SD3-60 AIRCRAFT MAINTENANCE MANUAL 20.pdf(3) If internal damage or serviceability is suspected test...

zSD3-60 AIRCRAFT MAINTENANCE MANUAL

CHAPTER 20 - STANDARD PRACTICES - AIRFRAME

TABLE OF CONTENTS

20-00-00 STANDARD PRACTICES, AIRFRAME - GENERALGeneral 1

20-01-00 STORES INFORMATIONGeneral 201Unpacking 201Transit packaging 201Storage packaging 201Acceptance checks 202Storage instructions 202Storage conditions 203Limiting period (shelf life) 203Return to manufacturer or base 203

20-09-01 TENSIONING OF CONTROL CABLESEstablishment of correct tension 1

20-09-02 LOCKING AND INSPECTION OF CABLE TURNBUCKLES DESCRIPTION & OPERATION

General 1Fit locking clips 1Inspect turnbuckles 1

20-09-03 BOLT SHORTENING - DESCRIPTION & OPERATIONGeneral 1Shortening 1Protective treatment after shortening 5

20-09-04 TORQUE LOADING OF 'AN' AND 'MS' COUPLINGSGeneral 1

20-09-05 ELECTRICAL BONDING - DESCRIPTION & OPERATIONGeneral 1Definitions 2External bonding 3Internal bonding 4Methods of bonding 7Inspection/Test 10Protection of bonds 10

ChapterSectionSubject Subject Page

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20-09-05 ELECTRICAL BONDING - MAINTENANCE PRACTICESGeneral 201Bonding 201

20-09-06 TORQUE LOADING OF STRUCTURAL AND ATTACHMENT BOLTS/NUTS

General 1Standard applications 1Torque Wrench 8Torque conversion 10

20-09-07 TORQUE TIGHTENING OF ELECTRICAL TERMINALSGeneral 1Procedure 1

20-09-08 TEMPORARY REPLACEMENT OF DAMAGED RIGID PIPES BY FLEXIBLE PIPES - MAINTENANCE PRACTICES

General 201

20-09-10 WIRE LOCKING OF THREADED ITEMS DESCRIPTION & OPERATIONScope 1Definition 1Wire Locking Practice 1

20-09-11 BORESCOPE INSPECTIONS - DESCRIPTION & OPERATIONGeneral 1Description 1Operation

20-09-12 FUEL TANK ACCESS AND CLOSE-OUT - MAINTENANCE PRACTICESGeneral 201Fuel Tank Access 201Fuel Tank Close-out 202

20-09-13 ELECTRICAL WIRING - MAINTENANCE PRACTICESGeneral 201

20-09-14 OPERATING CABLE END FITTINGS - MAINTENANCE PRACTICESInspection/Check 201

20-09-15 ZONAL INSPECTION REQUIREMENTS - INSPECTION/CHECKInspection/Check 601

20-09-16 ELECTRICAL HARNESSES - MAINTENANCE PRACTICESInspection/Check 201

20-09-17 FLIGHT COMPARTMENT PANEL 1C - GENERAL VISUAL INSPECTIONGeneral 601

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20-09-19 FLIGHT COMPARTMENT PANEL 1D - GENERAL VISUAL INSPECTIONGeneral 601

20-09-20 FLIGHT COMPARTMENT PANEL 2D - GENERAL VISUAL INSPECTIONGeneral 601

20-09-21 FLIGHT COMPARTMENT PANEL 4P - GENERAL VISUAL INSPECTIONGeneral 601



20-09-24 FLIGHT COMPARTMENT PANEL 10P - GENERAL VISUAL INSPECTION

General 601

20-09-25 FLIGHT COMPARTMENT PANEL 11P - GENERAL VISUAL INSPECTION

General 601






20-09-31 FLIGHT COMPARTMENT PANEL 10C - GENERAL VISUAL INSPECTION

General 601

20-09-32 FLIGHT COMPARTMENT GROUND STUDS AND ASSOCIATED WIRING - GENERAL VISUAL INSPECTION

General 601

Aug 10/09



20-09-33 FLIGHT COMPARTMENT RESISTORS AND ASSOCIATED WIRING - GENERAL VISUAL INSPECTION

General 601

20-09-34 FLIGHT COMPARTMENT SPEAKERS, PCB’s, AND ASSOCIATED WIRING - GENERAL VISUAL INSPECTION

General601

20-09-35 FLIGHT COMPARTMENT TB’s AND ASSOCIATED WIRING - GENERAL VISUAL INSPECTION

General 601

20-09-36 FLIGHT COMPARTMENT PNEUMATIC DE-ICER TIMER, PCB’S, AND ASSOCIATED WIRING - GENERAL VISUAL INSPECTION

General 601

20-09-37 FLIGHT COMPARTMENT FIRE BELL AND ASSOCIATED WIRING - GENERAL VISUAL INSPECTION

General 601

20-09-38 FLIGHT COMPARTMENT HYDRAULIC TEMPERATURE TRANSMITTER, TEMPERATURE CONTROLLER, AND ASSOCIATED WIRING - GENERAL VISUAL INSPECTION

General 601

20-09-39 FLIGHT COMPARTMENT TEMPERATURE CONTROLLER, AIR DATA SENSOR, ELECTRONICS UNIT, AND ASSOCIATED WIRING - GENERAL VISUAL INSPECTION

General 601

20-09-40 FLIGHT COMPARTMENT SPEAKERS, RESISTORS, HORN, FLOODLIGHT, AND ASSOCIATED WIRING - GENERAL VISUAL INSPECTION

General 601

20-09-41 FORWARD FUEL TANK/CENTRE WING CONNECTORS, TB’s, AND ASSOCIATED WIRING - GENERAL VISUAL INSPECTION

General 601

20-09-42 CONTROL SURFACE CABLES, CONTROL RODS, FUEL & HYDRAULIC PIPES, AND ASSOCIATED WIRING - GENERAL VISUAL INSPECTION

General 601

20-09-43 PASSENGER COMPARTMENT SIDEWALL STATION 175.80 TO 197.20 (RH) - GENERAL VISUAL INSPECTION

General 601

Aug 10/09




General 601

20-09-45 PASSENGER COMPARTMENT PANEL 3D - GENERAL VISUAL INSPECTION

General 601

20-09-46 PASSENGER COMPARTMENT PANEL 12P - GENERAL VISUAL INSPECTION

General 601


General 601

20-09-48 PASSENGER COMPARTMENT CEILING STATION 74.00 TO 300.77 - GENERAL VISUAL INSPECTION

General 601

20-09-49 POWER PLANT PANEL 19C (LH) AND 20C (RH) - GENERAL VISUAL INSPECTION

General 601

20-09-50 PROTECTION OF ELECTRICAL WIRING INTERCONNECTION SYSTEM - MAINTENANCE PRACTICES

introduction 201Recommendations and Precautions

Aug 10/09



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AMM20-00-00 2.0.0.0STANDARD PRACTICES, AIRFRAME - GENERAL

1. General

This chapter contains information on practices which are standard throughout the airframe section of the manual.


AMM20-01-00 3.0.0.0STORES INFORMATION

1. General

The information in this section serves as a guide to the packaging, storage and transit of items or components.

2. Unpacking

A. Procedure

(1) When opening a sealed polythene bag, cut the slit as near as possible to the original seal, allowing sufficient material for effective re-sealing.

(2) Remove protective caps, plugs and blanking covers only when the unit is to be tested or installed in the aircraft. Retain these items for re-use when units are being returned.

(3) Retain wooden cases and specially constructed containers for storage and transit purposes.

NOTE: Do not break up wooden cases and special containers, or leave to deteriorate.

(4) Whenever possible retain packing material for further use.

3. Transit packaging

A. Procedure

(1) All units are to be adequately packed in wooden cases, cardboard cartons or special containers to prevent damage and deterioration of the unit during transit.

(2) Cushioning materials are generally of rubberized hair or cellulose wadding, although corrugated cardboard or wood wool may be used, dependent upon the size and nature of the unit being packed and the method of transportation.

(3) Suitable labels are to be fixed to the units and externally on containers, clearly identifying the contents, and giving cure dates of rubber seals which impose a storage limiting period.

(4) Containers of delicate units are to be labelled with cautionary handling notes.

4. Storage packaging

Units are normally pre-packed for storage, to provide protection from damage and deterioration under temperate or tropical conditions. Certain metal components may also be treated with a temporary protective film coating, and protection against humidity may be provided by the inclusion of desiccant packs.

A. Temperate areas



Units are to be wrapped in waxed paper or plastic film and placed in suitable cardboard boxes or other containers. The packaged units are to be clearly labelled to provide easy identification of contents.

B. Tropical areas

Units are to be placed in a polythene bag and heat sealed after as much air as possible had been excluded and then packed as prescribed for temperate areas.

5. Acceptance checks

The following general procedure is recommended if it is evident, or suspected, that a packaged unit has been damaged in transit.

A. Procedure

(1) Remove outer packing and carry out a thorough visual examination of the physical condition of the unit for evidence of damage, corrosion or deterioration.

NOTE: Do not unseal polythene bags or sealed containers unless absolutely necessary for inspection.

(2) Check that all protective caps, plugs and blanking covers have not worked loose.

(3) If internal damage or serviceability is suspected test the unit.

(4) Check the condition of any inhibiting material and desiccant packs for the presence of excessive moisture and renew as necessary before repacking for storage.

(5) Repack serviceable units for storage.

(6) Return unserviceable units to the manufacturer or base for rectification.

6. Storage instructions

A. General

The actual conditions of storage are of the utmost importance. The premises used must be kept clean, well ventilated and, with certain exceptions, well lighted. The store should be maintained at an even day temperature between 21°C (70°F) max. and 10°C (50°F) min. to minimize the effects of condensation. Concrete floors should be treated periodically to keep down dust. Open racks allow a free circulation of air and are preferable when the nature of the stock permits their use. when bins are used, the painted metal type is more suitable than wooden bins, since, with the latter there is a risk of corrosion due to mould and dampness.

B. Rotation of issue



Methods of storage should be arranged so that batches of materials and individually stored units can be issued in strict rotation, based on shelf life limiting periods. This is of particular importance where perishable goods (rubber, etc.) are concerned.

7. Storage conditions

A. Units and piece parts

Whenever possible retain units and piece parts in their original storage pack until issued for use.

Avoid compression damage if components are to be stored in stacks.

Do not store units and piece parts in the vicinity of corrosive gases, fluids or any electric machine or light source (e.g. mercury vapour lamps) whose operation produces ozone.

Regularly check desiccant packs fixed to stored units for moisture contamination, and renew if necessary.

B. Rubber parts

Store all rubber parts, flexible pipes and braided cordage in a relaxed condition.

Protect rubber parts from direct sunlight or strong artificial light and contamination from oils, grease and cleaning agents.

Do not use copper containers.

Every 6 months (approx.) examine rubber parts for ageing or perishing and re-dust with french chalk, if necessary.

Do not allow fabric-bonded rubber to become damp.

8. Limiting period (shelf life)

Remove, overhaul and test stored units on the expiry of the recommended limiting period, before returning for a further storage period.

Examine perishable items thoroughly for serviceability, and discard if any deterioration is evident or suspected.

9. Return to manufacturer or base

A. Procedure

(1) Adequately protect and pack all units being returned to the manufacturer or base to minimize transit damage or corrosion.

(2) Whenever possible use the original transit containers.



(3) Enclose a condensed history sheet giving the relevant details of the unit being returned.

(4) Clearly label all packages. A complete list of Vendors' (and Agents) addresses is given in Illustrated Parts Catalogue.



AMM20-09-01 4.0.0.0TENSIONING OF CONTROL CABLES

1. Establishment of correct tension

Those cable-controlled systems throughout the aircraft which are subject to specific tension requirements during rigging are listed in the table below (together with their respective nominal tensions). The nominal tensions are related to the aircraft mean operating temperature and this may well vary between operators due to geographic and climatic conditions. The method of establishing the relevant mean temperature is illustrated in the following example:-

The established mean temperature should be logged as that at which the quoted nominal tensions apply.

NOTE: For any variations from the logged mean temperature at the time of adjustment/check, the nominal tensions should be decreased for a lower than mean temperature, or increased for a higher than mean temperature by the amount quoted in column 3 of list overleaf.

°F °C

Max. ground temp. (say) = 113 45Min. temp. in flight (say) = 23 -5Hence mean temp. = 113 + 23 45 + (-5)

2 2= 68 20

SYSTEM NOMINAL TENSION ± ADJUSTMENT

Aileron trim control 30 lb. 1.5 lb/5°F (2.8°C)Rudder trim control 30 lb. 1.5 lb/5°F (2.8°C)Elevator trim control (including * servo, if fitted)

35 lb. 1.5 lb/5°F (2.8°C)

Autopilot (if fitted)* Aileron servo) 40 lb. 1.5 lb/5°F (2.8°C)* Rudder servo) See NOTE 40 lb. 1.5 lb/5°F (2.8°C)* Elevator servo) 40 lb. 1.5 lb/5°F (2.8°C)Flap control system 30 lb. 1.5 lb/5°F (2.8°C)Engine controls:Power 35 lb. 1.5 lb/5°F (2.8°C)Fuel 30 lb. 1.5 lb/5°F (2.8°C)Propeller RPM 30 lb. 1.5 lb/5°F (2.8°C)Fuel controls (airframe):LP valve control 30 lb. 1.5 lb/5°F (2.8°C)Crossfeed valve control 30 lb. 1.5 lb/5°F (2.8°C)Steering control system 35 lb. 2.5 lb/5°F (2.8°C)



NOTE: The required tensions relative to ambient temperature for the aileron, rudder and elevator primary servo loops are subject to a tolerance of +15 -20 lb.

Circuits denoted thus * are fitted to aircraft equipped with an autopilot.



AMM20-09-02 5.0.0.0LOCKING AND INSPECTION OF CABLE TURNBUCKLES DESCRIPTION & OPERATION

1. General

Turnbuckles employed in the various control-cable-operated systems throughout the aircraft are respectively locked and inspected as detailed in para 2. and para 3.

2. Fit locking clips

A. Procedure

With appropriate cable circuit correctly tensioned, proceed as follows:-

(1) Check that cable ends are equally disposed on each side of the turnbuckle.

(2) Check thread engagement

NOTE: For axially split claw types, employ inspection holes.

For turnbarrel types, ensure that not more than one thread is visible.

(3) At each end in turn, perform the following:-

(a) Align the slot in the barrel with the slot in the cable terminal.

(b) Refer to Figure 1. Hold the lock clip - Detail 'A' between the thumb and forefinger at the end loop - Detail 'B', and insert the straight end into the aperture formed by the aligned slots.

(c) Bring hook end of lock clip over the hole in the turnbuckle body and seat the hook loop in the hole.

NOTE: For axially split claw types, the hole nearest to end of insertion is used. For turnbarrel types the hole in the centre of the barrel is used.

(d) Refer to Figure 1. Apply pressure to the hook shoulder to engage the hook lip - see Details 'D' or 'E' as appropriate.

NOTE: Both locking clip hooks may be engaged on the same side of the turnbuckle or on opposite sides as respectively shown - see Details 'C', 'D' or 'E' as appropriate to type.

3. Inspect turnbuckles

A. Procedure

(1) Check that cable ends are equally disposed on each side of the turnbuckles.



(2) Check thread engagement

NOTE: For axially split claw types, employ inspection holes. For turnbarrel types, ensure that not more than one thread is visible.

(3) Check that locking clip hook lips are properly engaged in the turnbuckle barrel holes by applying a slight pull in the direction shown - see Detail 'C'.



Locking of TurnbucklesFigure 1



AMM20-09-03 6.0.0.0BOLT SHORTENING - DESCRIPTION & OPERATION

1. General

This section deals with the thread lengths of all bolts which have been shortened by the removal of thread surplus to that required for the nut plus an adequate allowance for safety.

WARNING: IF STANDARD BOLTS ARE FITTED AS REPLACEMENTS WITHOUT BEING SHORTENED TO THE ORIGINAL BOLT LENGTHS IT IS ESSENTIAL THAT A CHECK BE MADE FOR ADEQUATE CLEARANCE BETWEEN THE BOLT ENDS AND ADJACENT COMPONENTS, IN PARTICULAR AT MOVING PARTS THROUGHOUT THEIR TOTAL TRAVEL.

2. Shortening

Refer to Table 1. The thread protrusion through any type of nut must be within the limits quoted. Refer to Figure 1. For thread sizes or pitch not quoted the value of X must be between 1.5 and 2.5 times the thread pitch.



Thread ProtrusionFigure 1



Table 1

Replacement bolts for those whose Part No. are prefixed by the letter 'C' require to have their threads shortened to the values quoted. Refer to Table 2.

Bolt Diameter Code LetterDimension 'X' (in.)

Min. Max.

No 10-32 D 0.047 0.0781/4 -28 E 0.054 0.0895/16-24 G 0.063 0.1043/8 -24 J 0.063 0.1047/16-20 L 0.075 0.1251/2-20 N 0.075 0.125

9/16-18 P 0.083 0.1395/8-18 Q 0.083 0.139



Figure 2



Table 2

Refer to Table 2. For identification of bolts shortened, the bolt's Part No. must be prefixed by the letter 'C', the identification to be machine or vibro-percussion engraved.

Example:

3. Protective treatment after shortening

Table 3

Bolt diameter Code letter Dimension 'Y' (in.)

No 10-32 D 0.3901/4-28 E 0.460

3/16-24 G 0.4803/8 -24 J 0.5207/16-20 L 0.5901/2 -20 N 0.6909/16-18 P 0.7505/8-18 Q 0.810

C A173/ 5/ DPrefix for shortened length

Standard Bolt No. Bearing length 'L' in steps of tenths of an inch

Code letter for diameter

Steel Stainless Alum. Alloy

Bolts, shortened prior to assembly

Degrease, grit blast and cadmium plate

Nil Degrease grit blast and cadmium plate

Bolts shortened on assembly (general)

Epoxy primer

Bolts shortened on assembly (threads inside fuel tank)

Coat of Thiokol BR 1221 ST

Bolts shortened on assembly (threads inside oil/water tank)

- Non-poisonous clear varnish



AMM20-09-04 7.0.0.0TORQUE LOADING OF 'AN' AND 'MS' COUPLINGS

1. General

This section deals with the torque loading of 'AN' and 'MS' couplings.

Table 1

The corresponding tube outside diameter must be used to select the proper torque values. Torque wrenches must be calibrated on 95% of the related maximum torque value.

NOTE: The torque values on which the lines must be proof-tested are 60% of the related maximum torque value.

A. Flexible hoses

(1) High pressure hoses (1500 to 3000 psi) must be torque tightened to values quoted for cres-steel tubing. Refer to Table 1.

(2) Medium and low pressure hoses (below 1500 psi) must be installed in the aircraft with the torque values for aluminium alloy tubing. Refer to Table 1).

NOTE: The working pressures of flexible hoses are quoted by the vendor on the hose identification plates.

Tube outside diameter in

inches

Torque - value in inch pounds

Tube of aluminium alloy Tube of cres-steel

Min. Max. 95% of Max Min. Max. 95% of Max

1/8 - - - - - -3/16 - - - 90 100 951/4 40 65 60 135 150 145

5/16 60 80 75 180 200 1903/8 75 125 120 270 300 2851/2 50 250 240 450 500 4755/8 200 350 335 650 700 6653/4 300 500 475 900 1000 9501 500 700 665 1200 1400 1330

1.1/4 600 900 855 - - -1.1/2 600 900 855 - - -1.3/4 - - - - - -

2 - - - - - -



B. Bulkhead fittings

On replacement or re-installation of bulkhead fittings which have previously been installed with Loctite Nut Lock proceed as follows:

(1) Where Loctite Nut Lock is to be applied the threaded portion of the assembly nut and the union on which the assembly nut will be tightened must be free of contamination.

(2) The threads referred to in (1) must be brushed with Loctite activator N (drying time at least 15 minutes).

CAUTION: TAKE CARE TO LIMIT THE APPLICATION ONLY TO THE MATING THREADS.

(3) Tighten the assembly nut to the specified torque values for cres-steel. Refer to Table 1.

(4) Apply Loctite Nut Lock sparingly with a brush around the threaded section of the union at the assembly nut only.

CAUTION: TAKE CARE TO LIMIT THE APPLICATION ONLY TO THE MATING THREADS. ENSURE THAT NO LOCTITE NUT LOCK SPREADS TO THE PIPE COUPLING THREADS.

NOTE: Loctite Nut Lock will spread into the mating threads due to its capillary properties.

C. Pipe couplings and adapters

Pipe couplings and adapters must be torque tightened in accordance with the figures quoted for cres-steel tubing. Refer to Table 1.

D. Witness marks

After couplings have been correctly torque-tightened a stripe must be painted on couplings and adjacent parts to show alignment so that slackening can more easily be spotted.


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AMM20-09-05 8.0.0.0ELECTRICAL BONDING - DESCRIPTION & OPERATION

1. General

The purpose of Bonding (i.e. connecting together all metallic parts by effective electrical conductors) is to provide an electrical path of negligible impedance throughout the structure of an airframe.

A. Purpose

(1) The safe transmission of lightning discharges.

(2) The equalising of static charges which may build up on the adjacent part of the aircraft due to the motion of fluids in pipes or the motion of the aircraft through hail, rain or charged dust.

(3) The reduction of interference through static discharges between adjacent parts of the airframe for the improvement of radio transmission and reception.

(4) The prevention of shock to personnel from any high voltage.

(5) The prevention of static discharges which might constitute a fire or explosion hazard in the vicinity of fuel lines and equipment.

Bonding must not be confused with grounding continuity of the electrical system.

Condition 1 presents a complex problem by reason of the steep wave fronts of lightning discharges. A lightning discharge comprises an initial condenser discharge, having a potential between the points of discharge, i.e. cloud to cloud or cloud to earth - of several million volts, followed by a rapidly attenuating oscillatory discharge reducing in frequency and amplitude to zero. The almost vertical wave front of the initial discharge corresponds, for impedance purposes, to that of a VHF wave form.

Bonding introduced into the airframe system for the safe transmission of lightning discharges must therefore possess negligible impedance; that is to say it must be as straight as possible and of adequate gauge.

There are three conditions for lightning 'strike' on an aircraft. In the first, the aircraft may approach a cloud at a static potential sufficiently different to that of the airframe to break down the intervening airspace. By reason of the relatively low capacity of the aircraft, the current of this equalising discharge will be low and the damaging effect negligible.

In the second, the aircraft intervenes in a straight discharge between two clouds or one cloud and earth. The current of this discharge may be several hundred amperes for a few microseconds and, providing that it is properly distributed along the airframe, little or no damage will ensue.



In the third condition, which is comparatively rare, the aircraft intervenes in a simultaneous cloud to cloud to earth discharge. In this form - commonly known as 'fork lightning' - the current may rise to many thousands of amperes and the damage to the aircraft will be most extensive. The worst damage will be at the points of entry and exit and may range from completely burnt away antenna masts to holes in the metal skin of the airframe.

In all these conditions the extent of the damage will depend upon the efficiency of the bonding. A high impedance bond may result in a local 'side-flash' where discharge prefers to take the lower impedance of a short air gap to that of a sharply bent metal lead-with local damage conditions which could endanger the safety of the aircraft.

From this brief summary it can be appreciated that bonds introduced as a protection from the effects of lightning discharges;

(a) must be as straight as possible

(b) must be of adequate gauge

Conditions (3), (4) and (5) are subsidiary to condition (2), that is, they depend upon the equalization of static potentials throughout the aircraft. Providing that the whole metal structure is bonded throughout, it must be, for all practical purposes, at the same potential. Local metal areas which may, for some reason or other, acquire a static charge at a potential greater than that of the adjacent structure can dissipate it in a spark which can introduce extraneous noises in the audio circuits of the radio and intercommunication system.

Alternatively if touched by personnel, or member of the aircrew it may give a shock. Proper bonding will equalise potentials of different areas and eliminate these conditions.

B. Summary

The following are the fundamental requirements for bonding;

(1) All bonding jumpers must be as short and as straight as possible but not so short as to restrict the freedom of a moving part or put strain upon the bond.

(2) All bonding jumpers must be of adequate gauge and be securely connected at each end.

(3) All bonds must be protected from ingress of moisture and from corrosion due to electrolytic action.

(4) The total resistance across any bonded system, measured from any point on a bonded area to the main structure of the aircraft must not exceed 0.05 ohms.

(5) Bonding features disturbed during removal operations are to be re-made and tested after installation. Refer to para. 6.

2. Definitions

A. Bond



A stable path of low resistance between any two parts of an aircraft. A bond may be either 'inherent' or by 'bonding jumpers'.

B. Inherent Bonding

Bonding may be considered as inherent where the bond is in the form of a permanent metal-to-metal joint made by welding, brazing, sweating or swaging or by a semi-permanent metal-to-metal joint held together by screw threaded devices, rivets (at least two), tie rods, structural wires under tension, pin fittings driven tightly home, or clamps permanently immovable after installation in such a manner as to present an unbroken external conducting skin of minimum impedance on the aircraft. As a general rule protective finishes need not be removed from between inherently bonded surfaces providing electrical continuity is assured.

C. Bonding Jumper

A short length of 26 SWG soft copper strip or short length of flexible copper braid terminating at each end in a lug, attached to the braid by an approved form of crimp. Soldering is not permitted.

3. External bonding

With the exceptions of the antennae (see also Antennae Installations below) and metal parts of radomes and fairings of insulating material, all external metal surfaces must be bonded together and to the airframe in such a manner as to give full protection to the aircraft against lightning discharge.

A. Antennae installations

Radiating elements, excluding radar scanners and similar types, where the counterpoise is actually a part of the equipment, shall be so installed as to provide a homogeneous counterpoise or ground plane, of negligible impedance within the operating frequency ranges of the electronic equipment involved, and of adequate dimensions to ensure obtaining satisfactory radiation patterns. When antennas are so designed that their efficient operation depends on a low resistance low reaction return current path from a homogeneous ground plane to metal portions of the antennae, they shall be so installed that r-f currents flowing on the external surface of the aircraft will have a low impedance path of minimum length to the appropriate portions of the antennae. In particular, mating surfaces designed to be electrically continuous shall be clean metal surfaces, free from anodic film, grease, paint, lacquer, or other high resistance films to ensure negligible r-f impedance between the adjacent metal parts.

B. Control surfaces

It should be established that the bearings in control surface hinges will withstand a lightning discharge without dangerous seizure and if not then the bearing should be bonded across by a jumper. In which event the bonding jumper must be as flexible and as short and of as low an impedance as is practicable and should not be tinned. Great care should be taken to avoid any possibility of jamming the controls and any possibility of intermittent contact.



C. Engine mounts

Where an engine is insulated in any way from the engine mounting the engine must be electrically connected to the main earth system of the aircraft by two detachable bonds, one on each side of the engine.

D. Refuel/defuel points

Bonding sockets (SDM.245) are provided at each fuel filling point to provide a means of bonding refuelling equipment including the refuelling nozzle to the aircraft. The connecting is so positioned that it can be made before the filler cap is removed. The efficiency of the connection is not dependent upon the particular type of refuelling equipment being used. Metal pipe inlets are securely bonded to the aircraft structure as close as possible to the open end of the pipe. The bonding jumper is as short as the free movement of the pipe will allow without straining the bond.

E. Aircraft to ground bonding point

It is important that the bonding system of the aircraft is brought into instantaneous electrical contact with the ground when the aircraft lands. This is to ensure that no static electrical charge, which might cause sparking or shock, remains on metallic parts of the aircraft. This is accomplished through either the aircraft electrical conducting nose wheel or main wheel tyres as the case may be. But in addition to this the aircraft is provided with a suitable aircraft to ground 'quick release' bonding point, located at the refuel/defuel panel for use when the aircraft is grounded and gives full protection against shock to personnel.

F. Moveable metal surfaces

Where metal surfaces are moveable in relation to or hinged onto the aircraft structure as for example entrance doors, hatches, hinged fairings, inspection doors, turrets, etc. and where the contact resistance is more than 0.05 ohms. - each joint is bridged by an approved braided bonding jumper with an additional bond for each 10 sq.ft. of surface or 10 linear feet of hinged junction. If such hinged metal surfaces are closed in flight and secured in position by not fewer than two screw fastenings the surfaces may in general be considered as being inherently bonded.

G. External non-metallic parts

When non-metallic parts are fitted externally to the aircraft in situations where they may be exposed to lightning discharges or when they form part of the primary structure or where damage to these may endanger the safety of the aircraft (e.g. by the disruption of a radome) they are fitted with external bonding primary conductors complying with this instruction (para 5.).

4. Internal bonding

All metal parts within the fuselage, whether fixed or moveable, which are capable of acquiring an appreciable static charge above airframe potential are bonded to the main airframe either directly



or through other bonds, except only where the integrity of the aircraft electrical system is involved.

When an electrically non-conducting process is used for joining metal parts of the aircraft structure, these parts are bonded together.

NOTE: Bonding connections are located in protected areas where practicable and whenever possible are located near a hand hole, inspection cover or some other accessible location to permit ready inspection and replacement.

A. Electrical component cases

The metal cases of all electrical components which are within reach of the personnel whilst in flight are securely bonded to the structure whether inherently through the metal base of the component, or where this is not possible, through a bonding jumper.

B. Aircraft and engine control rods and cables

All control rods, cables, metal pulleys and joints are bonded to the structure either directly or through other bonds (para 5.).

Bonding across pin joints may be by a flexible bonding jumper secured to the joints by No.6 -32 UNC cadmium plated stainless steel screws and lockwashers, the screws being located so that they are in the reinforced tube area adjacent to the pin joint.

C. Equipment trays and instrument panels

Instrument panels, equipment trays and crates insulated from the main aircraft structure by shock absorbing mountings are bonded to the structure by bonding jumpers unless the mountings already incorporate a means of bonding. Securing bolts for components or shock absorber mountings may be used as bonding connections and sufficient slack in the bonding jumper must be left to allow the panel or tray freedom of movement on the mounting.

D. Refuelling equipment

All equipment associated with the fuel system of the aircraft is securely bonded to the main aircraft structure in such a manner as to prevent the discharge of any electrical potential in the vicinity of the fuel lines or orifices. All bonding connections are positive, that is to say they are securely attached to the equipment and the aircraft structure. Rubbing or sliding contacts are avoided.

E. Fuel pipes

All metal fuel pipes are electrically continuous throughout their length and securely bonded to the aircraft structure either by bonding jumpers, metal cleats or clamps. Flexible connections in pipe lines, unless inherently bonded are bonded across by bonding jumpers attached by metal clamps to the metal fuel pipes. In the case of fuel pipes of non-metallic construction which have metallic unions, each is bonded separately to the airframe.



F. Fuel valves

The bodies of electrically or manually operated fuel valves in pipe lines must be bonded to the main aircraft structure and/or to the associated pipelines. Where the normal fixing arrangements provide inherent bonding to meet the requirements of the section on INSPECTION and TESTING no further bonding is necessary. Otherwise bonding jumpers must be installed.

G. Fuel measuring equipment (electrical)

Electrical accessories in contact with fuel or fuel equipment satisfy the bonding and explosion proof requirements specified by the makers and all parts of such equipment specified by the makers as being at ground potential in addition, satisfy the requirements of the section on INSPECTION and TESTING.

H. Hydraulic and air pipes and metal ducts

All hydraulic pipes, compressed air pipes and metal ducts carrying ventilating air or cables are bonded to the aircraft structure. Hydraulic and air pipes conform to the section on fuel pipes (5), and metal ducting is provided with such additional bonding as may be necessary to meet the requirements of the section on INSPECTION and TESTING.

I. Metal screened cables

Bare metal screened cables are not used. Covered metal screened cables as specified on drawings are bonded.

J. Small metal parts

Small metal components, such as the bodies of plug and socket connectors on actuators, motors and other electrical devices, and on cable runs, nameplates on insulated covers, metal instrument coves, metal clips retaining cable looms and similar metal areas not exceeding 100 square inches need not be bonded to the aircraft structure.

K. Flexible armoured piping

Flexible tubing in pipelines comprising a metallic structure, with the exceptions of the flexible tubing used to connect oxygen masks to economisers, are bonded at their extremities and at intermediate points not more than 5 feet apart.

L. Control and distribution panels

As a safety precaution, all control and distribution panels are bonded to the main grounding system.

M. Avionic equipment

The metal frame and mounting structure carrying each avionic unit is bonded to the aircraft structure by at least one primary conductor or its equivalent.



5. Methods of bonding

CAUTION: BONDING CONNECTIONS CARELESSLY PREPARED AND PROTECTED COULD BE OF GREATER DANGER TO THE AIRCRAFT THAN THE ABSENCE OF BONDING.

From the information contained in para 1., para 3. and para 4. of this section it will be appreciated, that proper and comprehensive bonding is of primary importance relative to the safety of the aircraft, its aircrew, ground crew and personnel.

Furthermore the effectiveness of any method of bonding (no matter how good) can be nullified by carelessness in the preparation and protection of the bond.

The following methods of bonding, preparation and protection must be strictly adhered to.

A. Bonding dissimilar metals

In bonding, the necessity for jointing dissimilar metals is often unavoidable. In some cases the jumpers and other elements of the bonding connection are so selected as to minimise the possibility of corrosion and if possible, to ensure that if corrosion does occur, it will be in replaceable elements such as jumpers, washers and separators etc. and not in aircraft structure. Washers are not surface coated in any manner that would impair electrical conductivity. Unprotected stainless steel washers are not used. The acceptable methods of making up connections between bonding jumpers and structure of various metals are indicated. Refer to Table 1. Note that the metals are listed in the order of decreasing activity in salt water and the higher metal in the series will be the one attached in case of galvanic action between any two. In general the greater the separation between any two listed metals, the more violent the corrosive activity to be expected. The screws and nuts to be used in making the connection are indicated as Type 1 Cadmium or zinc plated, or aluminium and Type 2 stainless steel. Where either type screw is indicated as acceptable Type 2 is preferred from a corrosive standpoint.

Table 1

Metal Structure(Outer Finish Metal) Connection for Aluminium Jumper Connection for Copper Jumper

Magnesium and Mg. Base Alloys

Direct or Mg. washer

Type 1 Screw A.L. or Mg. washer

Type 1 Screw

Zinc, Cadmium, Aluminium and Al. Alloys

Direct Type 1 Screw Aluminium Type 1 Screw

Steel (except stainless steel)

Direct Type 1 Screw Direct Type 1 Screw

Tin, lead and Pb. Sn Solders

Direct Type 1 Screw Direct Type 1 or 2 Screw



B. Preparation for bonding

All surfaces intended for bonding must be clean and free from rust or paint, enamel, lacquer, anodic treatment or other protective treatments to ensure good electrical contact.

NOTE: An anodic surface is an almost perfect insulator for a potential difference of up to 130 volts, but is readily punctured by the rotation of a bolt head or the forming of a rivet. In these latter cases it is unnecessary to remove the anodic finish. However, when two anodic surfaces are clamped together without any relative motion being involved, the anodised surface should be removed over an area strictly limited to that necessary to ensure efficient contact, and the assembly coated with a suitable protective material such as a jointing compound containing barium chromate.

As a general rule protective finishes must not be removed from between inherently bonded surfaces.

In every case where removal of the protective treatment is necessary for bonding purposes, the assembly must be completed and re-protected immediately, in accordance with para 7.

If scrapers or abrasives are used they shall be of such a nature as to produce a clean, smooth surface without removing excessive material under the protective finish. Abrasives which will cause corrosive action, if particles embed themselves in the metal, shall not be used.

Emery paper shall not be used.

An acceptable preparation for bonding is as follows:-

(a) Abrade an area of 1.5 x contact surface area, of the bonding jumper clamp using 240, 320 or 400 grit Silicone Carbide or Aluminium oxide abrasive paper. Use water

Copper and Cu. Base Alloys

Tinned or Cadmium Plated Washer

Type 1 or 2 Screw

Direct Type 1 or 2 Screw

Nickel and Ni. Base Alloys


Type 1 or 2 Screw

Direct

Direct

Type 1 or 2 Screw

Type 1 or 2 ScrewStainless Steel Tinned or

Cadmium Plated Washer

Type 1 or 2 Screw


Silver, Gold and Precious Metals


Type 1 or 2 Screw


Metal Structure(Outer Finish Metal) Connection for Aluminium Jumper Connection for Copper Jumper



or an approved solvent to lubricate the action and to produce a smooth, level, fine grained surface.

(b) Remove all traces of abrasive residue, particularly from crevices, by solvent cleaning.

(c) Allow the solvent to dry before the next operation.

(d) Treat the abraded surfaces with Alocrom 1000/1200, or Alodine 1000/1200, or equivalent (MIL-C-5541 Class 3) conversion coating.

NOTE: Bare metal surface chemical treatment, and fitting of bonding jumper and clip is to be completed within one hour of the abrading operation to prevent oxidation of the metal substrate.

C. Preventing of intermittent contact

Precautions must be taken to prevent intermittent or vibratory contact between metal parts.

Intermittent contact shall be prevented on pipes control wires and rods, metal braided cables and flexible conduit systems for L.T. wiring. It is preferable to prevent intermittent contact by maintaining a definite electrical contact, but where for mechanical reasons this is not

possible, the adjacent parts shall be insulated from each other. Flexible metal conduit shall be installed with sufficient cleats to prevent intermittent contact occuring with other conduits etc.

D. Bonding jumpers

The use of flexible bonding jumpers is avoided and wherever possible normally, strips of 26 SWG. Soft Copper are used. The number of bonding jumpers is kept to a minimum within the requirements of this instruction, by careful design. Where the use of flexible jumpers is unavoidable they do not exceed 6 inches long.

The termination of the bonding jumper at the aircraft structure is made with a screw or nut and bolt of not less than No. 10-32 UNF. in. in size, with spring washers. On no account are self-tapping screws to be used for bonding-purposes. Jumper connections are not compression fastened through plywood or other non-metallic materials.

The bonding connections are such that vibration, expansion contraction or relative movement incident in normal service will not loosen them to such an extent that their effectiveness as a shunt path for electrical discharges will be impaired.

Bonding connections should be located in protected areas where practicable and whenever possible shall be located near a hand hole, inspection cover or some other accessible location to permit ready inspection and replacements.



Bonding leads should be as short and as straight as possible, loops or sharp bends shall not be permitted, but sufficient slack should be allowed to ensure that breakage does not occur under the stresses which may be set up in service. Care should be taken to ensure that jumpers are incapable of making intermittent contact with adjacent metal parts.

No bonding jumpers may be installed which in any way weakens the vital structure of the aircraft nor may it be installed in such a manner as to interfere in any way with the operation of the moveable surface or components of the aircraft.

The practice of connecting jumpers together to extend their length is not permitted. Not more than three bonding connections may be made to any one point on the aircraft structure.

Soldering of the bonding jumper in any way is not permissible.

E. Sizes of bonding jumpers - primary conductors

This paragraph refers to those strips in the main earth system and those bonding strips provided for lightning protection. The minimum cross sectional area in these cases shall be 0.0045 sq. in. (or 1/4 in. x 26 SWG), but 0.009 sq. in. (or 1/2 in x 26 SWG) for cases where a single strip is likely to carry the whole discharge from an isolated section.

F. Sizes of bonding jumpers - secondary conductors

This paragraph refers to those conductors provided for the equalization of static charges, bonding and screening of radio apparatus etc. but not for carrying lightning discharge currents. Refer to Figure 1 and Refer to Figure 2. The minimum cross-sectional area in these cases should be 0.001 sq. in. which corresponds to 44 strands of 39 SWG for braided conductor. Where a single wire is used, then the minimum size shall be 18 SWG. Where flexible jumpers are used, they shall be in accordance with SDM (A) 277, Issue 2.

6. Inspection/Test

NOTE: Testing and inspection of subassemblies must not be accepted as automatically clearing the bonding when finally installed in the aircraft. All bonding must be re-checked when in the aircraft. If, during the testing of the bonding, the protective finish of any part is visibly damaged, the area in question must be re-protected before final approval.

A. Examination of new bonding jumper installations

Each bond, after installation, shall be examined and tested to ensure:-

(1) That it is not taut or sufficiently flexed such as to foul adjacent structure.

(2) That it is firmly secured at both ends.

(3) That it does not restrict or foul movement of control rods, cranks, cables or other moveable equipment, either associated with or in the vicinity of the bond.



B. Testing of new bond installations

Equipment:

A 4-wire electrical bonding meter (AVO BT51 or equivalent) must be used to measure electrical bonding resistances, unless otherwise specified.

WARNING: FOR ELECTRICAL BONDING TESTS OF THE FUEL SYSTEM OR WHEN IN A FLAMMABLE VAPOUR ENVIRONMENT, A LOW READING ‘EXPLOSION PROOF’ OHMMETER SUCH AS THE BCD ELECTRONICS LIMITED MODEL MI-G-KIT OR EQUIVALENT (APPROVED FOR USE IN ENVIRONMENTS CLASSIFIED BY THE U.S. NATIONAL ELECTRICAL CODE AS DIVISION 1, CLASS 1, GROUPS A, B, C AND D) MUST BE USED.

NOTE: If a different ohmmeter from that specified previously is to be used, for alternative instructions, contact:-

Bombardier Aerospace (Shorts)Tel: +44 (0)7850 770826Fax: +44 (0)2890 733253Email: [email protected]

Measurement:

Each new electrical bond must be tested to ensure that the resistance of the bond, measured from either termination to the nearest point on the aircraft structure, does not exceed 0.05 ohms.

NOTE: If a reading exceeds this value, determine the cause, rectify and repeat the test.

Additionally, ensure that the electrical bonding requirements for specific systems and structural electrical bonding maintenance practices are accomplished. Refer to 20-09-05, pb201.

7. Protection of bonds

Where it is found necessary to remove any protective treatment on metallic surfaces; for bonding purposes, the completed assembly shall be re-finished and protected with etch primer and PR1005L Blue Acrylic coating (or equivalent), within 24 hours of the Inspection approval, and within one week of the removal of the finish.

Jointing compounds (e.g. to DTD 900/4502/4506/4493) must not be used on the mating surfaces of any bond.

A. Protective treatment

To be applied after assembly of the bond.

(1) Aluminium alloy and non-stainless steel material



(a) Paint locally with pre-treatment standard weight etch primer to DTD.5555 scheme 1 and finish with one coat of glossy enamel to DTD.827 colour to BS.381C/108, or equivalents.

(2) Magnesium alloy material

(a) Dry assembly at 70°C approx. and within 4 hours apply two coats of chromate rich primer to S B PLC. Spec. No. 135 and finish with one coat of glossy enamel to DTD.827 colour to BS.381C/108, or equivalents.

(3) Tungum, stainless steel and copper materials

(a) One coat of glossy enamel to DTD.827 colour to BS.381C/108, or equivalents.

(4) Important note for areas in contact with fuels

CAUTION: CARE SHOULD BE TAKEN TO AVOID PAINT SPREADING TO FLEXIBLE BONDING JUMPERS.

(a) Especially integral tanks, bonding or earthing connections shall be in accordance with the notes except that the paint scheme (including primer called up in notes (1) and (2) shall be omitted and the area affected cleaned free from dirt, grease, oil, paint or other contaminant and covered with sealing compound to spec. DTD.900/4502 or /4506, or equivalents.



Bonding MethodsFigure 1



Typical Flexible Sleeved Joint BondingFigure 2



Table 2

NOTE: Code B for No. 6 U.N.C. End Connection

Code C for No. 10 U.N.F. End Connection

Code E for 1/4 U.N.F. End Connection

Code G for 5/16 U.N.F. End Connection

Call up example AS3360 C3C

PART No. END CONNECTION FOR BOLT SIZE LENGTH(INS)

AS 3360 B3B No. 6 U.N.C. & No. 6 U.N.C. 3AS 3360 B4B No. 6 U.N.C. & No. 6 U.N.C. 4AS 3360 B5B No. 6 U.N.C. & No. 6 U.N.C. 5AS 3360 B6B No. 6 U.N.C. & No. 6 U.N.C. 6AS 3360 B3C No. 6 U.N.C. & No. 10 U.N.F. 3AS 3360 B4C No. 6 U.N.C. & No. 10 U.N.F. 4AS 3360 B5C No. 6 U.N.C. & No. 10 U.N.F. 5AS 3360 B6C No. 6 U.N.C. & No. 10 U.N.F. 6AS 3360 B3E No. 6 U.N.C. & 1/4 U.N.F. 3AS 3360 B4E No. 6 U.N.C. & 1/4 U.N.F. 4AS 3360 B5E No. 6 U.N.C. & 1/4 U.N.F. 5AS 3360 B6E No. 6 U.N.C. & 1/4 U.N.F. 6AS 3360 C3C No. 10 U.N.F. & No. 10 U.N.F. 3AS 3360 C4C No. 10 U.N.F. & No. 10 U.N.F. 4AS 3360 C5C No. 10 U.N.F. & No. 10 U.N.F. 5AS 3360 C6C No. 10 U.N.F. & No. 10 U.N.F. 6AS 3360 C3E No. 10 U.N.F. & 1/4 U.N.F. 3AS 3360 C5E No. 10 U.N.F. & 1/4 U.N.F. 5AS 3360 C6E No. 10 U.N.F. & 1/4 U.N.F. 6AS 3360 C6G No. 10 U.N.F. & 5/16 U.N.F. 6AS 3360 E4E 1/4 U.N.F. & 1/4 U.N.F. 4AS 3360 E5E 1/4 U.N.F. & 1/4 U.N.F. 5



AMM20-09-05 9.0.0.0ELECTRICAL BONDING - MAINTENANCE PRACTICES

1. General

WARNING: THIS MAINTENANCE PROCEDURE (OR PART OF) IS A FUEL TANK SAFETY CRITICAL ITEM, AND CLASSIFIED AS AN AIRWORTHINESS LIMITATION ITEM (ALI) BY THE AIRCRAFT OEM (REFER TO FUEL SYSTEM AIRWORTHINESS LIMITATION ITEMS - CHECKS, PB601).THE CONTENTS OF THIS PROCEDURE MUST BE STRICTLY ADHERED TO AND MUST NOT BE ALTERED TO ENSURE THAT UNSAFE CONDITIONS DO NOT DEVELOP BY MAINTENANCE, MODIFICATION OR REPAIR.

To achieve satisfactory bonding tests it will be necessary to locally remove or penetrate the protective finish of selected parts. When this occurs restore the protective finish as specified in refer to 20-09-05, pb1.

WARNING: ENSURE THAT THE FOLLOWING FIRE PRECAUTIONS ARE OBSERVED WHEN WORKING ON THE FUEL TANKS.

CHECK THAT ALL ELECTRICAL SUPPLIES IN THE AIRCRAFT ARE OFF. REMOVE THE BATTERIES AND ENSURE THAT GROUND SUPPLY IS NOT CONNECTED TO THE AIRCRAFT.

ENSURE THAT ALL HANDLAMPS OR TORCHES USED TO ILLUMINATE THE INTERIOR OF THE TANKS ARE OF AN APPROVED ‘EXPLOSION PROOF’ DESIGN SUITABLE FOR USE IN ENVIRONMENTS CLASSIFIED BY THE U.S. NATIONAL ELECTRICAL CODE AS DIVISION 1, CLASS 1, GROUPS A, B, C, & D, AND ARE IN GOOD CONDITION.

CONNECT AN EARTH (GROUND) WIRE TO THE AIRCRAFT STRUCTURE, ANY PLATFORMS, AND CASINGS OF ELECTRICALLY POWERED EQUIPMENT USED DURING THIS TASK.

ENSURE THAT SUITABLE FIRE FIGHTING EQUIPMENT IS AVAILABLE AND IS CAPABLE OF REACHING ANY PART OF THE AIRFRAME.

CAUTION: THERE MUST BE NO FUEL ON THE AIRCRAFT DURING BONDING CHECKS. THE OXYGEN SYSTEM, IF FITTED, MUST BE REMOVED.

UNLESS OTHERWISE INSTRUCTED, FOR BONDING AND INSULATION CHECKS OF EQUIPMENT AND PIPEWORK INSIDE THE FUEL TANKS, IT IS HIGHLY RECOMMENDED THAT THE TANKS MUST BE DRAINED AND VENTED PRIOR TO WORK COMMENCING.

A. Isolate power supplies

(1) Remove the main batteries (refer to 24-33-01, pb201).

(2) Remove the tail emergency battery (refer to 24-33-06, pb201).



(3) Ensure external ground supply is disconnected:-

(a) Close the ground supply connector flap door and secure in closed position with masking tape.

(4) Prominently tag the battery and ground supply locations with a CAUTION, as detailed in chapter 12-09-03, pb1.

2. Inspection - Visual Check of Bonding Jumpers

WARNING: START OF FUEL TANK SAFETY CRITICAL SECTION.

Each bond must be examined to ensure:-

(1) That it is not taut or sufficiently flexed as to foul adjacent structure.

(2) That it is firmly secured at both ends.

(3) That there is no corrosion and/or damage (eg. fretting of bonding lead) to the bond installation. Corroded bonding surfaces must be repaired, and corroded or damaged bonding leads must be replaced (refer to 20-09-05, pb1).

(4) That it does not restrict or foul movement of control rods, cranks, cables or other moveable equipment, either associated with, or in the vicinity of the bond.

WARNING: END OF FUEL TANK SAFETY CRITICAL SECTION.

3. Bonding Tests

The following tests should be carried out using a 4-wire low reading ohmmeter unless otherwise stated. The resistance of the bond must be measured from either termination to the nearest point on the aircraft structure.

NOTE: In the case of a reading which exceeds the specified value, determine the cause, rectify, and repeat the test.

(1) Check that the resistance between the following extremities does not exceed 0.05 ohms:-

(a) Nose to fin

(b) Nose to left and right wing tips

(c) Fin to wing tips, left and right

(d) Left to right wing tips.

NOTE: Where extremities are of composite construction tests should be made to nearest metallic structure.



(2) Check that the resistance between the following components and an adjacent part of the main airframe does not exceed 0.05 ohms:-

(a) All control surfaces

(b) All doors, panels, latches on the outside of the aircraft

(c) Each engine

(d) Each landing gear leg

(e) Main instrument panel

(f) Avionic instrument trays

(g) Each starter generator.


(3) Check that the resistance between the following items and an adjacent part of the main airframe does not exceed 1.0 ohm unless otherwise stated:-

(a) Fuel system

Before performing the following steps, ensure that a visual check of the bonding jumpers (refer to para. 2.) has been completed.

WARNING: FOR ELECTRICAL BONDING TESTS OF THE FUEL SYSTEM OR WHEN IN A FLAMMABLE VAPOUR ENVIRONMENT, A LOW READING ‘EXPLOSION PROOF’ OHMMETER SUCH AS THE BCD ELECTRONICS LIMITED MODEL MI-G-KIT OR EQUIVALENT (APPROVED FOR USE IN ENVIRONMENTS CLASSIFIED BY THE U.S. NATIONAL ELECTRICAL CODE AS DIVISION 1, CLASS 1, GROUPS A, B, C AND D) MUST BE USED.

NOTE: If a different ohmmeter from that specified previously is to be used, for alternative instructions, contact:-


Check the bonding of the fuel system as follows:-

1 Fuel tanks - all internal pipework.



WARNING: IF DISTURBED AND/OR DISASSEMBLED, THE BONDING LEADS ON THE FUEL VENT PIPES AT THE EXTERNAL FORWARD AND AFT TANK INTERFACES MUST UNDERGO A VISUAL CHECK (VCK), AFTER RE-ASSEMBLY.

2 Fuel tanks - each and every section of external fuel pipework including valves (refer to 12-10-28, pb1).

3 Fuel quantity indication system amplifier (0.05 ohms).

4 Booster pump body to aircraft structure.


(b) Hydraulic system

Before performing the following steps, ensure that a visual check of the bonding jumpers (refer to para. 2.) has been completed.

Check the bonding of the hydraulic system as follows:-

1 Reservoir and accumulator fill system - each and every section of pipework including valves.

2 Pump suction, pressure and case drain - each and every section of pipework including valves.

3 Flaps - each and every section of pipework including valves.

4 Brakes - each and every section of pipework including valves.

5 Landing gear - each and every section of pipework including valves.

6 Steering - each and every section of pipework including valves.

4. Aircraft to Ground Resistance

A. Check that the resistance between the main airframe and the ground

(1) Use a 500 volt Megger to measure the resistance between the main airframe and the ground. Make sure it does not exceed 10 Megohms, when the nose wheel is standing on a wet contact surface.

5. Insulation Resistance


A. Insulation resistance of float switch assembly (on-aircraft)

(1) Temporarily install any tank access panels removed in previous steps.



(2) Refuel the tank to the full level using the normal refuelling procedure (refer to 12-10-28, pb301), to ensure that the float switch flange is fully immersed in fuel.

(3) Perform a 500 Volt insulation resistance test between each of the pins in turn on the switch connector and the aircraft structure. Record the values.

NOTE: Refer to Figure 1 of 28-21-00, pb1.

(4) If the resistance measured is equal or less than 10 Megohms then the switch must be removed and replaced with a new or manufacturer overhauled assembly. refer to 28-21-21, pb201, and for limitations refer to 5-20-02, pb1.

(5) If the resistance measured is greater than 10 Megohms then:-

(a) Drain the tank, temporarily remove the tank access panels and vent the tank until the tank vapour space is considered acceptable to work in.

(b) Use the previously referred ‘explosion proof’ ohmmeter to measure the electrical resistance between the switch flange and the structure. Record the value.

NOTE: This will either be a value less than 20 ohms, ‘too big’, or ‘no go’ assuming that the previously specified bonding meter is used.

(c) If the value recorded is less than 20 ohms, then the previously recorded insulation resistance reading is valid and the float switch assembly has passed the test.

(d) If the value recorded is ‘too big’ or ‘no go’, the previously recorded insulation resistance reading may not be valid, then:-

1 Remove the float switch assembly from the tank. refer to 28-21-21, pb201.

2 Perform an additional insulation resistance bench test. Refer to para. 5.B.

B. Insulation resistance of float switch assembly (bench test)

(1) Set the switch assembly on a suitable insulation material, in a well ventilated area.

(2) Perform a 500 V insulation resistance test between each of the switch connector pins, in turn, and the switch mounting flange. Record the readings and evaluate as follows:-

(a) If the insulation resistance recorded is equal or less than 10 Megohms, then the switch assembly must be replaced with a new or manufacturer overhauled assembly. refer to 28-21-21, pb201, and for limitations refer to 5-20-02, pb1.

(b) If the insulation resistance recorded is greater than 10 Megohms, then the float switch assembly is functional and can be refitted. refer to 28-21-21, pb201.

(3) Install any access panels previously removed for venting.



AMM20-09-06 10.0.0.0TORQUE LOADING OF STRUCTURAL AND ATTACHMENT BOLTS/NUTS

1. General

This section contains information concerning standard torque requirements, which must be applied to ensure that components are properly secured, but not overstressed.

Throughout the aircraft, structural and attachment bolts/nuts which have had witness marks applied using red putty (Para 2.C.) have been torque tightened to the standard range; this range is in accordance with the appropriate table as follows (derived from Bombardier Aerospace, Shorts Process Specification PS904):

- Tightening Torques for BS A103 U.N.F. Nuts with A102, A108, A111, A113, A173, A212, (55 ton) Bolts (Refer to Table 1).

- Tightening Torques for BS A27 BSF Nuts with A102, A108, A111, A113, A173, A212, (55 Ton) Bolts (Refer to Table 2)

- Tightening Torques for Self-Locking Nuts with A102, A108, A111, A113, A173, (55 Ton) and Special 65 Ton Bolts (Refer to Table 3).

- Tightening Torques for Steel Threaded Fasteners (Non Self-Locking) (Refer to Table 4).- Tightening Torques for Steel Threaded Fasteners (Self Locking) (Refer to Table 5).

Bolts and nuts which have had witness marks applied using green putty, have been subjected to special torque considerations and are covered by special drawing instructions:

- Controlled Torque Tightening of Fuselage Located Attachments (Refer to 53-40-01, pb1.)- Controlled Torque Tightening of the Engine Mounting Frame Attachments (Refer to 54-40-01,

pb1.)- Controlled Torque Tightening of the Horizontal Stabilizer Attachment Nuts (Refer to 55-10-01,

pb201.)- Controlled Torque Tightening of the Elevator Attachment Nuts (Refer to 55-20-00, pb201.)- Controlled Torque Tightening of the Wing Strut Attachment Nuts (Refer to 57-00-16, pb201.)- Controlled Torque Tightening of the Centre-Wing to Fuselage Attachment Bolts (Refer to 57-

10-01, pb1.)

2. Standard applications

A. Installation of Bolts and Nuts

CAUTION: FAILURE TO CARRY OUT THE FOLLOWING INSTRUCTIONS COULD RESULT EITHER IN AN INADEQUATE CLAMPING LOAD, OR, IF THE CORRECT TORQUE LOAD IS EXCEEDED, IN DAMAGE TO THE THREADS WHICH MAY NOT BE OBVIOUS AT THE TIME BUT MAY CAUSE FAILURE OF THE JOINT LATER.

(1) Ensure that bolt and nut thread are free from grime or dirt. Trichlorethane may be used to remove temporary corrosion preventatives from non pre-lubricated fasteners.

(2) All holes must be in good alignment and the joint faces parallel.



(3) Kaylock (H14) and AS8600 self-locking nuts are pre-lubricated and are to be applied (without additional lubricant) to dry (cadmium plated) threads.

(4) Aeroshell Grease 8 (DEF STAN 91-54) must be applied to ordinary, thin, slotted and castellated nuts, the bolt threads and bearing faces between the nuts and washers, or below the bolt head as applicable. This is in addition to the application of standard jointing compounds to the bolt shank under head region and washer/component interface.

(5) In nacelle applications, the nut threads, bolt threads and the bearing faces between the nut and washers, or below the bolt head as applicable, may be lubricated with engine oil approved for the powerplant.

(6) The bolt length and washer thickness must be such that the nut will not engage the first incomplete thread next to the bolt shank.

(7) All nut threads must be engaged and the complete chamfer on the end of the bolt must protrude beyond the nut.

(8) Torque tightening of bolted assemblies involving non-captive nuts is to be accomplished by torquing the nut. Bolts in close ream or interference fit holes must not be installed by wrenching from the head side.

(9) Inadvertent over-tightening to greater than 10% in excess of the stipulated torque will require that the nut and bolt are discarded and replaced with new parts.

(10) When tightening castellated nuts, the nut is to be tightened to 10% below the required torque value, after which it is to be further tightened to the first opportunity to permit split pin installation. If alignment for split pin installation results in a torque level greater than 10% of the required value, both the nut and bolt are to be replaced.

(11) When using jointing compound between clamped faces, tightened joints are to be rechecked for tightness after a period of at least 10 minutes. Similarly, joints incorporating polysulphide sealants between clamped faces are to be rechecked for tightness after a lapsed time greater than 50% of the specified cure time.

(12) In a joint comprising more than two laminates, release torque and re-apply to allow for bedding down.

(13) Torque wrench application is to conform to the requirements of para 3. Pay particular attention to the setting and/or reading of torque wrenches when used in conjunction with an extension spanner.

(14) Ordinary, thin, slotted and castellated nuts must not be torque tightened more than three times.

(15) Self locking nuts must not be torque tightened more than twice unless the run-down torque required to overcome the locking device is proven to be in excess of the value given. Refer to Table 6.



B. Installation of Washers

(1) Washers should not be installed unless they are of the same type and quantity as originally designed.

(2) When only one washer is used, it will be installed under the unit bolt head or nut, wherever the torque is applied.

C. Application of witness marks

(1) When satisfied that the joints concerned have been tightened to the correct torque value, the torqued fasteners are to be identified by means of a torque stripe witness mark. Identification is to consist of a continuous/discontinuous stripe of tamper proof putty, approximately 3 mm (0.12 in.) wide, extending across the fastener and onto the adjacent structure. Refer to Figure 1.

(2) Where the external appearance of the aircraft may be affected, identification may be omitted

(3) Red putty is to be used to identify bolts torqued to standard values (this section). Green putty is used to identify bolts torqued to non-standard values (para 1.).

(4) Identification is to be applied to the nut whenever practical, otherwise the head of the bolt or screw is to be marked. Refer to Figure 1.

(5) If at any time, an identification stripe is found misaligned, indicating movement of the fastener after final torquing, the fastener is to be retorqued by backing off one full turn and retightening to the specified torque value, after which re-identification is required.

(6) Where subsequent priming or painting may obliterate the identification stripe, re-identification is unnecessary, providing the existing identification is intact prior to such priming or painting.



Stripe Identification of Torqued FastenersFigure 1



Tightening Torques for BS A103 U.N.F. Nuts with A102, A108, A111, A113, A173, A212, (55 ton) BoltsTable 1

Tightening Torques for BS A27 BSF Nuts with A102, A108, A111, A113, A173, A212, (55 Ton) BoltsTable 2

Tightening Torques for Self-Locking Nuts with A102, A108, A111, A113, A173, (55 Ton) and Special 65 Ton Bolts

Table 3

TYPE OF NUT CONTROLLED TORQUE VALUES lb in. (Nm) FOR LUBRICATED THREADS

10.32(0.19 in.) 1/4 in. 5/16 in. 3/8 in. 7/16 in. 1/2 in. 9/16 in. 5/8 in. 3/4 in.

Ordinary and Castle

27(3.05)

72 (8.13)

132 (14.9)

228 (25.8)

336 (38.0)

504 (56.9)

708 (80.0)

984 (111.2)

1620 (183.0)

Slotted 24(2.71)

54 (6.10)

96 (10.8)

162 (18.3)

216 (24.4)

336 (38.0)

454 (50.2)

648 (73.2)

1056 (119.3)

Thin 19(2.15)

48 (5.42)

84 (9.49)

150 (16.9)

222 (25.1)

330 (37.3)

456 (51.5)

648 (73.2)

1068 (120.7)

TYPE OF NUTCONTROLLED TORQUE VALUES lb in. (Nm) FOR LUBRICATED THREADS

1/4 in. 5/16 in. 3/8 in. 7/16 in. 1/2 in. 9/16 in. 5/8 in. 3/4 in.

Ordinary and Castle

54(6.10)

120 (13.6)

210 (23.7)

324 (36.6)

480 (54.2)

684 (77.3)

900 (101.7)

1524 (172.2)

TYPE OF NUT TYPE OF BOLT

CONTROLLED TORQUE VALUES lb in. (Nm) FOR PRE-LUBRICATED THREADS

10.32(0.19 in.) 1/4 in. 5/16 in. 3/8 in. 7/16 in. 1/2 in.

AS 8600 and Kaylock H14

55 ton 26(2.94)

84(9.49)

150(16.9)

270(30.5)

420(47.15)

804(90.8)

Special 65 ton

35(3.95)

108(12.2)

186(21.0)

330(37.3)

516(58.3)

984(111.2)



Tightening Torques for Steel Threaded Fasteners (Non Self-Locking)Table 4

NOTE: Silver plated nuts in combination with unplated bolts, unplated nuts in combination with silver plated bolts, and unplated nuts with unplated bolts.

Cadmium plated nuts with cadmium plated bolts, cadmium plated nuts with unplated bolts, and unplated nuts with cadmium plated bolts.

Tightening Torques for Steel Threaded Fasteners (Self Locking)Table 5

NOTE: Silver plated nuts in combination with unplated bolts, unplated nuts in combination with silver plated bolts, and unplated nuts with unplated bolts.

Cadmium plated nuts with cadmium plated bolts, cadmium plated nuts with

UNF THREAD SIZEBARE OR SILVER COATED THREADS CADMIUM COATED THREADS

Nm lb in Nm lb in

No. 6-32 1.13 10 0.90 8No. 8-32 1.69 15 1.13 10No. 10-32 3.95 35 2.82 250.2500-28 11.3 100 8.47 750.3125-24 19.2 170 15.3 1350.3750-24 33.9 300 26.6 2350.4375-20 50.8 450 40.7 3600.5000-20 85.4 755 65.0 5750.5625-18 107.0 950 84.1 7450.6250-18 153.0 1355 122.0 1080

UNF THREAD SIZEBARE OR SILVER COATED THREADS CADMIUM COATED THREADS

Nm lb in Nm lb in

No. 6-32 1.36 12 1.13 10No. 8-32 2.26 20 1.69 15No. 10-32 4.52 40 3.39 300.2500-28 11.3 100 10.2 900.3125-24 23.7 210 19.2 1700.3750-24 41.8 370 35.0 3100.4375-20 55.4 490 46.3 4100.5000-20 89.3 790 72.3 6400.5625-18 114.0 1010 93.8 8300.6250-18 164.0 1450 136.0 1200



unplated bolts, and unplated nuts with cadmium plated bolts.

Maximum Prevailing or Run-Down Torque for Self-Locking Nuts and Wire Thread InsertsTable 6

UNF THREAD SIZEMAXIMUM RUN-DOWN TORQUE

lb in Nm

No. 6-32 6.0 0.68No. 8-32 9.0 1.01No. 10-32 18.0 2.030.2500-28 30.0 3.390.3125-24 60.0 6.780.3750-24 80.0 9.040.4375-20 100.0 11.30.5000-20 150.0 17.00.5625-18 200.0 22.60.6250-18 300.0 33.9



3. Torque Wrench

A. Application

(1) Refer to Figure 2. On either dial type or 'breaking' type wrenches, torque pressure should be applied at 90° to the centre line of the wrench, with one hand only, the thumb gripping the handle and not lying along it.

(2) Ideally, measurement of torque when using dial/scale type wrenches should be in the middle to upper range of scale to ensure maximum accuracy.



Figure 2



B. Extension Spanners

(1) When extension spanners are used they should be in line with the torque wrench, Refer to Figure 2.

(2) When extension spanners are used in conjunction with dial/scale torque wrenches the applied load will be greater than that specified when using the torque wrench only. To ensure that the indicated torque on the dial/scale provides the actual torque required, the following formula must be used:-

Required torque setting = actual torque required X (W / W + E)

W = distance between centres of torque head and handle of wrench.

E = length of extension spanner between centres

Example: To calculate the torque setting for a specified load of 132 in. lbs. when using a 6 inch extension spanner with a 12 in. long (10 in. between centres) wrench apply the formula as follows:-

132 x (10 / 10 + 6) = 82.5 in. lb

NOTE: When substituting values in the formula they should be kept in the same unitary system. Refer to Table 7.

(3) If a 'breaking' type torque wrench is used in conjunction with an extension spanner, the extension spanner must be interposed between the wrench and the setting rig during the setting procedure.

4. Torque conversion

It is often advantageous to change a torque specification from lbf.in. to lbf.ft. or kgf.m. or any other possible values referred to in the following chart.

Torque Conversion ChartTable 7

GRAMS F INCHES

OUNCES F INCHES

POUNDS F INCHES

POUNDS F FEET

KILOGRAM F CENTIMETRES

KILOGRAM F METERS

NEWTON METERS

7.09 0.2514.17 0.5021.26 0.7528.35 1113.40 4 0.25226.80 8 0.50453.60 16 1 1.15 0.0115 0.1129

96 6 0.50 6.91 0.069 0.677



192 12 1 13.82 0.138 1.355384 24 2 27.64 0.276 2.712576 36 3 41.46 0.415 4.067768 48 4 55.28 0.553 5.423960 60 5 69.10 0.691 6.779

72 6 82.92 0.829 8.13484 7 96.74 0.967 9.49096 8 110.56 1.106 10.846

108 9 124.38 1.244 12.202120 10 138.20 1.382 13.548

GRAMS F INCHES

OUNCES F INCHES

POUNDS F INCHES

POUNDS F FEET

KILOGRAM F CENTIMETRES

KILOGRAM F METERS

NEWTON METERS



AMM20-09-07 11.0.0.0TORQUE TIGHTENING OF ELECTRICAL TERMINALS

1. General

All electrical terminals and connections should be subjected to controlled torque tightening to prevent overtightening and ensure good electrical contact.

Torque Values for Unified Thread TerminalsTable 1

NOTE: Tolerances on quoted figures is ± 5%

Torque Values for Metric Thread TerminalsTable 2


Torque Values for BA Thread TerminalsTable 3


2. Procedure

A. Preparation

(1) All threads must be clean and free from dirt etc.

(2) Thickness of washer, lugs etc., on terminals should be such that the nut or screw is not forced onto thread run-out when tightened.

(3) Torque applied should be within middle range of the torque spanner selected, to ensure maximum accuracy.

(4) Where special adapters are required for accessibility the spanner/adapter should be calibrated by the relevant inspection facility.

(5) Should the wrench selected be of the pre-set variety (which slip when the required torque is applied), exercise care to prevent violent recoil as it returns to its original position. Should violent recoil occur, slacken the terminal and retighten.

Terminal Diameter No. 4 No. 6 No.8 No.10 1/4 in. 5/16 in. 3/8 in.Torque Ib.in. 3.5 9.0 15.0 22.0 45.0 95.0 110.0

Terminal Diameter 5mm 8mm 10mm 12mmTorque Ib.in. 22.0 95.0 110.0 132.0

Terminal Diameter 8 BA 6 BA 4 BA 2 BATorque Ib.in. 4.0 7.0 12.0 24.0



(6) In a joint comprising more than two laminates, release the applied torque, then re-apply to allow for bedding down.

(7) Carefully check to ensure no gap remains under the nut or screw head or between laminate faces, to avoid subsequent bedding down and loosening of the joint.

NOTE: Preset torque spanners for Ward Brooke terminal blocks are detailed as tool T-20-04 in Chapter 20 of the Illustrated Tool and Equipment Manual.




AMM20-09-08 12.0.0.0TEMPORARY REPLACEMENT OF DAMAGED RIGID PIPES BY FLEXIBLE PIPES - MAINTENANCE PRACTICES

1. General

Fractured rigid pipe assemblies may be replaced temporarily by flexible hose assemblies of appropriate construction, diameter and length subject to the following restrictions.

A. Limitations

(1) Jury installations are temporary and must be replaced by definitive replacement pipe assemblies at the earliest opportunity, not exceeding 200 flights from the time of failure.

(2) It is essential that 'U' traps are avoided in the pitot static system and inverted 'U' traps in the fuel system.

(3) Ensure that the minimum bend radii specified on the hose is not exceeded.

B. Approved materials

(1) If a replacement hydraulic pipe (3000 psi service) is not available the substitute flexible hose assembly must conform to MIL-H-38360B amendment 1. The hose assembly must have a chafe guard.

(2) Hydraulic suction and return pipes must be replaced with flexible hose conforming to MIL-H-27267B. The hose size designation must correspond to the outside diameter of the fractured pipe and a chafe guard or fire sleeve fitted depending on location.

(3) Fractured fuel pipes with a rating of 1000 psi max. must be replaced with flexible hose assemblies conforming to MIL-H-83797.

(4) Fractured pitot static and other low pressure pneumatic lines with a rating of 150 psi must be replaced with flexible hose assemblies conforming to MIL-H-5593 or MIL-H-8794.


AMM20-09-10 13.0.0.0WIRE LOCKING OF THREADED ITEMS DESCRIPTION & OPERATION

1. Scope

The following information defines the requirements for wire locking practice.

For Aerospace purposes the locking wire and the locking wire hole sizes are in accordance with Def. Stan. 95-7/1.

Normally, wire to D.T.D. 189A is to be used, or second choice AMS 5689A. Both are corrosion resisting steel for temperatures up to 600°C.

NOTE: Locking wire should be supplied to AS44725.

Wire to D.T.D. 5087 is only to be used where high temperature applications necessitate or where, for safety reasons it is considered desirable to use only one type of wire throughout an equipment or installation as the wire materials are not interchangeable. Wire diameters are 0, 54/0, 46 mm (0.021/0.018") and 0, 84/0, 76 mm (0.033/0.029").

2. Definition

Wire locking is the method of securing together two or more items with a wire which is fitted in such a manner that any tendency for an item to loosen will be counteracted and prevented by the wire locking.

3. Wire Locking Practice

A. Procedure

(1) Ensure all connections are tight before locking, cable, wires and similar items which are connected by adjustable end fittings, turnbuckles etc. must be correctly tensioned; ensure that the threads are in safety and lock nuts are tight before locking.

(2) Locking wire is not to be re-used and must be renewed whenever disturbed.

(a) Two methods of fitting locking wire are illustrated:

1 The single strand method.

2 The double twist method.

(b) The single wire method is to be used where appropriate such as in a closely spaced, close geometrical pattern (Triangle, Square, Rectangle, Circle) on items in electrical systems, and in places that would make the single wire method more advisable. In such cases the single wire will be limited to the pattern or group of similar items. (Refer to Figure 1 - Detail 'C'.).



(c) The maximum number of items to be wire locked together in a series by the single strand method will be determined by the number of items that can be wire locked by a 600 mm (24.0") length of wire.

(d) In the double twist method, one piece of wire is threaded through the locking wire hole to approximately mid-length of the wire, the two strands so formed being twisted together. One twist is defined as being produced by twisting the wires through an arc of 180° and is equivalent to half of a complete turn. For items with holes drilled across the corners, (Refer to Figure 1 - Detail 'A.') and for holes drilled diametrically. Refer to Figure 1 - Details 'B', 'D', 'E', 'F', 'G', 'H' & 'I'.

(e) Three items is the maximum number in a series to be locked together by the double twist method.

(f) Wire is to be pulled taut while being twisted and the number of twists (per 25 mm) for each material and diameter is given in ( Refer to Table 1.).

Table 1

(g) Caution must be exercised during the twisting operation to keep the wire taut without over-stressing or allowing it to become nicked, kinked, or otherwise mutilated, except the abrasions normally caused by commercially available pliers which is acceptable.

(h) Locking wire must not be installed in such a manner as to cause the wire to be subjected to, or cause, chafing and fatigue through vibration or additional tension other than the tension imposed on the wire to prevent loosening of the items being locked.

(i) Wire locking of flexibly mounted components or assemblies are to be arranged, that neither the characteristics of the mounting or the efficiency of the locking is impaired in operation.

(j) Lengths of wire between points of attachment must be kept to a minimum and not be greater than 3.15 in. (80 mm). A minimum clearance between unsupported lengths of locking wire and moving parts of 0.59 in. (15 mm) is required.

(k) In adjacent items, the line of approach of the locking wire should be as near tangential as possible to the parts being locked, and the locking wire installed in such a manner that the strand through the hole will have a tendency to tighten the

Lockwire Number of Twists per 25 mm (0.98")Spec Dia. (mm)

D.T.D. 189A 0.5 (0.020") 0.8 (0.032")

10 to 136 to 12

D.T.D. 5087 0.5 (0.020") 0.8 (0.032")

5 to 74 to 6



item being locked. Care should be taken to differentiate between items with left and right hand threads.

(l) The locking wire is to be inserted through the hole in the first item and bent round the head of the item. The direction of wrap and twist of strands will be such that the loop around the items comes under the strand protruding from the hole, so that the loop will stay down and will not tend to slip up and leave a slack loop. Refer to Figure 1 - Details 'A' to 'H'.

(m) Twist the strands while taut until the twisted part is just short of the hole in the next unit to be locked. The twisted portion should be within approximately 0.12 in. (3 mm) of the hole in either item.

(n) Insert the uppermost strand through the hole in the second item and follow the procedure in para 3.A.(2)(l) above. If there are more than two items in the series, repeat the above procedure. After wiring the last item, continue twisting the wires to form a pigtail of a minimum of three twists and cut off the excess wire.

(o) Bend the pigtail in toward the unit in such a manner as to prevent it becoming a snag, and where possible tucking it under another wire to eliminate sharp metal spikes, and so minimize hazard from electrical discharge. This is especially important near fuel tanks and any regions needing frequent inspection.

(p) Where an anchor lug is used, the wiring is to commence at the lug which will be aligned with the wire in such a manner that there is no tendency to impart radial movement to the lug. Refer to Figure 4 - Details 'A' and 'B'.

(q) Where the wire traverses the body of the item to be locked, the angle of approach of the wires to the longitudinal axis of the item must not be less than 45°, turnbuckles excepted. Refer to Figure 2 - Detail 'B'.

(r) Where a pipe adaptor is used, the pipe union nut is to be wire locked to the component - not to the adaptor. Refer to Figure 3 - Detail 'B'. Adjacent union nuts may be locked together. The same wire must not lock more than two union nuts.

(s) The use of lead seals attached to locking wire is prohibited in future design work on aerospace vehicles and items of equipment used in aerospace vehicles.

(t) Particular care must be taken when locking is associated with possible movement in two places.



Figure 1



Figure 2



Figure 3



Figure 4



Figure 5



Figure 6



Figure 7



AMM20-09-11 14.0.0.0BORESCOPE INSPECTIONS - DESCRIPTION & OPERATION

1. General

Visual inspection is a non-destructive testing method used to detect various types of surface flaws such as cracks, corrosion, contamination, damaged fasteners, etc.

Visual inspection can be done with the naked eye, magnifying aids, or precision optical equipment. Optical equipment, such as rigid or flexible borescopes, can be used to inspect inaccessible areas such as internal surfaces of tubes, bore and enclosed areas.

2. Description

A. Magnifiers

Hand-held magnifiers (1.5X to 10X) can be used for more detailed visual inspections and to increase the rate of inspection.

B. Rigid Borescopes

Rigid borescopes (Refer to Figure 1) are limited to applications with a straight-line path between the observer and the inspection surface.

A typical basic rigid borescope has the following features:

- Optical lens(es) incorporated in a fixed, rigid tube.The tube can have a variety of lengths from 0.5 to 100 ft (0.15 to 30.48 m), and diameters from 0.16 to 2.75 in (0.41 to 6.99 cm).

- Magnification of 3X to 4X.For borescopes with higher power, up to 50X is available.

- Built-in illumination system or light source.The illumination system can either be a distal lamp or a light guide bundle. The various features can include orbital scan, various viewing heads and adjustable focusing of the objective lens.

- Field of view of approximately 55 degrees.Different fields of view can be obtained by simply changing the rigid tube.

There are five typical directions and field of view with rigid borescopes as follows:

- Direct- Right angle- Forward oblique- Retrospective- Circumferential.

Apr 24/0320-09-11 Page 1EFFECTIVITY: All


C. Flexible Borescopes

Flexible borescopes (Refer to Figure 2) are primarily used to inspect surfaces that do not have a straight path to the point of observation.

A typical flexible borescope has the following features:

- A light guide bundle.

- An objective lens.

- An image guide bundle.This is used to carry the image formed by the objective lens back to the eyepiece for viewing.

- Interchangeable viewing heads.

- Remote controls for articulation of the distal tip (interchangeable).

These borescopes have a range of diameters from 0.055 to 0.50 in (0.140 to 1.27 cm) and lengths up to 40 ft (12 m). The field of view is controlled by articulating the distal tip and is typically 40 to 60 degrees.

NOTE: In cases where areas are difficult to access it can be necessary to use a specially shaped rigid tube. The tube is used to guide the flexible borescope to the inspection area.

D. Additional Inspection Aids

Other aids such as adjustable viewing mirrors and a flashlight may be necessary to accomplish a visual inspection.

3. Operation

A. Preparation of Inspection Surfaces

Where necessary, tasks such as the removal of access panels and/or components are done before the inspection.



WARNING: OBEY THE PRECAUTIONS THAT FOLLOW WHEN YOU USE SOLVENTS:USE APPROVED EYE, MOUTH AND BODY PROTECTION.DO THE WORK IN AN AREA THAT HAS A GOOD FLOW OF CLEAN AIR.MAKE SURE THAT THE AREA HAS NO SPARKS, FLAMES, OR HOT SURFACES.OBEY THE MANUFACTURERS INSTRUCTIONS.DO NOT LET THE SOLVENT TOUCH YOUR SKIN, EYES, OR MOUTH.IF IRRITATION OCCURS, GET MEDICAL AID IMMEDIATELY.SOLVENTS ARE POISONOUS AND CAN CAUSE INJURY.

It is essential that the surfaces to be inspected are as clean as possible. The surfaces must be free of grease, oil, dirt, scale, or other contaminants that may prevent the surface flaws fro being seen.

B. Inspection Procedure

Ensure the inspection area is well illuminated.

Do a visual inspection of the area for signs of cracks, corrosion, and other types of surface defects as specified in the applicable documentation.

NOTE: A crack usually appears as a fine dark line on a painted surface. It may consist of a single or multiple lines that or jagged or branching.

Ensure that a fine line is not due to an entrapped hair or threadlike fibre.

Discoloration, bulging, and/or a white powder (corrosion product) on the paint surface can be signs of corrosion.

Record and report all relevant indications.



Rigid BorescopesFigure 1



Flexible BorescopesFigure 2




AMM20-09-12 1.0.0.0FUEL TANK ACCESS AND CLOSE-OUT - MAINTENANCE PRACTICES

1. General

WARNING: THIS MAINTENANCE PROCEDURE IS A FUEL TANK SAFETY CRITICAL ITEM, AND CLASSIFIED AS A CRITICAL DESIGN CONFIGURATION CONTROL LIMITATION (CDCCL) BY THE AIRCRAFT OEM (CHAPTER 5-20-02, PB1).THE CONTENTS OF THIS PROCEDURE MUST BE STRICTLY ADHERED TO AND MUST NOT BE ALTERED TO ENSURE THAT UNSAFE CONDITIONS DO NOT DEVELOP BY MAINTENANCE, MODIFICATION OR REPAIR.

2. Fuel Tank Access

WARNING: ENSURE THAT THE FOLLOWING FIRE PRECAUTIONS ARE OBSERVED WHEN WORKING ON THE FUEL TANKS:-

CHECK THAT ALL ELECTRICAL SUPPLIES IN THE AIRCRAFT ARE OFF. REMOVE THE BATTERIES AND ENSURE THAT GROUND SUPPLY IS NOT CONNECTED TO THE AIRCRAFT.

ENSURE THAT ALL HANDLAMPS OR TORCHES USED TO ILLUMINATE THE INTERIOR OF THE TANKS ARE OF AN APPROVED ‘EXPLOSION PROOF’ DESIGN SUITABLE FOR USE IN ENVIRONMENTS CLASSIFIED BY THE US NATIONAL ELECTRICAL CODE AS DIVISION 1, CLASS 1, GROUPS A, B, C, & D, AND ARE IN GOOD CONDITION.

CONNECT AN EARTH (GROUND) WIRE TO THE AIRCRAFT STRUCTURE, ANY PLATFORMS, AND CASINGS OF ELECTRICALLY POWERED EQUIPMENT USED DURING THIS TASK.

ENSURE THAT SUITABLE FIRE FIGHTING EQUIPMENT IS AVAILABLE AND IS CAPABLE OF REACHING ANY PART OF THE AIRFRAME.

A. Isolate power supplies

(1) Remove the main batteries (refer to 24-33-01, pb201).

(2) Remove the tail emergency battery (refer to 24-33-06, pb201).

(3) Ensure external ground supply is disconnected:-

(a) Close the ground supply connector flap door and secure in closed position with masking tape.

(4) Prominently tag the battery and ground supply locations with a CAUTION, as detailed in chapter 12-09-03, pb1.

Jan 31/1220-09-12 Page 202EFFECTIVITY: All


3. Fuel Tank Close-out

WARNING: AFTER ALL INTERNAL-TO-TANK MAINTENANCE, FUEL TANK CLOSE-OUT CHECKS MUST BE CONDUCTED.

When maintenance procedures that require tank access have been completed, do an internal inspection for the conditions that follow, in case these features have been accidently disturbed:-

(1) Make sure that both fuel vent system bonding leads in cell 2 of the forward fuel tank are securely installed and do not foul adjacent pipes/structure.

(2) Make sure that the sensor cables for the fuel contents gauging system (FCGS) and for the float switches, which go into or through the tank, are not in contact with the adjacent structure. Replace any broken cable attachments.If it has been necessary to remove any cable attachment feature (ty-wraps) to facilitate internal-to-tank maintenance, accomplish a detailed visual inspection of the cable local to each disturbed attachment to ensure the cable has not been accidently damaged before replacing each ty-wrap.

NOTE: Refer to 12-10-28, Figure 301, for float switch location.

(3) Make sure that there are no unwanted or foreign objects inside the tank. Use a vacuum hose to remove, if necessary.



AMM20-09-13 1.0.0.0ELECTRICAL WIRING - MAINTENANCE PRACTICES

1. General

WARNING: THIS MAINTENANCE PROCEDURE IS A FUEL TANK SAFETY CRITICAL ITEM, AND CLASSIFIED AS A CRITICAL DESIGN CONFIGURATION CONTROL LIMITATION (CDCCL) BY THE AIRCRAFT OEM (REFER TO 5-20-02, PB1).THE CONTENTS OF THIS PROCEDURE MUST BE STRICTLY ADHERED TO AND MUST NOT BE ALTERED TO ENSURE THAT UNSAFE CONDITIONS DO NOT DEVELOP BY MAINTENANCE, MODIFICATION OR REPAIR.

The integrity of the Fuel Contents Gauging System (FCGS) wiring has been assessed as being a critical design feature in preventing a potential ignition source from reaching the fuel tanks and causing an explosion.

The following maintenance practices must be followed to ensure the integrity of the FCGS wiring is not compromised, either during scheduled or unscheduled maintenance, or when incorporating modifications:-

- FCGS co-axial cables inside the fuel tank and the wiring bundles/harnesses in which they are incorporated external to tank, are subject to mandatory inspections (refer to 5-20-01, pb601).

- Damaged FCGS co-axial cable assemblies must not be repaired. They must be replaced.If damage is identified on any wire that is part of a bundle/harness that contains FCGS cables, the damage must be reported. For assessment and authorisation of the necessary corrective action, contact:-


- If incorporating a modification, the routing of additional electrical power/signal cables is not permitted within six inches of the FCGS cables (refer to 5-20-02, pb1 and chapter Figure 201 (Sheet 1)).

- If incorporating a modification, it is not permissible to route any additional power/signal cables within the fuel tank, or to clip such cables to the outside surface of the fuel tank or to fuel pipes (refer to 5-20-02, pb1).

- If performing maintenance or incorporating design changes in the vicinity of a wire bundle/harness that incorporates FCGS cables, adequate protection must be used to prevent accidental damage or contamination of the wire bundle/harness and an inspection must be performed after completion of these tasks to assess the integrity of the FCGS cables (refer to 5-20-02, pb1 and chapter Figure 201 (Sheet 1)).



- A wire bundle/harness that contains FCGS cables should not be divided unless absolutely necessary. If a wire bundle has to be divided, care must be taken not to stress the cables as this may cause damage.It is preferred practice that replacement cables are installed without disturbing the existing wire bundle/harness and that replacement cables are run external to the bundle with due reference to the CDCCL’s established in refer to 5-20-02, pb1.



AMM20-09-14 1.0.0.0OPERATING CABLE END FITTINGS - MAINTENANCE PRACTICES

1. Inspection/Check

Refer to Figure 201.

A. Inspect a cable end fitting

Special tools and equipment:

Magnifying equipment (X20)Rigging pins (if required)

(1) Locate the associated end fitting to be inspected.

NOTE: Disassembly of the cable at the turnbuckle joint is not required for this inspection, however, if an end fitting is suspect, it will assist further detailed examination.

(2) Remove (if fitted) the vinyl polymer or polypropylene type ident marker from the cable assembly.

(3) Use a minimum amount of solvent cleaner to carefully remove any residual adhesive from the end fitting.

NOTE: Record the part number of the affected cable assembly in the aircraft log book, for reference.

(4) Use a dry cloth to remove any protective grease from the turnbuckle and cable end fitting.

(5) Clean (if required) the end fitting with a cloth and the minimum amount of solvent cleaner.

NOTE: Make sure that the solvent cleaner does not get on the wire rope cable.

(6) Inspect the cable end fitting(s) for evidence of pitting/corossion or cracking with the magnifying equipment, as follows:-

(a) Give particular attention at the swaged area of the fitting, the radii where the fitting changes dimension and to areas that may have been covered by identification sleeves.

NOTE: Any pitting/corrosion of the fitting is considered unacceptable.

Any corrosion found at the end of the cable where it is joined to the fitting is considered unacceptable.

Any crack found in the fitting is considered unacceptable.

(7) If pitting/corrosion or cracking is evident, replace the cable assembly before further flight.



(8) Perform any associated rigging instructions.

(9) Perform any associated Duplicate Inspection for security of locking devices and full and free movement on that part of the system that is disturbed as a result of the inspection, or where any cable assembly has been replaced.

(10) Perform subsequent inspection of new cables as recommended in the associated section of the Maintenance Programme.

(11) If pitting/corrosion or cracking is not evident, re-apply the cable lubricant as detailed in 12-22-09, pb201.

(12) Perform subsequent inspection of existing cable end fittings as recommended in the associated section of the Maintenance Programme.



Control Cable End Fittings Fitted with Turnbuckle - TypicalFigure 201 (Sheet 1)

Typical Control Cable End Fitting Fitted to Cable - With Evidence of Pitting/CorrosionFigure 201 (Sheet 2)

END FITTING MS21260 END FITTING MS21260 TURNBUCKLE



End Fitting with Severe Pitting/Corrosion - Resulting in Cracking on the Swaged ShoulderFigure 201 (Sheet 3)

End Fitting with Severe Pitting/Corrosion - Resulting in FailureFigure 201 (Sheet 4)

Aug 10/0920-09-15 Page 601EFFECTIVITY: All


AMM20-09-15 1.0.0.0EWIS ZONAL INSPECTION REQUIREMENTS - INSPECTION/CHECK

1. General

This maintenance procedure defines how a general visual inspection of aircraft zones containing electrical wiring interconnection system (EWIS - refer to Recommended Maintenance Programme, Section 5-28-01) should be accomplished, and applies to both the stand alone GVI’s and zonal GVI’s established within the Shorts Recommended Maintenance Programme.

The Enhanced Zonal Inspection Programme for the aircraft EWIS is a procedure by which the aircraft is examined on a scheduled basis. The programme makes sure that all EWIS, and other installations that can affect EWIS, receive sufficient inspection for correct installation and general condition.

2. Explanation

The aircraft consists of areas divided (internally and externally) into major zones, major sub-zones and zones in accordance to ATA Specification 100. Zonal tasks include one or more than one zone, for inspection purposes.

To find zone, access panel and aircraft station data, refer to chapter 6-30-00, pb1.

3. Zonal Inspection

Zonal Inspections are General Visual Inspections (GVI). The only inspection aids necessary are a flashlight and an inspection mirror. You must remove the seats, carpets, fairings, doors, access/trim panels in the zone, as necessary, to complete the Zonal Inspection. You must sufficiently lift the insulation material to do the structural inspection when necessary. Do the Zonal Inspection within arms-reach distance.

Section 5-28-01 of the Shorts Recommended Maintenance Programme defines fully the difference between a zonal and a stand alone GVI.

A. Tools & Equipment

B. Job Set-Up

(1) If necessary, remove the applicable access panels, fairings or doors.

(2) Sufficiently lift the insulation material to do the structural inspection when necessary.

Light Source Commercially AvailableMirror Commercially AvailableMaintenance Stand (if necessary) Commercially Available



C. Procedure

Do a general visual inspection of the zonal area(s) as follows:

NOTE: Use a mirror and light source as inspection aids when necessary.

(1) Examine the equipment, the structure, all connectors and control cables, as applicable, for:

(a) Cleanliness. Make sure the area is clean.

(b) Damage, cracks, deterioration of protection treatment and corrosion.

(c) Signs of wear, chafing, dents, loose or damaged fasteners, distortion, fouling, bowing, scoring and fraying.

(d) Correct installation of control rods, pulleys, wiring harnesses, electrical bonding, ground studs and tubing.

(e) Correct installation of connectors and backshells. Make sure that no red witness bands are visible.

(f) Correct installation of those connectors and backshells, with other forms of lightning and high intensity radiated fields (HIRF) protection.

(g) Signs of fluid leakage, overheating and unusual discoloration.

(h) The correct operation of the drain holes. Make sure that the drain holes are clean, not blocked, and that the area is not moist.

(i) Correct installation of insulation blankets. Make sure that the insulation blankets do not show signs of damage (e.g. cuts or rips) or deterioration. Make sure that the insulation blankets are not contaminated with lint, dust, grease or liquids.

(j) Examine the access panels, fairings or doors removed for access.

(2) Examine the applicable composite structure/material for:

(a) Cleanliness. Make sure the area is clean.

(b) Discoloration because of overheating.

(c) Do a “tap” test to examine the composite structure for signs of delamination.

(d) Foreign matter, signs of scratches, crazing, cracks, blisters, dents, orange peeling, pitting, air bubbles, porosity, resin-rich and resin-poor areas, and wrinkles.

(e) Correct installation of control rods, pulleys, wiring harnesses, electrical bonding and tubing.



(f) The correct operation of the drain holes. Make sure that the drain holes are clean, not blocked, and that the area is not moist.

(3) In the areas that follow, examine the elements of the electrical wire interconnection system (EWIS) for:

(a) Wire/Wire Harnesses

1 Signs of contact/chafing between wire bundles, or between wire bundles and structure.

2 Sagging wire bundles. Make sure that wire bundles are correctly supported and secured.

3 Damaged wires. Make sure that there is no signs of mechanical impact, overheating or localized chafing.

4 Missing or incorrectly installed lacing tape/cable ties.

5 Deformed or incorrectly installed wiring protection sheaths or conduits.

6 Damage (rubbing) where the end of the sheath meets the end-attachment device.

7 Missing or damaged grommets.

8 Dust and lint accumulation.

9 Surface contamination by metal shavings (swarf).

10 Contamination by liquids.

11 Deterioration of previous repairs (e.g. splices).

12 Deterioration of production splices.

13 Inappropriate repairs (e.g. incorrect splices).

14 Inappropriate attachments to or separation from fluid lines.

(b) Connectors

1 External corrosion on receptacles.

2 Broken backshell tail.

3 Missing rubber pad or packing on backshell.

4 Lack of backshell wire-securing device.



5 Broken fool-proofing chain.

6 Missing or broken safety wire.

7 Signs of overheating (discoloration) on terminal lugs/blocks.

8 Misalignment of torque stripe.

(c) Switches

1 Damaged rear protection cap.

2 Secure and in place.

(d) Ground Points

1 Corrosion.

(e) Bonding Braids/Bonding Jumpers

1 Broken or disconnected braids.

2 Corroded or broken multiple strands.

(f) Wiring Clamps or Brackets

1 Corrosion.

2 Damage (Broken, missing, bent or twisted clamps or brackets).

3 Faulty attachment (bad attachment or fastener missing).

4 Unstuck or detached.

5 Damaged protection/cushion.

(g) Supports (Rails or Tubes/Conduit)

1 Damage (broken or deformed).

2 Fastener missing.

3 Missing edge protection on rims of feed-through holes.

4 Damaged racetrack cushion.

5 Obstructed drainage holes (in conduits).

(h) Circuit Breakers, Contactors or Relays

1 Signs of overheating (discoloration).



2 Signs of arcing.

D. Close Out

(1) Remove all tools, equipment, and unwanted materials from the work area.

(2) Install the insulation material lifted for access.

(3) Install the applicable access panels, fairings or doors removed for access.



AMM20-09-16 1.0.0.0ELECTRICAL WIRING INTERCONNECTION SYSTEM (EWIS) - MAINTENANCE PRACTICES

1. Cleaning of the EWIS

A. General

The maintenance procedure that follows is for the cleaning of the EWIS. The cleaning is applicable to the Zonal Inspections that have been highlighted by the EWIS Inspection Programme as requiring EWIS cleaning. The intent of the cleaning is to remove loose combustible material such as dust and lint.

B. Tools and Equipment

C. Consumable Materials

D. Reference Information

E. Job Set-Up

WARNING: REMOVE ALL ELECTRICAL POWER FROM THE AIRCRAFT BEFORE YOU DO MAINTENANCE. PUT WARNING PLACARDS AT THE EXTERNAL POWER RECEPTACLE AND IN THE FLIGHT COMPARTMENT. THIS IS NECESSARY TO PREVENT ELECTRICAL SHOCKS TO PERSONS AND DAMAGE TO THE EQUIPMENT.

(1) De-energize the aircraft electrical systems (refer to 12-09-03, pb1).

Approved mask with air filters Commercially availableApproved safety goggles Commercially availableContainer, metal Commercially availableVacuum cleaner - dry/wet Commercially availableSoft bristle brush Commercially available

Solvent - Isopropyl AlcoholWiper cloth - white cotton (lint-free)Protective gloves - neoprene

Electrical Supply on Ground - General Precautions 12-09-03, pb1, para.3



WARNING: OBEY THE MANUFACTURER’S MATERIAL SAFETY DATA SHEETS FOR CONSUMABLE MATERIALS. IF YOU DO NOT DO THIS, IT CAN CAUSE INJURIES TO PERSONNEL.

HAVE A GOOD FLOW OF CLEAN AIR AND APPROVED BODY PROTECTION WHEN YOU USE SOLVENTS. DO NOT GET SOLVENTS ON YOUR BODY OR BREATHE THE FUMES. KEEP FLAMES AND SPARKS AWAY FROM THE AREA. MANY SOLVENTS ARE POISONOUS AND FLAMMABLE.

(2) Obey the safety precautions that follow:

(a) Put on rubber gloves and safety goggles, and wear a mask.

(b) Do not touch the solvent with your skin. If your skin touches the solvent, clean the skin with warm water and soap.

(c) Make sure that there is a sufficient flow of clean air when you use the solvent.

(d) Keep the solvent away from any source of ignition.

(e) Refer to the manufacturer’s Material Safety Data Sheet (MSDS) for the applicable safety data on all the specified material.

F. Procedure

CAUTION: BE CAREFUL WHEN YOU CLEAN THE EWIS. IF YOU ARE NOT CAREFUL, YOU CAN CAUSE DAMAGE TO THE EWIS.

BE CAREFUL WHEN YOU CLEAN EWIS ADJACENT TO INSULATION BLANKETS. IF YOU ARE NOT CAREFUL, YOU CAN CAUSE DAMAGE TO THE INSULATION BLANKETS.

BE CAREFUL WHEN YOU CLEAN IN AREAS OF DENSE ELECTRICAL WIRING. CLEAN AS MUCH OF THE CONTAMINATION FROM THE WIRES AS POSSIBLE, BUT DO NOT MOVE THE WIRES. IF YOU ARE NOT CAREFUL, YOU CAN CAUSE DAMAGE TO THE ELECTRICAL WIRING.

(1) Clean the EWIS of the applicable zone as follows:

(a) Use a vacuum cleaner with a soft brush attachment to carefully remove dust and lint from the EWIS and adjacent areas.



(b) Use a soft bristle brush to carefully dislodge any debris from the EWIS and adjacent areas

NOTE: If you find fluid leakage on the EWIS, use a clean, lint-free cloth to carefully remove the fluid from the EWIS.If necessary, use a clean, lint-free cloth, lightly moist with isopropyl alcohol to remove accumulated fluid residue.

It is not necessary to remove all the contamination from the EWIS. You must remove a sufficient amount of contamination so that the possibility of combustion has been significantly reduced.

(2) If any solvent is spilled, dry the area with a lint-free cloth before the solvent evaporates.

G. Close Out

(1) Dispose of the contaminated solvent and wiper cloths according to your local government health and safety regulations.



AMM20-09-17 1.0.0.0FLIGHT COMPARTMENT PANEL 1C - EWIS - GENERAL VISUAL INSPECTION

1. General


B. Job Set-Up

(1) Remove and retain the studs or bolts, and washers that attach access panel 121AZ (refer to chapter 6-30-00, Figure 3 and AIPC chapter 53-20, Figures 0001, 0001A, 0002 or 0003, as appropriate).

(2) Remove the left main battery (refer to 24-33-01, pb201).

(3) Remove and retain the bolts that attach the Panel 1C cover.

C. Procedure

Do a general visual inspection of Panel 1C as follows:

NOTE: Use a mirror and light source as inspection aids where necessary.

(1) Examine the following components in conjunction with detailed information in chapter 20-09-15, para. 3.C:-

- wire harness- panel connectors- relay and contactors- terminal blocks.

CAUTION: ANY RESTORATIVE CLEANING UNDERTAKEN MUST NOT COMPROMISE THE INTEGRITY OF THE EWIS (REFER TO CHAPTER 20-09-16).

D. Close Out

(1) Install the Panel 1C cover with the retained bolts.

(2) Install the left main battery (refer to 24-33-01, pb201).

(3) Install access panel 121AZ with the retained studs or bolts, and washers.

(4) Remove all tools and equipment from the work area.

Light Source Commercially AvailableMirror Commercially Available




1. General


B. Job Set-Up

(1) Remove and retain the studs or bolts, and washers that attach access panel 122AZ (refer to chapter 6-30-00, Figure 3 and AIPC chapter 53-20, Figures 0001, 0001A, 0002 or 0003, as appropriate)).

(2) Remove and retain the two bolts that attach the Panel 2C cover.

C. Procedure




- wire harness- panel connectors- relay and contactors- terminal blocks.


D. Close Out

(1) Install the cover on Panel 2C with the retained bolts.

(2) Install access panel 122AZ with the retained studs or bolts, and washers.





AMM20-09-19 1.0.0.0FLIGHT COMPARTMENT PANEL 1D - EWIS - GENERAL VISUAL INSPECTION

1. General


B. Job Set-Up

(1) Gain access to Panel 1D in the flight compartment (refer to chapter 39-11-00, Figure 1).

C. Procedure

Do a general visual inspection of Panel 1D as follows:



- wire harness- circuit breakers- spirap/sleeving- beading- terminal blocks- connectors- relay- diodes.


D. Close Out





AMM20-09-20 1.0.0.0FLIGHT COMPARTMENT PANEL 2D - EWIS - GENERAL VISUAL INSPECTION

1. General


B. Job Set-Up

(1) Gain access to Panel 2D in the flight compartment (refer to chapter 39-11-00, Figure 1).

C. Procedure

Do a general visual inspection of Panel 2D as follows:



- wire harness- circuit breakers- spirap/sleeving- beading- terminal blocks- connectors- relay- diodes.


D. Close Out





AMM20-09-21 1.0.0.0FLIGHT COMPARTMENT PANEL 4P - EWIS - GENERAL VISUAL INSPECTION

1. General


B. Job Set-Up

(1) Gain access to Panel 4P in the flight compartment (refer to chapter 39-11-00, Figure 1).

C. Procedure

Do a general visual inspection of Panel 4P as follows:



- wire harness- spirap/sleeving- beading- clamps/brackets- splices- terminal blocks- connectors- switches.


D. Close Out






1. General


B. Job Set-Up


C. Procedure


CAUTION: DO NOT DISTURB OR DAMAGE THE WIRING.



- wire harness- spirap/sleeving- clamps/brackets- splices- connectors- switches.


D. Close Out






1. General


B. Job Set-Up


C. Procedure


CAUTION: DO NOT MOVE THE WIRING WHEN ATTACHED. IF SIGNIFICANT CONTAMINATION IS PRESENT, RELEASE THE WIRING SO THAT NO EXCESSIVE STRESS IS PUT ON SUPPORT DEVICES AND/OR ASSOCIATED CONNECTORS.



- wire harness- spirap/sleeving- splices- connectors- switches.


D. Close Out






1. General


B. Job Set-Up


C. Procedure







D. Close Out






1. General


B. Job Set-Up

(1) Gain access to the front of Panel 1P in the flight compartment (refer to chapter 39-11-00, Figure 1).

(2) Gain access to the rear of Panel 1P through the forward baggage compartment as follows:-

(a) Remove and retain the bolts and washers that attach the removable bulkhead, panel 210CZ (refer to chapter 6-30-00, Figure 2 and AIPC chapter 25-10, Figure 0035).

NOTE: Make a note of the position of the different types of bolt, for subsequent installation.

C. Procedure





- wire harness- spirap/sleeving- earth studs- TB’s/RTB’s- bonding leads/straps- switches- clamps/brackets- splices- relay & contactors.


D. Close Out




(1) Install the removable bulkhead, panel 210CZ, with the bolts and washers, as noted during removal.





1. General


B. Job Set-Up

(1) Gain access to the front of Panel 2P in the flight compartment (refer to chapter 39-11-00, Figure 1).




C. Procedure







D. Close Out





1. General


B. Job Set-Up

(1) Gain access to the front of Panel 5P in the flight compartment (refer to AIPC chapter 39-10, Figure 0012).




C. Procedure







D. Close Out





1. General


B. Job Set-Up

(1) Gain access to Panel 8C (refer to AIPC chapter 39-30, Figure 0025 or 0026) through the forward baggage compartment, as follows:-

(a) Remove and retain the bolts and washers that attach the removable bulkhead, panel 210CZ (refer to chapter 6-30-00, Figure 2).


C. Procedure







D. Close Out






1. General


B. Job Set-Up

(1) Gain access to Panel 9C (refer to AIPC chapter 39-10, Figure 0065) through the forward baggage compartment, as follows:-

(a) Remove and retain the bolts and washers that attach the removable bulkhead, panel 210CZ (refer to chapter 6-30-00, Figure 2 and AIPC chapter, 25-10, Figure 0010).


(b) Detach access panel 220AZ (refer to chapter 6-30-00, Figure 3).

C. Procedure







D. Close Out

(1) Attach access panel 220AZ.





1. General


B. Job Set-Up

(1) Gain access to Panel 10C (refer to AIPC chapter 39-10, Figure 0065) through the forward baggage compartment, as follows:-

(a) Remove and retain the bolts and washers that attach the removable bulkhead, panel 210CZ (refer to chapter 6-30-00, Figure 2).

NOTE: Make a note of the position of the different types of bolt for subsequent installation.

(b) Detach access panel 220MZ (refer to chapter 6-30-00, Figure 3 and AIPC chapter 25-10, Figure 0010).

C. Procedure







D. Close Out




(1) Attach access panel 220MZ.

(2) Install the removable bulkhead, panel 210CZ, with the bolts and washers as noted during removal.




AMM20-09-32 1.0.0.0FLIGHT COMPARTMENT GROUND STUDS AND ASSOCIATED WIRINGEWIS - GENERAL VISUAL INSPECTION

1. General


B. Job Set-Up

(1) Gain access to ground studs and associated wiring, as follows:-

(a) Detach access panel 220CZ (refer to chapter 6-30-00, Figure 3 and AIPC chapter 25-10, Figure 0010).

C. Procedure

Do a general visual inspection of ground studs and associated wiring, as follows:




- wire harness- spirap/sleeving- earth studs.


D. Close Out

(1) Attach access panel 220CZ.





AMM20-09-33 1.0.0.0FLIGHT COMPARTMENT RESISTORS AND ASSOCIATED WIRINGEWIS - GENERAL VISUAL INSPECTION

1. General


B. Job Set-Up

(1) Gain access to resistors and associated wiring, as follows:-

(a) Detach access panel 220DZ (refer to chapter 6-30-00, Figure 3 and AIPC chapter 25-10, Figure 0010).

C. Procedure

Do a general visual inspection of resistors and associated wiring, as follows:




- wire harness- spirap/sleeving- earth studs- TB’s/RTB’s- resistor.


D. Close Out

(1) Attach access panel 220DZ.





AMM20-09-34 1.0.0.0FLIGHT COMPARTMENT SPEAKERS, PCB’S, AND ASSOCIATED WIRINGEWIS - GENERAL VISUAL INSPECTION

1. General


B. Job Set-Up

(1) Gain access to the speakers, PCB’s, and associated wiring, as follows:-

(a) Remove and retain the bolts that attach access panel 220EZ (refer to chapter 6-30-00, Figure 3 and AIPC chapter 25-10, Figure 0030).

C. Procedure

Do a general visual inspection of the speakers, PCB’s, and associated wiring, as follows:




- wire harness- spirap/sleeving- earth studs- TB’s/RTB’s- relays.


D. Close Out

(1) Install access panel 220EZ with the retained bolts.





AMM20-09-35 1.0.0.0FLIGHT COMPARTMENT TB’S AND ASSOCIATED WIRINGEWIS - GENERAL VISUAL INSPECTION

1. General


B. Job Set-Up

(1) Gain access to the TB’s and associated wiring, as follows:-

(a) Detach access panel 220FZ (refer to chapter 6-30-00, Figure 3 and AIPC chapter 25-10, Figure 0030).

C. Procedure

Do a general visual inspection of the TB’s and associated wiring, as follows:




- wire harness- TB’s/RTB’s.


D. Close Out

(1) Attach access panel 220FZ.





AMM20-09-36 1.0.0.0FLIGHT COMPARTMENT PNEUMATIC DE-ICER TIMER, PCB’S, AND ASSOCIATED WIRINGEWIS - GENERAL VISUAL INSPECTION

1. General


B. Job Set-Up

(1) Gain access to the pneumatic de-icer timer, PCB’s, and associated wiring, as follows:-

(a) Remove and retain the bolts that attach access panel 220GZ (refer to chapter 6-30-00, Figure 3 and AIPC chapter 25-10, Figure 0030).

C. Procedure

Do a general visual inspection of the pneumatic de-icer timer, PCB’s, and associated wiring, as follows:




- wire harness- spirap/sleeving- earth studs- TB’s/RTB’s- relays.


D. Close Out

(1) Install access panel 220GZ with the retained bolts.





AMM20-09-37 1.0.0.0FLIGHT COMPARTMENT FIRE BELL AND ASSOCIATED WIRINGEWIS - GENERAL VISUAL INSPECTION

1. General


B. Job Set-Up

(1) Gain access to the fire bell and associated wiring, as follows:-

(a) Detach access panel 220JZ (refer to chapter 6-30-00, Figure 3 and AIPC chapter 25-10, Figure 0030).

C. Procedure

Do a general visual inspection of the fire bell and associated wiring, as follows:




- wire harness- TB’s/RTB’s.


D. Close Out

(1) Attach access panel 220JZ.





AMM20-09-38 1.0.0.0FLIGHT COMPARTMENT HYDRAULIC TEMPERATURE TRANSMITTER, TEMPERATURE CONTROLLER, AND ASSOCIATED WIRING - EWIS - GENERAL VISUAL INSPECTION

1. General


B. Job Set-Up

(1) Gain access to the hydraulic temperature transmitter, temperature controller, and associated wiring, as follows:-

(a) Detach access panel 220KZ (refer to chapter 6-30-00, Figure 3 and AIPC chapter 25-10, Figure 0010).

C. Procedure

Do a general visual inspection of the hydraulic temperature transmitter, temperature controller, and associated wiring, as follows:




- wire harness- earth studs- TB’s/RTB’s- connectors- resistors.


D. Close Out

(1) Attach access panel 220KZ.





AMM20-09-39 1.0.0.0FLIGHT COMPARTMENT TEMPERATURE CONTROLLER, AIR DATA SENSOR, ELECTRONICS UNIT, AND ASSOCIATED WIRING - EWIS - GENERAL VISUAL INSPECTION

1. General


B. Job Set-Up

(1) Gain access to the temperature controller, air data sensor, electronics unit, and associated wiring, as follows:-

(a) Detach access panel 220LZ (refer to chapter 6-30-00, Figure 3 and AIPC chapter 25-10, Figure 0010).

C. Procedure

Do a general visual inspection of the temperature controller, air data sensor, electronics unit, and associated wiring, as follows:




- wire harness- connectors.


D. Close Out

(1) Attach access panel 220LZ.





AMM20-09-40 1.0.0.0FLIGHT COMPARTMENT SPEAKERS, RESISTORS, HORN, FLOODLIGHT, AND ASSOCIATED WIRING - EWIS - GENERAL VISUAL INSPECTION

1. General


B. Job Set-Up

(1) Gain access to the speakers, resistors, horn, floodlight, and associated wiring, as follows:-

(a) Detach access panel 220NZ (refer to chapter 6-30-00, Figure 3 and AIPC chapter 25-10, Figure 0030).

C. Procedure

Do a general visual inspection of the speakers, resistors, horn, floodlight, and associated wiring, as follows:




- wire harness- spirap/sleeving- earth studs- TB’s/RTB’s.


D. Close Out

(1) Attach access panel 220NZ.





AMM20-09-41 1.0.0.0FORWARD FUEL TANK/CENTRE WING CONNECTORS, TB’S, AND ASSOCIATED WIRINGEWIS - GENERAL VISUAL INSPECTION

1. General


B. Job Set-Up

(1) Gain access to the connectors, TB’s, and associated wiring, as follows:-

(a) Remove and retain the bolts that attach the access panels 240MR, 240LR, 240NL and 240PL (refer to chapter 6-30-00, Figure 6 and AIPC chapter 53-30, Figure 0035).

NOTE: The panels can be removed as one complete unit, or individually. If removed individually, retain the joint pieces that will become detached if all the bolts between the panels are removed.

Make a note of the position of the different attachments, for subsequent installation.

C. Procedure

Do a general visual inspection of the connectors, TB’s, and associated wiring, as follows:




- wire harness- spirap/sleeving- beading- TB’s- connectors.


D. Close Out

(1) Install access panels 240MR, 240LR, 240NL and 240PL with the attachments as noted during removal.




AMM20-09-42 1.0.0.0CONTROL SURFACE CABLES, CONTROL RODS, FUEL & HYDRAULIC PIPES, AND ASSOCIATED WIRING - EWIS - GENERAL VISUAL INSPECTION

1. General


B. Job Set-Up

(1) Gain access to the cables, rods, pipes, and associated wiring, as follows:-

(a) Remove and retain the bolts that attach the access panels 250AL, 250AR, and 250DR (refer to chapter 6-30-00, Figure 7 and AIPC chapter 53-30, Figure 0035).

NOTE: Panels 250AL and 250AR can be removed as one complete unit, or individually. If removed individually, retain the joint piece that will become detached if all bolts between the panels are removed.

Make a note of the position of the different attachments, for subsequent installation.

C. Procedure

Do a general visual inspection of the cables, rods, pipes, and associated wiring, as follows:




- wire harness- spirap/sleeving- beading- connectors.


D. Close Out

(1) Install access panels 250AL, 250AR, and 250DR with the attachments as noted during removal.





AMM20-09-43 1.0.0.0PASSENGER COMPARTMENT SIDEWALL STATION 175.80 TO 197.20 (RH)EWIS - GENERAL VISUAL INSPECTION

1. General


B. Job Set-Up

(1) Gain access to the area between Stn 175.80 and 197.20 (RH), as follows:-

(a) Remove the double passenger seat installation at the inspection area (if required). Refer to AIPC chapter 25-20, Figure 0075 or 0076.

(b) Remove the overhead locker at the inspection area (if required). Refer to AIPC chapter 25-20, Figures 0020 to 0030.

(c) Remove access panels 262NZ and 262TZ (refer to chapter 6-30-00, Figure 4).

(d) Remove the soundproofing blankets (refer to AIPC chapter 25-20, Figure 0010)

C. Procedure

Do a general visual inspection of the area between Stn 175.80 and 197.20 (RH), as follows:




- wire harness.


D. Close Out

(1) Install the soundproofing blankets.

(2) Install access panels 262NZ and 262TZ.

(3) Install the overhead locker (if removed).

(4) Function check the overhead locker (refer to chapter 25-20-16, pb201).




(5) Install the double passenger seat (if removed).





1. General


B. Job Set-Up


(a) Remove the double passenger seat installation at the inspection area (if required). Refer to AIPC chapter 25-20, Figures 0075 or 0076.


(c) Remove access panels 263NZ and 263TZ (RH). Refer to chapter 6-30-00, Figure 4.


C. Procedure





- wire harness- splices- clamps/brackets.


D. Close Out


(2) Install access panels 263NZ and 263TZ.






(5) Install the double passenger seat (if removed).




AMM20-09-45 1.0.0.0PASSENGER COMPARTMENT PANEL 3D - EWIS - GENERAL VISUAL INSPECTION

1. General


B. Job Set-Up

(1) Gain access to Panel 3D, as follows:-

(a) Open the panel cover. Refer to AIPC chapter 39-10, Figure 0105.

C. Procedure

Do a general visual inspection of Panel 3D, as follows:




- wire harness- panel connectors- diodes- potentiometers.


D. Close Out

(1) Close the panel cover.





AMM20-09-46 1.0.0.0PASSENGER COMPARTMENT PANEL 12P - EWIS - GENERAL VISUAL INSPECTION

1. General


B. Job Set-Up

(1) Gain access to Panel 12P, as follows:-

(a) Remove and retain the bolts that attache the panel cover. Refer to AIPC chapter 39-10, Figure 0040.


C. Procedure

Do a general visual inspection of Panel 12P, as follows:




- wire harness- switches- spirap/sleeving- splices- clamps/brackets- beading- panel connectors.


D. Close Out

(1) Install the panel cover with the retained bolts, as noted during removal.






1. General


B. Job Set-Up


(a) Remove the double passenger seat assembly at the inspection area (if required). Refer to AIPC chapter 25-20, Figure 0075 or 0076.


(c) Remove access panels 264MZ and 264RZ (RH). Refer to chapter 6-30-00, Figure 4.


C. Procedure





- wire harness- spirap/sleeving- earth studs- connectors- splices- clamps/brackets- beading- bonding.


D. Close Out





(2) Install access panels 264MZ and 264RZ.



(5) Install the double passenger seat assembly (if removed).




AMM20-09-48 1.0.0.0PASSENGER COMPARTMENT CEILING STATION 74.00 TO 300.77EWIS - GENERAL VISUAL INSPECTION

1. General


B. Job Set-Up

(1) Gain access to the area between Stn 74.00 and 300.77, as follows:-

(a) Remove access panels 261JZ, 261KZ, 262KZ, 262LZ and 263LZ. Refer to chapter 6-30-00, Figure 4.

(b) Remove the soundproofing blankets (refer to AIPC chapter 25-20, Figure 0010).

NOTE: Make a note of the position of the blankets for subsequent installation.

C. Procedure

Do a general visual inspection of the area between Stn 74.00 and 300.77, as follows:




- wire harness- spirap/sleeving- earth studs- TB’s- connectors- splices- clamps/brackets- bonding.


D. Close Out

(1) Install the soundproofing blankets as noted during removal.

(2) Install access panels 261JZ, 261KZ, 262KZ, 262LZ and 263LZ.




AMM20-09-49 1.0.0.0POWER PLANT PANEL 19C (LH) AND 20C (RH) - EWIS - GENERAL VISUAL INSPECTION

1. General


B. Job Set-Up

(1) Gain access to the rear of the associated power plant, as follows:-

(a) Remove and retain the bolts that attach access panel 440AB. Refer to chapter 6-30-00, Figure 8 and AIPC chapter 54-10, Figure 0015.

(b) Remove and retain the bolts and washers that attach the cover of panel 19C (LH) or 20C (RH). Refer to AIPC chapter 39-10, Figure 0075.

C. Procedure

Do a general visual inspection of panel 19C (LH) or 20C (RH), as follows:




- wire harness- relay & contactors- diodes- busbar/link- spirap/sleeving.


D. Close Out

(1) Install the cover of panel 19C (LH) or 20C (RH) with the retained bolts and washers.

(2) Install access panel 440AB with the retained bolts.





1.0.0.0PROTECTION OF ELECTRICAL WIRING INTERCONNECTION SYSTEMMAINTENANCE PRACTICES

1. Introduction.

Protection of the Electrical Wiring Interconnection System (EWIS) provides a means of employing a “protect and clean” philosophy when undertaking a maintenance, repair or alteration operation on the aircraft. The programme ensures that all EWIS components receive adequate protection from metal shavings, debris and contamination that may result from structural repairs, STC installations or other alterations undertaken in the vicinity of the EWIS.

The development of the protection and caution recommendations detailed in this EWIS Protection Programme are required by H25.5 (a)(1)(vi) of part 25 and are in accordance with the guidelines presented in FAA Advisory Circular 25-27.

2. Recommendations and Precautions

A. Structural repair, maintenance or STC alterations on or to the aircraft:

(1) Survey the work area before beginning any of these tasks, to identify all EWIS components that may be subject to contamination.

(2) Cover or remove all EWIS and electrical components located in the debris field.

(3) During and upon completion of the task, ensure that all EWIS components, electrical components and wiring are cleaned in accordance with AMM 20-09-16.

(4) Exercise extreme caution to protect wiring from mechanical damage caused by tools or other equipment.

(5) Determine the location of EWIS components and wiring with relation to drilling the aircraft structure.

(6) Carefully displace or cover all wiring adjacent to drilling or riveting operations, to reduce the possibility of mechanical damage.

(7) Prevent debris such as drill shavings, drill bits or other mechanical detritus from penetrating or otherwise contaminating EWIS components or wiring.

B. Installation, repair or modification of EWIS components or wiring:

(1) Ensure that all EWIS component selection, routing & segregation, splice selection, repair or replacement of protective covers, pinning & de-pinning of connectors, and clamping configurations are in accordance with AMM 20-09-16 and the relevant manufacturer’s Material / Component Data sheets.

(2) Minimise disturbance to existing adjacent wiring during maintenance tasks.



(3) Ensure that any displaced wiring, resulting from a maintenance task, is returned to its normal configuration.

C. Installation/Removal of Components (related to attached wiring):

(1) Minimise component handling and movement during installation and/or removal.

(2) Use appropriate tools to loosen couplings on connectors.

(3) Use the plug body and not the attached wiring to pull upon when disconnecting.

(4) Ensure that the connector is fully seated when reconnecting and that there is no sign of tension in the associated wires.

(5) Ensure that all connectors are covered immediately upon disconnection with protective caps, plugs or receptacles.

(6) Plastic bags may be used in lieu of protective caps, but only as a temporary fit as there may be a risk of contamination.

NOTE: A humidity absorber is recommended for use with plastic bags.

D. Service or repair of Water/Waste Systems:

(1) Cover exposed EWIS components and wiring adjacent to the waste/water system in order to prevent those components being contaminated.

NOTE: If contamination occurs, clean in accordance with AMM 20-09-16.

E. Service or repair of Oil Systems:

(1) Cover exposed EWIS components and wiring adjacent to the Oil system to be repaired/serviced in order to prevent those components being contaminated.


F. Service or repair of Hydraulic Systems:

(1) Cover exposed EWIS components and wiring adjacent to the Hydraulic system to be repaired/serviced in order to prevent those components being contaminated.


G. Service or repair of Oil Systems:

(1) Cover exposed EWIS components and wiring adjacent to the Oil system to be repaired/serviced in order to prevent those components being contaminated.




H. Access to maintenance/ repair zone on aircraft:

(1) Exercise extreme caution when you gain access to the maintenance/repair zone on the aircraft, to avoid damage to adjacent EWIS components including wiring that may be hidden or obscured from view (e.g. covered by insulation blankets).

CAUTION: DO NOT USE WIRE LOOMS AND OR HARNESSES AS SUPPORTS OR FOOT/HAND HOLDS.

(2) Use protective boards or platforms for protection and support where necessary.

(3) Adequately release wiring from it’s clamps or fixing provision, to permit access to the work area without causing damage.

(4) Return all impacted wiring to it’s original position upon completion of the task.

SD3-60 AIRCRAFT MAINTENANCE MANUAL 20.pdf(3) If internal damage or serviceability is suspected test...

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