during starting.

(4) Turbine Section

The LP and HP turbines are housed in the rear of the gas generator case, and the

power turbines (PT) in the turbine support case. Concentric shafts connect thetwo-stage power turbine to the gearbox and the single-stage LP and HP turbines tothe impellers. The central PT shaft is supported by the No. 1 (ball), No. 2 (roller)and No. 7 (roller) bearings. The intermediate LP turbine shaft is supported by theNo. 3 (ball) and No. 6 (roller) bearings. The HP turbine shaft (integral withimpeller) is supported by the No. 4 (ball) and No. 5 (roller) bearings.

C. Accessory Drives (Ref. Fig. 7)

An inclined bevel gearshaft (5) transmits drive from a gear (4), secured to the impeller(3) forward of No. 4 bearing, to the bevel gear (2) of the accessory drive coupling gearshaft(1). The centrifugal breather impeller (8) is mounted on the gearshaft (1). A spur gear(14) drives the fuel pump driveshaft (6) through gear (11), and another spur gear (7)

meshes with gear (10) on the starter-generator driveshaft (9). Provision is made forhand cranking the HP rotor using a socket wrench extension tool in the end of thestarter-generator driveshaft. Access is gained after removal of a cover opposite thestarter-generator. The oil pumps are driven by driveshaft (13) through bevel gears(12) and (15).





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3 4

5

12

6

11

16

2

1

14710

9

8

13

15

C11186C

Turbomachinery Accessory Drive GeartrainFigure 7





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D. Identification of Engine Bearings, Flanges and Stations

(1) Engine Bearing Identification (Ref. Fig. 8)

All the bearings used in the engine have position numbers from 1 thru 30 as persteps (2), (3) and (4).

NOTE: The term Not Used is given to bearing numbers which are not, at this

time, applicable to the engine model specified in this manual.

(2) Engine Main Bearings

The main bearings in the turbomachinery have numbers per Table 1.

TABLE 1, Main Bearing Identification

BEARING NO. POSITION TYPE

1 Power Turbine Shaft Ball

2 Power Turbine Shaft Roller

3 Low-pressure Impeller Ball

4 High-pressure Impeller Ball

5 High-pressure Impeller Roller

6 Low-pressure Turbine Roller

7 Power Turbine Shaft Roller

Key to Figure 7

1. Accessory Drive Coupling Gearshaft

2. Bevel Gear

3. HP Impeller4. Bevel Gear

5. Gearshaft

6. Fuel Pump Driveshaft

7. Spur Gear

8. Centrifugal Breather Impeller

9. Starter-generator Driveshaft

10. Spur Gear

11. Spur Gear

12. Bevel Gear

13. Oil Pump Driveshaft

14. Spur Gear15. Bevel Gear

16. Bevel Gear (Ref.)





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B B

A A

No. 18BEARING No. 15BEARING

No. 19BEARING

No. 9BEARING

No. 8BEARING

C32417C_1

Bearing IdentificationFigure 8 (Sheet 1 of 4)





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No. 25BEARING

No. 25BEARING

No. 28BEARING

No. 28BEARING

No. 29BEARING

No. 6BEARING

No. 7BEARING

No. 1BEARING

No. 2BEARING

No. 3BEARING

No. 30BEARING

No. 4BEARING

No. 5BEARING

(FRONT) (REAR) (FRONT) (REAR) (LOWER)

No. 27BEARING

C32417C_2

Bearing IdentificationFigure 8 (Sheet 2)





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NO.8BEARING

NO.9BEARING

NO.11BEARING

NO.12BEARING

NO.13BEARING

NO.14BEARING

SECTION AA

FWD

NO.11BEARING

NO.12BEARING

NO.13BEARING

NO.14

BEARING

FWD

SECTION BB

NO.20BEARING

(FRONT)

NO.20BEARING(REAR)

NO.22BEARING(FRONT)

NO.22BEARING(REAR)

NO.23BEARING

(FRONT)

NO.23BEARING(REAR)

C33359






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SECTION

NO. 25 BEARING(FRONT)


NO. 24 BEARING(REAR)




CC

FWD

C32419






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(3) Reduction Gearbox Bearings

The RGB bearings have numbers per Table2.

TABLE 2, Reduction-gearbox Bearing Identification


8 Input Drive Shaft Roller

9 Input Drive Shaft Roller

10 NOT USED NOT USED

11 First-stage Helical Gear Roller

12 First-stage Helical Gear Roller

13 Second-stage Spur Gearshaft (Pinion Gear) Roller

14 Second-stage Spur Gearshaft (Pinion Gear) Roller

15 Propeller Shaft Roller16 NOT USED NOT USED


18 Propeller Shaft Ball

19 Propeller Shaft Roller

20 (Front and Rear) Overspeed-governor Drive Gearshaft Roller


22 (Front and Rear) Idler Drive Gearshaft Roller

23 (Front and Rear) Integrated Drive Generator Gearshaft Roller

(4) Accessory Gearbox Bearings

The accessory gearbox bearings, in the upper section of the rear inlet case, and inthe angledrive gearbox which is on the intercompressor case, have numbersper Table 3.

TABLE 3, Accessory-gearbox Bearing Identification


24 (Front and Rear) Starter-generator drive Gearshaft Roller

25 (Front) Main-accessory-drive Gearshaft Roller

25 (Rear) Main-accessory-drive Gearshaft Ball

26 (Front) Fuel-pump Drive Shaft Roller

26 (Rear) Fuel-pump Drive Shaft Ball

27 Oil-pump Drive Shaft Ball

28 (Front) Accessory-drive Horizontal Gearshaft Roller





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TABLE 3, Accessory-gearbox Bearing Identification (Contd)


28 (Rear) Accessory-drive Horizontal Gearshaft Ball

29 (Upper) NOT USED NOT USED29 (Lower) Accessory Drive Housing Roller

30 Accessory-drive Lower Bevel Gearshaft Ball

E. Oil System (Ref. Figs. 9 through 13)

The oil system is a wet sump system, cooled by an aircraft mounted air-cooled oil coolerand an integral fuel-cooled oil cooler. The oil is stored in a tank that is integral withthe rear inlet case. The tank has a filler neck and cap, contents gage and scavenge chipdetector. The system is composed of three subsystems: the pressure system, whichsupplies oil to the reduction gearbox and turbomachinery, the scavenge system, whichreturns the used oil to the tank and the vent and breather system which vents the bearing

cavities and removes oil from the vented air (Ref. Figs. 9 and 10).

(1) Pressure System

(a) Turbomachinery

A spur gear type pressure pump is mounted, in a pack with the scavengepump, on the right side of the rear inlet case. An integral cast passage connectsthe oil tank to the inlet side of the pump. A pressure relief valve returns oil tothe tank to prevent a pressure surge during cold starting.

Airframe-supplied tubes connect the outlet to the airframe air cooled oil cooler.From the cooler the oil flows via a heat exchanger (airframe component) to

the pressure regulating valve and the pressure filter.

The pressure regulating valve (Ref. Fig. 11) consists of a piston valve andspring in a ported sleeve. It maintains a constant oil pressure above and inrelation to the air pressure in the No. 3 and 4 bearing cavity. If oil output pressure,taken from a tapping downstream of the check valve, overcomes the airpressure plus spring pressure, the valve opens a port. Oil is bled from the mainpressure line by the port and returned to the inlet side of the pump, reducingoutput pressure. Air pressure plus spring pressure overcomes the reduced oilpressure, closing the bleed port at the desired pump output pressure. Thecheck valve output pressure is also connected, via a restrictor to an oil pressuretransducer and to the low oil pressure switch.

The pressure filter has a bypass valve to ensure adequate flow if the filter isblocked; an indicator warns of impending blockage. From the filter the oil flowsin two directions: to the oil pressure check valve housing and to the fuelheater (then, in turn, to the fuel-cooled oil cooler).





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TO

REDUCTION

GEARBOX

OIL

COOLEROIL TO FUEL HEATER

OIL PRESSURE

TRANSDUCERAIR FROM NO.3 & 4

BEARING CAVITY

MAIN OIL

PRESSURE

FILTER

RESTRICTOR

PRESSURE

REGULATING

VALVE

IMPENDING

BYPASS

INDICATOR

FROM OIL COOLER TO OIL COOLER

PRESSURE REIEF

VALVE

OIL PUMP

(PRESSURE)

LOW OILPRESSURESWITCH

VIA IDG HEATEXCHANGER

C69190_1A

Turbomachinery Oil System - SchematicFigure 9 (Sheet 1 of 2)





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CHECK VALVEBLEED LINE

OIL TEMP.

BULB

RESTRICTOR

STRAINER STRAINER STRAINER

STRAINER

STRAINER

INLET STRUT

ANTI ICING

VENT

VENT

ACCESSORY

GEARBOX

GRAVITYDRAIN

NO.1 & 2

BEARING CAVITY

JET PUMP

GRAVITY

DRAIN

NO.3 & 4

BEARING CAVITY

NO.5

BEARING CAVITY

DRIVESHAF

TF

ROM

H.P.

SHAFT

OIL TANK

SCREEN CHIP D ETECTOR

NO.6 & 7

BEARING CAVITY

BLOWDOWN

SCAVENGE FROM

REDUCTION GEARBOXNO.6 & 7 CAVITY

SCAVENGE PUMP

PRESSURE OIL

SCAVENGE OIL

VENT AIR

DRAIN AND UNPRESSURIZED OIL

C69190_2A

Turbomachinery Oil System - SchematicFigure 9 (Sheet 2)





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PROPELLER VALVEMODULE PUMP

ELECTRICFEATHERING PUMP

RESTRICTOR

OVERSPEEDMODE

GOVERNINGMODE

DRAIN

VALVE MODULE

R.G.B. AUXILLARY

MAIN OIL PRESSUREFROM TURBOMACHINERY

DRAIN

ACTUATOR

CHIP DETECTOR

SCREEN

REDUCTION GEARBOXSCAVENGE PUMP

SCAVENGE OIL

SIGNAL PRESSURE OIL

ENGINE OIL (PRESSURE)

PROPELLER

PROPELLER

REDUCTION GEARBOX

TURBOMACHINERY

PROPELLER VALVE MODULEOIL (BOOSTED)

REDUCTION GEARBOXSCAVENGE FILTER

BYPASSINDICATOR

MAIN OIL TANK

OVERSPEEDGOVERNOR

BYPASS

PRESSURE OILDISTRIBUTION BYINTERNAL GALLERIES

OIL TANK(PRESSURIZED)

IMPENDING

C38658

Reduction Gearbox Oil System - SchematicFigure 10





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OIL IN

OIL OUT

BEARING OILPRESSURE SENSING

AIR PRESSURE SENSING

FROM NO.3 & NO.4BEARING CAVITY

PORT NOTUSED

C31422

Oil Pressure Regulating Valve - 34CutawayFigure 11





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Oil goes through internal passages to the check valve housing. After enteringthe housing, the oil flows in two directions. One part goes through an internalpassage in the housing wall, past the temperature bulb and externally to aconnection on the rear inlet case. The other part goes through the check valveafter 25% NH has been exceeded.

From the connection on the rear inlet case, oil flows by internal passages tothe accessory gearbox through the inlet struts (for de-icing) to the No. 1 and 2bearing cavity. Some of the accessory gearbox oil flows via a strainer tolubricate the drive gears and associated components. Oil flowing to the No. 1and 2 bearing cavity passes through a strainer. Pressure oil is also used toactuate a jet pump which scavenges No. 2 bearing area.

The check valve consists of a piston valve and spring in a ported sleeve.During starting and shutdown, the valve stops oil going to the No. 3, 4, 5, 6and 7 bearing cavities when pump outlet pressure is below a minimum value.This ensures that sufficient pressurized air is available at the bearings toenable the seals and blowdown scavenge system to function correctly and

prevent oil flooding. From the check valve, oil flows through strainers to lubricatethe bearings and associated components in the bearing cavities. Oil flowsthrough a restrictor before reaching the strainer in the line to the No. 6 and 7bearing cavity.

Oil flows through tubes to the oil-to-fuel heater and fuel-cooled oil cooler, thento the reduction gearbox and oil-cooled AC generator.

The fuel-cooled oil cooler (Ref. Fig. 12) is a heat exchanger with two flowcircuits: engine lubricating oil and fuel. The oil circuit has two flow paths (bypassand internal) and a valve that controls flow between the paths. The valveremains in the open position, allowing oil to bypass the core until the temperaturereaches 60 to 71C (140-160F). Within this temperature range bypass flow

is cut off and routed through the internal path. To ensure the cooler is not overpressurized, the valve opens, allowing oil to bypass when the pressuredifferential across the valve exceeds 40 psig (276 kPa).

(b) Reduction Gearbox

Inside the gearbox (Ref. Fig. 10) the oil flows into an auxiliary oil tank (whichis part of the casting). The auxiliary tank is pressurized when the engine isrunning, and is always full of oil (even when the engine is not running).

Oil from the tank flows, by internal passages and tubes, to the electric featheringpump and the propeller valve module (PVM) pump. The PVM receivespressure oil from the electric feathering pump and the PVM pump and signal

pressure oil from the overspeed governor (when in the governing mode). In theoverspeed mode, signal pressure oil is drained through the overspeedgovernor. Pressure oil from the PVM actuates the pitch control mechanism inthe propeller.

Oil from the auxiliary tank is distributed through internal galleries to thereduction and accessory geartrains and bearings.





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OIL OUT

FUEL OUT

FUEL IN

OIL IN

TEMPERATURECONTROLVALVE

OIL OUT

FUEL OUT

OIL IN

OIL IN

FUEL IN

DETAIL A

A

OIL OUT

C63098

Fuel-cooled Oil Cooler - SchematicFigure 12





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(2) Scavenge System

(a) Reduction Gearbox

Scavenge oil from the gearbox accessories, gears and bearings drains into a

cavity in the bottom of the reduction gearbox rear housing. The cavity has a chipdetector. A scavenge pump, which is part of the pump pack on the right sideof the rear inlet case, draws the oil through an external tube on the left side of thefront inlet case. The tube is looped upward to prevent gearbox oil fromflooding the oil tank when the engine is not running. The tube connects to aninternal oilway (which provides anti-icing of the intake) in the front inlet case.From the inlet case, the oil flows through a tube to the scavenge pump, thenthrough the scavenge filter, which is equipped with a valve to bypass the filter inthe event of blockage. An indicator warns of impending blockage. From thescavenge filter, the oil flows to the tank.

(b) Turbomachinery

Oil from the accessory casing and the No. 1 bearing cavity is scavenged bygravity. The No. 2 bearing cavity oil is scavenged through a venturi by gravityaided by pressure oil, which induces a jet-pump action. Oil from the No. 3,4 and 5 bearing cavities is scavenged by gravity and assisted by air (blow-down)from the bearing labyrinth seals. The No. 6 and 7 bearing cavity oil isscavenged through an external tube connected to the scavenge pump.

(3) Vent and Breather System

The oil tank and No. 1 and 2 bearing cavity are vented internally, and the No. 6and 7 bearing cavity externally, to the accessory gearbox. A centrifugal oil separator(breather impeller) installed in the accessory gearbox removes oil before ventedair is carried by an external tube and discharged into the exhaust.

The impending bypass indicators (Ref. Fig. 13) fitted to the pressure and scavengefilters sense pressure filter differential. When activated, a signal gives advancewarning of a filter blockage.

F. Fuel and Control System (Ref. Figs. 14 through 21)

The engine fuel and control system governs the power produced by the engine bycontrolling the fuel flow. The fuel flow is controlled by the power lever and fuel shut off(condition) lever through two integrated systems: the mechanical fuel system and theelectronic fuel system.

(1) Engine Fuel System

The engine mechanical fuel system (Ref. Fig. 14) is made up of a fuel heater, afuel pump and a mechanical fuel control unit (MFCU), which are mounted on theaccessory drive casing. It also comprises a flow divider and dump valve andfuel nozzle manifold mounted on the gas generator case.





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RIGHT SIDE SCAVENGE OIL FILTER

LEFT SIDE MAIN PRESSURE OIL FILTER

C30204A

Oil System Impending Bypass Indicators - LocationFigure 13





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(a) The fuel heater (Ref. Fig. 15) consists of a filter and fin-type heater in twointegral housings. The filter housing contains a bypass valve to ensure anadequate fuel flow in the event of blockage and an indicator to warn of impendingblockage. The heater housing is divided into two circuits. Turbomachinerylubricating oil flows through one circuit to transfer heat to the fuel, which flows

through the other circuit. A thermal sensor in the fuel circuit operates avalve to regulate the oil flow in order to maintain the required fuel temperature.The fuel pressure differential switch located in the fuel filter housing outletport activates a warning indicator.

(b) The fuel pump (Ref. Fig. 16) is a positive displacement spur gear assemblyconsisting of a fuel ejector (jet pump), a self-relieving inlet screen, two spurgears, an outlet filter and a bypass valve. Fuel from the MFCU bypass outletpasses through the jet pump, positioned ahead of the main inlet, to maintain aconstant inlet pressure. The self-relieving inlet screen, when blocked, liftsfrom its seat and allows fuel to enter the pump housing. Two spur gears pumpfuel through the outlet filter. A bypass valve diverts fuel to the outlet port inthe event of filter blockage: the differential pressure switch signals the impending

blockage and activates a warning.

(c) The mechanical fuel control unit (MFCU) (Ref. Figs. 17 and 18), mounted onthe fuel pump, controls the engine fuel flow and thus the power output. TheMFCU consists of the following components:

1 Power Lever and Cam Assembly:

The power lever shaft incorporates two speed set cams, which move acam lever when the power lever is advanced. A spring connects the camlever to the governor lever and exerts a force on the governor lever as afunction of PLA. The governor lever is pivoted, and one end operatesagainst an airflow restrictor to form the governor orifice (Ag). A ball bearing

on the governor lever contacts the top of the flyweight bearing assembly.When the power lever is advanced, the cam applies tension to the spring,which applies a force on the governor lever to close Ag.

2 Flyweight Assembly:

The flyweights are mounted on a platform on the driveshaft, and as thedriveshaft revolves, centrifugal force causes the weights to pivot about theirmounting points and contact the bottom face of the bearing assembly. Asthe driveshaft speed increases, increased centrifugal force causes theweights to apply an increasing force against the bearing assembly. Thiscauses the bearing assembly to move upward on the driveshaft and applypressure to the ball bearing on the governor lever arm. The governor

orifice Ag opens whenever the driveshaft speed increases enough toovercome the force applied by the governor lever spring.

3 Orifices (Fixed and Variable):

High pressure compressor discharge pressure (P3) is supplied to theMFCU and metered through a fixed orifice to produce Px pressure. Px isused to pressurize the chamber containing the acceleration bellows, inside





49/551

the deceleration bellows and the governing bellows, and is meteredthrough a fixed orifice to produce Py pressure. Py pressurizes the chambercontaining the deceleration and governing bellows and is tapped off(then vented to atmosphere) via the governor (Ag) and stepper motor (Ap)flapper valve orifices. In addition, a Py tapping is connected to the

overspeed governor.

4 Flapper Valves (Ag and Ap):

Ag is controlled by the mechanical speed governor and Ap, which parallelsAg, by the stepper motor. Movement of either flapper valve changes Pywith respect to Px and repositions the bellows assembly.

5 Mode Cam Select Mechanism:

The mode select mechanism is used to transfer control between the EECand the MFCU. The system is activated automatically by the EEC when asystem fault occurs and also by cockpit command. A solenoid operated

pneumatic servo mechanism is used to select the appropriate cam whichtransfers control between the EEC and MFCU.

In EEC mode, a high mechanical governor speed schedule is selected bythe EEC cam to close valve Ag and allow the EEC to control parallel valve Apthrough the stepper motor. In manual mode, the manual cam holds valveAp in the closed position and selects a low mechanical governor speedschedule which allows valve Ag to be controlled by the power leverangle (PLA).

6 Bellows Assembly:

Consists of deceleration, governor and acceleration bellows connected by a

shaft linked to the fuel metering valve. Pressure differential betweeninside (Px) and outside (Py) pressures causes the deceleration bellows toexpand and reduce fuel flow. An increase in Px pressure acting on theevacuated acceleration bellows increases fuel flow.

During acceleration, flapper valves Ag and Ap are closed; this equalizesand increases Px and Py air pressures. As Px increases, the accelerationbellows contract, opening the metering valve and increasing fuel flow.

When governing, Py is reduced slightly below Px air pressure to give thefuel flow required to run at the selected power.

During deceleration, when the EEC is not operating, spring force on the

governor flyweights is reduced, opening flapper valve Ag which bleeds andreduces Py pressure around the deceleration bellows (Px pressure inthe bellows is not affected). The bellows expand, reducing fuel flow untilthe deceleration stop is contacted. As governor speed reaches the desiredlower setting, spring force overcomes flyweight force, the valve closesand Py pressure increases. This moves the bellows away from the stop intothe governing range to control fuel flow at the selected power level.





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HEATED OIL

INLET OUTLET

FUEL FILTER

BYPASS

IMPENDINGBYPASS

SWITCH

FUELHEATER

FUEL PRESSURE

SENSING PORT

FUEL FILTER / HEATER UNIT

AIRFRAME / ENGINE

FUEL CONNECTION

C17520_1A

Fuel System - SchematicFigure 14 (Sheet 1 of 2)





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FUEL PUMP UNIT

FUEL TEMP PORT

MOTIVE FLOW PUMP

BYPASS FLOW

DUMP VALVE

PUMP

AIRFRAME EJECTOR PUMP

MOTIVE

FLOW VALVE

FLOWMETER

(OPTIONAL)

OUTLET

FILTER

MECHANICAL

FUEL CONTROL UNIT

BYPASS

SELF

RELIEVING SCREEN

FLOW

DIVIDER

OIL

COOLER

INLET OUTLET

PRIMARY & SECONDARY

FUEL NOZZLES

OIL

VENT

AIRCRAFTDRAINTANK

WASTE FUELEJECTOR TANK

AIRFRAME / ENGINE

CONNECTION

C17520_2A

Fuel System - SchematicFigure 14 (Sheet 2)





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HEAT EXCHANGERAND VALVE BODY

FUEL IN

OIL OUT

OIL IN

FUEL FILTER

FUEL OUT

PRESSUREDIFFERENTIALSWITCH

FUEL OUT

FUELFILTER

FUELIN OIL OUT

OIL IN

THERMALELEMENT

VALVECOMPRESSIONSPRING

VALVESLEEVE

C15046B

Fuel Heater - 34 View and SchematicFigure 15





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OUTLET FILTER IMPENDINGBYPASS SWITCH

FUEL IN

FUEL OUT

BYPASS FUEL RETURNOUTLET FILTERBYPASS VALVE

SELF RELIEVINGINLET SCREEN

OUTLET FILTER BYPASS VALVE

IMPENDING

BYPASS SWITCH

OUTLET FILTER

GEAR PUMP

INLET PORT

OUTLET PORT

FUEL EJECTOR

BYPASS RETURN PORT

SELF RELIEVINGINLET SCREEN

C15047B

Fuel Pump - 34View and SchematicFigure 16





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FUEL CONTROLRIGGING HOLE

FUEL SHUTOFFRIGGING HOLE

POWER LEVER

FUEL SHUTOFF LEVERFUEL OUTLET

FUEL MOTIVEFLOW OUTLET

y

3

P AIR OUTLET

P AIR INLET

C30201

Mechanical Fuel Control Unit (MFCU) - 34ViewFigure 17





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METERED FUEL OUTPRESSURIZING VALVE

ON

OFF

CONDITION / FUELSHUTOFF LEVER

METERING VALVEP3

P0

MANIFOLDPRESS.REGULATOR

FUEL DRAINBELLOWS ASSY.POWER LEVER

IDLEMAX. FORWARD MAX. REVERSE

DEC. BELLOWS

GOV. BELLOWS

ACC.BELLOWSPLA. INPUT

RVDT

BYPASS VALVE

BYPASS RETURNTO PUMP

TORQUETUBE

PRESSURERELIEF VALVEMOTIVE FLOWVALVE

BLEED

P3

MOTIVE FLOW

REGULATOR

P3 AIR INLET

FUEL INLET

DRAIN

EEC MODE CAM

& FOLLOWER LEVER

MANUAL MODE CAM& FOLLOWER LEVER

DRAIN

PRESSURERELIEF VALVE

NH DRIVE INPUT

NH GOVERNORFLYWEIGHTS

GOVERNOR LEVER

GOVERNOR ORIFICE (Ag)

STEPPER MOTORORIFICE (Ap)

ELECTRICALCONNECTOR

SERVO VALVESTEPPER MOTOR& GEARHEAD

Py TO PROPELLEROVERSPEED GOVERNOR

MODE CAM SELECT SOLENOID

LEGEND

DIFFERENTIAL PRESSURECOMPRESSOR DISCHARGE PRESSUREHIGH PRESSURE ROTOR SPEEDENRICHMENT PRESSURE

GOVERNING PRESSUREROTARY VARIABLE DIFFERENTIAL TRANSFORMERAMBIENT PRESSURE

P3NHPx

PyRVDT

P0

PxORIFICEPyORIFICE

C15041A

Mechanical Fuel Control Unit (MFCU) - SchematicFigure 18





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During deceleration, when the EEC is operating, the stepper motor opensflapper valve Ap, bleeding and reducing Py pressure around the decelerationbellows. The bellows expand, reducing fuel flow until the decelerationstop is contacted. When the desired power level is reached, the valve closes,increasing Py pressure to move the bellows away from the stop into the

governing range.

7 Motive Flow Valve: The valve is spring loaded, closes and opens when thepressure of unmetered fuel overcomes the spring force. The valve providesfuel to operate a jet pump located in aircraft fuel tank.

8 High Pressure Relief Valve: Consists of a relief valve, a ported sleeve anda valve spring. The relief valve operates in parallel with the differentialpressure regulator to prevent excessive buildup of fuel pressure in the mainfuel control body.

9 Differential Pressure Regulator (Pd Regulator): Maintains a constantpressure drop across the metering valve by bypassing excess fuel flow to the

fuel pump ejector pump. Bimetallic disks under the spring compensatefor variations in specific gravity due to fuel temperature change. An externaladjustment screw on the regulator cover is used to adjust for maximumPd.

10 Metering Valve: Composed of a needle valve operating in a sleeve.Actuation of the valve changes the orifice area, which regulates the flow offuel to the engine. Positioning of the needle valve is controlled by thebellows assembly in the pneumatic section through a torque tube that actsas a fuel/air seal.

11 Pressurizing Valve: Maintains a minimum fuel pressure in the MFCU duringlow flow conditions when starting.

12 Shutoff Valve: An input shaft driven by the condition/fuel shutoff leveroperates a valve that passes metered flow to the bypass port, consequentlyclosing the pressurizing valve and shutting down the engine.

13 Manifold Pressure Regulator: Regulates starting fuel flow as a function ofcompressor discharge pressure (P3). The valve is normally open, and asP3 increases, the valve closes.

14 Stepper Motor: Alters the position of the valve (Ap) which bleeds Pypressure to change metered fuel flow to the engine. The motor is controlledby the EEC.

15 Rotary Variable Differential Transformer: Fitted to the power lever shaft andsignals power lever angle to the EEC.

16 Mode Select Solenoid: Energized when selecting EEC mode.





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17 The MFCU has an identification circuit in the wiring which is read by theEEC. If an MFCU having a lower fuel flow but not the identification circuitis installed on a PW127H engine, a fault is generated which prevents theMFCU from going into EEC mode. The code for the fault is stored in theEEC memory, thereby facilitating the identification of MFCUs which cannot

meet the fuel flow requirements of PW127H engines.

(d) The flow divider and dump valve (Ref. Fig. 19) is connected to the fuelmanifold at the bottom of the gas generator case (flange F to K). It comprisesprimary and secondary spool valves in a housing equipped with inlet anddump ports. The primary valve opens, giving access to the primary manifold,when the inlet fuel pressure overcomes the valve spring. The secondary valveopens when the primary manifold pressure overcomes the secondary valvespring. When the fuel inlet pressure ceases, the valves close the inlet and openthe dump ports, allowing residual fuel to drain from the manifold through theflow divider to the dump port.

(e) The fuel manifold delivers fuel to the combustion chamber. The manifold

consists of sheathed nozzle adapter assemblies (Ref. Fig. 20), which protrudeinto the combustion chamber, connected to three flexible tubes. One tubesupplies primary fuel and the other two (which are connected), secondary fuelto the fuel nozzle adapters. Nozzle adapter assemblies are produced byDelavan. Some nozzles have a fine center hole for primary fuel flow and anannular orifice for secondary flow; others have no center hole and are equippedfor secondary flow only. The sheath which surrounds the nozzle conveys air,from the compressor, to cool the nozzle and atomize the fuel.

(f) To ensure adequate drainage of fuel after shutdown, spring-loaded valves areinstalled at the front and rear of the underside of the gas generator case. Thevalves open when the pressure inside the case falls to near ambientpressure. The front valve has an adapter installed with a tube connected to the

adapter to drain the fuel to the main fuel drain valve. In addition, an elbowand tube is fitted to the exhaust duct and connects to the main fuel drain valve.

(g) To eliminate atmospheric pollution and fuel wastage, the dump valve isconnected to a waste fuel ejector.

1 The fuel waste ejector (Ref. Fig. 21), located in the airframe, comprises atank with inlet and outlet connections and a vent. The tank containsnon-return valves, a motive flow ejector pump, a strainer, and afloat-operated drain valve.





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INLET PORT CLOSEDPRIMARY, SECONDARYAND DUMP PORTS OPEN

INLET AND PRIMARYPORTS OPENSECONDARY ANDDUMP PORTS CLOSED

INLET, PRIMARY ANDSECONDARY PORTSOPEN, DUMP PORT CLOSED

VALVE SPRINGSTRANSFER VALVE

PRIMARY MANIFOLD PORT

SECONDARY MANIFOLD PORTFUEL MANIFOLDADAPTOR MATING FACE

DUMPPORT

INLET PORT

INLET PORT

BODY ASSEMBLY

DUMP PORT

SPRING HOUSING

SECONDARYMANIFOLD PORT

PRIMARY MANIFOLD

PORT

C38659

Flow Divider and Dump Valve - SchematicFigure 19





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SECONDARY

PRIMARY

COOLINGAIR

SWIRLVANE

C38663

Fuel Manifold Adapter and Nozzle - Cross-sectionFigure 20





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2 During engine operation, fuel drains from the dump valve and is collectedin the ejector tank. As the fuel level rises, the float moves upwards, raisinga lever and unseating a valve covering an orifice. Fuel from thehydromechanical fuel control flowing through a venturi causes a pressuredrop below the orifice. Fuel pressure acting on top of the orifice, combined

with the pressure drop on the bottom, opens a non-return valve locatedon the bottom of the orifice. Fuel is then drawn from the tank through theorifice, to be conveyed by a tube to the inlet side of the fuel pump. When thetank fuel level drops, the float moves down and the orifice is covered bythe valve. The non-return valve then closes, preventing fuel from themechanical fuel control from entering the tank from the orifice. The ejectortank is vented to an airframe tank, which also collects fuel and oil fromvarious drains on the engine.

(2) Engine Control System

(a) Electronic Engine Control

The electronic engine control (EEC) (Ref. Figs. 22 and 23) is located on the leftside of the front inlet case. The EEC operates in conjunction with themechanical fuel control unit (MFCU) and the autofeather unit (AFU) to providecontrol of engine power.

In EEC mode, the EEC has inputs from the Power Lever Angle (PLA), RatingSelector Switch (RSS), ambient conditions and aircraft requirements (e.g. bleeddemand). From these inputs, the EEC determines the power required. Thevalue of the power required is stored internally in the EEC and is also an outputto the aircraft cockpit instrumentation where it is displayed as an equivalenttorque value. The control system then adjusts fuel flow to obtain the powerrequired and ensure it does not fluctuate.

The EEC also controls minimum power turbine speed (NPT), HP compressorrotor speed (NH) until just above flight idle, acceleration and deceleration.

In addition, the EEC controls the intercompressor bleed valve (IBV) whichensures surge free transient operation.

In manual (degraded EEC) mode, the majority of the control functions aretaken over by the Mechanical Fuel Control Unit (MFCU). In this mode, the MFCUcontrols high pressure rotor speed based on power lever angle. Monitoringand adjustment of the torque (power) produced is the responsibility of the personrunning the engine.

In manual mode, the intercompressor bleed valve remains controlled by the

EEC and engine acceleration is usually faster than in EEC mode .

Below 30% NH (e.g. starting), fuel flow is controlled by the MFCU only. Above30% NH, the EEC maintains closed loop control as described above.

The EEC, operating on 28 VDC, corrects and changes fuel flow throughvarious inputs, both airframe and engine, as follows:





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VENT WASTE FUEL INLET

WASTE FUEL EJECTOR TANK

MOTIVE FLOW INLET

FUEL OUTLET

C11865

Waste Fuel Ejector - 34 ViewFigure 21





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C38697

Electronic Engine Control - 34 View and SchematicFigure 22





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INDICATOR

ENGINETORQUE 1

NH1

NH2

T1.8

TORQUE 2

PAMB

BLEEDTORQUEMOTOR

AUTOFEATHER

UNIT

(AFU)

ELECTRONICENGINE

CONTROL

(EEC)

DISCRETESTO & FROMOPPOSITE

ENGINE EEC

STEPPERMOTOR

FUEL PUMP

RVDTMECHANICAL

FUEL CONTROLUNIT (MFCU)

LOWPRESSURE

FUEL IN

NH

N H

Wf

P3BYPASSFLOW

MOTIVE

FLOW

PLA

CLA

AIRFRAME

ARINC 429 OUTPUT

AUTOFEATHERRELAY

LOW TORQUE

LAMP

AUTOFEATHERARMED LAMP

ACTUAL TORQUETORQUE BUG

COCKPIT DISPLAYS

28 VDC

AUTO FAIL

LAMP

ARINC 429INPUT FROM ADC

ENGINECONTROLSYSTEM FAULT

UART / ARINCMAINTENANCEDIAGNOSTICS

DISCRETES

CONDITION FUELSHUT OFF LEVER

POWERLEVER

RVDT

PVM

CLA

PLA

WF

PAMB

P1.8

T1.8

NH

P3

ROTARY VARIABLE DIFFERENTIAL TRANSFORMER

PROPELLER VALVE MODULE

CONDITION LEVER ANGLE

FUEL FLOW

AMBIENT PRESSURE

TOTAL INLET PRESSURE

TOTAL INLET TEMPERATURE

HIGH PRESSURE ROTOR SPEED

INTERSTAGE AIR PRESSURE

POWER LEVER ANGLE

PVM

PLA

PLA

FUEL FLOW

C63872

Engine Control and Electrical System - SchematicFigure 23





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(b) Airframe Inputs

1 Mode selector.

Manual switch: This switch selects manual (MFCU) control of the engine.

2 EEC rating selector.

Selects the required bug power rating - i.e., ATO (alternate take off), MCT(maximum continuous), CLB (maximum climb) and CRZ (maximumcruise).

3 Propeller feathered signal (feather discrete).

This signal comes from either the condition lever angle switch, manualfeather switch or autofeather relay to cancel propeller underspeed fuelgoverning whenever the propeller is feathered.

4 Uptrim relay.Sends uptrim signal when commanded by opposite engine autofeathercontrol unit (AFU).

5 Engine trim switch.

Adjusts the measured power lever angle to eliminate power lever staggerdue to system tolerances.

6 LRU fault select.

Maintenance activated switch controls display of EEC fault codes.

7 Propeller brake signal.

Selects NH limited APU mode operation.

8 Ground test switch.

Not used.

9 Bleed signal (2 Discrete Inputs).

Indicates bleed air extraction level and lowers thermal power limit ofengine.

10 Air data computer.

Electrical signals from the computer transmit outside air temperature (OAT),altitude pressure (PALT) and indicated airspeed (IAS). These signals arenormally used instead of those from engine sensors to compute and transmita signal to the torque gage which positions the bug to control engine fuelflow. The engine sensors are used only when a fault occurs in the air datainput to the EEC.





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(c) Engine Inputs

1 Ambient pressure (PAMB).

Pneumatic signal to a transducer installed in the EEC.

2 Total inlet pressure (P1.8)

Pneumatic signal to a transducer installed in the EEC. This is used togenerate an airspeed signal used by the control logic.

3 Total inlet temperature (T1.8).

Electrical signal from a sensor installed in the rear inlet case.

4 High pressure turbine rotor speed (NH).

Electrical signals from pulse pick-up probes installed in the accessory

gearbox.5 Torque and power turbine rotor speed (NPT).

Electrical signals from a torque sensor installed in the reduction gearboxinput housing. The sensor has two coils. If the signal from No. 1 coil deviatesbeyond set limits, the EEC uses the signal from No. 2 coil and a fault isrecorded in the EEC memory. The torque signal is modified by acharacterization plug to compensate for torque shaft variations due totolerances.

(d) EEC output

The airframe and engine inputs are processed by logic in the EEC andcompared with reference data stored in the units memory. Commands are thengenerated and transmitted to:

1 The MFCU stepper motor to adjust fuel flow.

NOTE: After a major EEC or EEC input failure, then stepper motor isfrozen (fail fixed), holding fuel flow and power stable under steadystate conditions until reversion to manual occurs. Reversion tomanual is automatic when PLA is below 65 degrees (i.e. at lowpower), ensuring power changes during the reversion areminimized.

2 A reference bug on the torque indicator. The position of the bug shows theactual rated engine torque for the current operating conditions. The powerlever may be adjusted to bring engine torque into line with rated torque.

3 The torque indicator to show the actual torque produced by the engine.





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4 The intercompressor bleed valve which is opened to bleed LP compressorair and prevent surge, stalls and reduce noise at low power and duringrapid power lever movement. The valve is closed when the MFCU is inmanual mode. The following two modes are used to generate the commandstransmitted to the intercompressor bleed valve:

a Electronic mode: normal control depending on NH, PLA and PAMBinput.

b Degraded mode (Ref. step (d) 7): Control depends on NH input.

5 A cockpit warning light (auto fail lamp) when a failed fixed condition occurs.

6 The EEC degraded lamp located on the maintenance panel when a faultoccurs in the EEC.

7 There is a degraded mode which occurs automatically after a major EEC orEEC input failure. The MFCU stepper motor is frozen (fail fixed) holding

fuel flow steady or the units reverts to manual control where the fuel flow iscontrolled by the power lever angle (PLA). Existing commands maycontinue to be generated by the EEC, depending on the type of failure.

(e) Most control system faults are recorded in the EEC memory and identified by atwo-digit code which can be shown on a maintenance panel or ARINC 429receiver.

(3) Autofeather Unit

The autofeather unit (AFU) (Ref. Fig. 24) is mounted on the left side of the frontinlet case (flange B to C) adjacent to the EEC. The unit comprises two circuit boardscontained in a metal case. The case has four mounting pads and two electrical

connectors. The AFU operates on 28 VDC and receives signals from the AFU of thesecond (twin) engine. A torque shaft characterization plug is installed on theconnectors located at the top of the AFU.

The plug contains links which are set up during the calibration of the torque shaftand testing of the engine. They bring the torque signals to a nominal value andcompensate for any differences due to material inconsistency and machiningtolerances of the torque shaft. Should an engine fail, its AFU will initiate the enginesautofeather system and signal the EEC and AFU of the twin engine. In that eventthe EEC of the twin engine increases power (uptrim) to compensate for the failedengine. The twin AFU disables its autofeather system to ensure both engines arenot feathered at the same time.

G. Propeller Control System

In addition to the components of the fuel control, the engine power output is governedby the propeller overspeed governor. The propeller control system consists of theelectronic propeller control (EPC), propeller valve module (PVM), the propeller overspeedgovernor and the hydraulic pump described below.

(1) The EPC is mounted on the airframe (Ref. AMM).





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VIBRATION ISOLATEDMOUNTING PAD

ELECTRICAL CONNECTOR

TORQUE SHAFT CHARACTERIZATIONPLUG RECEPTACLE

28 VOLTS

TORQUE

AUTOFEATHER UNITOF SECOND ENGINE

AUTOFEATHERENABLE

AUTOFEATHER TEST

AUTOFEATHERUNIT

ENGINE ELECTRONIC CONTROL

OF SECOND ENGINE

AUTOFEATHER UNITOF SECOND ENGINE

EEC LOCAL

AUTOFEATHER

ENGINE OUT

C14834A

Autofeather Unit - 34 View and SchematicFigure 24





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(2) The PVM is mounted behind the propeller shaft on the rear face of the reductiongearbox. A power lever on the PVM controls reverse pitch and beta scheduling. Acondition lever governs the propeller pitch range and, therefore, propeller speed. Aswitch is linked to the PVM condition lever to restrict the use of reverse pitch.The PVM receives oil from a pump mounted on the reduction gearbox. The oil

pressure is transmitted to the propeller pitch change system by a transfer tube thatruns through the propeller shaft.

H. Inlet Temperature and Torque Sensing Systems (Ref. Fig. 25 and Fig. 26)

The inlet temperature and torque sensing systems consist of a total inlet temperature(T1.8) sensor and the engine torque sensor. These units provide signals which are passedto the engine control system by the engine electrical harness.

(1) The total inlet temperature (T1.8) sensor (Ref. Fig. 25), mounted in the rear inletcase (flange C to D), consists of a resistor in a sleeve fitted with a threadedconnector. It receives a fixed low current input from the EEC. The resistance of thesensor changes with temperature, varying the current returned to the EEC in

proportion.

(2) The torque sensors (Ref. Fig. 26) have identical tubular housings with a magnetand coil at the inner (tip) end. A six-pin electrical connector and mount flange areat the outer end. The engine torque shaft assemblies consist of an outer reductiongearbox torque shaft and an inner torque shaft metering tube. Teeth on the innershaft and on the ou

pw127 maintenance manual chapter 72-00

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