Book 6 Module 7A

CATEGORY B1 B2 ENGINEERING DRAWING

AERONAUTICAL STANDARDS

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issue number.

Licence By Post © Copyright B EASA 66 7A.5 ISSUE 07 1210

© Licence By Post No part of this study book may be re-produced or distributed in any form or by any means, or stored in a data base or retrieval system in whole or in part without prior written permission from Licence By Post. Books in the LBP series are regularly up-dated/re-written to keep pace with the changing technology, changing examination requirements and changing legal requirements.

AUTHORITY It is IMPORTANT to note that the information in this book is for study/training purposes only. When carrying out a procedure/work on aircraft/aircraft equipment you MUST always refer to the relevant aircraft maintenance manual or equipment manufacturer’s handbook. You should also follow the requirements of your national regulatory authority (the CAA in the UK) and laid down company policy as regards local procedures, recording, report writing, documentation etc. For health and safety in the workplace you should follow the regulations/ guidelines as specified by the equipment manufacturer, your company, national safety authorities and national governments.

WITH SPECIAL THANKS TO British Standards Institute (BSI) and the Civil Aviation Authority (CAA) for permission to reproduce drawings. Notes BSI, ISO and EN standards may be obtained on-line from www.standardsuk.com. CAA publications may be obtained on-line from

www.caa.co.uk/publications. Many official publications may be viewed free of charge on the net.

CONTENTS Page Engineering drawings 1

Drawing production 1 Validity 2

Types of orthographic drawing 5 Drawing layout 6 Drawing queries 8 Parts referencing systems 9

Types of drawing 10 Orthographic projection 10 Isometric drawing 12 Oblique drawing 13 Lines 14

Dimensioning 17 Sectioning and hatching 19

Abbreviations and symbols 19 Electrical symbols 26 Wiring codes 31

Wiring diagrams and schematics 32 Manufacturer’s manuals 34 The ATA100 (iSpec 2200) system 34 Standard manual topic referencing 34

AMTOSS codes 39 The FIN codes 43 Amendments/revisions to manuals 43 Engineering standard specifications 46

HOW TO TACKLE THIS BOOK The B1/B2 engineer should be able to ‘read’ an engineering drawing and understand the symbols, lines, conventions and the types of drawings used. You should be able to describe the process by which a drawing becomes an ‘approved’ drawing, how it is amended and what procedure to adopt if it is found to be in error. Technical drawings may be supplied as hard copy drawings; as part of the hard copy manual (AMM, SRM etc); in fiche (a type of film) or roll film format, or in soft copy form such as CDs. Fiche and roll film drawings are viewed on special large screen viewers, some with printer facilities so hard copies can be obtained. These types of viewers are becoming old fashioned. Drawings on CDs are viewed using a computer. It would be a good idea if you could look at drawings related to the aircraft you are working on and take note of: * The projection used. * The layout. * Any symbols used. * Any conventions used. * Any reference to standard specifications (BSI, SI etc).

* Authorisation and other qualifying signatures. * The title, drawing number, and issue number.

You should have a general knowledge of standard specifications, globally these range from additives in food-stuffs to technical drawing standards to engineering standards, but you should know about those related to engineering – aircraft engineering in particular. When working on aircraft/with publications/drawings take note of any reference to standard specifications. One or two of the more regularly used ones you should commit to memory. Note. Drawings from CAP562 may not be found in that publication due to amendment action by the CAA.

ENGINEERING DRAWINGS

As a human being the most effective way of inputting information to the brain is visually. This means that drawings are the best way of conveying an idea from one engineer to another. The designer works on an idea and puts it down on paper (or inputs it to a drawing programme on a computer), this is sent to the drawing office where a more formal drawing is produced and sent to workshops where the ‘idea’ is manufactured and turned into an artefact. The company will produce drawings for manufacturing purposes and for maintenance purposes. The designer/draughts-person must include in the drawing all the information to manufacture, assembly, install, inspect, modify or check the particular piece of equipment. The drawings must convey all the information necessary to manufacture and operate the equipment in a presentation that is easily understood by a competent engineer. If the item is just a single piece of equipment such as bolt then one designer can do the work of designing and producing all the drawing/s. When it comes to a complex item such as an aircraft, an engine, or a component then it will take a team of designers and a team of draughtsmen/women to complete the task – and this team (along with the thousands of drawings produced) will need a complete design and drawing office and a separate organisation just to control the design/drawing process. Drawing Production In general, a drawing is produced by an organisation and this is given a unique drawing number and title. This is entered in a drawing register together with details such as the designer, the draughts person, date etc. If the drawing is subsequently changed (a change not affecting interchangeability) then its issue number is changed. The register is than up-dated to include the new issue number and brief details of the change. If the change affects interchangeability then a new drawing is issued with a new drawing number. The drawing may be produced by a draughts-person using the old fashioned rule, pencil, drawing paper, T squares, drawing table etc – with the drawings stored flat in large draws. Paper designations commonly used are AO, A1, A2 and less commonly A3 and A4. These paper sizes are to specification ISO ‘A’ series specified in ISO216. There is a ‘B’ series which provides intermediate sizes. The sizing starts at 4A0 with a size 1682mm x 2378mm and each subsequent size is obtained by folding the paper in half. The following table shows some of the more important sizes. Note the half value in each case for the next smaller size.

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A SERIES B SERIES

CODE SIZE (mm) USES CODE SIZE (mm)

4AO 1682 x 2378

2AO 1189 X 1682

AO 841 x 1189 TECHNICAL DRAWINGS B0 1000 x 1414

A1 594 x 841 TECHNICAL DRAWINGS B1 707 x 1000

A2 420 x 594 FLIP CHARTS B2 500 x 707

A3 297 x 420 LARGE TABLES B3 353 x 500

A4 210 x 297 WRITING PAPER COPYING PAPER B4 250 x 353

TABLE 1 PAPER SIZES

Hard copy drawings are normally received by the maintenance engineer as either separate sheets of paper (the larger sizes rolled up in cardboard tubes) or as part of the usual range of aircraft manuals. Most drawing/design offices now do all their work on computers using one of several propriety brands of software packages. Each person may have his/her own computer or may be connected to one central computer for the whole office. This means that drawings can be completed on the screen with registration of each drawing in the drawing register being done automatically. Drawings are imported electronically into the manual and the manuals (AMM, SRM, IPC, FIM etc) are issued to the aircraft operators as a hard copy or on a CD (ROM). The CD is loaded into the computer and (sometimes) a code word has to be inputted (company password and operator password) to gain access. In some cases the same information can be down-loaded via the net using a subscription service and pass-word system. Drawings (and text) can be viewed on-screen and hard copy obtained via the printer. Drawings, whether hard copy or soft copy, must be issued by an approved organisation and certified as correct by the chief draughtsman/woman. Validity All aircraft and parts manufactured in the UK must be made and assembled in compliance with approved drawings and specifications. That is, drawings issued by an approved company (Primary Company or Design Organisation). It is the responsibility of the approved Inspection Organisation to ensure that all parts are ‘correct to drawing unless an appropriate concession has been issued.

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Drawing practice in the UK should conform to BS8888 (was BS308). It covers computer generated drawings as well as conventional hard copy drawings and deals with drawing practices world-wide. It is a specification and not a guidance document as was BS308 so tighter control can be exercised. Both standards will run together as drawings to BS308 will be in circulation for many years.

Design organisations amend both BS and SBAC systems to suit their own design office standards, so non standard symbols may be found in some aircraft drawings. For current projects, the ISO system for dimensioning and tolerancing of drawings is used (ISO 8015 – due to be replaced by ISO 14405), but at the present time, imperial units, terms and tolerances may be found on many drawings, particularly related to aircraft of American manufacture.

Drawing symbols may also be used that are specified in ATA100 (iSpec 2200) but again the specification allows the use of local, national and manufacturer’s symbols. The most common form of drawing used in engineering is called an Orthographic Projection.

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DRAWING FROM CAP562

Fig. 1 TYPICAL ORTHOGRAPHIC TECHNICAL DRAWING

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TYPES OF ORTHOGRAPHIC DRAWING Drawings are designed to perform specific functions and to that end will contain different information depending on the intended actions of the engineer.

Single Part (Detail) Drawing Shows all the information necessary to completely define an item to be manufactured or inspected, ie, shape, size, material, heat treatments, surface finish, etc. There may even be notes on the drawing as to specific operations such as casting details, machining details etc. Collective Single Part (Tabular) Similar to the above drawing but shows essentially similar items which have slight differences, ie washers of differing sizes, finish and/or material, rivets of differing lengths, special bolts etc. Assembly Drawing (figure 1) Shows the positioning of all the single parts necessary to make a component or part of a component and gives all the information necessary for its correct assembly. An essential part of the drawing is a Schedule of Parts which may be incorporated on the drawing or as a separate sheet. Items within the schedule will be referenced by ‘ballooning’ on the drawing or by grid referencing. For example, the items in the drawing above are referenced by ballooning and each balloon refers to the specific item in the table of parts. QUESTION With reference to figure 1. Why is the Parts List numbered from

the bottom up? (1 min) ANSWER This allows the draughts person to add parts as he/she thinks fit. QUESTION Can the list be numbered from the top down – and when? (2 mins) ANSWER Yes – if the parts list starts at the top of the drawing.

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Installation Drawing Issued when-ever it is necessary to specify the exact installation of components into an airframe engine or component (eg the aircraft fuel system into the structure). May be handed Left Hand or Right Hand.

General Arrangement (GA) Drawing Produced for main assemblies such as the fuselage, systems, etc, or sometimes parts of main assemblies. They usually indicate profile and overall dimensions and often internal details as well (sectioned). DRAWING LAYOUT

All drawings must bear the following information: * Descriptive title. * Drawing number. * Issue number. * Alterations list. * Name of approved issuing company. Much of this is in the Title Block of the drawing - except for the alterations list (bottom right hand side of the drawing in figure 1). Descriptive Title Kept reasonable short because of space limitations. May not mean too much on its own, but the drawing is positively uniquely identified by its drawing number and the name of the issuing firm. Drawing Number This positively identifies the drawing and appears at least once on the drawing. Its composition is up to the individual company design/drawing office. When a drawing comprises several sheets, each bears the same drawing number, but is annotated “sheet 1 of 3, sheet 2 of 3” etc. The drawing number may also be the Part Number of the item it describes. QUESTION The drawing number often appears in the top left hand corner of

the drawing up-side-down (figure 1). What is the reason for this? (2 mins)

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ANSWER Drawings are stored flat in draws and when searching for a particular drawing the whole sheet does not need to be disturbed as all the numbers are on the bottom right hand corner – it is just the corners of the sheets that need to be turned up to check the numbers. This applies to all drawings including any drawing put in the draw the wrong way round.

Issue Number and Alterations List The first drawing drawn and issued is issue 1 – although it will not be annotated as such. If the drawing is subsequently changed for any reason this change is noted in the Alterations List with date of entry and the Issue Number is added (issue 2). Thus it is important in that when referring to a drawing the correct Drawing Number is used and it is the correct Issue Number. Unaffected parts use the old issue number and new parts use the later issue number. If the change affects interchangeability then the drawing is re-issued with a new drawing number (issue 1) and the part/component is made to the new drawing specification and given a new part number. When the first drawing is produced the drawing office will allocate a number and title and record that number and title in the Drawing Master List. This will be in the master register either in bound book form or, more commonly, on a computer. The drawing office will record the details of any subsequent change in the Drawing Master List. Scale Rarely shown as all dimensions are indicated on the drawing and most drawings are either scaled up or scaled down anyway. A scale of 1:1 means that the drawing is full size. A scale of 1:2 indicates that the drawing is half size etc. Remember, you should not take dimensions straight off the drawing (using a rule or dividers etc). Even if the drawing has a scale of 1:1 the drawing could have shrunk or distorted due to the drawing manufacturing process. This means that all dimensions must be read from the drawing and not scaled. As the drawing says (figure 1) ‘DO NOT SCALE’.

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Handed Parts Refers to parts that are identical but are ‘handed. Just like the hands on the human body - they are the same - but opposite when viewed palm down on a flat surface. On drawings, may be shown as RH, LH, Port or Left, Starboard or Right. The convention on technical drawings is to have the left hand, upper, inner or forward part, taking the odd number part number and the opposite hand item to have the consecutive even numbers. This is not too unlike the FIN numbering system (see later pages). DRAWING QUERIES If you find some discrepancy between a drawing and the part you are working on then:

* Check the drawing title, who issued it, its number and issue number - that it is the correct one and up-to date.

* Check you are working on the correct equipment – part number -

description – IPC – aircraft type/variant and registration – engine type etc.

* Check the mod state of the part/component.

* Contact the issuing drawing office by telephone or email. State

drawing number, title and issue number and related equipment. * If the problem is still not resolved then raise a ‘Drawing Query’

form. Drawing Query Form If your company has a Drawing Control Office or Publications and Documents Control Office then the form is submitted to them – if not then you will have to submit it to the manufacturer yourself. If the drawing is in electronic format then an email should be sent to the manufacturer and/or their online drawing query form completed and sent. Details on the form should include a full description of the part being worked on (with photographs, hand sketches/drawings etc) to include formal name, part number, serial number and modification state.

Include any details if the problem affects other aircraft/equipment and, by-all-means, make any suggestions as to what might be the cause – if you think you know.

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The Drawing Query Form should have a unique identity number with all associated documents, photographs etc having connected reference numbers. A copy of all documents being sent should be made and an entry made in the Master List of Drawing Queries (held by the company). The results of the query could be: * An immediate provisional answer.

* Temporary fully approved answers in the form of a drawing office instruction.

* Permanent answer by means of a new or re-issued drawing. The Query Form and the Drawing Office Instruction should be identified on the amended/re-issued drawing. Any other affected documents/drawings should also be suitable cross referenced. If speed is of the essence then a telephone call to the manufacturer followed by faxed documents can get things started straight away. No doubt with some companies this can all be done on-line using scanned-in document evidence/photographs etc. PARTS REFERENCING SYSTEMS These are used to locate items on an orthographic drawing (and on other drawings). The most common systems used are the Grid Reference system and the Balloon Reference system. The Grid Reference system uses a letter reference column going up the right hand side of the drawing (figure 1) and a numbering line along the bottom of the drawing from right to left. QUESTION With reference to figure 1 identify the part grid reference D5.

(2 mins) ANSWER A ‘U’ shaped channel. The Balloon Reference system uses a ‘balloon with a leader line pointing to the item concerned. It is usually numbered and referenced to the Parts List on the drawing and possible to associated documents.

For example, in figure 1, item 6 is an ANGLE part number A2R 21 33 quantity 1 material L72 18SWG. This item was affected on the change of issue to issue 2 (check Drawing Changes top left hand side).

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The Parts List may be called a Parts Schedule. If any item does not have a Part Number then the material specification is usually used (as with the brackets in figure 1) and sometimes the annotation ND is put in the Ref No column (ND = No Drawing exists).

TYPES OF DRAWING Besides free-hand sketches (which have their place in the scheme of things) technical drawings can be produced in several formats. They can be Orthographic – which is what we have been talking about so far or they can be Axonometric. In general terms an orthographic drawing (or orthographic projection) is one where the part is viewed one side at a time, with several sides shown. An axonometric drawing is a pictorial drawing showing just the one view of the part. Figure 2 shows how the two main types can be broken down into several different systems.

TECHNICAL DRAWING

ORTHOGRAPHIC AXONOMETRIC

FIRST ANGLE T HIRD ANGLE ISOMETRIC OBLIQU E DIMETRIC CABINET CAVALIER

Fig. 2 DRAWING TYPES Orthographic Projection This form of drawing is predominant in engineering. It allows more precise details to be given of a part and allows for many views to be projected – including as many ancillary views as the draughtsman/woman requires. The basis of the system relies on a four quadrant framework with planes arranged at right angles to each other (ortho = at right angles to). This produces four angles of projection – 1st, 2nd, 3rd, and 4th. To avoid confusion only two angles are used 1st and 3rd. Both are approved internationally with equal status. Should the drawing warrant it a view can be projected for each side of the object (6 sides) with as many auxiliary projections produced as necessary.

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With First Angle projection the Front Elevation (FE) of the part is drawn in the plane of the paper and any side that is viewed is drawn on the opposite side of the FE. This means that the plan is shown at the bottom and the underneath view would be shown on the top (figure 3). With reference to figure 3. Consider the front elevation (B). Viewing B from the side (C) (left hand side) projects that side elevation onto the opposite side (right hand side) of the FE. The plan (as viewed from the top) is projected underneath the FE.

DRAWING FROM CAP562

Fig. 3 FIRST ANGLE ORTHOGRAPHIC DRAWING With Third Angle orthographic projection the Front Elevation is drawn in as before but all side views are projected on to the same side. This means that the plan is drawn on the top of the FE and side (C) is projected onto the same side (figure 4). Note that both drawings just show two views from the front view (FE) but could show many more if required. Also note the symbol in both cases indicating the angle of projection – also shown in figure 1. Considering a box has 6 sides so an orthographic projection can have 6 elevations (views) – if necessary. To add to this it can have an infinite number of auxiliary views. It is usual for orthographic projections to have 2 or three views.

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DRAWING FROM CAP562

Fig. 4 THIRD ANGLE ORTHOGRAPHIC DRAWING

Isometric Drawing

Iso means equal and refers to the equal angles subtended at the centre of an isometric cube (figure 5). Typical of all axonometric drawings this projection gives a good pictorial view of a part but can give problems when it comes to dimensioning and when trying to project other views.

The angles at the centre are 120°. All vertical lines are drawn vertically and all

horizontal lines are drawn at an angle of 30° to the horizontal. Lengths of all sides are drawn without changing the ratio. That is – with the cube shown in

figure 5 the lengths of the vertical lines are the same as the lengths of the 30° lines.

Fig. 5 ISOMETRIC PROJECTION OF A CUBE

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Oblique Drawing With this method of projection one side of the object is drawn in the plane of

the paper and the other sides are taken away at 45° ‘into’ the plane of the paper. Figure 6 shows the sides going into the plane of the paper up and to the right of the ‘front face’ but they can go to the left and down if necessary. As with the isometric projection it is an axonometric drawing. It shows a good ‘picture’ of the object but is difficult to dimension more complex objects and difficult to project other views. Figure 6 shows a Cabinet Oblique Projection of a cube. This means that the lengths going into the page are reduced by halve to make the object look more in proportion. Figure 7 shows the same cube but in Cavalier Oblique Projection with all sides having the ratio 1:1:1. Any dimensions shown on the drawing would be those of the actual object.

Fig. 6 OBLIQUE CABINET PROJECTION OF A CUBE

Fig. 7 OBLIQUE CAVALIER PROJECTION OF A CUBE

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Fig. 8 DIMETRIC PROJECTION

Variations of axonometric projections are used to suit different requirements. One such variation is called the Dimetric Projection (figure 8). Other drawings may show perspective – which means that lines going into the page tend to converge – just like when looking at the lines of a straight railway track from a bridge. Over a long distance they will converge to a point.

LINES Lines on a drawing can be continuous or dotted. Either sets of lines can be thick or thin and the dotted lines can be short dots or long dots. To add to this the lines on a drawing may be a combination of both. What ever type of line is used will give that line a meaning and you as an engineer will interpret that as a function. The following figure 9 and table 2 should be studied in conjunction with each other to the extent that you should have a reasonable knowledge of the more commonly used lines. The line types in table 2 are balloon referenced in figure 9. You should commit to memory the description and main application of the lines A to K in table 2.

In very general terms all lines are thin lines (about 0.3mm thick) except for outlines (about 0.7mm thick). This is a very general statement and does not hold true all the time – check table 2.

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DRAWING FROM BS308

Fig. 9 TYPES OF LINES

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TABLE FROM BS308

TABLE 2 TYPES OF LINE

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Dimensioning The following general rules apply:

* The whole drawing should be dimensioned in the same units, eg mm or inches. They should not be mixed up on the same drawing.

* Dimensioning should be clear, unambiguous and not duplicated.

* The figures should be read from the bottom of the drawing or from the right (see figures 1 and 10).

* The dimension figures should be placed on top of the dimension

line to which they refer or within a broken dimension line – but the drawing must be all the same style.

* Dimension lines are thin continuous lines with narrow filled in

arrows. * Projection lines are thin continuous.

* Ideally dimensions should be from a datum to help prevent accumulation of errors (figure 11).

* Tolerancing can be shown as in figure 12 but the drawing must

have the same style throughout.

* Any symbols used must be in accordance with BS8888 and placed in front of the value to which they refer.

* Screw threads should be dimensioned as per figure 13.

Fig. 10 DIMENSIONING

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Fig. 11 DIMENSIONING FROM A DATUM

Fig. 12 TOLERANCING

DRAWING FROM BS308

Fig. 13 DIMENSIONING THREADED PARTS

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Sectioning and Hatching Where more detail is needed a view may be sectioned (figures 9, 13 and 15). The section lines a thin continuous and are equally spaced across the sectioned area (spacing depending on the size of the area). Their angle can be any angle so long as it conveys to the engineer that it is a sectioned area (figures 14 and 15).

DRAWING FROM BS308

Fig. 14 HATCHING

DRAWING FROM BS308

Fig. 15 HATCHING ADJACENT PARTS

It is convention not to hatch some items, these include:

* Nuts, bolts, rivets, taper pins etc, when fitted as part of an assembly drawing.

* Webs – across their thick section.

ABBREVIATIONS & SYMBOLS

Used extensively in drawings, associated documents and aircraft manuals. The range is vast and what follows in this book is just a sample of those in more common use for the aircraft engineer. Many of these symbols are specified in standard specifications – see later text.

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DRAWING FROM BS308

Fig. 16 SCREW THREAD SYMBOLS Screw Thread Drawing Symbols (figure 16)

External (a) Stud side view.

(b) Stud end view. (c) Stud sectioned side view. (d) Stud sectioned end view. Internal (e) Hidden detail end view. (f) Blind hole side view hidden detail.

(g) Sectioned end view. (h) Blind hole side view (sectioned). (i) Hidden detail side view – thread passes all the way through.

(j) End view. (k) Sectioned side view – thread passes all the way through.

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One way of remembering screw thread symbols is to imagine cutting the screw thread. For an external (male) thread you start with a round rod and cut the thread into the rod, so the symbol has an unbroken circle on the outside and a broken circle on the inside. For an internal (female) thread you start with a hole and cut the thread into the metal on the outside of the hole, so the symbol has a continuous circle on the inside and a broken circle on the outside.

DRAWING FROM BS308

Fig. 17 SPLINES & SERRATED SHAFTS – SYMBOLS Figure 18 shows the usual form for showing repeated parts. This can apply to holes, rivets, bolts, brackets etc. Figure 19 shows how long parts can be reduced for drawing purposes – provided there is no change of any detail along the length. The top left picture shows a tube and the picture beneath shows a round solid bar.

DRAWING FROM BS308

Fig. 18 CONVENTION FOR REPEATED ITEMS

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DRAWING FROM BS308

Fig. 19 CONVENTION FOR INTERRUPTED VIEWS

DRAWING FROM BS308

Fig. 20 CONVENTION FOR BEARINGS

DRAWING FROM BS308

Fig. 21 FURTHER CONVENTIONS

Figure 20 shows the convention for showing bearings and figure 21 shows the symbols for showing various machinings on round bars.

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DRAWING FROM BS308

Fig. 22 MACHINING SYMBOLS Figure 22 shows machining symbols and conventions used in technical drawings. The symbol shows that the surface has to be machined and the numbers show the surface texture values (how smooth the surface has to be). Table 3 deals with commonly used abbreviations and symbols. Take a few moments to make sure you know what they all mean. Table 4 shows symbols used on drawings and associated documents used in overhaul facilities. You would not normally come across these too often but you should have, at least, some idea of their use.

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TERM

ABBREVIATION

TERM

ABBREVIATION

ACROSS FLATS ASSEMBLY BRITISH STANDARD CENTRES CENTRE LINE CHAMFERED CHEESE HEAD COUNTERBORE COUNTERSUNK CYLINDER or CYLINDRICAL DEGREE (angle) DIAMETER in text with a dimension FIGURE FULL INDICATED MOVEMENT HARDNESS - Brinell - Rockwell

- Vickers HEXAGON HEXAGON HEAD HYDRAULIC INCH INSULATED INTERNAL DIAMETER LEFT HAND LONG MACHINE MACHINED MATERIAL MAXIMUM MAXIMUM MATERIAL CONDITION MILLIMETER MINIMUM MINUTE of angle NOT TO SCALE NUMBER OUTSIDE DIAMETER

A/F ASSY BS CRS CL or C CHAM CH HD C’BORE CSK CYL ° DIA ∅ FIG FIM HB HR + letter scale HV HEX HEX HD HYD IN or “ INSUL I/D LH LG M/C M/CH MATL MAX MMC or M MM MIN ‘ NTS NO O/D

PATTERN NUMBER PITCH CIRCLE DIAMETER PNEUMATIC POUND weight RADIUS REFERENCE REQUIRED REVOLUTIONS PER MNUTE RIGHT HAND ROUND HEAD BRITISH ASSOCIATION BRITISH STANDARD FINE BRITISH STANDARD PIPE BRITISH STANDARD WHITWORTH UNIFIED COARSE UNIFIED FINE UNIFIED SPECIAL SCREWED SECOND of angle SHEET SKETCH SPECIFICATION SPHERICAL DIAMETER SPHERICAL RADIUS SPOTFACE SQUARE SQUARE INCH STANDARD STANDARD WIRE GAUGE TAPER THREADS PER INCH UNDERCUT VOLUME WEIGHT

PATT NO PCD PNEU LB RAD or R REF REQD RPM or REF/MIN RH RD HD BA BSF BSP BSW UNC UNF UNS SCR “ SH SK SPEC SPHERE ∅ SPHERE R S’FACE SQ SQ IN or IN2 STD SWG TPI U’CUT VOL WT

TABLE 3 ABBREVIATIONS & SYMBOLS

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TABLE FROM CAP562

TABLE 4 SYMBOLS USED ON PROCESS TREATMENT DRAWINGS & DOCUMENTS

Table 5 shows some of the symbols used on drawings to denote the geometry of an item – its position, form, attitude etc. Not often come across in assemble drawings but are used in drawings associated with machine work – single part drawings, detail drawings etc.

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TABLE FROM CAP562

TABLE 5 GEOMETRIC SYMBOLS Electrical Symbols The symbols used in electrical drawings and aircraft manuals, and wire identification codes, should conform to standards as laid down in ATA100 (iSpec 2200) standards or standards applicable to those specified in a particular country, or to those that conform to standards laid down for a particular manufacturer.

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When looking a different manufacturer’s manuals various symbols will be found representing a particular component. In some drawings/manuals a legend is provided while in others a drawing standard is specified. It is interesting to note that ATA100 (iSpec 2200) does not actually show any drawing symbols but refers the reader to other standards – in some respects like BS8888. The following table (table 6) is split up into 6a, 6b, etc and shows the most commonly used electrical symbols. You should study all the symbols and note what they mean.

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TABLE 6a ELECTRICAL SYMBOLS - 1

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TABLE 6b ELECTRICAL SYMBOLS - 2

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TABLE 6c ELECTRICAL SYMBOLS - 3

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Fig. 23 EXAMPLE OF AIRCRAFT WIRING CODE

Wiring Codes When a cable is manufactured by the cable manufacturer, data is printed on at regular intervals giving information such as cable manufacture’s name, cable size, cable ident codes etc. When the cable is fitted into the aircraft the aircraft manufacturer will give the cable another code relating to the circuit/system the cable is fitted into. Should also include a FIN code. This aircraft manufacturer’s code is either printed onto sleeves that are stretch fitted to both ends of the cable or, much more commonly, printed at regular intervals along the entire length of the cable. This printing usually being carried out automatically (once set up) by a machine using a heat printing process (it may also carry out electrical checks such as insulation checks on the cable at the same time). Figure 23 shows an example of an aircraft manufacturer’s code. While you should read and understand the details there should be no need to commit them to memory. The explanation of each element of the code is: (1) Used where components have identical circuits. (2) Indicates the circuit (and associate circuit) function.

(3) Allocated to differentiate between cables that do not have a common terminal in the same circuit. Beginning with the number 1 in the circuit with a different number being given to each cable.

(4) This identifies the segment of a cable between two terminals and differentiates between segments of the circuit when the same cable number is used throughout. Segments are given an alphabetical letter starting with A and missing out I and O.

(5) Cable size. (6) Indicates cable type and connection function.

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Fig. 24 AIRCRAFT WIRING CODE – EXAMPLE

Figure 24 shows an example of an aircraft manufacturers’ coding system on a drawing. Some manufacturers might use standard schemes, others might use their own. Most manufacturers include their name on the cable and also the trade name of the cable. Note that only 1 wire is used from component to component and most circuit drawings will have many wires. Note the similar code structure for each cable along each run. Note also the third digit change as the ‘cable run’ progresses from left to right.

WIRING DIAGRAMS & SCHEMATICS Issued by the manufacturer of the equipment/aircraft/engine to show the layout of a circuit or system without regard to the actual appearance of the components or their location in the aircraft. It is a line drawing showing components as squares or blocks and cables as lines. Each wiring diagram/schematic will have a title block similar to a technical drawing. It will show details such as: * Title. * Drawing number or code number.

* Issue number and/or date or amendment state or Change Letter.

* ATA reference number. * Number of sheets. * Aircraft/equipment applicability. * Names of designers, draughts-person, approval signature etc.

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They may be available in paper form or on CD. Many are produced in book form, for example the LAMM schematics for McDonnell Douglas. Should there be any conflict between a wiring diagram/schematic and production drawings then the production drawings are to be taken as the authority.

Fig. 25 EXAMPLE OF A WIRING DIAGRAM TITLE BLOCK

Wiring diagrams/schematics usually come with a location list, location drawings, master index, symbols legend, abbreviations list etc. The master index is the same as used for AMMs, IPCs, etc for cross referencing purposes. Schematics are drawn to ATA100 (iSpec 2200) standard and come in three levels.

First Level BLOCK DIAGRAM. System block diagrams with broad scope and little depth.

Second Level SIMPLIFIED SCHEMATIC. Have a less broad scope but

more depth than the block diagram. Contain schematic symbols but not individual wires. Are intermediate between First Level and Third Level.

Third Level SYSTEM SCHEMATIC. A detailed drawing with limited

scope but great depth. Shows all LRUs, functional wiring, and functional interfaces with other sub-systems.

A second level drawing is drawn if the complexity of the system is such that an overview of its operation is not possible with the third level drawing. A block drawing is produced if the system and sub-systems are of major complexity and it is the only way that a proper understanding of the complete system can be obtained. First and second level drawings are identified by a code (usually 4 digits) with the third level having an additional digit. On the schematic, all LRUs are identified by an ATA number which directs the reader to the schematic where the LRU is shown in detail. Wires will be coded using the ATA100 (iSpec 2200) codes.

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MANUFACTURER’S MANUALS Published by the manufacturers of aircraft and equipments. To be used during the maintenance, overhaul, and repair of aircraft, engines, and equipment. Manuals published by manufacturers include – Aircraft Maintenance Manual (AMM), Illustrated Parts Catalogue (IPC), Overhaul Manual, Structural Repair Manual (SRM), Wiring Manual, Fault Isolation Manual (FIM) etc. Each must have a ‘Statement of Initial Certification’ - that it conforms to BCARs (A5-3) - signed by the manufacturer. (BCARs are slowly being superseded by JARs and EASA regulations, but are still current as aircraft are still flying that have been certified under the BCAR standard.) All manuals must conform to ATA*100 specification (ATA iSpec2200) as far as layout is concerned. May also be issued as an IBM Word For Windows compatible disc (on CD ROM – Read Only Memory). * ATA = Air Transport Association – based in America.

THE ATA ISPEC 2200 SYSTEM STANDARD MANUAL TOPIC REFERENCING Prior to the introduction of the ATA100* standard presentation of technical data in the manufacturer’s manuals was not laid out to any standardised format. Consequently, for example, the subject of towing was found in chapter 9 of the Vicker’s manual, but in the De Haviland manual it was in a different chapter. This meant confusion, time wasting, and inconvenience for operators working with different types of aircraft. With the introduction of the ATA100 (now iSpec 2200) standard a particular subject could be found in the same chapter irrespective of the aircraft manufacturer – Airbus, Boeing, Fokker etc. Every chapter in each manual for all aircraft will have an unchanging chapter number and title. The chapter numbers are grouped under headings, the order of which is largely alphabetical. The chapters listed below do not necessarily occur in all manuals – for example, chapters 5 to 10 will be in the AMM only.

* ATA100 and ATA2100 (Digital Data Standards) have been combined into ATA iSpec 2200.

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Chapters FOR OPERATOR USE ONLY CHAPTER 1 to 4 Reserved for airline use AIRCRAFT GENERAL CHAPTER 5 Time limits/Maintenance checks

6 Dimensions & charts 7 Lifting & shoring

8 Levelling & weighing 9 Towing & taxiing 10 Parking & mooring 11 Required placards

12 Servicing 13 to 19 These chapters are left unassigned for any additional data

the manufacturer may wish to include at a later date.

AIRFRAME SYSTEMS CHAPTER 20 Standard practices - airframe

21 Air conditioning 22 Auto flight 23 Communications 24 Electrical power 25 Equipment/Furnishings 26 Fire protection 27 Flight controls 28 Fuel 29 Hydraulic power 30 Ice & rain protection 31 Instruments 32 Landing gear 33 Lights 34 Navigation 35 Oxygen 36 Pneumatics

37 Vacuum 38 Water/Waste

39 to 48 These chapters are unassigned for additional data that may be required at a later date.

49 Airborne auxiliary power

continued

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AIRFRAME STRUCTURES CHAPTER 50 Unassigned

51 Structure 52 Doors 53 Fuselage 54 Nacelles/Pylons 55 Stabilisers 56 Windows 57 Wings

58 to 59 Unassigned PROPELLERS CHAPTER 60 Standard practices prop/rotor

61 Propellers 62 to 64 Unassigned

65 Rotors 66 to 69 Unassigned POWER PLANT CHAPTER 70 Standard practices engine

71 Power plant 72 Engine 73 Engine fuel & control 74 Ignition 75 Air 76 Engine controls 77 Engine indicating 78 Exhaust 79 Oil 80 Starting 81 Turbines 82 Water injection 83 Accessory gear boxes

84 to 89 Unassigned GENERAL CHAPTER 90 Unassigned

91 Charts

Sections Each chapter is broken down into Sections. Each section deals with a subject area within it’s chapter eg, section 10 of chapter 73 deals with ‘distribution’ and is written as 73 – 10.

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Subjects Each section is divided into Subjects eg, subject 41 of Section 10, Chapter 73 deals with ‘Fuel Pumps’ and is written 73 – 10 – 41.

Composition The three elements – Chapter, Section, and Subject are each made up of 2 digits and go to make up the ATA100 (iSpec 2200) page numbering system, eg:

73 – 10 – 41

FIRST ELEMENT SECOND ELEMENT THIRD ELEMENT

73 - 10 - 41 CHAPTER SECTION SUBJECT eg ENGINE FUEL eg DISTRIBUTION eg HP FUEL PUMP & CONTROL Page Numbering (topics) In addition to the ‘three element’ system, the subjects are further broken down in order to provide ‘topics’. This makes for easier referencing. The system uses standard page numbering but the numbers are grouped in blocks. TOPIC PAGE BLOCKS

Description & operation (D & O) 1 to 99 Fault isolation (FI) 101 to 199 Maintenance practices (M/P) 201 to 299

Each topic is made up of several sub-topics, ie, ‘Maintenance Practices’ is made up of the following sub-topics: Servicing; Removal/installation; Adjustments/ tests; Inspection/checks; Cleaning/painting; Approved repairs. Where these sub-topics are brief they will all be dealt with under the topic heading ‘Maintenance Practices’. Where the sub-topics are lengthy and their combination would require many pages, then each sub-topic is treated as a topic. The standard page numbering would continue as follows (next page):

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TOPIC PAGE BLOCKS Servicing (SRV) 301 – 399 Removal/installation (R/I) 401 – 499 Adjustment/test (A/T) 501 – 599 Inspection/check (I/C) 601 – 699 Cleaning/painting (C/P) 701 – 799 Approved repairs (AR) 801 – 899 Dispatch deviation 901 – 999 The ‘three element number’ together with the page number will appear on the bottom right hand corner of each page (figure 26).

73-10-41 Page 203

Fig. 26 PAGE IDENTIFICATION

Overhaul Manual Page Numbering TOPIC PAGE BLOCK

Description & operation 1 to 99 Disassembly 101 to 199 Cleaning 201 to 299 Inspection/check 301 to 399

Repair 401 to 499 Assembly 501 to 599 Fits & clearances 601 to 699 Testing 701 to 799 Trouble shooting 801 to 899 Storage instructions 901 to 999

Special tools fixtures & equipment 1001 to 1099 Illustrated parts list (where applicable) 1101 to 1199

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AMTOSS CODES The AMTOSS (Aircraft Maintenance Task Orientated Support System) code is a two/three digit code for use when recording the actual tasks performed on aircraft. The code is used on work cards/job cards/computer records etc so when work done is recorded on automated data storage systems the referencing/retrieval of the data is made easier.

This code is part of the ATA100 (iSpec 2200) system and can be found be in some AMMs. Having said this Airbus (and presumably other manufacturers) can supply manuals with or without the AMTOSS code. (With at least one airline the code has lead to confusion and a near serious accident – an Airbus aircraft taking off with the spoilers on one wing deployed [after maintenance work], but the pilot managed, with some difficulty, to go-around and land the aircraft safely.) Procedures on aircraft are standardised into the following structure: Tasks are procedures for specific maintenance requirements. For example: R/I page blocks normally contain two tasks:

1. Removal of the LRU. 2. Installation of the LRU.

A/T page blocks may contain three tasks:

1. Operational test of the system. 2. Functional test of the system. 3. System test of the system.

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1. General 2. (TASK)

A. General B. Equipment C. Consumable Materials D. Parts E. References F. Access G. (TOPIC)

(1) (SUB-TASK) (a) Sub-step (b) Sub-step (c) Sub-step

(2) (SUB-TASK) (3) (SUB-TASK) (a) Sub-step

TOPICS are generic headings used in tasks to group sub-tasks. There are one or more topics in each task. SUB-TASKS are the major action steps in tasks. A sub-task refers to specific equipment. For example, ‘Disconnect hydraulic lines’ is a sub-task. Separate skill requirements are put in separate sub-tasks.

For example, a step involving hydraulic pipelines is never combined with an action involving electrical wiring.

All tasks and sub-tasks are coded with an AMTOSS identification code in the AMM unless specified by the operator. A typical AMTOSS identification codes would include the task and the sub task. For example: Task: ATA100/iSpec 2200 code Page Paragraph Task 29-11-05-404-001-002 This code refers to the

installation of the engine driven hydraulic pump.

Sub-Task: AMTOSS Function Code S874-001-002 The code 87 refers to the

bleeding of air from the hydraulic system.

Listed below are the AMTOSS function codes. It should not be necessary to commit them to memory, but you should have some knowledge of them. 00 REMOVAL

01 REMOVE/OPEN FOR ACCESS 02 REMOVE UNIT/COMPONENT 03 DISCONNECT/LOOSEN/REMOVE ITEM 04 DEACTIVATE 07 ERASE ELECTRONICALLY STORED DATE 08 REMOVE TEST EQUIPMENT 09 REMOVE SUPPORT EQUIPMENT

continued

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10 CLEANING

11 CHEMICAL 12 ABRASIVE 13 ULTRASONIC 14 MECHANICAL 15 STRIPPING 16 MISCELLANEOUS CLEANING 17 FLUSHING

20 INSPECTION/CHECKS

21 GENERAL VISUAL 22 DETAILED DIMENSIONAL 23 PENETRANT 24 MAGNETIC 25 EDDY CURRENT 26 X-RAY/HOLOGRAPHIC 27 ULTRASONIC 28 SPECIFIC/SPECIAL 29 BOROSCOPE

30 REPAIR

31 WELDING/BRAZING 32 MACHINING/REAMING/BLENDING 33 COMPOSITE 34 FIBREGLASS/PLASTIC/HONEYCOMB/EPOXY 35 MISCELLANEOUS REPAIR 36 LEAKAGE REPAIR 37 PAINTING 38 PLATING 39 SEALING

40 INSTALLATION

41 INSTALL/CLOSE ITEMS REMOVED/OPENED FOR ACCESS 42 INSTALL UNIT/COMPONENT 43 INSTALL ITEM/RECONNECT/TIGHTEN/SAFETY 44 REACTIVATE 47 LOAD ELECTRONICALLY STORED DATA 48 INSTALL TEST EQUIPMENT 49 INSTALL SUPPORT EQUIPMENT

continued

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50 MATERIAL HANDLING

51 SHIPPING 52 RECEIVING 53 PACKING 54 UNPACKING 55 STORAGE 56 MARSHALLING 57 ENGINE FERRY/POD MAINTENANCE 58 AIRCRAFT HANDLING

60 SERVICING/PRESERVING/LUBRICATING

61 SERVICING 62 PRESERVING 63 DEPRESERVING 64 LUBRICATING 65 FUELING/DEFUELING 66 DE-ICING/ANTI-ICING 67 DISINFECT/SANITISE 68 DRAIN FLUID

70 TESTING/CHECKING

71 OPERATIONAL 72 FUNCTIONAL 73 SYSTEM 74 BITE 75 SPECIAL 76 ELECTRICAL 78 PRESSURE 79 LEAK

80-99 MISCELLANEOUS

81 FAULT ISOLATION 82 ADJUSTING/ALIGNING/CALIBRATING 83 RIGGING 84 PREPARE FOR…/RESTORE…TO NORMAL 85 OPERATOR MODIFICATION INCORPORATION 86 AIRCRAFT/SYSTEM CONFIGURATION 87 BLEEDING 88 HEATING/COOLING 90 CHANGE = REMOVE + INSTALL 91 STANDARD PRACTICES 93 MARKING 94 JOB SET-UP/CLOSE-UP 95 MASKING 96 REPLACE 97 DATA RECORDING/CALCULATING 98 MANUAL OPERATION OR POSITIONING 99 ILLUSTRATIONS

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THE FIN CODE The equipment on the aircraft is identified by a unique identification number called a Functional Item Number (FIN). The basic element of the FIN is a two letter code indicating the system/circuit that the equipment belongs to. To this code are added suffixes and/or prefixes which provide the unique identification number for that item of equipment in that system/circuit. For example: 2CA1 PREFIX. SECOND CIRCUIT LETTER SUFFIX. FIRST OF

COMPONENT CODE SEVERAL SIMILAR IN CIRCUIT CA SYSTEMS

If components are handed, even suffixes indicates a component on the right-hand side and odd numbers indicate a component on the left-hand side. More details of the actual aircraft FINs can be found in the: * Aircraft Schematic Manual (ASM) * Aircraft Wiring Manual (AWM) * Aircraft Wiring List (AWL)

AMENDMENTS/REVISIONS TO MANUALS Manufacturer’s review their manuals frequently and change them as required. Changes are brought about because of: * Aircraft modifications. * Correcting errors in the manuals - technical or typing errors. * Modifying the manual in the light of experience. This means that amendments are issued as required. Holders of manuals are responsible for ensuring that their copies are kept up to date and engineers that use the manuals are also responsible for ensuring they are up-to-date before issuing any certification (CRS) (AN3 – now moved to CAP 562).

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Amendments for manuals are issued on: Yellow paper – temporary. White paper – permanent.

They are also accompanied by a ‘Letter of Transmittal’ on which the issuer certifies the accuracy of the information and gives instructions as to what to do. Manual holders should check the authenticity of these letters.

Cassette/CD Rom Systems Used by many organisations instead of hard copy manuals to include AMMs, IPCs, FIMs, manufacturer’s drawings etc. CDs are usually used with a PC, lap-top, or similar computer incorporating a screen and printer. Cassettes use film and a film projector/copier. Cassette/CD systems reduce storage space (the CD/cassette can be put away in a drawer whilst manuals for a large aircraft will take up a lot of shelf space) and are more convenient to use – though if you have trouble with the hardware (computer/cassette reader etc) this may not be the case. Film Systems Microfilm cassettes are used with a Cassette Reader using a lens and lamp system to project the images (pictures and text) onto a built-in screen. The film (simply pages of text and pictures in black and white) is wound forward or backward (similar to a video) using a in-built electric motor. Some cassette readers have a facility to print hard copy via a printer.

Microfiche is another method of storing technical information – drawings or otherwise. Again it is a film system where photographs are taken of each page of the manual (as for microfilm) and miniaturised. These are put onto a negative microfiche film about 10cm by 15cm. Each microfiche film will contain hundreds of pictures (pages) and the films are stored in indexed boxes. To view a film it is placed on a glass platter within a lamp and lens system and the pictures are projected onto a screen. The screen enlarges the pictures so they are readable. The platter is moveable so it can be moved back and forth as well as sideways to view the appropriate image. The platter is moved a very small amount to move from one page to another. An index of pages is provided to assist in location. They do not normally have printer facilities attached and both film systems above are old and not used much.

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Computer Systems These allow the user to view the pages of the manual (including drawings) on the screen and print what-ever hard copies he/she wishes for use at the work location.

Hard copies (from the printer) obtained by this system are usually used once only, and therefore handling damage/deterioration is not a problem, as with hard copy manuals. If a subscription service is provided manuals and technical documents can be viewed on-line via the web. Computers used include desk-top computers, lap-tops (specially made – toughened - for engineering purposes and body mounted voice commanded computers with a miniature screen fitted to a head band and placed in front of the eye of the operator.

Fig. 27 HANDS FREE BODY MOUNTED COMPUTER

Amendments are carried out by the issue of a new CD/cassette/fiche. Each CD/cassette/fiche must be clearly marked as to its amendment state and more recent amendments must be recorded and kept in a folder which should be kept next to the viewer.

Engineers, using these systems, must ensure that they have checked both the CD/cassette/fiche and the folder to ascertain the correct amendment state. For computer systems, some manufacturers only allow access after inputting the operator’s access code and a user code, for others, assess codes are not required. On-line systems are kept up to date by the manufacturer. Check your company’s system. NB. Aircraft constructors may produce their own systems which may require that users are trained in their use.

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ENGINEERING STANDARD SPECIFICATIONS

There is a vast array of engineering standards, some local to a particular manufacturer, some national and others international. The aim of standard specifications is to provide a documented system for the economical production of artefacts (in this case components for aircraft) that allow interchangeability and standard procedures (engineering or administrative) and a common means of presenting information. Examples:

Production – nuts and bolts to standard sizes and materials, PCBs to standard layout, etc (PCB = Printed Circuit Board).

Procedures – stores procedure, quality control procedures etc.

Information – layout of maintenance manuals (ATA100/iSpec 2200), drawing symbols and layout (BS8888) etc.

Local Standards Most firms will have standard procedures (published or otherwise) associated with sales, accountancy, procurement, manufacture etc. In many cases the firm will adopt national or international standards for these areas.

Manufacturing parts for aircraft, for example, will require documentation procedures, manufacturing procedures and quality control procedures as required by the CAA and these will all meet national, European and international standards. National and international standards are agreed standards within the industry they concern. They are not imposed on anyone and any organisation or individual can ignore them if they/he/she wishes. If the standard is generally recognised throughout the industry it would be folly to ignore it.

If, for example, when designing an aircraft all the rivets where to be made to non standard sizes and materials, the rivet manufacturer would have to put his prices up – putting the price of the aircraft up and possible putting prospective customers off because of the difficulty of getting spares.

Not to mention the fact that the CAA might not give it a C of A because the rivets do not conform to the required standards. You can still build the aircraft – but it may not fly. Governments, of course, can make standards compulsory.

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History (should not be examinable but does give perspective to the issue of standards) ‘Standards’ are not new. Possible the first attempt at standardisation was in the area of speech and the writing of music. Later in 1215 the Magna Carta (signed at Runnymede in the UK) famous for declaring that men can only be tried by their equals also stated that there should be a standard measure throughout the realm for ale, wine, corn and cloth. Engineering standards go back nearly as long, with a flourish in the number of standards produced coming with the industrial revolution. In 1880 Sir Joseph Whitworth (of Whitworth screw thread fame) complained about the non standardisation of candles and candle holders. Initially standards were local to an area (the Newall system for example, was associated mostly with the North of England). Electrical engineers where one of the first to recognise the need for international standards and in 1906 the International Electrotechnical Commission (IEC) was founded. Today it is composed of over 40 national committees with the UK BSI acting for the British IEC committee. In 1926 the ISA was formed, to be replaced in 1947 (after the war), by the ISO (International Organisation for Standardisation). ISO is the international standards agency for all areas except those covered by the IEC. The ISO promotes the development of international standards from over 90 different national standards authorities with BSI (for the UK) being a leading member. All authorities have the right of representation on the various committees. The European Committee for Standardisation (CEN) was founded in 1961 and comprises the national bodies of the EU and other European countries. When CEN publishes European standards they are adopted as national standards by the countries approving them. CENELECT is the electrotechnical equivalent of CEN. National Standards/International Standards

All parts used on aircraft have to conform to either national or international standards. In some cases a local standard has, because of usage, become a national standard and sometimes developed later into an international standard.

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The range of standard specifications is vast and growing all the time. Older (national) standards are being replaced by EN (European) standards and international (ISO) standards. Listed below are just some that are related to aircraft engineering (to keep fully abreast of all the changes you are advised to use the internet):

* AC. Air Corp standard. An older American standard.

* AN. An American Army/Navy standard that is used for many small parts on aircraft. Tends to be found on older aircraft.

* BSI. British Standards Institute. Used widely in the UK for all

aspects of aircraft engineering including manufacture (eg aluminium alloy made to BSL86 specification), information (eg drawings drawn to BS8888 standard).

The BSI has 14 classifications from Commercial to Health and

Safety including Materials, Manufactured Components, Quality Control etc.

Some further examples:

BS 8888 Engineering drawing practice (was BS308). This

standard is a standard in its own right but also acts as a reference to other standards, eg:

ISO 128 International standard for the production of technical drawings.

ISO 7573 Technical drawings – item lists. ISO Tolerancing.

BS 5070 Drawings – symbols. ISO 7200 Title blocks and data fields.

BS EN ISO standards cover many areas including software drawing systems, dimensioning, tolerancing etc (EN = European Norm).

BS EN 22553 Welding, brazing and soldering symbols. BS 2917 Symbols for fluid power systems. BS 3939 Electrical and electronic symbols. Now

withdrawn and replaced with BS EN 60617. BS EN 60617 Electrical/electronic symbols. BS EN 20286 Limits and fits.

* DTD. Directorate of Technical Development. An (older) UK based

standard, eg DTD585 – hydraulic fluid.

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* MIL. (Military) A US military standard common to all the US services and used widely for the specification of oils, fuels, equipments etc on civil aircraft. May be written as MIL-SPEC, MIL-STD etc.

* MS. Military Standard. American. Example: MS20470 AD 5-12

denotes a rivet (size, shape of head and material).

* NAS. National Aerospace Standard. UK based.

* SBAC. Society of British Aerospace Companies. Specifications relating to aircraft parts.

* ISO. International Organisation for Standardisation. Has 40 ‘fields’

of interest from Sociology to Domestic Equipment. Of interest to the aircraft engineer is field 49 (the 40 fields are not numbered consecutively). This has sub fields on:

Materials

Fasteners Components Structure Engines Electrical equipment Instruments Cabin equipment

Cargo equipment etc.

* ATA. The ATA100/iSpec 2200 system is well known throughout civil aviation, but less well known are the other standards ATA produce. ATA is a voluntary US industry agreement association covering many areas in aviation. Just a few are:

100 Technical data presentation 101 Ground equipment 103 Jet fuel quality 104 Training 105 Training for NDT 106 Approved parts 107 Visual inspection

111 Airworthiness co-ordination 113 Human factors 117 Wiring

2100 Digital standards (now incorporated into ATA iSpec 2200)

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Additional standards organisations include (national & international):

AECMA Association Europeene des Constructeurs de Material Aerospatial

AFNOR French Standards CEC Canadian Electrical Code CECC Electronics Components Committee CGSB Canadian General Standards Board CSA Canadian Standards Association DIN German/English Standards EUROCAE European Organisation for Civil Aviation Equipment JIS Japanese Standards SA Standards Australia VDE Verband Deutscher Elektrotechniker VDI Vereins Deutscher Ingenieure AN Air Force-Navy Aeronautical Standard Drawings AND Air Force-Navy Aeronautical Design Standards DODISS Department of Defence Index of Specifications & Standards FAA Federal Aviation Administration Standards FIPS Federal Information Processing Standards AIA Aerospace Industries Association ANSI American National Standards Institute ARINC Aeronautical Radio Inc SAE Society of Automotive Engineers

”””””””

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