The Ohmmeter.

ohmmeter is a meter movement, a battery, and a series resistance.

idea behind the ohmmeter is to force a current to flow through an unknown resistance and then measure the current.

The purpose of the battery is to supply an EMF to force current through the unknown resistance. The meter movement measures the resulting current. The test probes have long leads and they simplify the job of connecting the ohmmeter to the unknown resistance

Scale Calibration.

on the ohm's scale, the zero indication is on the right side of the scalethe scale is non-linear.

Creating Higher Ranges.

a higher resistance range can be implemented. First, a switch is added so that you can select either of the two ranges. Second, a higher voltage battery is added.

Finally, a higher value series resistor is included in the circuit.To increase the range by a factor of 10, both the voltage and the total series resistance must increase by a factor of 10.When the switch, S1 is in the position shown, the meter operates exactly like the one shown in earlier Figures. However, when Sl is switched to the x 10 position, the 15 volt battery is switched in series with Rs, Rl, R2, and the meter. The higher voltage does not cause excessive current through the meter since the series resistance has been increased by the addition of R3

This technique cannot be carried much further because increasing the range by an additional factor of 10 would require a 150 volt battery

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Creating Lower Ranges

This is done by switching a small value shunt resistor in parallel with the meter and its series resistance.

Multimeters.

the voltmeter. ammeter, and ohmmeter The most serious disadvantage of the single multimeter, when compared to 3 separate meters, is that only one measurement can be monitored at any given time.

The ohmmeter portion of the multimeter has only two ranges. On the This meter has three DC voltage ranges, two ohmmeter ranges, and three current ranges. Function switch S2 determines if the multimeter is to act as an ammeter, a voltmeter, or an ohmmeter. Range switch S1 determines the range of the meter.

When used as a voltmeter, S2 must be placed in the VOLTS position and81 must be placed in one of the voltage range positions: 1 V, 10 V, or 100V. LO range, B1 supplies the current that causes the meter to deflect when S2 is the OHMS position and a resistance is connected between the two test probes.In the HI 0 position, a higher voltage battery and a larger value series resistor are used to increase the resistance range. When function switch S2 is placed in the CURRENT position, the two test probes are connected directly to opposite ends of the meter movement. When the range switch S, is placed on one of the current ranges, a resistor is placed in parallel (shunt) with the meter moveme

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Electronic Multimeter.

These contain electronic circuits that can amplify small voltages and currents. These instruments use devices such as transistors and integrated circuits electronic meter has a much higher resistance than the electrical meter.

Good electrical meter has sa sensitivity of 20000 ohms/V. Thus on the 10V range its resistance is 20000Kohm x 10 = 200Kohm. Most electronic meters have resistance of 10 or 11 Mohm on all DC ranges.

Measurement Inaccuracies.

Voltmeter loading error is minimised by using a voltmeter that has a high resistance compared to the resistances under measurement.the ammeter introduces an error when it is used to measure current. Since the ammeter has a certain amount of resistance, it increases the overall circuit resistance when it is connected in series with the circuit. Of course, this reduces the current flowing in the circuit.

As a result, the ammeter indicates a value of current lower than the actual current in the circuit without the meter connected. To minimise the error, an ammeter with a very low value of resistance must be used

If the resistance value of the ammeter is known, its loading effect can be predicted and taken into consideration so that a more accurate interpretation of the reading can be made.

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when the ammeter is set to a low current range, the ohm-meter may produce enough current to harm the ammeter. The resistance of a meter movement is an important factor in deSigning meter circuits. The technique outlined above can be used to determine the resistance of any meter movement as well as that of an ammeter.Aside from loading errors, the prime source of measurement inaccuracies is the tolerance of the components that make up the meter. The meter movement may have an inaccuracy of ± 2% or ± 3% of full scale.most common error is that caused by parallaxfor a correct reading, always read the scale "straight on" from directly in front of the metclose one eye, and read the scale. "straight on" with the other eye. Some meters have a mirror on the scale to help eliminate parallax errors.

V.h.f omnidirectional range (VOR) Ramp Testing

providing a means of simulating various VOR radials. Most test sets include provision for testing ILS as well as VOR.

CRM 555

Modulation of the carrier is such that the simulated bearing may be set to any reading between 0 and 360° with a calibration accuracy of ± I or may be switched in 45°steps with an accuracy of ± 0.5°. Carrier power can be attenuated in 1 dBsteps between 0 dBm and -120 dBm

TIC T-27Bfacilities are not as extensive as either of the previously mentioned test sets but it has the advantage of ease of operation and less cost. It is FCC type accepted. Operation is on 108.00 MHz radiated from a telescopic antenna. Bearings of 0, 90, 180 and 2700 can be simulated both TO and FROM, alternately variation, 90-110° 'to' or 270-290° 'from',is available. A ± 1° switch gives a useful sticky needle check

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Instrument Landing System Ramp Testing.

TICT-30B.for testing the marker, localiser and glideslope receivers respectively

Cossor CRM 555.Forty localizer and forty glideslope channels may be selected, all crystal controlled. There are seven d.d.m. settings for localizer-simulated deviation and five for glidepathModulating tones of 400, 1300 and 3000 Hz are available for marker checks. 020 Hz modulation is available for audio checks

IFR NA V-402 AP.contains a modulated signal generator for marker, VOR, localizer, glideslope and communications testing. The output of the test set is variable between -7 and -110 dBm on all frequencies set by a variable frequency control The localizer deviation can be switched Tone deletion can be selected. All three marker tones are available, as is 1020 Hz for audio cheek

Distance Measuring Equipment Ramp Testing.will test by radiation, simulate various ranges and velocities, operate on at least one spot frequency for mode X and mode Y, and provide for simulation of identification

TIC T-24A.A battery-operated, one-man test set operated from the cockpit and testing by radiation. velocity, inbound or outbound, can be selected Squitter is selectable at 700 or 2700 pulse pairs per second. Identity is available as 1350 or equalised 1350 pulse pairs per secon

ATC 600A.Channels 17X and 17 Yare available with range simulation fromo to 399.9 nautical miles in 0.1 nautical mile incrementsATC 600A operates on channels 17X and 17Y. The range can be set from 0 to 399 nautical miles in 1 nautical mile steps.Twelve different velocities may be simulated in the range 50-2400 knots inbound or outbound.

ATC Transponder Ramp Testin

can be tested in situtest by radiation, be capable of interrogating on at least modes A and C, be capable of simulating a side lobe interrogation, display the transponder reply and provide a means of measuring the transponder transmitter frequency.

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ATC 6OOA. it can test both DME and ATC transponderPI, P2 and P3 pulses are generated and used to key a crystal-controlled1030 MHz oscillator1. P1-P3 interval - to check decoder;

2. P2 amplitude - to check SLS;

3. Transmitter power output - to check MTLThere is also a numerical readout which shows either the pilot code or the altitude in thousands of feet. In addition to this basic information the following can be checked:

1. F2 timing;2. power output of transponder (± 50 per cent accuracy);3. frequency of the transponder transmitter;4. percentage reply;5. invalid altitude code, Le. no C pulses or C1 and C4 together;6. absence of code pulses in reply to mode C interrogation.

Supply is by rechargeable battery or a.c., battery operation is limited by a timer.

TIC T-33B and T-43B. TIC T-33B and T-43B.Specifications for the two test sets are identical except for theaddedfacility of direct connection of an encoder which is available on the T-43B.use of the ATe600A as a bench test, although it should be noted that a particular ATC600A is best used as either a bench test set or a ramp test set but notboth. do not have facilities for continuously varying P1-P3 spacing or strobing the F2 pulse, and do not indicate invalid or 'no altitude' information or transmitter power.TIC test sets are designed for use in the cockpit on the ground or in flight, the antenna being mounted on the test set as opposed to the ATC600A where the antenna is mounted on a tripod near the aircraft antenna.

Specifications for the two test sets are identical except for theaddedfacility of direct connection of an encoder which is available on the T-43B.use of the ATe600A as a bench test, although it should be noted that a particular ATC600A is best used as either a bench test set or a ramp test set but notboth. do not have facilities for continuously varying P1-P3 spacing or strobing the F2 pulse, and do not indicate invalid or 'no altitude' information or transmitter power.TIC test sets are designed for use in the cockpit on the ground or in flight, the antenna being mounted on the test set as opposed to the ATC600A where the antenna is mounted on a tripod near the aircraft antenna.

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Radio Altimeter Ramp Testing and Maintenance.The radio altimeter should read nearly zero feet when switched on. If the antennas are . mounted forward of the main wheels the reading will be less than zero; jf aft of the main wheels greater than zero. When self-test is operated the correct reading should be obtained and the flag should appear. While keeping the self-test switch pressed the DH bug may be adjusted from a higher to a lower reading than the height pointer

The Model 43 THRULINE

Model 43 Wattmeter consists of a line section, "QC" (Quick-Change) type connectors and an indication meter; both housed in a rugged, corrosion resistant aluminium caseLine Section: The line section is a high precision 50 Ohm coaxial air line designed for transmission line insertion between the transmitter and the antenna or load"OC" - Type Connectors: The Model 43 wattmeter is supplied with two female "Nil-type connectors.Indicating Meter: The instrument's indicating meter is a shock mounted30 microampere meter with 3 expanded scales of 25, 50 and 100;permitting full scale direct power readings from 100 milliwatts to 10,000 watts.Plug-in Elements: Plug-in elements determine the power rating and the frequency range read both forward and reflected power.Remote Installation: The AF line section can be removed easily from the Model 43 wattmeter and inserted at any desired point in the line

Series 4410.capable of reading seven different power ranges. The power ranges of the different elements overlap. These power ranges include: 0.002-1 OW, 0.02-100W, 0.2-1000W and 2-10,OOOW.All ranges are in frequency bands from 200KHzto 2300MHz.

VSWR Checks.In-Line Wattmeter.Particular attention should be given to the wattmeter's ability to discriminate between forward power and reflected power, its accuracy at high forward powers and lowreflected powers, its impedance and frequency range: should be connected adjacent to the transmitter and, with the system transmitting on a free channel (HF systems in the CW or AM mode), the forward power should be noted. Any additional lengths of test cable used must have the correctcharacteristic impedance and be as short as possibleThe coupling element should be reversed and, with the transmitter on, the reverse power should be notedattenuation in the aerial feeder will reduce the forward power, and the reflected power. It will however show if there is an unacceptable amount of reverse power at the transmitter. wattmeter should be connected adjacent to the aerial, or adjacent to the aerial tuning unit for HF systems,any reflecting surface near the aerial can reflect power back into an aerial and along the transmission

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Air Data Test Set Description

The ADTS 405 is a rack-mounted system and, with external pressure and vacuum supplies connected, provides measurement and control for leak checks, calibration accuracy checks and functional tests of air data instruments, components and systems

ADTS 405F is a self-contained air data test system providing complete pressure and vacuum measuring and control for on-aircraft sense and leak testing, calibration accuracy checks and functional tests of air data instruments, components and systems. The unit comprises an electronics rack and pump rack enclosed in a high density, polyethylene cas

ENGINEERING DRAWINGS DIAGRAMS AND STANDARDS

Blueprints.are only one source of information used in the construction of an airplane, vehicle, or productOf equal importance aredocuments, standards, and other publicationsThe most commonly used specifications fall in four categories:procedures and specificationsFederal specifications production and tooling documents drawingsInformation found in one specification is not found in another specification.blueprint usually tells only what to be done; other specification tell how it is to be done.The blueprint system is used by the engineer to communicate his ideas to the various people who buy the raw material, plan the manufacturing sequences, built the parts and finally buy the product.

Production Drawingshe engineer uses both words and pictures to describe a product.On older drawings, a parts list or list of materials, notes, an application of usage, and a picture are shown on a manually prepared form. Thistype of drawing is referred to as "a drawing with an internal parts list". most of the recent drawings On tthe parts list, notes, and application are contained in an automated or manually prepared drawing called NPL". Each PL contains one or more sheets or pages.The common picture drawing form sizes are:A-8.5 x 11in E-36 x 50in8-11 x 17in F-30 x SOinC-17 x 22in 1-36x 94inD-22 x 34in J-36x 138inhe above drawing sizes are available in two formats: one prepared forg~vernment funded programs; the other prepared for commercial programs.The information that the engineer adds to the drawing form is locatedin three.areas:1.) Title block2.) Revision block3.) Picture areaThe title block and revision block are found in the same location on all drawings.

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Aircraft Drawings

Methods Of IllustrationThe orthographic projection, auxiliary, isometric, oblique, and perspective methods of illustration are all common to the aviation maintenance industry.

Orthographic Projectionin orthographic projection there are six possible views from which an object can be drawn: the front. rear top. bottom. left side, and right side. All rays extending. from the part are parallel and perpendicular to the side they are viewed from.six views are not needed to illustrate a part. In fact, one-view, two-view, and three-view drawings are the most common. In a three-view drawing the front, right side, and top views are illustrated.

Isometric Drawings

An isometric drawing is a projection of a three-dimensionalobject on a flat plane.With this type of drawing an object is rotated so three sides are visible.to make an isometric drawingan object is rotated so that three views are visible and touching the drawing plane.In an isometric drawing all distances are the same length as the actual sidesmost pictorial drawings are illustrated in this way.

Oblique Drawings

is an isometric drawing with one object face parallel to the drawing planewo axes are perpendicular to each other, with the front of the object identical to the front view of an orthographic drawing. The depth axis of the oblique drawing is typically any convenient angle and most often about 30 degrees. There are two special types of oblique drawings. They are the cabinet drawing, and the cavalier drawing. A cabinet drawing gets its name from drawings used for cabinet work. In these drawings, the oblique side Is at a 45 degree angle to the front side and is 1/2 the scale. Cavalier drawings use the same scale for the front view as the oblique side lines. the oblique sides are still set at a 45 degree angle to the front view. This creates a distorted picture of an object's true proportions. These drawings are primarily used when detailing is required on the oblique side.

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Detail DrawingsDrawings used in the detailing or fabrication 01 single parts are called"detailN drawings. Sometimes these drawings may be called "tab"drawings. Detail drawings do not put parts together.If the word "assembly" or "installation" does not appear in the title, the drawing is a detail drawing.The size of the drawing gives no indication of the drawing type. Some detail drawings are small, whereas others are large. Detail drawings do not ordinarily show location, position, or fastening methods. They will occasionally show where a fastener eventually be installed, but they do not show the fastener itself.etail drawings are designed primarily to give instruction for fabricationpersonnel and provide only information used to make a part,Detail information includes:- Size and shape description- Material and heat treatment requirements- Protective finish instruction (painting, plating, etc.)- Machine finish if required (surface smoothness for metal)- Part numbering and marking instructions- The next higher drawing number (where the part will be used)

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Assembly DrawingsAssembly may comprise only two parts or it may comprise manIn some cases a large assembly may comprise several small assemblies fastened together.Information about how to locate the parts in reference to each other and about how to fasten them together is called "assembly information".The primary function of the assembly drawing is to show the relationship of two or more parts and subordinate assemblies, or a group of assemblies to form an assembly of a higher order.An assembly drawing must provide five items for information:- A list of required component parts and process specifications- Location dimensions (showing exactly how parts fit together)- Fastening methods- A part number for the finished assembly- The next higher drawing number (where the assembly wi" be used) assembly drawing may provide detail fabricationinformation about some or all the parts from which it is made. Many assembly drawings contain some detail fabrication information.Detailing a part requires a complete picture description. If a part is detailed on an assembly drawing, the assembly drawing completely describes that part.A part that is detailed on one drawing can be shown on many drawings but cannot be detailed on an other drawing. Most assembly drawings are recognised by their drawing titles, which must contain the word "assembly" or "assemblies'."An assembly is a multiple piece item that can be disassembled into its component parts or units without destruction; it does not independently of itself perform or fulfil a specific complete function but is essential for the completeness or proper operation of a more complex item of equipment with which it is mechanically combined'

Installation DrawingsInstallation drawings are designed to describe exactly where on theairplane or vehicle, or in a portion of the airplane or vehicle, certain parts or assemblies are to be permanently affixed. Installationdrawings must provide the following information:~A list of required component parts and process specifications

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~ Location dimensions (in reference to the entire airplane or vehicle)~ Fastening methods- A part number for the finished installation (tabulation)- The next higher drawing number (used-on drawing number) Note: Some of this information is found in the PL.Note that the items listed above are almost identical to those listed for assembly drawings. The major difference between the two lies in the interpretation of the word "lccatlon". Assembly drawings give locations of parts onlyinstallation drawings give position within the aircraft or vehicle structure.most of the installation drawings are combination assembly-installation drawings.

Sectional DrawingsIt is often necessary to show the internal construction or shape of a part, and this is most generally done with the use of the sectional drawing.If only the shape of a cross section of a part needs to be shown, this can be done with either a revolved or removed sectionBlock DiagramsEach block shown represents many components and is usually a printed-circuit board or some other type of replaceable module.When troubleshooting a system using this type of drawing, the technician identifies the problem and then replaces the module that receives the correct input, but does not produce the required output.

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Logic FlowchartsAs a further aid to troubleshooting, the logic flowchart has been developed.When troubleshooting a system or problem using this aid the technician starts at the oblong START I INSPECTION symbol andfollows the arrows. This type of charts identifies the probable faults a system can develop and specifies the fix for each one. And by using this chart, troubleshooting time is reduced to a minimum.

Schematic DiagramsA schematic diagram is to explain a principle of operation, rather than to show the parts as they actually appear, as they actually function

Exploded-View DrawingIllustrated parts lists often make use of exploded-view drawings to show every part that is in an assembly. All of the parts are in theirrelative position, but are expanded outward, so that each part can be identified both with its physical appearance or by its name or by a reverence number that is coded to the parts list.

Drawing Description1) title block2} revision block3) notes area4) zoning5) drawingarea

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Title BlockThe title block consists of a drawing number andcertain other data concerning the drawing and the object it represents.production drawings contains following information:The title block1) DRAWING NUMBER: The drawing number is in 1/2-in-high characters.2) TITLE: The title of a drawing is in 1/4-in-high characters.3) SCALE: The scale of which the majority of views and sections are drawn is entered as a fraction.DIMENSIONAL TOLERANCE NOTES: Pre-printed here are the general tolerances to be used to the various drawing dimensions if atolerance is not otherwise shown on the drawing.5) SH of : The total number of sheets

Revision BlockRevising an engineering drawing requires the co-ordination of many organisation s and individuals. Revisions result from customerrequests, correction of errors, new design developments, and new materials and processes.The revision block in the upper right-hand corner of the drawing is used to show the ADCN's and DCN's that have been incorporated in the drawing.The ADeN (Advance Drawing Change Notice) is used to give advance notification that the drawing will be changed in the near future.The DCN (Drawing Change Notice) is a record of changes which navealready been made to the drawing.The DDA (Drawing Departure Authorisation) is used to authorise theshop to vary from the requirements of the drawing.

Notes AreaNotes too lengthy to be placed on other parts of the drawing are placedinto the "notes" area. These notes also provide sources of commoninformation, thereby avoiding needless repetition. Most notes fall in one of the following tree categories:- General notes- Symbol explanations- Flag notesGeneral Notes (GN)Frequently, the designer wishes to make special notations that apply to the entire drawing or a large portion of it rather than to one or two specific locations. Such notations are classified as "general notes" or "miscellaneous notes" and are included in the "notes" area of the drawing. They are individual statements not identified by flags orsymbols.

Symbol Explanations1) NAS523-type symbols2) Fastener code block3) Flag notes

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Zoning horizontal zones labeled A, B, C, etc. are, in the most cases, shown on the right-hand side (Zone letters read from right to left, starting with number "1fl.

maginary lines drawn horizontally from the limits of the area represented by "C" and vertically from the limit of the area represented by "4" would form a imaginary square of box on the sheet. This square, is a exact location on the sheet.- C4 means zone 4- C4-2 means C4 on sheet 2

Drawing AreaThe drawing area is the designer'sanswer to a design problemcommunication between the engineer and the blueprint readerdrawing found in the picture area is the basis of this communication process, and all other areas in the drawing are made to support the picture.

Drawing NumberThe drawing number contains two groups of numbers separated by adash. This number is important because it is always used when referring to that particular drawinDrawing Number 69-16330Part Number 69-16330-45The part, assembly, or installation number consists only of the numberof the drawing on which the fabrication, assembly, or installation information was given, followed by a dash number (-3, -5, etc.). The dash number .is a serial number that is added to distinguish between two or more parts (or assemblies) bearing the same basic part number. Drawing numbers on 707, 727, 737 drawings consists of:- The first digit representing the company division that originates the drawing.- The second digit representing the size or type.- The drawing serial number, separated by two digits or letter.

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ScaleThe scale defines the size of the picture as compared to the size of the actual part, assembly, or installation. The scale appears in the title block of only those sheets on which pictures are shown

ToleranceNo two detail parts may be identical, no assembly can be made exactly like an other assembly, and no one installation can be made identicalto another.The general tolerance on each blueprint is entered in the sheet 1 title block. Tolerances vary depending upon the individual requirements.

Automated Parts List (APL)Drawings not on APL parts list are:- ElectricaVelectronic diagram drawings- Production illustration drawings- Wire bundle assembly drawings- Specification control drawings- System diagram drawings

All APL parts lists contain the following main sections:- Header or title block- Application list- Revisions- Parts usage index- Assembly breakdown list- Flag notes-general notes- Standard drawing notes- Explanations of note symbols- Parts list index

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Electrical Wiring Diagramswiring diagrams typically identify each component within a system by its part number and its serial number, including any changes that were made during the production run of an aircraft.Some diagrams show only one circuit while others show several circuits within a system.

Schematic, DiagramsA schematic diagram is used to illustrate a principle of operation and, therefore, does not show parts as they actually appear or functionschematic diagrams do indicate the location of components with respect to each other and in the case of a hydraulic system, the direction of fluid flow. Because of this, schematic diagrams are best utilised for troubleshooting.

ATA 100

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The first number in the three-part subject number is the CHAPTER numberThe middle part of the number is the SECTION number and serves to identify all of the coverage pertaining to a system, subsystem and serves to identify the major functional system The last part of the number is the SUBJECT number and serves to identify all information relative to a specific unit,The four elements of page identification, which are located along the lower border are:(1) Chapter-Section-Subject Number(2) Page Number(3) Page Date(4)' Page Code Number

LIST OF EFFECTIVE PAGESThe list is a numerical list of effectiv~ pages for the chapter and is located at the beginning of the chapter.

NORMAL REVISION SERVICERevision service to this manual will be issued f~eqUentIY. Pages which are revised will be so indicated on the list of e1ective pages by an asterisk (") and identified by both a date and a [page code.

TEMPORARY REVISION SERVICE. printed on yellow paper, will be issued as necessary to alert the customer of configuratio differences and to provide temporary instruction prior to the next $cheduled revision.

MAINTENANCE MANUAL.Contains the information necessary to enable the mechanics to service, trouble-shoot, functionally check and repair all systems and equipment installed in the aircraft. The Maintenance Manual does not contain information relative to work normally performed on units or assemblies away from the aircraft.

Customised.The term customised indicates a manual that contains information applicable to a particular customer only.

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Effectivity.A six digit Effectivity code is located in the Effectivity block on each page. The first three digits indicate the first aircraft to which this Effectivity applies. Then there is a hyphen followed by a further three digits which indicates the last aircraft.

The Illustrated Parts Catalogue (IPC) contains information for use in provisioning, requisitioning, storing and issuing replaceable aircraft parts and units and in identifying parts.The Numerical Index is a complete alpha-numerical listing of all partnumbers contained in the Detailed Parts List of the Illustrated PartsCatalogue. The index is divided into two sections, NumericalIndex-Alpha and Numerical Index-Numeric.Illustrated parts catalogue.

When a number of parts on an Illustration are arranged in a rhythmic or straight line pattern and all parts in the pattern are the same, only the items on each end of the pattern will be indexed.

A double headed arrow is used to showa) Differences in configuration of parts between two parts. b) Illustrated dlfferences between optional parts .. The delivered on aircraft part are shown, tile optional parts areshown as variations.c) Differences between left and rigllt sides when the left is being shown as typical.

OVERHAUL MANUAL.

The Overhaul Manual consists of individual subject publications covering the overhaul of components used onaircraft, together with descriptive, disassembly, cleaning, inspection I check, repair, reassemble, functional test and parts identification information necessary to overhaul the part. Included in the Overhaul Manual are engine build-up procedures.Information contained in this publication coversitems which have been provisioned as "rotable" or "Repairabfe" items.This manual does not contain information relative to work normally performed on the line or in the maintenance operation. Instructions are furnished to enable an experienced mechanic to rebuild and fully test overhaulable assemblies removed from the aircraft.

The first number in the three-part subject number is the Chapter Number, and serves to identify the functional system to which the subject pertains.

The middle number is the Section Number and serves to group all the individual subjects which are related in a subsystem.

The last number identifies a specific subject and identifies and groups all pages relative to a specific assembly or component.

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WIRING DIAGRAM MANUAL.

The Wiring Diagram Manual (WDM) contains the information necessary to enable the electrician to troubleshoot, functionally check and repair all systems and electrical equipment installed in the aircraft. It covers the configuration of the aircraft as delivered to the customer. The manual consists of two volumes:

STRUCTURAL REPAIR MANUALContains material identification for structure subject to;Field repair typical repairs generally applicable to structural components of the aircraft that are most likely to be damaged.Information relative to material substitution. Fastener installation.Aircraft alignment check procedure.Where repairs are not included in the Manual, it does not follow that the structure concerned is non-repairable, but that the application of a typical repair has not been found to be practicable.

The material presented in this manual is divided into seven chapter under the following headings; -1. Structures General.2. Doors.3. Fuselage.4. Nacelles) Pylons5. Stabilisers6. Windows7. WingsEach Chapter is divided into sections which, in tum, consist of a group of related subjectA brief description of some procedures that must be performed concurrently with structural repair, such as protective treatment of the repair parts.

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ILLUSTRATED TOOL AND EQUIPMENT L I ST

The Illustrated Tool and Equipment List provides descriptive information, illustrations and explanations of the use of alldesigned tools, ground handling equipment and test equipment , maintenance and overhaul of the aircraft and the designed components installed on the aircraft.

Bolt and Hole SizesSlight clearances in boltholes are permissible wherever bolts are usedin tension and are not subject to reversal of load. A few of the appli cations in which clearance of holes may be permitted are in pulley brackets, conduit boxes, lining trim, and miscellaneous supports and brackets.Boltholes are to be normal to the surface involved to provide fullbearing surface for the bolt head and nut and must not he oversized or elongatedOversized or elongated holes in noncritical member's can usually be drilled or reamed to the next larger size.The fit of holes and bolts cannot he defined in terms of shaft and hole diameters; it is defined in terms of the friction between bolt and hole when sliding the bolt into place. it is permissible to use the first lettered drill size larger than the normal bolt diameter, except where the AN hexagon bolts are used in Iightdrive fit (reamed) applications and where NAS close-tolerance bolts or AN clevis bolts are used.Classes Of Fit Class 1 is a loose fit. Class 2 is a free fit.Class 3 is a medium fit.Class 4 fit is a close fit.Aircraft bolts are manufactured in the Class 3, medium fit. A Class 1 fit can easily be turned with the fingers. A Class 4 fit requires a wrench to turn the nut onto the bolt.

Precision manufactureGauge blocks are considered to be very accurate standards of length but even these are not exact.In, for example, manufacturing a shaft which has to run freely in a bearing, there must be enough space for a film of oil between the two in order to prevent wear.The difference between the maximum and minimum sizes (limits) is called tolerance. he ISO system of Limits and FitsThe ISO system of Limits and Fits gives a range of sizes to which parts should be made if the type of fir is known. The following list gives you examples of the types of fits used:

a) ClearancefitIn this assembly there is a space between the two parts. The shaft isalways smaller than the part it fits into.

b) InterferencefitIn thls assembly there is no space between the parts. The shaft is always larger than the part it fits into. This means that force is required to assemble the parts.

c) TransitionfitThis is a range of fits that can be either clearance or interference. The shaft can be larger or smaller than the part it fits into.

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TolerancesThe type of fit between two assemble parts depends on the size towhich each part is made.f the basic size (also known as the normal size) of the part is 25mm then the limits could be given as25.01 -Upper limit24.99-Lower limitIf you subtract the lower limit from the upper limit the reult is known as the tolerance.25.01 Upper limit24.99Lower limit

There are two systems of fits in use1) The Hole Basis System Of FitsThis is the preferred system. The range of fits is obtained by manufacturing the hole to a fixed size and the shaft size is varied. This system is preferred because reamers, for example, are made in a range of standard sizes2) The Shaft Basis System OF FitsIn this system the shaft is the fixed size and the hole sizes are varied. This system is sometimes used when a variety of components, e.g. bearings, couplings, gears etc. are all to fit the same shaft.

Bowing LimitsWhen testing a member for bow, the test must be done on that part of the member in which the section is uniform. There are two methods of testing a hollow member for bow. By using Straightedge and Feeler Gauge, or by using a Three Point Trammel.

Limit GaugesThe use of any system of limits and fits makes it possible to gauge the size of a componentsentially gauging a component is carried out to ensure that the actual size is within the limits of size. To this end you need two gauges 10r each basic size.one gauge for the upper limitone gauge for the lower limit

In practice the "go" and "not go" gauges are often combined. The go gauge should fit over the shaft. The not go gauge should not be able to pass over the shaft.If the "go" gauge did not fit over the shaft then the shaft diameter would be too large.If the "not go" gauge passes over the shaft then the shaft diameterwould be to small.

Adjustable thread calliper gaugesThe anvils of these gauge's can be set to the limit given on the data sheet.The go anvil is set to the upper limit. This anvil should pass over theshaft.The not go anvil is set to the lower limit. This anvil should not be able to pass over the shaft.

Gauging HoleThe "go" plug gauge is made to the lower limit.The "not go" plug gauge is made to the upper limit.If the "not go" plug gauge passes through the hole then the hole diameter is too large.If the "go" plug gauge does not enter the hole then the hole diameter is too small.

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Checking For Wear

Check Bearings For WearFirst radial wear should be measured by applying a reversing radial of ten to fifteen pounds and total diametrical play measured. A reversing load of the same magnitude should then be applied in an axial (thrust) direction and axial play measured.

Check Bearing Breakaway TorqueBreakaway preload torque checks are made by measuring the torque required to rotate one race with the other race fixed. The bearing must _ be free of lubricants or any other contaminants.

Check Bearing Rotational TorqueRotational preload torque checks are made by measuring the torque required to rotate one race with the other race fixed. The bearing must be free of lubricants or any other contaminants.

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