Engineering Drawing, Diagrams, and Standards PDF

Engineering Drawing Symbols Electromechanical Valve Symbols The following tables show symbols that are typically encountered in engineering drawings: Electro mechanical valve symbols 2023-11-24 B-07b Maintenance Practices CASA Part 66 - Training Materials Only Page 316 of 498 Hydraulic and Pneumatic...

Engineering Drawing Symbols Electromechanical Valve Symbols The following tables show symbols that are typically encountered in engineering drawings: Electro mechanical valve symbols 2023-11-24 B-07b Maintenance Practices CASA Part 66 - Training Materials Only Page 316 of 498 Hydraulic and Pneumatic Symbols Hydraulic system symbols Hydraulic and pneumatic system symbols 2023-11-24 B-07b Maintenance Practices CASA Part 66 - Training Materials Only Page 317 of 498 Electrical Symbols Common electrical symbols Welding Symbols Welding symbols 2023-11-24 B-07b Maintenance Practices CASA Part 66 - Training Materials Only Page 318 of 498 Types of Drawings Engineering Drawings As an aircraft engineer, you must become familiar with several types of drawings and graphic representations. Each type of drawing is designed to transmit a certain piece of information. Different drawing types include: Working drawings Sectional drawings Exploded views Block diagrams Logic flow charts Electrical wiring diagrams Pictorial drawings Schematic drawings. 2023-11-24 B-07b Maintenance Practices CASA Part 66 - Training Materials Only Page 319 of 498 Working Drawings Working drawings are the most common of these drawings. There are three types: detail assembly installation. Detailed Drawings When an aircraft is designed, a detail drawing is made for every part. A detailed drawing supplies all the information required to construct a part, including: All dimensions Materials Type of finish. Example of a detailed drawing 2023-11-24 B-07b Maintenance Practices CASA Part 66 - Training Materials Only Page 320 of 498 Example of a detailed drawing - A gyroscope flywheel 2023-11-24 B-07b Maintenance Practices CASA Part 66 - Training Materials Only Page 321 of 498 Assembly Drawings After individual parts are fabricated, they are assembled into various sub-assemblies with the aid of an assembly drawing. An assembly drawing depicts the relationship between two or more parts. These drawings reference individual parts by their: Description Part number Fastener types Numbers needed. Example of an assembly drawing 2023-11-24 B-07b Maintenance Practices CASA Part 66 - Training Materials Only Page 322 of 498 Aviation Australia Example of an assembly drawing found in an AMM (Note: Part numbers are removed, but would typically be included) 2023-11-24 B-07b Maintenance Practices CASA Part 66 - Training Materials Only Page 323 of 498 Installation Drawings All sub-assemblies are brought together in an installation drawing. This type of drawing shows the general arrangement or position of parts with respect to an aircraft and provides the information needed to install them. Like the assembly drawing, the bill of material on an installation drawing lists the fasteners needed as well as any instructions required for the installation. Dimensions are given only for adjustments necessary for the part to function. Aviation Australia Example of simplified drawing showing assembly installation in relation to the aircraft 2023-11-24 B-07b Maintenance Practices CASA Part 66 - Training Materials Only Page 324 of 498 Exploded Views Illustrated parts drawings often use exploded view drawings to show every part in an assembly. In this type of drawing, all parts are typically in their relative positions and expanded outwards. Each part is identified by both its physical appearance and its reference number, which is used on the parts list. Assembly drawings and installation drawings often make use of the exploded view. Exploded view drawing 2023-11-24 B-07b Maintenance Practices CASA Part 66 - Training Materials Only Page 325 of 498 Sectional Drawings Four types of sectional drawings are used to illustrate the internal shape of a part: Revolved section Removed section Half section Complete section. A revolved section illustrates simple items with no interior parts. A portion of an object is revolved to show a different view. A removed section illustrates simple objects by using a cutting plane line. Revolved and removed section drawings The half-sectional view allows the inside and outside of a part to be seen at the same time. The complete sectional view allows only the inside to be seen. 2023-11-24 B-07b Maintenance Practices CASA Part 66 - Training Materials Only Page 326 of 498 Half-section view Full sectional view with revolved top and side view 2023-11-24 B-07b Maintenance Practices CASA Part 66 - Training Materials Only Page 327 of 498 Half cross-sectional view with revolved top and side view 2023-11-24 B-07b Maintenance Practices CASA Part 66 - Training Materials Only Page 328 of 498 Block Diagrams With electrical systems and electronic components becoming more complex, procedures and graphical aids have been developed to aid you in locating problems. A block diagram consists of individual blocks that represent several components or replaceable modules. Troubleshooting consists of identifying and replacing a malfunctioning sub-assembly, and block diagrams greatly enhance this process. © Aviation Australia Example of a block diagram - Electronic Centralised Aircraft Monitor (ECAM) 2023-11-24 B-07b Maintenance Practices CASA Part 66 - Training Materials Only Page 329 of 498 Logic Flow Charts Logic flow charts are another aid used in troubleshooting. A logic flow chart represents the mechanical, electrical or electronic action of a system without expressing construction or engineering information. When using a logic flow chart, go to the oblong START symbol and follow the arrows through the logical testing sequence. On most flow charts, rectangular boxes explain a procedure, while diamonds identify questions that require a specific answer. In other words, after using a rectangular box to test something, you must match the existing condition before proceeding to the next course of action. Each diamond has one input and at least two outputs. To ensure that all discrepancies are addressed, you must follow a flow chart to the oblong END OF TEST symbol. In addition to identifying the probable cause of a problem, many flow charts specify a fix for each circumstance. Using this information reduces troubleshooting time to a minimum. Logic flow chart 2023-11-24 B-07b Maintenance Practices CASA Part 66 - Training Materials Only Page 330 of 498 Electrical Wiring Diagrams Electrical wiring diagrams are included in most aircraft service manuals and specify things like the wire identification and terminal types to be used for a particular application. Furthermore, wiring diagrams typically identify each component within a system by its identification number (including wire gauge, aircraft section or zone, wire source and destination) and any changes that were made during the production run of an aircraft. Because of this, wiring diagrams are extremely valuable for troubleshooting. Wiring diagram Example of a simple electrical wiring diagram 2023-11-24 B-07b Maintenance Practices CASA Part 66 - Training Materials Only Page 331 of 498 Schematic Diagrams A schematic diagram is used to illustrate a principle of operation and therefore does not show parts as they actually appear or function. However, schematic diagrams do indicate the location of components with respect to each other, and in the case of an air conditioning system, the direction of flow. Because of this, schematic diagrams are best utilised for troubleshooting. Example of a schematic - A B777 hydraulic system 2023-11-24 B-07b Maintenance Practices CASA Part 66 - Training Materials Only Page 332 of 498 Pictorial Diagrams Pilot’s handbooks and some training manuals often use pictorial diagrams of electrical and hydraulic systems. A pictorial diagram contains pictures of components instead of the conventional electrical symbols found in schematic diagrams. In most cases, pictorial diagrams help a person visualise the operation of a specific system. Pictorial diagrams 2023-11-24 B-07b Maintenance Practices CASA Part 66 - Training Materials Only Page 333 of 498 Methods of Illustrating Introduction to Methods of Illustrating The methods of illustrating a part refer to its orientation with respect to how it is viewed on a flat plane. Methods of illustration common to the aviation maintenance industry include: Orthographic projection Isometric drawing Oblique drawing. Orthographic Projection Most drawings used in the construction of a detailed part are drawn using the orthographic projection. This method provides six possible views from which an object can be drawn: 1. Front 2. Rear 3. Top 4. Bottom 5. Left side 6. Right side. Orthographic projection Each view is drawn as if you put an object in a transparent box and viewed it from one of the box faces. All rays extending from the part are parallel and perpendicular to the side they are viewed from. 2023-11-24 B-07b Maintenance Practices CASA Part 66 - Training Materials Only Page 334 of 498 More often than not, six views are not needed to illustrate a part. In fact, one-view, two-view and three-view drawings are the most common. Isometric Drawings Isometric drawing is a form of pictorial presentation that is most used for aircraft drawing and sketching. An isometric drawing is a projection of a three-dimensional object on a flat plane. In this type of drawing, an object is rotated so that three views are visible and touching the drawing plane. Isometric drawing Oblique Drawings An oblique drawing is an isometric drawing with one object face parallel to the drawing plane. In other words, two 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 45°. Oblique drawing 2023-11-24 B-07b Maintenance Practices CASA Part 66 - Training Materials Only Page 335 of 498 Allowance and Tolerance Tolerance Nominal size is the actual size of the component as annotated in the drawing or blueprint. Tolerance is the difference between the maximum and minimum limits of basic or nominal size. It is also the difference between the upper and lower deviations in basic or nominal size. Tolerances are assigned to mating parts. For example, the hole of bearing in the part must accommodate the shaft. A system is two or more mating parts. One of the great advantages of using tolerances is that it allows for interchangeable parts, thus permitting the replacement of individual parts. Tolerances Tolerances can be expressed as direct limits, or as tolerance values applied directly to a dimension. 2023-11-24 B-07b Maintenance Practices CASA Part 66 - Training Materials Only Page 336 of 498 This includes: Geometric tolerance Notes referring to specific conditions A general tolerance note in the title block. Tolerance can be limit, unilateral or bilateral: Limit tolerance – upper and lower dimensional sizes are stacked on top of each other. Unilateral tolerance – a target dimension is given along with a tolerance. Bilateral tolerance – variation from a target dimension is shown occurring in both positive and negative directions. 2023-11-24 B-07b Maintenance Practices CASA Part 66 - Training Materials Only Page 337 of 498 Allowance Allowance is the minimum clearance (called positive allowance) or maximum interference (negative allowance) which exists between mating parts. It may also be described as the clearance or interference which gives the tightest possible fit between mating parts. It is also the fit that two mating features would have if they were both at their maximum material limits. Clearance means no contact by the parts being produced. Interference is a fit in which the hole is smaller than the shaft or item being placed into the hole. Maximum Material Condition (MMC) is the condition in which a feature of a finished part contains the maximum amount of material, that is, the largest shaft or smallest hole. Least Material Condition (LMC) is the condition in which a feature of a finished part contains the least amount of material, that is, the smallest shaft or the largest hole. Allowance 2023-11-24 B-07b Maintenance Practices CASA Part 66 - Training Materials Only Page 338 of 498 For example (in the diagram above): Basic size: 1.500 in. Tolerance on the shaft: 0.002 in. Tolerance on the hole: 0.001 in. Allowance: 0.004 (tightest possible fit – maximum material limit). Tolerance Allowance Tolerance Hole Shaft Lower limit Lower limit Upper limit Upper limit © Aviation Australia Allowance and tolerance 2023-11-24 B-07b Maintenance Practices CASA Part 66 - Training Materials Only Page 339 of 498 Title Blocks Engineering Drawing Title Block A title block is generally printed in the lower right corner of every aircraft drawing. It contains the information necessary to manufacture the illustrated part. If special or additional information is needed, it is typically listed to the left of the title block. When the print is correctly folded, the title block is positioned on the outside for easy reference. It contains material specifications such as rivet codes, fasteners, etc. Title block It also includes information such as the: Title Scale Drawing number Tolerances Surface finish Materials and fastener specifications (bolts, rivets, screws, etc.). The part name is put in the box labelled ‘title’. In most cases, the subject is listed first. For example, a drawing of an autopilot servo bracket would be titled ‘Bracket, Autopilot Servo’. 2023-11-24 B-07b Maintenance Practices CASA Part 66 - Training Materials Only Page 340 of 498 Drawing Number A drawing number or part number is assigned to each drawing. The part carries this number throughout its entire life. If an aircraft has a left-hand and a right-hand part, they typically have the same part number. However, the left-hand part number is followed by a -1, while the right-hand part number is followed by a -2. Title block - drawing number Scale The scale indicates the size of a drawing and is noted with comments such as FULL, HALF or 1 INCH = 1 FOOT. If the drawing is essentially full-scale, typically some details are drawn to another scale. The notation indicating this is FULL EXCEPT AS NOTED, with a note placed next to each detail that is not drawn to full scale. If the drawing does not include any parts that are drawn to scale, the word NONE is used in this blank. Title block - scale 2023-11-24 B-07b Maintenance Practices CASA Part 66 - Training Materials Only Page 341 of 498 Size Letters are typically used to specify the size of a drawing. A-size is 8.5 × 11 in. (210 × 297 mm). B-size is 11 × 17 in. (297 × 420 mm). C-size is 17 × 22 in. (420 × 594 mm). D-size is 22 × 34 in. (594 × 841 mm). Larger drawings are made on paper 36–42 in. wide and are specified as R-size drawings. Title block - size Tolerances In the column entitled UNLESS OTHERWISE SPECIFIED are the standards of manufacturing tolerances used by the design company. Here, the manufacturer specifies the linear and angular dimensional tolerances along with a note specifying the standard for surface roughness. Title block - tolerances 2023-11-24 B-07b Maintenance Practices CASA Part 66 - Training Materials Only Page 342 of 498 Bill of Material Just above the title block and extending upwards as needed is a list of every material needed to manufacture the part. The quantity required, part number, description, size and specification number for these materials are all indicated. Title block - bill of material Application The block marked APPLICATION indicates where the part is used. It shows the model of aircraft the part is used on and the part number of the next assembly. Also indicated is the quantity of parts needed for both the next assembly and the final assembly. Title block - application 2023-11-24 B-07b Maintenance Practices CASA Part 66 - Training Materials Only Page 343 of 498 Notes Notes are added to a drawing to identify a deviation from the norm, give additional information, list alternatives, call attention to an item or specify modifications to an original design. Notes are related to the drawing or other relevant drawings. Notes are typically found in a block or placed in a location that does not interfere with the drawing. Drawing notes 2023-11-24 B-07b Maintenance Practices CASA Part 66 - Training Materials Only Page 344 of 498 Revision Block In the upper right corner of a drawing is a block where revisions are recorded. For example, if revision A is issued by the engineering department, the letter A is indicated in this space along with the description of the revision, the date the revision was released, and the initials of the person approving the revision. You should always check to make sure you have the most current revision. Revision block Zones Aircraft drawings are usually 36-42 in. wide and several feet long. Since these drawings are so large, it is often difficult to find detailed views without a system of location. Therefore, a system similar to the grid on a map is used. The grid is made by marking the edges of the drawing every 12 in. both vertically and horizontally. The vertical marks are identified by letters, with A for the bottom 12 in., B for the next 12 in. and so on. The horizontal marks are identified by numbers beginning with 1 on the far right side. The combination of vertical and horizontal coordinates identifies a zone. For example, if a revision is noted as a dimension change in zone C-7, you should know that this change is made somewhere in the section 3 ft from the bottom and 7 ft from the right edge. 2023-11-24 B-07b Maintenance Practices CASA Part 66 - Training Materials Only Page 345 of 498 Dimensioning Dimensions In order for a drawing to be meaningful, it must show the shape of a part and accurately give all needed dimensions. Dimensions that appear on a drawing represent the perfect size and are called basic or nominal dimensions. Drawing dimensioning 2023-11-24 B-07b Maintenance Practices CASA Part 66 - Training Materials Only Page 346 of 498 Placement of Dimensions Most aircraft drawings are dimensioned using a reference edge from which all dimensions are made. Holes are typically located with reference to one corner of a part. This makes finding the centre of each hole easier to locate, with no cumulative errors. Cumulative errors exist if one hole is measured from the centre of the adjacent hole. There are two ways of placing dimensions on a drawing. One is to write all dimensions perpendicular to the dimension lines. When this is done, the numbers are parallel to the right edge of the drawing for vertical dimension lines and at various angles across the drawing for parts that have angled surfaces. The second and more conventional method is to write all dimensions parallel to the bottom of the drawing. Drawing dimension placement 2023-11-24 B-07b Maintenance Practices CASA Part 66 - Training Materials Only Page 347 of 498 Manufacturer’s Publications Aircraft Maintenance Manual Aircraft manufacturers provide various manuals with their products to assist engineers in inspection, maintenance and repair. With few exceptions, manufacturer’s manuals are acceptable data. The engineer must use these manuals when performing maintenance. Aircraft maintenance manual A manufacturer’s maintenance manual is the primary reference tool for the aviation maintenance engineers working on aircraft. Airframe maintenance manuals generally cover an aircraft and all of the equipment installed on it when it is in service. Power plant maintenance manuals, on the other hand, cover areas of the engines that are not dealt with in the airframe manual. Maintenance manuals provide information about routine servicing, system descriptions and functions, handling procedures, and component removal and installation. In addition, they contain basic repair procedures and troubleshooting guides for common malfunctions. The maintenance information they present is considered acceptable data by the FAA, and may be approved data for the purpose of major repairs and alterations. 2023-11-24 B-07b Maintenance Practices CASA Part 66 - Training Materials Only Page 348 of 498 Flight Safety Foundation Aircraft maintenance manuals may be located digitally or stored physically for reference 2023-11-24 B-07b Maintenance Practices CASA Part 66 - Training Materials Only Page 349 of 498 Power Plant Manuals Power plant maintenance manuals, on the other hand, cover areas of the engines that are not dealt with in the airframe manual. Maintenance manuals provide information about routine servicing, system descriptions and functions, handling procedures, and component removal and installation. In addition, they contain basic repair procedures and troubleshooting guides for common malfunctions. The maintenance information they present is considered acceptable data by the FAA, and may be approved data for the purpose of major repairs and alterations. AMM power plant 2023-11-24 B-07b Maintenance Practices CASA Part 66 - Training Materials Only Page 350 of 498 Illustrated Parts Catalogue Parts catalogues show the location and part numbers of items installed on an aircraft. They contain detailed exploded views of all areas of an aircraft to assist the engineer in locating parts. Illustrated parts catalogues are generally not considered acceptable data for maintenance and repair by the FAA. Illustrated Parts Catalog - IPC Overhaul Manual Overhaul manuals contain information about the repair and rebuilding of components that can be removed from an aircraft. They contain multiple illustrations showing how individual components are assembled and list individual part numbers. 2023-11-24 B-07b Maintenance Practices CASA Part 66 - Training Materials Only Page 351 of 498 Wiring Manuals The majority of aircraft electrical systems and their components are illustrated in individual wiring manuals. Wiring manuals contain schematic diagrams to aid in electrical system troubleshooting. They also list part numbers and locations of electrical system components. Wiring manual Structural Repair Manuals For repair of serious damage, structural repair manuals are used. These manuals contain detailed information for repairing an aircraft’s primary and secondary structure. The repairs described in a structural repair manual are developed by the manufacturer’s engineering staff, and thus are usually considered approved data by the FAA. Service Bulletins and Notes One way manufacturers communicate with aircraft owners and operators is through Service Bulletins and service notes. Service Bulletins are issued to inform aircraft owners and engineers of possible design defects, modifications, servicing changes or other information that may be useful in maintaining an aircraft or component. On occasion, Service Bulletins are made mandatory and incorporated into airworthiness directives to correct an unsafe condition. 2023-11-24 B-07b Maintenance Practices CASA Part 66 - Training Materials Only Page 352 of 498 Aircraft Maintenance Manual Storage Microform and Microfiche Microforms come in a number of formats. The most familiar of these are 16- or 35-mm roll microfilm and microfiche, the latter resembling a plastic file card. Roll microfilm, in either 16- or 35-mm formats, can be cut into short strips and housed in clear ‘jackets’ to produce a microfiche. Three types of film are common in microform collections: silver-gelatine, diazo and vesicular. Microfilm use Microform Storage Environments Temperature and Relative Humidity In general, microform requirements resemble those of other photographic materials. Year-round relative humidity of lower than 50% is recommended for all film types. An upper limit of 40% is recommended for silver-gelatine films to minimise the likelihood of microscopic blemishes from silver oxidation (sometimes called ‘measles’). Temperatures should not exceed 70 °F; cooler temperatures are preferable. Master films should be stored at maximums of 65 °F and 35% RH, ±5%. ANSI/NAPM IT9.11-1993 and ANSI/PIMA IT9.2-1998 specify exact conditions for archival storage of film. 2023-11-24 B-07b Maintenance Practices CASA Part 66 - Training Materials Only Page 353 of 498 If low temperatures are maintained for the storage of collections, and if readers are located outside of the storage areas, a conditioning period is required to allow gradual warming of cold films before they are read. Rapid transfer from a cold to a warm space may cause water condensation on the surface of the films. Handling of Film Since acidic oils and fingerprints can damage film, users should always wear gloves when handling master negatives. All films should be handled by the edges or leaders. Only one microform at a time should be removed from its enclosure. Fiche should be re-sleeved immediately after use; film should be immediately re-boxed. In addition, rolled film should never be pulled tight on the reel as this can cause abrasions. It is essential to educate staff and users regarding the proper handling of microforms to promote longevity of the film. Equipment Ease of use and maintenance should be considered in choosing equipment. Microform readers generate heat; ANSI standards specify an upper limit of 167 °F for temperature at the film plane. Some diazo films are damaged at this temperature, and prolonged exposure of small areas of film (e.g. a single frame) should be avoided for this reason. As mentioned above, vesicular film damage can occur at temperatures below the ANSI limit, so special care is warranted. Microform-reading machines should be turned off if the user leaves the equipment. Reader lens size should take into account the reduction ratios used for filming. In preservation microfilming, the image is usually reduced between 8X and 14X, so lens magnification should be in similar ratios. Zoom lenses, which allow for changing magnification, are available. Equipment should be inspected weekly and maintained daily. Dirty equipment decreases image quality. A staff member should have assigned responsibility for equipment maintenance and should be trained by the manufacturer's personnel. Dust on the glass flats is magnified by the optics of the reader. Dust can also be transferred to the microform, where it might obscure details and even damage film. Dust covers should always be used whenever the film reader is not in use. Grime builds up on the edges of glass flats to create another source of film abrasion. For this reason, glass flats and carriers should be cleaned daily. A regular schedule for cleaning lenses, mirrors and the matte surface of viewing screens should also be established, but this cleaning must be done with extreme care as these items can be easily damaged and/or made to appear smeared or mottled. Instructions for equipment maintenance are beyond the scope of this topic. What Is a Microfiche Card? Microfiche are 4 × 6 in. (11 × 16 cm) plastic cards on which photographic images are placed. Each microfiche card in this library can hold 98 to 133 pages of text, depending on the size of the original pages. The cards are read with microfiche readers, which magnify the image back to its original size and project it onto a reader screen. 2023-11-24 B-07b Maintenance Practices CASA Part 66 - Training Materials Only Page 354 of 498 How Long Does It Take to Learn to Use the System? Within their file box, the microfiche are organised according to the chapters in the Appropriate Technology (AT) Sourcebook. A new user can become familiar with the system in less than 15 min. On the cards themselves are several other features which make this system easy to use: Title – Every card features the title of the book prominently in a yellow strip across the top. Microfiche filing number – For easy location of the card within the set, this index number is also indicated in the AT Sourcebook. Introductory page – For each book, the ordering and publisher’s information is listed at the beginning of the card for ease in obtaining paper copies if desired. Aircraft Manual Digital Formats Aeroplane maintenance documents traditionally have been published in conventional paper and microfilm formats. There's no longer any reason to rely on the old storage and retrieval systems. The computer The computerised format helps maintenance organisations save time and money, improve the quality of their work and do something positive for the environment as well. Boeing offer this digital tool for all Boeing and Douglas-built aircraft models to help aircraft maintainers streamline their maintenance processes. 2023-11-24 B-07b Maintenance Practices CASA Part 66 - Training Materials Only Page 355 of 498 Digital IPC The support product is a series of compact discs called Boeing Digital Technical Documents. Each CD contains a complete manual and quick-search index. In conventional paper form, a single manual is actually a multi-volume set of loose-leaf binders. As an example, the primary AMM for the 777 takes up 24 binders and requires 10 ft of shelf space. The CD product incorporates the widely available Adobe Acrobat® Reader® software. The CDs can be loaded into any basic computer workstation. Documents viewed on the computer screen have the same look of the printed pages familiar to aeroplane technicians, without the inconvenience of searching through paper or operating a microfilm enlarger. Temporary revisions to the manuals will be distributed on floppy disks that work in conjunction with the CDs. This will end the cumbersome and error-prone process of filing and retrieving paper revisions. Extensive airline tests of the CDs showed a reduction in search time of nearly 60%. There were also significant reductions in distribution and filing times. By digitising the maintenance manuals, Boeing has shrunk what was a ‘mountain’ of paper and microfilm. (Last year alone, Boeing distributed enough maintenance documents to create a stack of paper more than 24 mi (38 km) high and a stack of microfilm cartridges more than 14 mi (22 km) high.) 2023-11-24 B-07b Maintenance Practices CASA Part 66 - Training Materials Only Page 356 of 498 In addition to the basic AMM, documents available on CDs include the manuals for fault reporting, fault isolation, structural repair, and wiring and systems schematics, plus the illustrated parts catalogue and other documents. Boeing Digital Technical Documents is the latest in a series of innovative digital support products designed by Boeing to add value for its customers. Boeing was the first in the industry to offer spare parts ordering on the World Wide Web through the Boeing PART Page, and the first to offer direct access to technical databases through Boeing Online Delivery. The company also offers the Portable Maintenance Aid, a laptop-based digital troubleshooting tool for aeroplane mechanics. 2023-11-24 B-07b Maintenance Practices CASA Part 66 - Training Materials Only Page 357 of 498 ATA Specification 100 ATA Specification At one time, the organisation of data in manufacturer’s publications was left up to the individual producing the manual. As a result, there was little uniformity among different publications, and much time was wasted as technicians had to learn each manufacturer’s particular system. To correct this, the Air Transport Association of America (ATA) issued specifications for the organisation of manufacturers’ technical data. The ATA specification calls for organising an aircraft’s technical data into individual systems which are numbered. Each system also has provisions for subsystem numbering. For example, all of the technical information about the fire protection system has been designated as Chapter 26 under the ATA 100 specifications, with fire detection equipment further identified by the sub-section and subject/unit number 26-10-00 within that system. Because of this specification, maintenance information for all transport aircraft is arranged in the same way. ATA chapter numbering 2023-11-24 B-07b Maintenance Practices CASA Part 66 - Training Materials Only Page 358 of 498 Air Transport Association – ATA 100 System The ATA, an organisation of airlines and carriers, has established many standards and procedures that make airline operations more effective and efficient. One of the many specifications of value to you as a maintenance engineer is the ATA Specifications 100, which is the standard for the presentation of technical information. The ATA 100 is universally accepted throughout the world as the standard layout format. The ATA 100 specification requires the manufacturers of transport aircraft to publish their manuals according to an internationally accepted chapter numbering system. Manual Arrangement and Numbering Systems Aviation manuals are divided into chapters and groups of chapters. These chapters separate the manuals into the primary functions and systems of the aircraft. All chapters are further divided into sections and subjects to provide for sub-system and individual unit break-out. Each chapter, section and subject are identified by assigned numbers. Each page carries the assigned subject number and the revision date. Chapter Numbering The chapters in the maintenance manual provide a functional breakdown of the entire aeroplane. The chapter breakdown numbering system uses a three-element number (XX-XX-XX) dividing the material into chapters, sections and subjects. The three elements of the indicator each contain two digits. Here is an example: 28-21-20. The ATA Specification 100 is a six-digit numerical breakdown which provides a means for dividing material into System, Sub-system and Subjects. The first two numbers give the System/Chapter identification: 28-00-00 28- Fuel (System/Chapter) The next number (the third) gives the Sub-system: 28-20-00 28- Fuel (System/Chapter) 28-2 Distribution (Sub-system) 2023-11-24 B-07b Maintenance Practices CASA Part 66 - Training Materials Only Page 359 of 498 The next number (fourth) gives the Sub-sub-system: 28-21-00 28- Fuel (System/Chapter) 28-2 Distribution (Sub-system) 28-21 Pressure Fuelling (Sub-sub-system) The last two numbers (fifth and sixth) represent the Subject: 28-21-20 28- Fuel (System/Chapter) 28-2 Distribution (Sub-system) 28-21 Pressure Fuelling (Sub-sub-system) 28-21-20 Removal & Installation of Refuel Drain Shut-off Valve (Subject) ATA chapter numbering - build The chapter number (first element) and the first number of the second element are assigned by ATA Specification No. 100. Material which is applicable to a system as a whole uses zeros in the second and third elements of the numbers, that is, the chapter number followed by -00-00. 2023-11-24 B-07b Maintenance Practices CASA Part 66 - Training Materials Only Page 360 of 498 For example, 22-00-00 (Auto Flight) is used for general description information, which provides an outline breakdown of the sections in the chapter. List of Chapters The maintenance reference systems are divided into chapters. Regardless of the type of aircraft, similar information can be found in these chapters. ATA 100 chapter structure Below are chapters 00 to 23, showing each subject. 2023-11-24 B-07b Maintenance Practices CASA Part 66 - Training Materials Only Page 361 of 498 Chapters 00 to 23 Below are chapters 23 (continued) to 27, showing each subject. Chapters 23 continued to 27 2023-11-24 B-07b Maintenance Practices CASA Part 66 - Training Materials Only Page 362 of 498 As further examples, below are chapters 28 to 116, without each subject. Chapters 28 to 116 2023-11-24 B-07b Maintenance Practices CASA Part 66 - Training Materials Only Page 363 of 498 Aviation Standards in Aircraft Maintenance International Standards and ISO Standards are documented agreements containing technical specifications or other precise criteria to be used consistently as rules, guidelines or definitions of characteristics. Their goal is to ensure that materials, products, processes and services are fit for their purpose. What Is ISO? The International Organization for Standardization (ISO) is a worldwide federation of national standards bodies from more than 140 countries, one from each country. To complement product or service requirements stated in company specifications, international guidelines and standards have been developed, called International Standards and published by the ISO. ISO 9000 ISO 9000 is the family of quality management systems standards and deals with the fundamentals of quality management systems. ISO 9001 ISO 9001 deals with the requirements that organisations wishing to meet the standard must fulfil. Why Is International Standardisation Needed? International standardisation is well established for many technologies in such diverse fields as information processing and communications, textiles, packaging, distribution of goods, energy production and utilisation, shipbuilding, and banking and financial services. It helps make communication and cooperation in these industries easier among countries and language barriers, and will continue to grow in importance for all sectors of industrial activity for the foreseeable future. 2023-11-24 B-07b Maintenance Practices CASA Part 66 - Training Materials Only Page 364 of 498 Airworthiness Standards Before the FAA issues a Type Certificate for an aircraft, the manufacturer must demonstrate that the aircraft conforms to all airworthiness requirements. Airworthiness certificate These requirements pertain not only to the performance, but to structural strength and integrity as well. To meet these requirements, each individual aircraft produced from a given design must meet the same standards. To accomplish this, all materials and hardware must be manufactured to a standard of quality. Specifications and standards for aircraft hardware are generally identified by the organisation originating them. Note: AN standard parts have equivalent, or can be superseded by, MS standard parts. 2023-11-24 B-07b Maintenance Practices CASA Part 66 - Training Materials Only Page 365 of 498 Some of the most common standard specifications are: AN = Air Force/Navy NAS = National Aerospace Standard MS = Military Standard MIL = Military Specification NSO = NATO Standardization Office. The above standards also comply with ISO 9000. AN Specifications The AN system is one of the most widely used standards in aircraft hardware. It was developed, together with the MS system, by the US military to ensure quality and uniformity. Although it is described as obsolescent and as being replaced by the MS and NAS systems, fasteners and mating parts with AN part numbers are still in common use and are still being fitted to new aircraft at manufacture. Items manufactured to this standard are not limited to the military and are found in all classifications of aircraft. MS Specifications This standard was developed by the military and found its way into all aspects of aviation. The MS and MIL (military) standard incorporate most of the same hardware as the AN system. Cross referencing may allow the substitution of the MS hardware for AN hardware (and visa versa). Caution must be exercised to ensure any hardware substituted is indeed a proper replacement with all important characteristics of the original hardware intact. NAS Specifications This standard is based on approval of military hardware for the civilian aerospace industry. The NAS system provides a range of design and process standards, as well as material and parts specifications. The design standards cover information such as fastener head markings, plating and locking requirements. The parts specifications include a wide range of fasteners and a few washers and nuts. 2023-11-24 B-07b Maintenance Practices CASA Part 66 - Training Materials Only Page 366 of 498 MIL Specifications A MIL-STD (military standard) means an item that has been designed and assessed to comply with the requirements of US Military Standards (MIL-STD). These standards are developed and managed by the United States Military. They ensure a certain level of expectations for the performance and maintainability of military equipment including aviation parts and equipment. NSO Specifications The NSO is the standards-developing organisation (SDO) of the North Atlantic Treaty Organisation (NATO) military alliance. The NSO administers the development of military operational standards to enhance the interoperability and operational effectiveness of alliance military forces. The NSO liaises with (and influences) civilian SDOs. 2023-11-24 B-07b Maintenance Practices CASA Part 66 - Training Materials Only Page 367 of 498