BHT-ALL-SPM

BHT-ALL-SPM

STANDARD PRACTICES MANUAL (Applicable to all Bell Helicopter Models)

NOTICE The instructions set forth in this manual, as supplemented or modified by Alert Service Bulletins and other directions issued by Bell Helicopter Textron and Airworthiness Directives issued by the Federal Aviation Administration, must be strictly followed.

BHT-ALL-SPM

STANDARD PRACTICES MANUAL (Applicable to all Bell Helicopter Models)

NOTICE The instructions set forth in this manual, as supplemented or modified by Alert Service Bulletins and other directions issued by Bell Helicopter Textron and Airworthiness Directives issued by the Federal Aviation Administration, must be strictly followed.

COPYRIGHT NOTICE COPYRIGHT 2004 BELL ® HELICOPTER TEXTRON INC. AND BELL HELICOPTER TEXTRON CANADA LTD. ALL RIGHTS RESERVED

REISSUE — 23 MAY 2000 REVISION 1 — 30 JUNE 2004

BHT-ALL-SPM

PROPRIETARY RIGHTS NOTICE These data are proprietary to Bell Helicopter Textron Inc. Disclosure, reproduction, or use of these data for any purpose other than helicopter maintenance is forbidden without prior written authorization from Bell Helicopter Textron Inc.

Additional copies of this publication may be obtained by contacting: Commercial Publication Distribution Center Bell Helicopter Textron Inc. P. O. Box 482 Fort Worth, Texas 76101-0482

PN

Rev. 1

30 JUN 2004

BHT-ALL-SPM

WARNING THIS MANUAL APPLIES ONLY TO HELICOPTERS AND COMPONENTS MAINTAINED IN ACCORDANCE WITH BELL HELICOPTER TEXTRON (BELL) APPROVED PROCEDURES USING BELL APPROVED PARTS. ALL INSPECTION, REPAIR AND OVERHAUL PROCEDURES PUBLISHED BY BELL, INCLUDING PART RETIREMENT LIFE, ARE BASED SOLELY ON THE USE OF BELL PARTS THAT HAVE BEEN MAINTAINED USING BELL APPROVED DATA. THE DATA PUBLISHED HEREIN OR OTHERWISE SUPPLIED BY BELL IS NOT APPLICABLE TO NON-BELL PARTS OR PARTS THAT HAVE BEEN REPAIRED USING DATA AND/OR PROCESSES NOT APPROVED BY BELL. BELL IS NOT RESPONSIBLE FOR ANY PART OTHER THAN THOSE THAT IT HAS APPROVED. BEFORE PERFORMING ANY PROCEDURE CONTAINED IN THIS MANUAL YOU MUST INSPECT THE AFFECTED PARTS AND RECORDS FOR EVIDENCE OF ANY MANUFACTURE, REPAIR, REWORK OR USE OF A PROCESS NOT APPROVED BY BELL. IF YOU IDENTIFY OR SUSPECT THE USE OF PARTS NOT AUTHORIZED BY BELL, EITHER REMOVE THE AFFECTED ITEM FROM THE AIRCRAFT OR OBTAIN INSTRUCTIONS FOR CONTINUED AIRWORTHINESS FROM THE MANUFACTURER OR THE ORGANIZATION THAT APPROVED THE REPAIR.

30 JUN 2004

Rev. 1

Warning

BHT-ALL-SPM

LIST OF EFFECTIVE PAGES On a revised page, the portion of the text and illustration affected by the latest revision is indicated by a black vertical line. Original....................... 0........................1 MAR 90 Reissue ...................... 0........................ 8 SEP 92 Reissue ...................... 0.........................3 FEB 95 Reissue ...................... 0...................... 10 OCT 96

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Cover ..................................................................1 Title .....................................................................1 PN .......................................................................1 Warning...............................................................1 A/B ......................................................................1 Help.....................................................................1 Customer Feedback............................................1 i/ii.........................................................................1 Index 1 — Index 4...............................................1 Index 5/Index6 ....................................................1 Chapter 1-00-00 1/2 .......................................................................1 3/4 .......................................................................1 Chapter 2-00-00 1/2 .......................................................................0 3 — 20 ................................................................0 21/22 ...................................................................0 Chapter 3-00-00 1 — 20 ................................................................0 Chapter 4-00-00 1/2 .......................................................................0 3 — 30 ................................................................0 Chapter 5-00-00 1/2 .......................................................................0 3 — 6 ..................................................................0

Reissue.......................0 ..................... 20 AUG 99 Reissue.......................0 ..................... 23 MAY 00 Revision......................1 ...................... 30 JUN 04

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Chapter 7-00-00 1/2 ...................................................................... 0 3 — 10 ................................................................ 0 11/12 .................................................................. 0 Chapter 8-00-00 1 — 26 ................................................................ 0 Chapter 9-00-00 1 — 112 .............................................................. 0 113/114 .............................................................. 0 Chapter 10-00-00 1/2 ...................................................................... 0 3 — 10 ................................................................ 0 11/12 .................................................................. 0 Chapter 11-00-00 1/2 ...................................................................... 0 3 — 6 .................................................................. 0 7/8 ...................................................................... 0 Chapter 12-00-00 1/2 ...................................................................... 1 3/4 ............................................................Deleted 5 — 68 ......................................................Deleted Chapter 13-00-00 1/2 ...................................................................... 0 3 — 22 ................................................................ 0 23/24 .................................................................. 0

Chapter 6-00-00 1 — 20 ................................................................1

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VALUATE

L

OGISTICS

P

UBLICATIONS

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BHT-ALL-SPM

CONTENTS CHAPTER

SUBJECT Introduction .......................................................................................................................... Torque.................................................................................................................................. Corrosion Control and Protective Coverings/Coatings ........................................................ Painting ................................................................................................................................ Cleaning............................................................................................................................... Nondestructive Inspection.................................................................................................... Bonding................................................................................................................................ Miscellaneous Practices ...................................................................................................... Bearings, Sleeves, and Bushings ........................................................................................ Storage ................................................................................................................................ Use of Solvents.................................................................................................................... Nickel-Cadmium Aircraft Storage Battery ............................................................................ Consumable Materials .........................................................................................................

1 2 3 4 5 6 7 8 9 10 11 12 13

1

NOTE: The contents of Chapter 12 have been deleted. Please refer to the Bell Helicopter 1 Electrical Standard Practices Manual (BHT-ELEC-SPM) for information on Nickel-Cadmium Aircraft Batteries.

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i/ii

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ALPHABETICAL INDEX Subject

Paragraph/Table/ Figure Number A

Acrylic windows and windshields . . . . . . . . . . . . 7-7 Adhesive data . . . . . . . . . . . . . . . . . . . . . . . . . 13-2 Affect of applied force to rigid frame and audible indicating torque wrenches using nonconcentric attachments. . . . . . . . . F2-7 Alternates for Bell Helicopter Textron adhesives . . . . . . . . . . . . . . . . . . . . . . . . . . T13-2 Application of polyurethane enamel. . . . . . . . . 4-18 Polyurethane enamel — equipment requirements . . . . . . . . . . . . . . . . . . . . . 4-19 Polyurethane enamel — general information. . . . . . . . . . . . . . . . . . . . . . . 4-20 Polyurethane enamel — procedure requirements . . . . . . . . . . . . . . . . . . . . . 4-21 Polyurethane enamel — process control requirements . . . . . . . . . . . . . . . 4-22 Touch-up painting procedures for polyurethane enamel . . . . . . . . . . . . . . . 4-23 B

Bearing and sleeve replacement data . . . . . . . T9-4 Bearing inspection and replacement criteria . . T9-1 Bearing replacement . . . . . . . . . . . . . . . . . . . . . 9-4 Bearing removal . . . . . . . . . . . . . . . . . . . . . 9-5 Bearing rotational torque check . . . . . . . . . . . . F9-4 Bearing staking tool kit application. . . . . . . . . . T9-3 Bearing wear limits. . . . . . . . . . . . . . . . . . . . . . T9-2 Bearing installation — ring staking method. . . . . . . . . . . . . . . . . . . . . . . . . . . 9-6 Black oxide. . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-21 Gear tooth wear pattern inspection using Fluoroglide or Permalon 327 . . . . . . . . . 3-22

Subject

Paragraph/Table/ Figure Number

Bonded rod end bearings, inserts, and clevis — replacement . . . . . . . . . . . . . . . . . . 9-14 Bonding procedure. . . . . . . . . . . . . . . . . . . . 7-2 Bushings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-12 Bushing replacement . . . . . . . . . . . . . . . . . 9-13 C

Chemical film (chromic acid) treatment — magnesium . . . . . . . . . . . . . . . 3-15 Aluminum alloy — chemical film treatment (touchup) . . . . . . . . . . . . . . . . 3-16 Cadmium plating . . . . . . . . . . . . . . . . . . . . 3-17 Chromate conversion coating . . . . . . . . . . 3-18 Cleaning . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-1 Cleaning bearings . . . . . . . . . . . . . . . . . . . . 5-6 Cleaning carpet . . . . . . . . . . . . . . . . . . . . . . 5-3 Cleaning headliner and trim panels . . . . . . . 5-4 Cleaning hydraulic assemblies and servicing units. . . . . . . . . . . . . . . . . . . . . . 5-5 Cleaning metals (except titanium) . . . . . . . . 5-7 Cleaning plastic and glass . . . . . . . . . . . . . . 5-9 Cleaning titanium . . . . . . . . . . . . . . . . . . . . . 5-8 Cleaning upholstery . . . . . . . . . . . . . . . . . . . 5-2

Consumable material list . . . . . . . . . . . . . . . . T13-1 Consumable materials . . . . . . . . . . . . . . . . . . . . 1-2 Consumable materials . . . . . . . . . . . . . . . . . . . 13-1 Copper plating bath . . . . . . . . . . . . . . . . . . . . . T3-4 Corrosion corrective treatment . . . . . . . . . . . . . . 3-6

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Index 1

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ALPHABETICAL INDEX (Cont) Subject

Paragraph/Table/ Figure Number

Corrosion removal — aluminum parts . . . . . 3-8 Corrosion removal — elastomeric components . . . . . . . . . . . . . . . . . . . . . . 3-10 Corrosion removal — magnesium parts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-9 Corrosion removal — steel parts . . . . . . . . . 3-7 Corrosion prevention . . . . . . . . . . . . . . . . . . . . . 3-2 Corrosion preventive oil . . . . . . . . . . . . . . . . 3-4 Corrosion preventive treatment . . . . . . . . . . 3-3 Corrosion protection — control bolts, rotating and non-rotating . . . . . . . . . . . . . 3-5 Corrosion protection — faying surfaces . . . . . . 3-11 Corrosion protection — exceptions . . . . . . 3-14 Dissimilar metals . . . . . . . . . . . . . . . . . . . . 3-13 Similar metals. . . . . . . . . . . . . . . . . . . . . . . 3-12

D Definitions of similar and dissimilar metals. . . . T3-1

Subject

Paragraph/Table/ Figure Number F

Fabrication of bearing/sleeve removal and installation workaid tools . . . . . . . . . . . . . . . F9-1 Fabrication of bushing removal and installation workaid tools . . . . . . . . . . . . . . . F9-7

Fluid ounces/gallons to milliliters/liters and British Imperial ounces . . . . . . . . . . . . F8-10 Bearing inspection criteria . . . . . . . . . . . . . .9-1 Fluorescent magnetic particle inspection method (ASTM E1444) . . . . . . . . . . . . . . . . 6-17 Fluorescent penetrant inspection method (ASTM E1417). . . . . . . . . . . . . . . . . . . . . . . . .6-2

E Flyable storage . . . . . . . . . . . . . . . . . . . . . . . . .10-3 Depreservation and activation . . . . . . . . . .10-7 General procedures for flyable storage . . .10-4 Maintenance during flyable storage . . . . . .10-6 Preparation for flyable storage . . . . . . . . . .10-5 G English to metric and British Imperial units formulas . . . . . . . . . . . . . . . . . . . . . . . . F8-2

Environmental conditions . . . . . . . . . . . . . . . . . 10-2 Epoxy adhesive, mixing ratio, pot life, and curing schedule . . . . . . . . . . . . . . . . . . . . . . T7-1 Epoxy enamel application. . . . . . . . . . . . . . . . . 4-17 Epoxy polyamide primer application. . . . . . . . . . 4-6 Epoxy polyamide primer — equipment requirements . . . . . . . . . . . . . . . . . . . . . . 4-7 Epoxy/zinc coating . . . . . . . . . . . . . . . . . . . . . . 4-24 Control tube internal surface — refinishing. . . . . . . . . . . . . . . . . . . . . . . . 4-25 Epoxy zinc coating application . . . . . . . . . . 4-24

Index 2

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30 JUN 2004

Gear wear patterns . . . . . . . . . . . . . . . . . . . . . .8-12 Gear wear pattern check . . . . . . . . . . . . . .8-13

General rules. . . . . . . . . . . . . . . . . . . . . . . . . . . .7-1 I Inches to millimeters conversions . . . . . . . . . . F8-3 Inch/foot-pounds torque to newton-meters conversion . . . . . . . . . . . . . . . . . . . . . . . . . . F8-8

BHT-ALL-SPM

ALPHABETICAL INDEX (Cont) Subject

Paragraph/Table/ Figure Number

Intermediate storage . . . . . . . . . . . . . . . . . . . Depreservation and activation . . . . . . . . . General inspection. . . . . . . . . . . . . . . . . . General storage procedures . . . . . . . . . . Inspection . . . . . . . . . . . . . . . . . . . . . . . . Maintenance during intermediate storage. . . . . . . . . . . . . . . . . . . . . . . . . Miscellaneous . . . . . . . . . . . . . . . . . . . . . Preservation for intermediate storage . . .

10-14 10-20 10-16 10-15 10-19 10-18 10-21 10-17

Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-1

Subject

Paragraph/Table/ Figure Number

Maximum temperature requirements . . . . . . . . T8-1 Measuring gear teeth and splines . . . . . . . . . . 8-10 Gear teeth and spline measuring pin kit. . . 8-11 Metric and British Imperial units conversions. . . . . . . . . . . . . . . . . . . . . . . . . . 8-19 Microinches to microns conversions. . . . . . . . . F8-6 Miscellaneous practices . . . . . . . . . . . . . . . . . . . 8-1 Control tube (adjustable) — alignment. . . . . 8-5 Data plate bonding . . . . . . . . . . . . . . . . . . . . 8-6 Electric arc etching — unauthorized procedure . . . . . . . . . . . . . . . . . . . . . . . . . 8-2 Studs and inserts replacement. . . . . . . . . . . 8-7 Surface roughness . . . . . . . . . . . . . . . . . . . . 8-3 Thread protection — adjustable . . . . . . . . . . 8-4 N Nondestructive inspection eddy current method . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-37

K Kydex and Royalite parts . . . . . . . . . . . . . . . . . . 7-9 L List of solvents commonly used . . . . . . . . . . . T11-2 Long term storage . . . . . . . . . . . . . . . . . . . . . 10-22

Nonstructural bonding with rubber base cement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-5 O

M

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Index 3

BHT-ALL-SPM

ALPHABETICAL INDEX (Cont) Subject

Paragraph/Table/ Figure Number

Subject

Paragraph/Table/ Figure Number

Organic protective requirements for metals . . . . . . . . . . . . . . . . . . . . . . . . . . . T3-2 Ounces and pounds force to newtons conversions . . . . . . . . . . . . . . . . . . . . . . . . . F8-4 Ounces and pounds mass (weight) to kilograms conversions . . . . . . . . . . . . . . . . . F8-5 P Paint application . . . . . . . . . . . . . . . . . . . . . . . . . 4-4 Painting — exterior surfaces . . . . . . . . . . . . 4-5 Painting requirements for exterior surfaces . . . T4-1 Polycarbonate parts . . . . . . . . . . . . . . . . . . . . . . 7-3 Polycarbonate parts repair . . . . . . . . . . . . . . 7-4 Pounds per square inch pressure to kilopascals conversions . . . . . . . . . . . . . . . . F8-7

Procedure for checking gear dimensions and measuring pin kits . . . . . . . . . . . . . . . . . F8-1 R

Repair of control tube assemblies with bonded or riveted clevises, inserts or rod end bearings . . . . . . . . . . . . . . . . . . . . . . . . . F9-8 Retaining compound. . . . . . . . . . . . . . . . . . . . . 8-16 Application of retaining compound . . . . . . . 8-17

Index 4

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30 JUN 2004

Ring staking . . . . . . . . . . . . . . . . . . . . . . . . . . F9-2 Pregrooved bearing installation — roll staking method . . . . . . . . . . . . . . . . . . . . .9-7 Roll or anvil staking pregrooved bearings . . . . F9-3 Bearing installation — roll staking method . . . . . . . . . . . . . . . . . . . . . . . . . . .9-8 Roll staking sleeves or bushings . . . . . . . . . . . F9-5 Bearing installation — segment staking method . . . . . . . . . . . . . . . . . . . . .9-9 Pregrooved bearing installation — staking method . . . . . . . . . . . . . . . . . . . .9-10 S Segment staking . . . . . . . . . . . . . . . . . . . . . . . F9-6 Protection of staked bearings . . . . . . . . . . .9-11 Selection and use of torque wrench . . . . . . . . . .2-5 Short term storage . . . . . . . . . . . . . . . . . . . . . .10-8 Depreservation and activation . . . . . . . . .10-13 General preparation . . . . . . . . . . . . . . . . . .10-9 Inspection . . . . . . . . . . . . . . . . . . . . . . . . .10-12 Maintenance during short term storage . . . . . . . . . . . . . . . . . . . . . . . . .10-11 Preservation . . . . . . . . . . . . . . . . . . . . . . .10-10 Silicone adhesives classification and properties . . . . . . . . . . . . . . . . . . . . . . . . . . T7-3 Silicone bonding . . . . . . . . . . . . . . . . . . . . . . . . .7-6 Solid film lubricant . . . . . . . . . . . . . . . . . . . . . . .3-19

BHT-ALL-SPM

ALPHABETICAL INDEX (Cont) Subject

Paragraph/Table/ Figure Number

Solid film lubricant repair . . . . . . . . . . . . . . 3-20 Solid film lubricant curing . . . . . . . . . . . . . . . . . T3-3 Solvents . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11-1 Solvents. . . . . . . . . . . . . . . . . . . . . . . . . . . 11-2 Spray equipment — epoxy polyamide primer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . T4-2 Epoxy polyamide primer — general information. . . . . . . . . . . . . . . . . . . . . . . . 4-8 Epoxy polyamide primer — procedure requirements . . . . . . . . . . . . . . . . . . . . . 4-10 Epoxy polyamide primer — process and product requirement . . . . . . . . . . . . . 4-9

Subject

Paragraph/Table/ Figure Number

Torque values . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-1 Special torques. . . . . . . . . . . . . . . . . . . . . . . 2-4 Recommended installation torque range . . . 2-3 Standard torque . . . . . . . . . . . . . . . . . . . . . . 2-2 Torque wrench concentric type attachments . . . . . . . . . . . . . . . . . . . . . . . . . F2-5 Torque wrench nonconcentric type attachments . . . . . . . . . . . . . . . . . . . . . . . . . F2-6 Treatment of fungus . . . . . . . . . . . . . . . . . . . . . 5-10 Fungus growth cleaning . . . . . . . . . . . . . . . 5-12 Fungus growth inspection . . . . . . . . . . . . . 5-11 U

Standard torque values . . . . . . . . . . . . . . . . . . F2-1 Standard torque values for flareless fittings. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . F2-4 Standard torque values for fluid connections . . . . . . . . . . . . . . . . . . . . . . . . . F2-2 Standard torque values for threaded studs. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . F2-3 Surface preparation for application of epoxy enamel. . . . . . . . . . . . . . . . . . . . . . T4-7 Surface preparation for application of epoxy polyamide primer . . . . . . . . . . . . . . . . T4-3 Epoxy primer (Super-Koropon application) . . . . . . . . . . . . . . . . . . . . . . 4-11 Surface preparation for application of epoxy primer (Super-Koropon). . . . . . . . . . . T4-4

Urethane adhesives, mixing ratio, potlife, and curing schedule . . . . . . . . . . . . . . . . . . . T7-2 Use of solvents Metals (except titanium) Nonmetals (plastics and glass) . . . . . . T11-1 Paint removers — types and usage . . . . . . . 4-2 Paint stripping — parts with Teflon bearings . . . . . . . . . . . . . . . . . . . . . . . . . . 4-3 Titanium (model 412, 214, & 222 main rotor flexures, 214ST hydraulic actuator valve bodies, nodal beam retention bolts, etc.) . . . . . . . . . . . . . . . T11-1 W Walkway coating application. . . . . . . . . . . . . . . 4-26

T Temperature conversions. . . . . . . . . . . . . . . . . F8-9

Thermal fit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-8 Methods of securing dimensional changes — thermal fit parts. . . . . . . . . . . 8-9

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Index 5 /Index 6

BHT-ALL-SPM

CHAPTER 1 — INTRODUCTION CONTENTS — MAINTENANCE PROCEDURES Paragraph Number

1-1 1-2

Title

Introduction ....................................................................... Consumable Materials ......................................................

Chapter Number

Page Number

1-00-00 1-00-00

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BHT-ALL-SPM

INTRODUCTION 1-1.

NOT RESPONSIBLE FOR PARTS OR P RO C E S SE S O T H E R T H AN T HO SE WHICH IT HAS ITSELF DEVELOPED OR APPROVED.

INTRODUCTION

This manual contains maintenance information and procedures that are common to all Bell Helicopter models. Typical information includes standard torque charts and application procedures, corrosion control, painting, cleaning, nondestructive inspection, bonding, miscellaneous practices, bearing, sleeve and bushing inspection and replacement, storage, use of solvents, and consumable materials.

WARNING

ALL REPAIR AND OVERHAUL PROCEDURES LIVES PUBLISHED BY BELL HELICOPTER TEXTRON, INCLUDING COMPONENT RETIREMENT LIFE, ARE BASED SOLELY ON THE USE OF BELL APPROVED PARTS AND PROCESSES. IF PARTS OR PROCESSES DEVELOPED OR APPROVED BY PARTIES OTHER THAN BELL HELICOPTER ARE USED, THEN THE DATA PUBLISHED OR OTHERWISE SUPPLIED BY BELL HELICOPTER ARE NOT APPLICABLE. THE USER IS WARNED TO NOT RELY ON BELL HELICOPTER DATA FOR PARTS AND PROCESSES NOT APPROVED BY BELL H E L I C O P T E R. A L L A P P L I C A B L E INSPECTIONS AND REPAIR METHODS MUST BE OBTAINED FROM THE SUPPLIER OF THE PARTS OR PROCESSES NOT APPROVED BY BELL HELICOPTER. BELL HELICOPTER IS

1-2.

CONSUMABLE MATERIALS NOTE Handling, storage and safety precautions for consumable materials shall be in accordance with the consumable material manufacturers instructions unless otherwise specified in this manual.

A list of consumable materials is contained in Chapter 13. This comprehensive listing provides a description, specification and suggested source. Within this manual, consumable items are referred to within the maintenance tasks by "C" number. When a task states to use solvent (C-304), refer to Chapter 13 and find item C- 304 for type of solvent to use.

CAUTION M E T R I C E Q U I VA L E N T S T O U . S . STANDARD WEIGHTS AND MEASURES ARE PROVIDED THROUGHOUT THIS MANUAL. WHILE PERFORMING MEASUREMENTS TO DETERMINE THE SERVICEABILITY OF A COMPONENT OR T O E S TA B L I S H A S P E C I F I E D DIMENSION, ONLY THE U.S. STANDARD VALUES SHALL BE USED.

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BHT-ALL-SPM

Bell Helicopter Textron

CHAPTER 2CONTENTS Paragraph Number 2-1 2-2 2-3 2-4 2-5 2-6

TORQUE

MAINTENANCE PROCEDURES Title

Torque Values .................................................................. Standard Torque ........................................................ Recommended Standard Torque Range................... Specified Torques ...................................................... Self Locking Nuts ....................................................... Selection and Use of Torque Wrench ........................

Chapter/Section Number

Page Number

2-00-00 2-00-00 2-00-00 2-00-00 2-00-00 2-00-00

3 3 4 5 5 5

FIGURES Figure Number

2-1 2-2 2-3

Title

Torque Wrench Concentric Type Attachments .......................................... Torque Wrench Nonconcentric Type Attachments .................................... Affect of Applied Force to Rigid Frame and Audible Indicating Torque Wrenches Using Nonconcentric Attachments ...............................

Page Number

19 20 21

TABLES Table Number

2-1 2-2 2-3 2-4 2-5 2-6 2-7

Title

Torque Value Chart (Dry) for Specified Nuts on 125000 PSI Minimum Ultimate Tensile Strength Fasteners ............... Torque Value Chart (Dry) for Specified Nuts on 160000 PSI Minimum Ultimate Tensile Strength Fasteners........................................... Torque Value Chart (Dry) for Specified Nuts on 180000 PSI Minimum Ultimate Tensile Strength Fasteners........................................... Standard Torque Values for Fluid Connections.......................................... Standard Torque Values (Studs) Part I ...................................................... Standard Torque for Dynamic Beam Seal Nuts (Operating Pressures to 5000 PSI, Titanium Material)............................... Recommended Standard Torque for Flared Fitting Nuts............................

Page Number

7....... 7 11 13 14 15 17 18

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TORQUE 2-1. 1.

TORQUE VALUES WARNING

Description.

DO NOT EXCEED THE MAXIMUM ALLOWABLE TORQUE VALUE. OVERSTRESSING OF THE BOLT OR NUT MAY RESULT.

a. Standard Torque. A general torque requirement which is applied to fasteners when a specified torque is not identified. Standard torques are listed in tables 2-1 through 2-5 and do not include Tare torque.

b. Specified Torque. A specific torque identified in the maintenance manual, in the maintenance manual, overhaul overhaul manual, manual, ASB AB or or TB for a particular fastener(s). Specified torque does not include Tare torque.

2-2.

1. The Standard Torque Charts list the recommended standard torque for various combinations of bolts and nuts. The torque listed is the standard torque, less friction drag of the self-locking feature (TARE). Refer to tables 2-1 through 2-3.

c. Tare Torque. Torque required to overcome resistance of self locking nuts against mating bolt, screw or stud threads. Tare torque must be measured using the same fastener combination that the torque will be applied to. Tare torque is unique to that fastener combination. The preferred method for measuring tare torque is to use a dial (indicator) type torque wrench, but may be measured by approaching the value with a "click" style torque wrench. The measured value must be compared to the Minimum Tare Torque Value. If measured value is less than the minimum listed, the lock nut must be replaced. d. Applied Torque. The total torque value applied to a fastener (preferably the nut in a nut/bolt combination). Applied torque is the Standard Torque or Specified Torque, plus the Tare Torque. It is unique to that fastener combination. An adjacent fastener combination utilizing the same hardware may require a different applied torque value. It is not acceptable to measure tare torque for one fastener combination and apply this tare torque value to all similar fasteners. Variations in wear, stress, and finish will impact tare values of fasteners of the same size and type. e. Shear Load. A dynamic force causing two parts in contact to move in a direction parallel to their point of contact.

STANDARD TORQUE

CAUTION RECOMMENDED STANDARD TORQUE RANGE IS GIVEN. TARE TORQUE SHALL BE ADDED TO TORQUE VALUE LISTED UNLESS OTHERWISE STATED. STANDARD TORQUE VALUE FOR FLUID CONNECTIONS IS GIVEN IN TABLE 2-4. STANDARD TORQUE VALUE FOR THREADED STUDS IS GIVEN IN TABLE 2-5. STANDARD TORQUE VALUE FOR DYNAMIC BEAM SEALNUT IS GIVEN IN TABLE 2-5. STANDARD TORQUE VALUE FOR FLARELESS FITTINGS IS GIVEN IN TABLE 2-6. 2.

Standard torque value charts usage.

a. To locate the correct standard torque for a bolt and, nut the following must be known: (1) Type of bolt used (AN, MS, NAS, etc.).

f. Tension Load. A static force applied 90 degrees to the plane of rotation of contiguous parts.

(2) Type of nut used (AN, etc.).

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(3) Thread size of bolt (10-32, 1/4 -28, 5/16 24, 3/8 -24, etc.).

Minimum Tare Torque Value (Cont)

(1) From table 2-1 through 2-3, locate the sheet that carries the primary bolt number (designation) and the number of the nut. From the appropriate sheet, locate thread size and read across for torque values.

CAUTION

2-3. TARE TORQUE MUST BE MEASURED ON THE SAME FASTENER COMBINATION THAT THE TORQUE WILL BE APPLIED TO. USING A DIAL INDICATOR TYPE TORQUE WRENCH, MEASURE TARE TORQUE OF SELF

LOCKING NUT TO BE INSTALLED. ALOCKING NUT TO BE INSTALLED. COMPARE VALUE TO MINIMUM TARE TORQUE VALUE LISTED BELOW. IF MEASURED TARE IS LESS THAN MINIMUM LISTED, REPLACE SELF LOCKING FASTENER. c. Minimum TARE torque value of self-locking

bolts and nuts is as follows:

Minimum Tare Torque Value MINIMUM TARE TORQUE (IN-LBS)

THREAD SIZE

3.5

1/4 - 28 5/16-24

TORQUE (IN-LBS)

7/8-14

70.0

1 -12

90.0

1 -1/8-12 1-1/4-14

117.0 143.0

1-3/8-12

170.0

1-1/2-12

197.0 STANDARD TORQUE

RECOMMENDED

RANGE

CAUTION MAXIMUM ALLOWABLE TORQUE SHALL

ONLY BE USED WHEN REQUIRED TO REQUIRED TO USED WHEN ONLY ALIGN BE CASTELLATED NUTS. DO NOT ADD PLAIN, FLAT WASHERS TO ANY DRIVE SYSTEM COMPONENT TO

OBTAIN SPECIFIED TORQUE. THE DRIVE SYSTEM INCLUDES ALL SHAFTS, DRIVE SYSTEM INCLUDES ALL SHAFTS, COUPLINGS, GEARBOXES AND COUPLINGS, GEARBOXES AND BEARING HANGERS USED IN THE TRANSMISSION OF ENGINE POWER TO THE MAIN AND TAIL ROTORS OR TO ANY REMOTE MOUNTED ACCESSORY. DRIVE SYSTEM COMPONENTS ARE IDENTIFIED WITH A PART NUMBER WHICH HAS THE SECOND SET OF THREE DIGITS (UNIVERSAL CODE) OF 040-, -044-, -140-, -340-, -342-, -344-, -540, -620-, -640-, -644-, AND -645-.

7/16-20

14.0

1/2-20

18.0

DO NOT SUBSTITUTE WASHERS OF DIFFERENT PART NUMBERS. DO NOT ADD FLAT WASHERS TO JOINTS SPECIAL WASHERS WHERE (CHAMFERED, CONCAVE, COUNTER BORED, DISSIMILAR METAL, KEYED,

9/16 -18

24.0

LOCK WASHER ETC.) ARE INSTALLED.

5/8-18

32.0

3/8-

3/4 -

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6.5 24 9.5

MINIMUM TARE

THREAD SIZE

b. When all three are known refer to figure 2-1.

16 50.0

1. Additional plain, flat washers of the same part number as those specified by the parts manual may be used when required for proper nut or cotter pin

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Bell Helicopter installation, or to allow specified torque to be attained. Not more than a total of three washers will be used; two under the nut for grip adjustment and one under the bolt or screw head for surface protection, unless otherwise permitted by the applicable maintenance manual.

b. The graduation increments of the torque wrench should not be greater than 10 percent of the torque value being measured. c. The torque wrench should be calibrated in the same torque units as the specified torque for the fastener.

2. If the maintenance or overhaul manual does not specify the location of the washers, they shall be placed under the bolt or screw head or under the nut, whichever is being rotated during tightening, except where one washer, under the bolt or screw head, is required for material protection.

2. Force Application on Torque Wrench Grip: A smooth steady force must be applied to obtain an accurate torque value. Rapid or jerky force can result in error in the torque applied.

3. The recommended standard torque range shall be used for all applications for bolts and nuts listed in tables 2-1 through 2-3. The following example provides a guide in the use of the torque value tables.

3. Tightening Fastener on the Head End: When a fastener is tightened from the head end, some of the torque applied is absorbed in turning the bolt in the hole. The amount of torque absorbed will vary. For this reason, torque values specified are for tightening fasteners on the nut end.

Example:

2-4.

4. If the fastener can be inserted through the hole and started into the nut by the fingers, use the specified torque range.

*

Type of bolt: MS9088.

*·

of nut: Type of Type nut: MS14145. MS14145.

*

Thread size of bolt: 1/4-28.

*

Recommended shear load installation torque range: 30 to 40 inch-pounds. SPECIFIED TORQUES

When torques are specified in procedural steps of the applicable maintenance or overhaul manual, they take preference over standard torque values given in tables 2-1 through 2-3. Add tare torque to all specified torque. 2-5.

SELF LOCKING NUTS

The seating torque values are in addition to the actual locking torque (tare torque) value of each self locking nut. The locking torque (tare torque) value for a self locking nut is that value after all nut threads are engaged. SELECTION 2-6. WRENCH 1.

AND

USE

OF

TORQUE

Selecting Torque Wrench:

a. The accuracy of most torque wrenches tends to decrease at the extremes of the torque range. The torque value being measured should be between the 30 and 80 percent points of the torque wrench range.

5. If the fastener is inserted through a hole that increases the tightening resistance, torque to the high limit of the specified torque range. 6. If the fastener is inserted into a threaded hole and if the hole thread length is more than the fastener diameter, use the specified torque range. If the hole thread length is less than the fastener diameter, use the lower limit of the torque range. 7. Tightening New Fastener: Tighten the fastener to the standard or specified torque value, as defined in paragraph 2-1.1. Loosen the fastener by backing off one-half turn. Retighten to desired torque value. This aids in cleaning and smoothing the threads and results in more accurate torque. 8. Re-torque - To be used when it is uncertain whether a joint has been properly torqued. If there is some concern that a fastener has been over-torqued, then the fastener should be discarded (both the nut and bolt). Re-torque should be accomplished by the following: (1) Remove all torque from the fastener (loosening) until no preload is on the fastener. (2)

Measure the tare torque.

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(3) Determine the specified torque or standard torque as applicable and add the tare torque to this to arrive at the applied torque. (4) Torque the fastener to this applied torque

11. Tightening Chilled or Heated Fastener: Do not tighten a chilled or heated fastener until it has returned to room temperature. Heated fastener may loosen when it cools. Chilled fastener may become overstressed when it warms.

value. If the fastener is one in a multi-fastener pattern requiring a torque sequence, then all the fasteners will require re-torque. 9. Fastener Thread Condition: Threads should be clean and free from nicks, burrs, paint, grease, and oil to obtain the correct torque. However, there are some applications where lubrication or antiseize compound is used on the threads. 10. Torque Check: This should be accomplished by torquing in the tightening direction. The value applied should be one of the following: a. If the applied torque is known from when the fastener was originally installed (i.e. recorded in a logbook), then this is the applied torque for torque check purposes. b. If the original applied torque was not recorded, then the applied torque for torque check purposes

12. Tightening Fastener on Part with a Slow Permanent Set: Hold desired torque until part is seated. 13. Tightening Fasteners in a Series: If fasteners are to be torqued in a series, select a median torque value within the torque required range. If some fasteners are tightened to the minimum value and others to the maximum, force is not distributed evenly. Unequal distribution of force may cause fastener failure. Do not apply final torque during the first drawdown. After the median torque value is applied, loosen fasteners one at a time and apply final torque. Tightening in a diametrically opposite (staggered) sequence is desirable in most cases. 14 Tightening Fasteners with Concentric Attachment: The use of a concentric attachment which operates concentrically with the torque wrench drive square presents no particular problem. The torque value applied is the torque value indicated. Refer to figure 2-1.

would be the minimum specified torque or minimum

standard torque as applicable plus the minimum acceptable tare torque, (refer to minimum tare torque value table). If during the application of the applied torque as detailed above, no motion is detected between the fasteners, then the joint is considered acceptable. Joints which are having a torque check performed as a part of a special inspection, as required after a specified number of flight hours, only need to be tightened. Looseness may occur until the components "seat" themselves and the fasteners simply need to be tightened. This is not cause for disassembly. If a specific torque sequence is to be followed, as torqued, then this same sequence should be followed during the torque check. Some fasteners in the sequence may accept additional torque while others may not; this is acceptable. Joints that have not retained torque will require disassembly and inspection 2-00-00 Page 6

Nonconcentric with Fastener 15. Tightening Attachment: The use of a nonconcentric attachment which does not operate concentrically with the drive square presents a mathematical problem. This type of attachment affects the lever length. The torque value applied is not the torque value indicated. It is necessary to calculate the effect of the lever length to determine the correct indicated torque value. Refer to figure 2-2. 16. Force application when using Nonconcentric Attachment: a. The point of force applied on a flexible beamtype torque wrench pivoted grip will not affect the calculated torque applied to the fastener. b. The point of force applied on rigid frame and audible indicating torque wrench grips will affect the calculated torque applied to the fastener. See figure 23 for proper and improper application of force and their effect.

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Table 2-1. Torque Value Chart (Dry) for Specified Nuts on 125000 PSI Minimum Ultimate Tensile Strength Fasteners PART I SHEAR LOAD

BOLT AN3 thru AN20 AN21 thru AN37 AN42 thru AN49 AN173 thru AN186 AN502 AN503 AN525 MS9088 MS20073 thru MS20081 MS24694 MS27039 NAS428 NAS1297

NUT AN316 AN320 MS14145 NAS1022

BOLT DIAMETER THREAD SIZE

RECOMMENDED STANDARD TORQUE RANGE

10 - 32

12 to 15 in-lb

1/4 -28

30 to 40 in-lb

5/16 - 24

60 to 85 in-lb

3/8 - 24

95 to 110 in-lb

7/16 - 20

270 to 300 in-lb

1/2 - 20

24 to 34 ft-lb

9/16 - 18

40 to 50 ft-lb

5/8 - 18

55 to 65 ft-lb

3/4 - 16

108 to 125 ft-lb

7/8 - 14

125 to 150 ft-lb

1-12

183 to 275 ft-lb

1-1/8 - 12

250 to 350 ft-lb

1-1/4-12

450 to 500 ft-lb

NOTE: The above values apply to any combination of bolt and nut shown unless otherwise specified. Tare torque must be added to all torque values. Refer to paragraph 2-3.

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Table 2-1. Torque Value Chart (Dry) for Specified Nuts on 125000 PSI Minimum Ultimate Tensile Strength Fasteners (Cont) PART II TENSION LOAD BOLT

BOLT

AN3 thru AN20 AN21 thru AN37 AN42 thru AN49 AN173 thru AN186 AN502 AN503 AN525 MS9088 MS20073 thru MS20081 MS24694 MS27039 NAS428 NAS1297

BOLT DIAMETER/ THREAD SIZE

NUT NUT

AN310 AN315 MS14144 MS21043 MS21044 MS21047 thru MS21051 thru MS21058 thru MS21069 thru MS21225 NAS509 NAS1473 NAS1474~

MS21049 MS21056 MS21062 MS21076

RECOMMENDED STANDARD TORQUE RANGE

10 - 32

20 to 25 in-lb

1/4 - 28

50 to 70 in-lb

5/16-24

100to140in-lb

3/8 - 24

160 to 190 in-lb

7/16 - 20

37 to 42 ft-lb

1/2 - 20

40 to 58 ft-lb

9/16 - 18

66 to 83 ft-lb

5/8- 18

91 to 108 ft-lb

3/4 - 16

191 to 208 ft-lb

7/8 - 14

208 to 250 ft-lb

1 - 12

308 to 458 ft-lb

1-1/8 - 12

416 to 583 ft-lb

1-1/4- 12

750 to 916 ft-lb

NOTE: The above values apply to any combination of bolt and nut shown unless otherwise specified. Tare torque must be added to all torque values. Refer to paragraph 2-3.

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Table 2-1. Torque Value Chart (Dry) for Specified Nuts on 125000 PSI Minimum Ultimate Tensile Strength Fasteners (Cont) PART III SHEAR LOAD BOLT DIAMETER/ THREAD SIZE

RECOMMENDED STANDARD TORQUE RANGE

AN3 thru AN20 AN21 thru AN37 AN42 thru AN49 AN173 thru AN186 AN502 AN503 AN525 MS9088 MS20073 thru MS20081 MS24694 MS27039 NAS428 NAS1 297

MS17826

10 - 32

7 to 12 in-lb

1/4 - 28

25 to 35 in-lb

5/16 - 24

50 to 70 in-lb

3/8 - 24

70 to 90 in-lb

7/16 - 20

110 to 150 in-lb

1/2 - 20

150 to 200 in-lb

9/16 -18

200 to 300 in-lb

5/8 - 18

300 to 420 in-lb

3/4 - 16

45 to 62 ft-lb

7/8 - 14

79 to 96 ft-lb

1 - 12

125 to 150 ft-lb

1-1/8 - 12

208 to 292 ft-lb

1-1/4-12

292 to 375 ft-lb

NOTE: The above values apply to any combination of bolt and nut shown unless otherwise specified. Tare torque must be added to all torque values. Refer to paragraph 2-3.

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Table 2-1. Torque Value Chart (Dry) for Specified Nuts on 125000 PSI Minimum Ultimate Tensile Strength Fasteners (Cont) PART IV TENSION LOAD

NUT

BOLT AN3 thru AN20 AN21 thru AN37 AN42 thru AN49 AN173 thru AN186 AN502 AN503 AN525 MS9088

MS17825

BOLT DIAMETER/ THREAD SIZE

RECOMMENDED STANDARD TORQUE RANGE

10 - 32

12 to 15 in-lb

1/4 - 28

30 to 40 in-lb

5/16 - 24

60 to 85 in-lb

3/8 - 24

95 to 110 in-lb

7/16 - 20

270 to 300 in-lb

1/2 - 20

24 to 34 in-lb

9/16 - 18

40 to 50 in-lb

5/8 - 18

55 to 65 in-lb

3/4 - 16

108 to 125 ft-lb

7/8 - 14

125 to 150 ft-lb

1 - 12

183 to 275 ft-lb

1-1/8-12

250 to 350 ft-lb

1-1/4 - 12

450 to 500 ft-lb

MS20073 thru MS20081

MS24694 MS27039

NAS428 NAS 297

NOTE: The above values apply to any combination of bolt and nut shown unless otherwise specified. Tare torque must be added to all torque values. Refer to paragraph 2-3.

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Table 2-2. Torque Value Chart (Dry) for Specified Nuts on 160000 PSI Minimum Ultimate Tensile Strength Fasteners PART I SHEAR LOAD BOLT DIAMETER/ THREAD SIZE

RECOMMENDED STANDARD TORQUE RANGE

20-057 MS16997 thru MS16998 MS20004 thru MS20024 NAS144 thru NAS158 NAS333 thru NAS340 NAS517 NAS623 NAS1101 NAS1189 NAS1190 NAS1303 thru NAS1320 NAS1351 NAS1352 NAS1801 NAS6203 thru NAS6220 NAS6603 thru NAS6620 NAS7500 thru NAS7516

AN310 AN315 MS14144 MS21043 MS21044 MS21047 thru MS21051 thru MS21058 thru MS21069 thru MS21225 NAS509 NAS1473 NAS1474

MS21049 MS21056 MS21062 MS21076

10 - 32

20 to 25 in-lb

1/4-28

50to70 in-lb

5/16 - 24

100 to 140 in-lb

3/8 - 24

160 to 190 in-lb

7/16 - 20

37 to 42 ft-lb

1/2 - 20

40 to 58 ft-lb

9/16 - 18

66 to 83 ft-lb

5/8- 18

91 to 108 ft-lb

3/4 - 16

191 to 208 ft-lb

7/8 - 14

208 to 250 ft-lb

1 - 12

308 to 458 ft-lb

1-1/8-12

416 to 583 ft-lb

1-1/4-12

750 to 916 ft-lb

NOTE: The above values apply to any combination of bolt and nut shown unless otherwise specified. Tare torque must be added to all torque values. Refer to paragraph 2-3.

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Table 2-2. Torque Value Chart (Dry) for Specified Nuts on160000 PSI Minimum Ultimate Tensile Strength Fasteners (Cont) PART II TENSION LOAD BOLT

BOLT

NUT NUT

BOLT DIAMETER/ THREAD SIZE

RECOMMENDED STANDARD TORQUE RANGE

20-057 MS21042 MS16997 thru MS16998 NAS577 MS20004 thru MS20024 NAS1291 NAS144 thru NAS158 NAS333 thru NAS340 NAS517 NAS623 NAS1101 NAS1189 NAS1190 NAS1303 thru NAS1320 NAS1351 NAS1352 NAS1801 NAS6203 thru NAS6220 NAS6603 thru NAS6620 NAS7500 thru NAS7516

10 - 32

30 to 40 in-lb

1/4 -28

75 to 95 in-lb

5/16 - 24

120 to 160 in-lb

3/8 - 24

25 to 28 ft-lb

7/16 - 20

39 to 43 ft-lb

1/2 - 20

53 to 71 ft-lb

9/16 -18

83 to 100 ft-lb

5/8 - 18

116 to 133 ft-lb

3/4 - 16

200 to 216 ft-lb

7/8 -14

333 to 375 ft-lb

1 -12

433 to 583 ft-lb

1-1/8 - 12

691 to 858 ft-lb

1-1/4 - 12

1441 to 1608 ft-lb

NOTE: The above values apply to any combination of bolt and nut shown unless otherwise specified. Tare torque must be added to all torque values. Refer to paragraph 2-3.

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Table 2-3. Torque Value Chart (Dry) for Specified Nuts on 180000 PSI Minimum Ultimate Tensile Strength Fasteners SHEAR LOAD

NUT

BOLT

BOLT DIAMETER/ THREAD SIZE

RECOMMENDED STANDARD TORQUE RANGE

20-065 20-069 MS21250 NAS624 thru NAS644

MS21042 NAS577 NAS1291

10 - 32

22 to 28 in-lb

1/4 -28

65 to 79 in-lb

5/16 - 24

112 to 158 in-lb

3/8 - 24

180 to 214 in-lb

7/16- 20

42 to 47 ft-lb

1/2 - 20

45 to 54 ft-lb

9/16 - 18

74 to 93 ft-lb

5/8 - 18

102 to 122 ft-lb

3/4 - 16

215 to 234 ft-lb

7/8 - 14

234 to 281 ft-lb

1 - 12

346 to 515 ft-lb

1-1/8 - 12

468 to 656 ft-lb

1-1/4 - 12

844 to 1030 ft-lb

NOTE: The above values apply to any combination of bolt and nut shown unless otherwise specified. Tare torque must be added to all torque values. Refer to paragraph 2-3.

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Table 2-4. Standard Torque Values for Fluid Connections

TUBE FLARE

SIZE

(MS33583 ORE OR (MS33583 MS33584)

STEEL TUBING

FLARE (MS33584)

NAS591 THRU NAS596

HOSE END FITTINGS AND

HOSE HOSE ASSY ASSY

(MS28740 AND

MS28759)

DASH STEEL TUBING NO.M28759)

AL. TUBING

3/16

30 to 45 in-lb

90 to 100 in-lb

70 to 100 in-lb

1/4

40 to 65 in-lb

135 to 150 in-lb

70 to 120 in-lb

4

60 to 96 in-lb

48 to 96 in-lb

5/16

60 to 80 in-lb

180 to 200 in-lb

85 to 180 in-lb

5

66 to 108 in-lb

60 to 108 in-lb

3/8

75 to 125 in-lb

270 to 300 kn-lb

100 to 250 in-lb

6

72 to 120 in-lb

72 to 120 in-lb

1/2

150 to 250 in-lb

450 to 500 in-lb

210 to 420 in-lb

8

144 to 232 in-lb

120 to 216 in-lb

5/8

200 to 350 in-lb

54 to 58 in-lb

300 to 480 in-lb

10

204 to 360 in-lb

144 to 360 in-lb

3/4

300 to 500 in-lb

75 to 83 ft-lb

41 to 70 ft-lb

12

300 to 540 in-lb

216 to 540 in-lb

1

41 to 58 ft-lb

100 to 116 ft-lb

58 to 95 ft-lb

16

42 to 58 ft-lb

480 to 696 in-lb

1-1/4

50 to 75 ft-lb

20

50 to 75 ft-lb

50 to 75 ft-lb

1-1/2

50 to 75 ft-lb

24

50 to 75 ft-lb

50 to 75 ft-lb

1-3/4

38

60 to 90 ft-lb

62 to 90 ft-lb

2

32

75 to 110 ft-lb

75 to 100 ft-lb

2-1/2

40

150 to 175 ft-lb

110 to 150 ft-lb

3

48

150 to 175 ft-lb

4

64

200 to 225 ft-lb

NOTE:

Flareless tubing connections shall be tightened as follows: Tighten the MS21921 nut 1/6 to 1/3 turn (1 to 2 flats) past point of sharp torque rise on all sizes and materials. The 1/6 to 1/3 turn (performed after the presetting operation) is the final installation torque

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Table 2-5. Standard Torque Values (Studs) Part I TORQUE RANGE

THREAD SIZE

STUD END

NUT END

TYPE "A"

TYPE "B" 30 to 40 in-lb

10 - 32

10 - 24

10 - 32

1/4 - 20

30 to 40 in-lb

30 to 40 in-lb

1/4 - 28

1/4 - 20

50 to 95 in-lb

50 to 70 in-lb

1/4 - 28

5/16 -18

50 to 110 in-lb

50 to 80 in-lb

5/16 - 24

5/16 - 18

100 to 225 in-lb

10 to 130 in-lb

5/16 - 24

3/8 -16

100 to 240 in-lb

100 to 160 in-lb

3/8 - 24

3/8 -16

175 to 375 in-lb

175 to 250 in-lb

3/8 - 24

7/16 - 14

175 to 475 in-lb

175 to 325 in-lb

7/16 - 20

7/16 -14

20 to 54 ft-lb

250 to 400 in-lb

7/16 - 20

1/2 -13

20 to 60 ft-lb

250 to 525 in-lb

1/2 - 20

1/2 -13

33 to 83 ft-lb

33 to 58 ft-lb

1/2 - 20

9/16 -12

33 to 95 ft-lb

33 to 70 ft-lb

9/16 - 18

9/16 -12

50 to 120 ft-lb

41 to 87 ft-lb

9/16 - 18

5/8 - 11

50 to 137 ft-lb

50 to 95 ft-lb

5/8 -18

5/8 -11

75 to 166 ft-lb

58 to 116 ft-lb

5/8 - 18

11/16 -11

75 to 200 ft-lb

75 to 141 ft-lb

* For nut torque, refer to applicable chart for type of nut used. NOTE:

Threaded Stud Type A: The grip portion of the stud is approximately the same diameter as the pitch diameter of the nut end thread. Type B: The grip portion of the stud is less than the minor diameter of the nut end thread. SPM-02-22285-1-T

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Table 2-5. Standard Torque Values (Studs) Part II (Cont) SHEAR 100-076

PIN 100-085

100-090

MS21042

NUT H541L

NAS1291

Thread size

Recommended Inch-pounds

Newton-meters

8-32

15 - 25

1.7 - 2.8

10 - 32

25 - 35

2.9 - 3.9

1/4 - 28

60- 80

6.8 - 9.0

5/16-24

130- 160

15-18

3/8 - 24

200 - 240

23 - 27

7/16 - 20

270 - 330

31 - 37

1/2 - 20

370 - 430

42 - 48

NOTE: The above values apply to any combination of pin and nut shown. TENSION PIN 100-047

100-048

100-049

100-059

NUT H541L

MS21042

Thread size

NAS1291

Recommended Inch-pounds

Newton-meters

8-32

30 - 40

3.4 - 4.5

10 - 32

40 - 50

4.6 - 5.6

1/4 - 28

115 - 130

13-14

5/16 - 24

200 - 250

23 - 28

3/8 - 24

360 - 420

41 - 47

Foot-pounds

Newton-meters

7/16 - 20

44 - 56

60 - 75

1/2 - 20

61 - 83

83 - 112

NOTE: The above values apply to any combination of pin and nut shown.

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Bell Helicopter Table 2-6. Standard Torque for Dynamic Beam Seal Nuts (Operating Pressures to 5000 PSI, Titanium Material) TORQUE RANGE

TORQUE MAXIMUM

COUPLING NUTS

JAM NUTS

FITTING SIZE

FT-LBS

FT-LBS

-04

10-14

12

-06

15 - 25

20

-08

30 - 40

35

-10

60 - 70

48

-12

70 - 80

60

-16

135-155

82

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Bell Helicopter Textron

Table 2-7. Recommended Standard Torque for Flared Fitting Nuts TORQUE RANGE TUBING NOMINAL OUTSIDE DIAMETER

ALUM ALLOY TUBING MS33583/ MS33584

STEEL TUBING MS33584

HOSE FITTINGS & ASSEMBLIES MS28740/ MS28759

NAS591 THR

STEEL FITTINGS NAS591 THRU NAS594

3/16

30 to 45 in-lb

90 to 100 in-lb

70 to 100 in-lb

1/4

40 to 65 in-lb

135 to 150 in-lb

70 to 120 in-lb

48 to 96 in-lb

60 to 96 in-lb

5/16

60 to 80 in-lb

180 to 200 in-lb

85 to 180 in-lb

60 to 108 in-lb

66 to 108 in-lb

3/8

75 to 125 in-lb

270 to 300 in-lb

100 to 250 in-lb

72 to 120 in-lb

72 to 120 in-lb

1/2

150 to 250 in-lb

450 to 500 in-lb

210 to 420 in-lb

120 to 216 in-lb

144 to 232 in-lb

5/8

200 to 350 in-lb

54 to 58 ft-lb

300 to 480 in-lb

144 to 360 in-lb

204 to 360 in-lb

3/4

300 to 500 in-lb

75 to 83 ft-lb

41 to 70 ft-lb

216 to 540 in-lb

300 to 540 in-lb

1

41 to 58 ft-lb

100 to 116 ft-lb

58 to 95 ft-lb

40 to 58 ft-lb

42 to 58 ft-lb

1-1/4

50 to 75 ft-lb

50-74 ft-lb

50 to 75 ft-lb

1-1/2

50 to 75 ft-lb

50 to 75 ft-lb

50 to 75 ft-lb

1-3/4

62 to 90 ft-lb

60 to 90 ft-lb

2

75 to 110 ft-lb

75 to 110 ft-lb

2-1/2

110-150 ft-lb

150-175 ft-lb

3

150 to 175 ft-lb

4

200 to 225 ft-lbs

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NOTE: APPLIED AND INDICATED TORQUE VALUES ARE THE SAME.

SPM-00020-00010-001-C00

Figure 2-1. Torque Wrench Concentric Type Attachments

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Textron

2 IN.

FORMULA TO OBTAIN CORRECT INDICATED TORQUE VALUE WHEN USING NONCONCENTRIC ATTACHMENT

12 IN.

200 IN-LB TW = (TA) X (L) (L) ± (A)

TW

TA

TW = INDICATED TORQUE VALUE ON TORQUE WRENCH TA = ACTUAL TORQUE VALUE APPLIED TO FASTENER

TW=

L = LEVEL LENGTH A = ATTACHMENT LENGTH

200 X12 200X12

=

2400 24

= 171.4 IN-LB

RESULTS: FASTENER TORQUED 200 IN-LB WHEN WRENCH INDICATES 171.4 IN-LB

FORMULA

EXAMPLE 1

12 IN.

200 IN-LB

120o INLB ATA

200 X 12

2400

RESULTS: FASTENER TORQUED 200 IN-LB WHEN WRENCH INDICATES 240 IN-LB EXAMPLE 2

2 IN.

TWA

200 X 12

2400

RESULTS: FASTENER TORQUED 200 IN-LB WHEN WRENCH INDICATES 174.5 IN-LB EXAMPLE 3 SPM-00020-00020-001-COO

Figure 2-2. Torque Wrench Nonconcentric Type Attachments

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4 IN. FORMULA TO OBTAIN CORRECT INDICATED TORQUE VALUE WHEN USING NONCONCENTRIC ATTACHMENT

(TA) X (L) (L) + (A)

2 IN. A

12 IN.

200 IN-LB

TW = INDICATED TORQUE VALUE ON TORQUE WRENCH TA = ACTUAL TORQUE VALUE APPLIED TO FASTENER L= LEVEL LENGTH A = ATTACHMENT LENGTH FORMULA

TA,

TW=

200 X 12 200X2 122

2400 240

=

171.41N-LB

RESULTS: FASTENER TORQUED 200 IN-LB WHEN WRENCH INDICATES 171.4 IN-LB PROPER APPLICATION OF FORCE EXAMPLE 1

2 IN.

IN.+21 N. =14

A

2 IN.

12 IN. -21N. =10

A-

L

L 200 IN-LB

200

TA

TW -200X(12+2)_

2800

=

175 IN-LB

(12-2)2

-

12

RESULTS: FASTENER TORUED 200 IN-LB RESULTS: FASTENER TORQUED 200 IN-LB WHEN WRENCH INDICATES 175 IN-LB IMPROPER APPLICATION OF FORCE EXAMPLE 2

WHEN WRENCH INDICATES 166.6 IN-LB IMPROPER APPLICATION OF FORCE EXAMPLE 3

SPM-00020-00030-001 -COO

Figure 2-3. Affect of Applied Force to Rigid Frame and Audible Indicating Torque Wrenches Using Nonconcentric Attachments

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CHAPTER 3 -

CORROSION CONTROL AND PROTECTIVE COVERINGS/COATINGS CONTENTS - MAINTENANCE PROCEDURES

Paragraph Number 3-1 3-2 3-3 3-4 3-5 3-6 3-7 3-8 3-9 3-10 3-11 3-12 3-13 3-14 3-15 3-16 3-17 3-18 3-19 3-20 3-21 3-22 3-23 3-24 3-25 3-26 3-27 3-28 3-31 3-32 3-33 3-34 3-35

Title G eneral ............................................................................. Corrosion Prevention ........................................................ Corrosion Preventive Treatment................................ Corrosion Preventive Oil............................................ Corrosion Protection - Control Bolts, Rotating, and Non-Rotating ....................................................... Corrosion Corrective Treatment ....................................... Corrosion Removal - Steel Parts ........................... Corrosion Removal- Aluminum Parts ..................... Corrosion Removal - Magnesium Parts ................... Corrosion Removal - Elastomeric Components ....... Corrosion Protection - Faying Surfaces ......................... Similar Metals............................................................. Dissimilar Metals ........................................................ Corrosion Protection - Exceptions .......................... Chemical Film (Chromic Acid) Treatment Magnesium ...................................................................... Aluminum Alloy - Chemical Film Treatment (Touchup) ................................................................... Cadmium Plating........................................................ Chromate Conversion Coating................................... Solid Film Lubricant .......................................................... Solid Film Lubricant Repair........................................ Black Oxide ............................................ Gear Tooth Wear Pattern Inspection Using Dry Film Lubricant............................................................. Copper Plating .................................................................. Plastic Media Blasting. ..................................................... Plastic Media Blasting Equipment - Description ...... Plastic Media Blasting Operator Training ................... Media Particles Method 1 ........................................... Media Particles Method 2........................................... PMB Method 2 (Open Booth) Procedures ................. Preparation of the Helicopter for PMB ....................... PMB Mapping Procedure ........................................... Organic Coat Removal Procedure ............................. PMB Clean-up Operation ...........................................

Chapter/Section Number

Page Number

3-00-00 3-00-00 3-00-00 3-00-00

3 4 4 4

3-00-00 3-00-00 3-00-00 3-00-00 3-00-00 3-00-00 3-00-00 3-00-00 3-00-00 3-00-00

4 4 5 5 5 6 6 8 8 8

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10 11 12 12 12 13

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13 14 15 16 17 17 17 18 19 19 19 20

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Bell Helicopter Textron TABLES

Table Number

3-1 3-2 3-3 3-4 3-5

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Title

Definitions of Similar and Dissimilar Metals................................................ Organic Protective Requirements for Metals .............................................. Solid Film Lubricant Curing ........................................................................ Copper Plating Bath ................................................................................... PMB Method 2 Parameters - Description.................................................

Page Number

7 7 13 15 18

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CORROSION CONTROL AND PROTECTIVE COVERINGS/COATINGS 3-1.

GENERAL

There are many various forms of corrosion which attack metal and metallic materials causing early part failure. Several types of corrosion most common in aircraft are listed below. Routine and preventive maintenance and inspections are designed to help prevent corrosion caused component failure. 1. Surface Corrosion. The direct surface attack form of corrosion is generally the least serious of the various forms of corrosion. It is the result of direct reaction of metal surfaces with oxygen in air and occurs more readily when metal surfaces are exposed to salt spray or salt-bearing air. Sulphur and chlorine compounds which may be present in smoke stack gases and engine exhaust gases also cause direct surface attack. Etching may be noticed on the surface when corrosion deposits are removed. If the metal is aluminum alloy with a coating of pure aluminum (ALCLAD), the affect on strength of ductility of metal is negligible; however, corrosion of a similar degree on non-clad metals may be considered serious. (Refer to applicable Component Repair and Overhaul Manual). The pits may become sites for crack development in parts which are critical in fatigue. 2. Galvanic Corrosion. This is caused by dissimilar metal contact in the presence of a liquid such as salt spray or condensate, forming a true chemical cell. This causes electrons to flow and the most easily oxidized surface becomes the anode and corrodes. The emitting surface becomes the cathode of the cell. 3. Pitting Attack. This is a special kind of galvanic reaction and is usually localized. It occurs at a point of weakness and is caused by a lack of homogeneity in the alloy surface. Pitting originates from mechanical contact, faulty heat treatment, or localized contamination that breaks down surface protection. These areas become anodic characteristics of the pit area. A deep penetrating attack develops rather than general surface attack. 4. Intergranular Corrosion. This is a selective type of corrosion and attacks along the grain boundaries of metal alloys. Aluminum alloys which contain appreciable amounts of copper and zinc and some stainless steels are vulnerable to intergranular corrosion. Piano hinges are an example of aluminum extrusions which are vulnerable. Lack of uniformity in

the alloy structure caused by heat treating procedures or localized overheating such as from fire damage, may result in intergranular corrosion. This corrosion may exist without visible evidence on exterior surfaces and serious structural weakening may occur without detection. 5. Exfoliation. This is a type of corrosion which most often occurs in aluminum parts made from plate, bar, tube and extrusions which have long, thin grains. Exfoliation corrosion is recognizable by the long, thin leafs of material which delaminate from the surface of a part. This type of corrosion often appears as a blister on the surface of a part. This is due to corrosion products between the grains forcing the grains apart, causing a bulge on the surface. Exfoliation corrosion is a form of intergranular corrosion. 6. Stress Corrosion. Stress affects metals that are too highly stressed under corrosive conditions. Shrink fit parts and parts subjected to cold working conditions are susceptible to stress corrosion cracking. Stressed metal tends to become anodic when in contact with stress-free metal. Galvanic corrosion occurs along the lines of stress and rapid failure of the part results. 7. Fatigue Corrosion. This is closely related to stress corrosion and appears in metals under cyclic stress in a corrosive surrounding. A jet engine turbine blade is an example of a part subject to fatigue corrosion. The corrosion causes sharp deep pits which, in turn, become the origin of cracks that may ultimately result in failure of the part. It is difficult to detect this type of attack in advance except as cracking develops. 8. Fretting Corrosion. This type corrosion develops when two heavily loaded surfaces contact each other and are subject to slight vibratory motion. The rubbing contact removes small particles of virgin metal from each surface. These particles will usually oxidize to form abrasive materials. The attack is compounded by the continued motion which prevents formation of any protective oxide film, creating a prime area for further corrosion to occur. Fretting is evident at an early stage by surface discoloration and the presence of corrosion particles in any lubricant present. Continued fretting will ruin bearing surfaces, destroy critical dimensions, and may be serious enough to eventually cause cracking and fatigue failure. Fretting may be controlled by preventing

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slippage of the two surfaces or by lubricating the surfaces.

Textron M

3-4.

CORROSION PREVENTIVE OIL MATERIALS REQUIRED

9. Hygroscopic Material Corrosion. This is caused by such materials as sponge rubber, felt, cork, etc., absorbing water and holding it in contact with the part. As a result, surface or galvanic corrosion may develop. 3-2.

CORROSION PREVENTION

3-3.

CORROSION PREVENTIVE TREATMENT MATERIALS REQUIRED

Refer to source. for specification specification and and source. to chapter chapter 13 13 for Refer NUMBER NOMENCLATURE C-125

Use preservative oil (C-125) as a general light corrosion preventive for bonded, exposed, and painted metals. CORROSION PROTECTION - CONTROL 3-5. BOLTS, ROTATING, AND NON-ROTATING MATERIALS REQUIRED

Refer to chapter 13 for specification and source. NOMENCLATURE

NUMBER C-105

Corrosion Preventive

C-304

Solvent

After parts are cleaned, control and precautionary measures shall be exercised at all times to prevent corrosion. Fingerprint residue, reactive with moisture in the air, will cause accelerated corrosion in the affected areas. In order to avoid these difficulties, the following procedures shall be applied to ferrous metal parts after cleaning and inspection. 1. Wash all ferrous parts in a clean rinse of solvent (C-304) then drain the parts.

Preservative Oil

Refer to chapter 13 for specification and source. NUMBER

NOMENCLATURE

C-101

Corrosion Preventive Compound

C-104

Corrosion Preventive Compound

Prior to assembly, coat all rotating and non-rotating control bolt shanks with corrosion preventive preventive compound (C-104) unless otherwise specified. After assembly, coat boltheads and exposed threads with corrosion preventive compound (C-101). CORROSION 3-6. MENT

2. Gently agitate parts in fingerprint remover corrosion preventive (C-105) and allow to drain.

CORRECTIVE

TREAT-

MATERIALS REQUIRED Refer to chapter 13 for specification and source.

NOTE Normally, parts treated with the above compounds may be left covered in indoor-304 storage for approximately six days without being affected. 3. Immediately prior to reassembly, clean parts with solvent (C-304) and coat with approved oil. Do not handle or assemble unoiled parts.

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NUMBER

C-500

NOMENCLATURE Solvent Crocus Cloth

Corrosion corrective treatment can be applied to all metal parts of the assemblies in varying degrees (unless otherwise specified in the text). The following method shall be applied to remove corrosion using the

BHT-ALL-SPM

Bell Helicopter Textron applicable information as a criteria to determine serviceability of the part. 1. Wash part in solvent (C-304) to remove loose foreign matter.

4. Surfaces shall be dried using an oven 150°F (65°C) maximum, clean dry rags, or using compressed air which has been filtered to render it oil and moisture free. 5.

2.

Dry the part.

3. Use crocus cloth (C-500) or hand buffing wheel with jewelers rouge to remove corrosion from affected area by polishing. Do not use any abrasive coarser than specified.

Treat for corrosion prevention (paragraph 3-2).

3-8. CORROSION PARTS

No polishing is acceptable on bearing surfaces. 3-7.

CORROSION REMOVAL -

Refer to chapter 13 for specification and source.

C-344

ALUMINUM

Refer to chapter 13 for specification and source. NUMBER

NOMENCLATURE

C-204

Primer

C-423

Abrasive Cloth or Paper

1. Remove corrosion using 400 grit abrasive cloth or paper (C-423).

STEEL PARTS

MATERIALS REQUIRED REQUIRED

NUMBER

-

MATERIALS REQUIRED

4. Clean parts to remove all traces of corrosion and polishing agents.

NOTE

REMOVAL

NOTE Depth of repair shall be twice the depth of corrosion not to exceed repair limits. Refer to applicable maintenance or CR&O manual for limits.

NOMENCLATURE Cleaner

1. Thoroughly mix one volume of cleaner (C-344) and three volumes of water.

2. Apply two coats of epoxy polyamide primer (C204) to repaired area. CORROSION 3-9. PARTS

REMOVAL -

MAGNESIUM

MATERIALS REQUIRED 2. Prepared surfaces which are to receive cleaner shall be free of oil, grease, shop soil, and paint. Recleaning shall be accomplished, as required, by any acceptable method. 3. Apply cleaner to metal surface by brushing or swabbing. The cleaner shall remain in contact with metal surface for one to three minutes and shall be followed by a thorough rinse.

NOTE Step 3 may be repeated, as required, to remove light rust. Apply cleaner to corroded only, then rinse. area

Refer to chapter 13 for specification and source. NUMBER

NOMENCLATURE

C-116

Chromic Acid

C-117 C-304

Hydroflouric Acid Solvent

C-305

Aliphatic Naphtha

C-309

Methyl-Ethyl-Ketone (MEK)

C-348

Alkaline Steel Cleaner

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c. Immerse AZ31 B alloy parts for 30 seconds to

NOTE A chromic acid bath is used to remove corrosion from magnesium parts. 1. Wipe parts clean before immersing in acid bath using solvent (C-304), MEK (C-309), or aliphatic naphtha (C-305).

one minute. Immerse all other alloys for four to five minutes. d. Thoroughly rinse parts d. Torouly rie remove all traces of fluode.

in fresh water to

8. Immediately after corrosion removal, chemical film treatment (paragraph 3-15).

3-10.

apply

CORROSION REMOVAL - ELASTOMERIC

COMPONENTS CORROSION REMOVAL PROCESS SHALL BE MONITORED TO ENSURE DIMENSIONS ARE MACHINED MAINTAINED, CORROSION LIMITS SPECIFIED FOR THE INDIVIDUAL PART ARE NOT EXCEEDED, AND CADMIUM PLATING IS NOT REMOVED FROM STUDS. 2. Mix a solution of 20 to 24 ounces of chromic acid (C-116) with one gallon of water.

Refer to chapter 13 for specification and source. NUMBER C-305 C-355

NOTE

Many elastomeric components on helicopter will be severely damaged, if they are allowed to remain in contact with oil. Oil contaminants should be removed on

regular basis, using mild detergent (C-355)

3. Immerse corroded part in mixture until corrosion has been removed.

5. Remove remaining contaminants from parts using alkaline cleaner (C-348). Follow manufacturer's instructions for use of cleaner on magnesium parts. 6. Rinse parts in fresh water until all cleaner is removed.

7. 7.

as follows: follows: parts as pickle parts Acid pickle Acid

a. Prepare a 15 to 20 percent (by weight) hydrofluoric acid solution (C-117). b. Allow solution to reach room temperature.

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Aliphatic Naphtha Detergent

NOTE

The mixture can be used at room temperature to 200°F (93°C). Preferred temperature range being from 160°F to 180°F (710 C to 820 C).

4. Thoroughly rinse part in fresh water until all corrosion removing products are removed.

NOMENCLATURE

and warm water.

1. 1

Scrub in main main used in components used elastomeric components crub elastomeric

rotor, swashplate pylon support, and airframe. Use mild detergent (C-355) and water. Rinse with water and dry with clean cloths. 2. Rinse both metal and rubber elastomeric component surfaces with aliphatic naphtha (C-305). Wipe dry with clean cloths.

3-11. CORROSION PROTECTION SURFACES

FAYING

Refer to tables 3-1 and 3-2 for definitions of similar and dissimilar metals and organic protective requirements.

Bell Helicopter Textrin

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I

Table 3-1. Definitions of Similar and Dissimilar Metals GROUP IV

GROUP III

GROUP II

GROUP I 1. Magnesium and its alloys.

1. Cadmium and its alloys

1. Iron

1. Copper

2. Aluminum Alloys of 5052, 5056, 5356, 6061, and 6063

2. Zinc and its alloys

2. Lead

2. Chromium

3. Aluminum and its alloys (Including the Aluminum Alloys in Group I)

3. Tin

3. Nickel

4. Titanium 5. Cobalt 6. Stainless Steel NOTES: 1. Metals classified in the same group are considered similar. 2. Metals classified in different groups are considered dissimilar. 3. For the purpose of this table, the metal referred to is the metal on the surfaces of the part.

Table 3-2. Organic Protective Requirements for Metals METAL

INTERIOR

EXTERIOR

Magnesium

0.4 mil (min) - epoxy polyamide primer

0.4 mil (min) epoxy polyamide primer, then applicable finish

Aluminum

0.4 mil (min) - epoxy polyamide primer

One coat of epoxy polyamide primer, then applicable finish

Copper alloys 400 series steel and low alloy steels (see NOTE) 200 and 300 series stainless steels

No protective finish required

Titanium NOTE When 400 series steels are used in high heat application, omit the organic finish.

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BHT-ALL-SPM 3-12.

3-13.

SIMILAR METALS

MATERIALS REQUIRED

MATERIALS REQUIRED Refer to chapter 13 for specification and source. NUMBER

Refer to chapter 13 for specification and source. NUMBER

NOMENCLATURE

C-204

Primer

C-308

Sealant

Faying surfaces of similar metals shall be protected by applying epoxy polyamide primer to interior or exterior surfaces as required by table 3-1. 1. Exterior surfaces. In addition to the 0.4 mil minimum thickness of epoxy polyamide primer (C-204) applied to each surface, magnesium faying surfaces on the interior or exterior surfaces of the helicopter shall be protected using sealing compound sealant (C308). The sealant shall be applied between surfaces and squeezed out at the boundaries. The squeeze-out shall be approximately 1/4 inch in width and shall be smoothed to fair in. 2. Interior surfaces. In addition to the 0.4 mil minimum thickness of epoxy polyamide primer (C-204) applied to each surface, magnesium faying surfaces shall be protected by placing either of the following materials between the surfaces:

DISSIMILAR METALS

C-204

NOMENCLATURE Primer

Faying surfaces of dissimilar metals (except magnesium) shall be protected by applying a 0.4 mil minimum thickness of epoxy polyamide primer (C-204) to each surface. 3-14. CORROSION EXCEPTIONS

PROTECTION

MATERIALS REQUIRED

NUMBER C-101

NOMENCLATURE Corrosion Preventive Compound Compound

C-104

Corrosion Preventive Compound

C-204

Primer

1. On parts that are to be welded or adhesive bonded.

a. Adhesive barrier tape (C-430). When adhesive barrier tape is used, it shall cover the entire faying surface area of one of the parts. Also, it shall extend at least 1/4 inch beyond the joint edges.

2. Slip fits. Use unreduced epoxy polyamide primer (C-204) except when anaerobic sealants are specified.

b. Sealing compound sealant (C-308). When sealing compound sealant (C-308) is used, it shall be applied between the surfaces and squeezed out at all boundaries. The squeeze-out shall form a fillet approximately 1/4 inch in width.

3. Press fits. Use unreduced epoxy polyamide primer (C-204) except when anaerobic sealant or adhesives are used. Press fitted parts, permanently housed in oil, shall be assembled with the oil to be used in the housing.

3. Butt joints. In addition to the 0.4 mil minimum thickness of epoxy polyamide primer (C-204) applied to each surface, the separating butt joints consisting of magnesium sheet and a sheet of any other material, including magnesium, shall be filled with sealing compound sealant (C-308).

4 Thermal fits. Assemble thermal fits without organic coatings.

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5. Staked bearings. Using one of the following methods, as applicable.

Bell Helicopter a. Use unreduced wet epoxy polyamide primer (C-204) on faying surfaces. Do not allow primer to get on seal or shield of bearing.

BHT-ALL-SPM

Textron

a. Mix magnesium alloy chemical film treatment as follows: MAGNESIUM ALLOY CHEMICAL FILM TREATMENT

b. If bearings operate in oil or other fluid, use fluid they operate in on faying surface.

MEASUREMENTS c. If bearings are installed with a sealant, do not use epoxy polyamide primer. 6. Adjusting threads. Coat threads with corrosion preventive compound (C-101) before and after each adjustment.

Sodium Dichromate (C-212),

16 to 24 oz. (473.00 to 609.00 liter)

Calcium (C-113) or Magnesium (C-115) Flouride,

1/3 oz. (9.86 liter)

and 7. Control bolts, rotating and nonrotating. Coat all rotating and nonrotating control bolt shanks with corrosion preventive compound (C-104) unless otherwise specified. 3-15. CHEMICAL FILM (CHROMIC TREATMENT - MAGNESIUM

ACID)

MATERIALS REQUIRED Refer to chapter 13 for specification and source. NOMENCLATURE ~NUMBER C-103

Chromic Acid

C-113

Calcium Fluoride

C-114

Corrosion Treatment

C-115

Magnesium Fluoride

C-116

Chromic Acid

C-118

Sodium Hydroxide

C-204

Primer

C-309

Methyl-Ethyl-Ketone (MEK)

C-318

Cleaning Compound

C-407

Abrasive Pad _C___-426Tape

1. Immersion Method. The following procedure is a dip tank formula and complies with DOW 7, Type III, and MIL-M-3171 Type III corrosion treatment (C-114).

Water to make

1 gal. (3.7854 liter)

(1) The pH factor of the solution shall be maintained between 4.1 to 5.5 while processing castings, and 4.1 to 5.0 while processing other magnesium. (2) The pH factor shall be adjusted and maintained with chromic acid (C-116) or caustic soda sodium hydroxide (C-118) as necessary. (3)

The solution shall be kept saturated with

fluorides by suspending a cloth or fiberglass bag filled with calcium fluoride (C-113) or magnesium fluoride (C-115) in the solution corrosion treatment (C-114). (4) The temperature of the solution shall not fall below 200°F (93°C) during treatment. b. Treat -parts for 30 ±5 minutes. Alloy EK60A may be treated for only 15 minutes due to faster coating action. c. After chemical treatment, the parts shall be thoroughly rinsed in room temperature water followed by a dip in hot water maximum 180°F (82°C), to facilitate drying. If a hot air dryer is used, a double water rinse shall precede the drying. d. Parts requiring painting as the next operation shall be painted as soon as practicable after drying, preferably within 24 hours. Bare steel inserts shall be oiled immediately after drying to prevent corrosion. 2. A brush-on method of chemical film treatment MIL-M-3171 type VI can be applied to magnesium parts that require touchup. This treatment is generally

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Bell Helicopter Textron

BHT-ALL-SPM used in refinishing procedures inexpensive. The treatment may brush and is not harmful when surfaces, nor does it present the related treatments.

and is relatively be applied with a trapped in faying toxicity hazards of

a. Preparation. Mask the area to receive treatment with masking tape (C-426) and wrapping paper to protect adjacent areas from coating. b. Cleaning. (1) Remove oil and grease with a clean cloth dampened with solvent MEK (C-309). (2) Scrub area with abrasive pad (C-407) and cleaning compound (C-318) 10 to 20 percent by volume in clean water. Thoroughly rinse with clean water. c. Drying. Allow surface to air dry or force dry using clean, filtered, compressed air and clean dry cloths. d. Mix magnesium touchup treatment solution as follows:

MAGNESIUM TOUCHUP TREATMENT SOLUTION MEASUREMENTS

NOTE Do not rinse area with hot water. Time between coating and water rinsing is not critical. In fact, where running water is not feasible, rinse step can be eliminated without altering coating effectiveness. f. Appearance. The treatment should provide an appearance that is continuous and uniform. The color should range from brassy iridescence to dark brown depending upon treatment time. Up to 1 minute of treatment produces a brassy film and from 2 to 3 minutes a dark brown coating. For best paint adhesion, dark brown coatings are preferred. Processed coatings require painting or sealing before exposure to overnight or outdoor atmospheric conditions. g. Primer. Apply one spray coat (0.6 minimum thickness) of primer (C-204). 3-16. ALUMINUM ALLOY TREATMENT (TOUCHUP)

CHEMICAL FILM

MATERIALS REQUIRED Refer to chapter 13 for specification and source. NUMBER

NOMENCLATURE

C-100

Chemical Film Material

C-204

Primer

C-304

Solvent

Chromic Acid (C-116),

1-1/3 oz (10 g)309

C-309

Calcium Sulfate (C-120),

1 oz (7.5 g)

C-318

Methyl-Ethyl-Ketone M (MEK) EthylKetone Cleaning Compound

C-407

Abrasive Pad

C-422

Aluminum Wool

C-426

Tape

and Water to make

1 gal. (1 liter)

touchup e. Treatment. Apply magnesium solution, or premixed solution chromic acid (C-103) liberally to area to be treated. Keep area wet with solution about 1 to 3 minutes, to produce a brown film. Treatment should not be less than 30 seconds nor longer than 3 minutes. Rinse area thoroughly with clean water and dry.

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mil

The chemical film treatment of aluminum alloy is a chromate conversion coating that increases the corrosion resistance and provides a base for organic finishes on all aluminum alloys. The chemical film coating has no significant abrasion resistance.

Bell Helicopter Textron I 1. Preparation. Mask the area to receive treatment with masking tape (C-426) and wrapping paper to protect adjacent areas from coating. 2.

Cleaning.

a. Remove oil and grease with a clean cloth dampened with a solvent (C-304) or MEK (C-309). b. Scrub area to be treated to clean bare metal using nylon web abrasive pad (C-407) or fine aluminum wool (C-422).

BHT-ALL-SPM

6. Appearance. The treatment should provide an appearance that is continuous and uniform. Color should range from golden iridescent to brown. Streaks and mottled areas caused by the surface condition of the metal, will be allowed provided there is chemical film coverage in these areas. 7.

Primer. Apply one spray coat (0.6 mil minimum

thickness) of epoxy polyamide primer (C-204) to interior and exterior surfaces. 3-17.

CADMIUM PLATING

c. Scrub area with nylon web abrasive pad and cleaning compound (C-318) 10 to 20 percent by volume in clean water. CAUTION d. Thoroughly rinse with clean water. e. Repeat steps c and d until water break-free surface cleanliness is achieved. 3. Drying. Allow surface to air dry or force dry using clean filtered compressed air and clean dry cloths. 4. Mix aluminum conversion coating chemical film material (C-100) as follows:

solution

ALUMINUM CONVERSION COATING SOLUTION RATIO RATIO BY VOLUME

Chemical Film Material

6 parts

Nitric Acid (C-432),

1 part

(C-100),

NOTE Selective brush cadmium plating is intended to be used for the repair and/or touchup of metal surfaces where existing cadmium plating has been damaged or partially removed. Bell Helicopter Textron approves the use of LHE brush cadmium plating methods and procedures established by: Selectrons, Ltd. New York, New York

and Distilled or Demineralized Water

BELL HELICOPTER TEXTRON DOES NOT AUTHORIZE CADMIUM PLATING OF STRUCTURAL PARTS IN THE FIELD USING ELECTRO DEPOSITED OR VACUUM DEPOSITED PROCEDURES.

256 parts

5. Treatment. Apply solution chemical film material (C-100) liberally to area to be treated. Keep area wet with solution 1 to 3 minutes. Rinse area thoroughly with clean water and dry.

or SIFCO Metachemical Div. of SIFCO Industries Inc. Cleveland, Ohio 44131.

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BHT-ALL-SPM 3-18.

CHROMATE CONVERSION COATING MATERIALS REQUIRED

3-19.

SOLID FILM LUBRICANT

3-20.

SOLID FILM LUBRICANT REPAIR MATERIALS REQUIRED

Refer to chapter 13 for specification and source. NUMBER C-112

NOMENCLATURE

Refer to chapter 13 for specification and source.

Chromate Conversion

NUMBERNOMENCLATURE

Coating

NOTE Chromate conversion coating is used over cadmium plated surfaces.

C-005

Solid Film Lubricant

C-021

Lubricant

C-305

Aliphatic Naphtha

C-486

Cheesecloth

1. Mix chromate conversion coating (C-112) as follows: NOTE CHROMATE CONVERSION COATING

Touch up repairs, not to exceed 10 percent of coated area are permitted. Use solid film lubricant (C-021) for touch up.

MEASUREMENTS Cadmium Chromate Conversion Coating (C-112),

6-1/2 (191.80 ml)

Nitric Acid (C-432),

2-3/4 oz.

and Water

1 gal

2. Apply chromate conversion coating (C-112) liberally to the area to be treated. Rinse area thoroughly with clean water or by swabbing with clean cloths wetted with water. Dry with clean dry cloths or dry compressed air. 3. The treatment shall provide an appearance that is smooth, fine grained, adherent, free from blisters, pits, nodules, and burned areas. The color should be bronze iridescent to light brown.

1. Clean area to be coated with clean cheesecloth (C-486) and aliphatic naphtha (C-305). Wipe dry with clean cheesecloth before naphtha evaporates. NOTE Mask surfaces not to be coated with lubricant. Allow sufficient time for solvent flashoff between coatings. 2. Apply a thin wet coating of required lubricant from table 3-3. Apply succeeding coats as required to achieve the designated depth of coverage. 3. Allow coating to air-dry for a minimum of 30 minutes prior to heat curing. 4. Heat cure solid film lubricant (C-005) or solid film lubricant (C-021). Refer to table 3-3 for material and curing temperature and time. 5. Complete recoating of surfaces with solid film lubricant shall be accomplished if lubricant has been removed by wear or repair.

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Table 3-3. Solid Film Lubricant Curing MATERIAL

CURE TEMPERATURE RANGE AND TIME TYPE I Solid Film Lubricant (C-005)

Steels (Except Carburized and Parts Containing Local Induction Hardened Areas) Corrosion Resistant Steels (Except 440)

350 ±15°F (177 ±9°C) for 1 hour

Plated Surfaces (Unless Limited by Base Material) Titanium and Titanium Alloys TYPE II Lubricant (C-021) Aluminum Alloys Magnesium Alloys Corrosion Resistant Steel (Type 440)

150 ±15°F (66 ±9°C) for 1 hour

Carburized Parts and Parts Containing Induction Hardened Areas NOTES: 1. Cure time begins when the part reaches the specified temperature. 3-21.

BLACK OXIDE

3-22. GEAR TOOTH WEAR PATTERN INSPECTION USING DRY FILM LUBRICANT MATERIALS REQUIRED

.................. CAUTION

Refer to chapter 13 for specification and source. BLACK OXIDE TREATMENT OF PARTS IS NOT REQUIRED OR AUTHORIZED.

NUMBER C-028

NOMENCLATURE Dry Lubricant

1. Spray three gear teeth approximately degrees apart with dry lubricant (C-028).

120

2. Assemble component and perform run-in and disassembly procedures, as required, to check gear tooth wear pattern.

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INHIBITED USING RODINE AID PICKLE INHIBITOR (C-417).

COPPER PLATING

3-23.

MATERIALS REQUIRED

IMMERSE CASE HARDENED PARTS A MAXIMUM OF TEN SECONDS.

Refer to chapter 13 for specification and source. NUMBER

NOMENCLATURE

7. Immerse part in acid pickle solution (40 to 60 percent Hydrochloric (muriatic) acid (C-431) by volume in water).

C-413

Stripper

C-415

Corrosion Preventive

8.

C-417

Inhibitor

9.

C-431

Hydrochloric (Muriatic) Acid

C-506

Potassium Cyanide

C-507

Sodium Cyanide

NOTE Copper plating is used to coat indicated areas. This procedure is to be used to remove copper plating and reapplying copper plate to the same area. 1.

Rinse part thoroughly in water.

Cyanide dip parts to passivate, if required, to hold parts prior to plating. Cyanide dip solution consists of two to six ounces of potassium cyanide (C-506) or sodium cyandide (C-507) per gallon of water. 10. If part is not going directly to plating bath, wash part thoroughly in clean water. 11. Copper plate part in solution given in table 3-4. Plating thickness shall be in accordance with dimensions specified in applicable maintenance chapter. Adjust voltage for current densities of 30 to 45 amps per square foot. Rotate part as necessary to eliminate unplated areas under clamps and to ensure a uniform thickness of plating is achieved.

Remove all oils and grease from component. 12. Rinse part thoroughly in clean water.

2. Strip existing copper plating using Metex copper F stripper (C-413) per manufacturers instructions. 3.

Rinse part thoroughly with water.

4. Clean part using corrosion preventive (C-415) following manufacturers instructions. 5.

Rinse part thoroughly with water.

6.

Mask areas that are not to be plated.

CAUTION ACID PICKLE (HYDROCHLORIC (MURIATIC) ACID (C-431) SOLUTION) WILL REMOVE ANY BLACK OXIDE COATING THAT IS PRESENT. USE AT ROOM ONLY SOLUTION TEMPERATURE AND KEEP FULLY 3-00-00 Page 14

13. Dry part and remove masking tape. 14. Perform embrittlement relief in accordance with instruction contained in appropriate maintenance text. 15. Apply corrosion preventive to part, if required (paragraph 3-2).

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Bell Helicopter Textron

Table 3-4. Copper Plating Bath INGREDIENT AND/OR CONDITIONS

CONTROL RANGE

Ph

12.5-13.5

Free Cyanide

1.4 - 2.5 oz/gal

Copper Metal

4.0 - 6.0 oz/gal

Rocheltex

4.0% - 8.0% by vol

Carbonates

9.0 oz/gal maximum

Temperature

140°F to 160°F

Wetting Agent

0.33% by vl maximum

This bath composition may be obtained by dissolving the following materials in water: Copper Cyanide

- 8.6 oz/gal

Potassium Cyanide

- 14.1 oz/gal

Potassium Hydroxide

- 1.0 oz/gal

Rocheltex

6.0% by vol

Copper Brightener

- 2.0% by vol

Wetting Agent

- 0.33% by vol

Copper metal concentration may be maintained by using Potassium Copper Cyanide: Double Salts or Copper Cyanide.

3-24.

PLASTIC MEDIA BLASTING CAUTION

Plastic Media Blasting (PMB) is a mechanical method to remove organic finish, fairing compounds and adhesives from helicopter parts and assemblies. The process is done with the use of compressed air to propel a stream of plastic particles at a part to abrade the paint. PMB can cause damage to helicopter parts if it is done by untrained personnel. PMB can cause warping of skins, roughing of surface finish, removal of corrosion protective inorganic surface treatments, penetration through of thin tapered metal fittings, and close fatigue cracks.

PMB MEDIA AND DUST CAN BLOCK OIL AND AIR PASSAGEWAYS OR CONTAMINATE BEARINGS, WHICH CAN LEAD TO PREMATURE FAILURE. 1

There are two ways to do PMB:

a. Method 1 Closed cabnet blasting of detail parts and assemblies. b. Method 2: Open booth blasting of the helicopter exterior or individual panels (metal or composite) that form the exterior of the helicopter.

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2. Even if PMB is done by a trained operator, damage to some materials can occur. It is not recommended to use PMB with all types of components or materials.

CAUTIONN USE EXTREME CARE WHEN USING PMB ON A GEARBOX CASE. THE GEARBOX CASE CONTAINS CORED AND/OR DRILLED OIL PASSAGES WHICH CAN BE BLOCKED WITH PMB MEDIA. 3. The example that follows gives a list of materials on which PMB method 1 is not recommended: a. Composite Surface: The resins and adhesive used incomposite parts are easily removed as the organic coating by PMB. Excessive resin removal can damage the structural composition of the parts. Resin removal cannot be controlled. b. Unsupported Skins: Unsupported (not stiffened or non-core bonded) aluminum skins, less than 0.032 inch (0.813 mm) thick can be distorted by PMB. The pummeling effect and the friction heat buildup of PMB cannot be prevented, c. Clad Aluminum and Cadmium Plated Surfaces: Ductile clad aluminum and cadmium plated surfaces are easily moved and removed by PMB. The clad on aluminum is not repeatable and cadmium plating is restricted to touch-up. 4. The method that follows gives material on which a PMB method 2 is not recommended:

abrasive blasting equipment is to be used for PMB. The blasting equipment must have indication and regulation devices to measure and control the blasting pressure. 2. The PMB equipment must have a separation system which is made up of a cyclone separator, a vibrator screen system, and dust bag to remove paint chips, dust, sand, metallic particles etc., produced by the blasting operation. 3. Manufacturers of cabinet and open booth for PMB include, but are not limited to, Paul & Griffin, Clemo, Zeroblast, and Turco. 4. Open booth (Method 2) operator must have the equipment that follows: a. Breathing Air: A compressor is used to provide breathing air for the operators along with the safety equipment that follows: b. Breathing Air Filter: A breathing air filter to remove particles, moisture, and vapor. Clemco Industries, Model CPF-80 or equivalent. c. Carbon Monoxide Monitor: A carbon monoxide monitor, Dynamation Inc., Model ABL-50 or equivalent. d. Voice Communications: Two radio headsets to permit communication between the blaster and the blast helper. e. Hearing Protection: All PMB personnel must wear hearing protection. f. Blast Suit: An "Apollo" helmet with a protection cover suit and gloves.

a. Cadmium Plated Surfaces: The cadmium plated surface is easily moved or removed by the PMB.

5.

b. b. Replacement Replacement of of the the cadmium cadmium plating plating is is to touch-up. restricted restricted to touch-up.

a. Safety Warning Light: A safety light is installed outside the personnel entrance doors and flashes during PMB operation.

Open booth equipment:

3-25. PLASTIC MEDIA BLASTING EQUIPMENT DESCRIPTION

b. Booth Door: The booth door opens outward.

1. The siphon feed abrasive blasting equipment is not to be used for PMB. Only direct pressure feed

c. Ground Cords: The ground cords are used to ground the helicopter or parts that are to be blasted.

-

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d. Emergency Lighting: An integrated emergency lighting system is used in the event of a power failure.

3-28.

MEDIA PARTICLES METHOD 2

MATERIALS REQUIRED e. Illuminated Exit Sign(s): An illuminated exit sign is used to show the exit(s) location.

Refer to chapter 13 for specification and source. NUMBER

f. Ventilation: A minimum cross-draft ventilation rate of 75 cubic feet per minute per square foot (2,12 cubic meters per minute per 926 square centimeters) of open face area.

C-318

Cleaning Compound

1. The media particles that are used in method 2 have the specification of MIL-P-85891, Type V. The particles are made from thermoplastic "Acrylic Plastic". The particles must be free of moisture and are not to exceed 200 parts per million of high density particle contamination.

3-26. PLASTIC MEDIA BLASTING OPERATOR TRAINING Only PMB operators with a thorough knowledge of helicopter components and the potential for direct and indirect damage are to be considered as PMB operators. The operator must have a working understanding of the PMB operation parameters and have the aptitude for PMB operation. The PMB operator has to be able to remove organic finishes layer by layer.

2. Particle Sizes: Only particle size of 20/30 is recommended. .

Color: White to light grey or unspecified color. b. Hardness:

3-27.

NOMENCLATURE

Barcol

hardness

46

to

54

(approximately MOH hardness 3.5).

MEDIA PARTICLES METHOD 1

1. The media particles that are used in method 1 have to meet the specification MIL-P-85891, Type II The particles are made of thermoset Urea Formaldehyde that have to be free of moisture. 2. Particle Sizes: 16/20, 20/30, 30/40, and 40/60 may be used. However, a particle size of 20/30 is recommended.

c. Manufacturers:

Blast

Off

Inc.,

U.S.

Technology Corp., T-Mech Co. d. P/N When Ordering White Color Particles: M85891-55-2030. e. P/N When Ordering Particles: M85891-56-2030. 3-29.

Unspecified

Color

PMB Procedure - Requirement

a. Color: Yellow or unspecified color. b. Hardness: Barcol hardness (approximately MOH hardness 3.5).

54

c. Manufacturers: Blast Technology Corp., Tri-Mech Co.

Inc.,

Off

to

62

U.S.

d. P/N When Ordering Yellow Color Particles: M85891-21-1620, M85891-21-2030, M8589121 3040, M85891-21-4060. e. P/N When Ordering Unspecified Color M85891-26-2030, M85891-26-1620, Particles: M85891-26-3040, M85891-26-4060.

1. Observe all of the operation limits given by the equipment manufacturers for cabinet blasting and open booth blasting modes open booth blastingmodes 2. PMB Method 1 (close cabinet) parameters Description. Description. a. Blasting Pressure: Never exceed 40 PSI (276 blasting pressure. (276 kPa) kPa) of of blasting pressure. The The normal normal operating operating blasting pressure is 20 to 30 PSI (138 and 207 kPa) for most applications. The pressure is to be measured at the nozzle and not from the regulating gauge. To check the nozzle pressure, use a hypodermic needle gauge positioned at a 45 degree angle to the main flow and away from the main flow.

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Textron

b. Impingement angle: The impingement angle is measured from the horizontal and is between 45 and 60 degrees.

3. Do not blast directly into the bond lines because the adhesive will be removed.

c. Nozzle Distance: The distance between the tip of the nozzle and the part to be blasted should never be closer than 4 inches (10.2 cm).

4. The best method to remove organic finishes is to use a combination of low blast pressure, a low impingement angle, and the longest nozzle distance.

d. Dwell Time: Never let the nozzle stay in a localized area for more than one second. It is recommended to make several passes over the area to be stripped rather than to let the nozzle stay in a localized area.

5. Do not increase the rate of production with an increase of the blast pressure and an increase of the impingement angle.

e. Flow Rate: The flow rate is between 140 and 170 Pounds per hour (63.6 and 77.2 kilograms per hour). 3-30. 1.

6. If the production rate must be increased, it is safer to increase the blast pressure and increase the zozzle distance. PMB METHOD 3-31. PROCEDURES PROCEDURES

PMB Method 1 Procedures Clean the component surface with (C-318).

2

(OPEN

BOOTH)

For the method 2 procedures refer to table 3-5.

2. Remove the organic finish from the necessary areas with a regular rate of stroke. Table 3-5. PMB Method 2 Parameters MATERIAL THICKNESS (INCH) (INCH)

SUPPORTED/ UNSUPPORTED NOTE (1)

AIR PRSSURE (PSI)(3) NOTE NOTE (2)

MEDIAFLOW RATE (LBS/HR) NOTE (3)

STANDOFF DISTANCE (INCHES) (INCHES)

Description

IMPINGEMENT ANGLE (DEGREES) (DEGREES)

NONCLAD

(SECONDS)

METAL 0.16 - 0.31

Supported/ Unsupported

30 ±2 30 +2

450 -480 450 -480

18 - 24 18 -24

15 -30