7.5 Engineering Drawings Flashcards
What are engineering drawings?
Engineering drawings are the language of engineers, conveying the designer’s requirements much clearer than words.
What must engineering drawings include?
Drawings must include sufficient information to enable manufacture, assembly, production planning, testing, and inspection of the particular component or assembly.
How should drawings be handled?
Drawings should be handled carefully as they are both expensive and valuable.
What is the proper way to open drawings?
Open drawings slowly and carefully to prevent tearing of the paper.
What should you do with fold lines on a drawing?
Smooth out the fold lines instead of bending them backwards.
How should drawings be protected from damage?
Never spread them on the floor or lay them on a surface covered with tools or other objects that may make holes in the paper.
What should hands be free of when handling drawings?
Hands should be free of oil, grease, or other unclean matter that can soil or smudge the print.
Can notes or marks be made on a print?
Never make notes or marks on a print, as they may confuse others and lead to incorrect work.
Who is permitted to make notes or changes on prints?
Only authorised individuals are permitted to make notes or changes on prints, and they must sign and date any changes they make.
What should be done when finished with a drawing?
Fold and return it to its proper place.
How should prints be folded for filing?
Prints are folded originally in an appropriate size for filing. Care should be taken so that the original folds are always used.
What do drawing standards cover?
Drawing standards cover items such as paper sizes, notes, numbering systems, geometric dimensions and tolerances, abbreviations, welding symbols, roughness symbols, and electrical symbols.
What measurements do drawing standards cover?
These standards cover metric and imperial measurements, as well as computer-drafting standards.
What are some common drawing standards used in industry?
Some common standards are published by the International Organization for Standardization (ISO), the American National Standards Institute (ANSI), and the British standard (BS8888), which is equivalent to the European standard.
What are the types of drawings important for aircraft engineers?
There are several types of drawings designed to transmit specific information, including working drawings, sectional drawings, exploded view drawings, block diagrams, logic flowcharts, electrical wiring diagrams, pictorial diagrams, and schematic diagrams.
What is the most common type of drawing in use?
The most common type of drawing in use is the working drawing.
What are the three types of working drawings?
The three types of working drawings are detail drawings, assembly drawings, and installation drawings.
What is a detail drawing?
A detail drawing provides all the information required to construct every part, including dimensions, materials, and type of finish.
What does a detail drawing not show?
Detail drawings do not show location, position, or fastening method.
What is an assembly drawing?
An assembly drawing depicts the relationship between two or more parts and shows how they are assembled.
What information is included in an assembly drawing?
Assembly drawings reference individual parts by their part number and specify the type and number of fasteners needed.
What is the purpose of installation drawings?
Installation drawings describe where parts or assemblies are to be permanently fixed on the aircraft or vehicle.
What are sectional drawings used for?
Sectional drawings are used to show a part’s internal construction or shape.
What are the four types of sectional drawings?
The four types of sectional drawings are revolved section drawings, removed section drawings, complete section drawings, and half section drawings.
What is an exploded view drawing?
Exploded view drawings show every part in an assembly in their relative position but expanded outwards for identification.
What is the purpose of block diagrams?
Block diagrams aid in troubleshooting complex electrical and electronic systems by representing components as individual blocks.
What are troubleshooting flowcharts used for?
Troubleshooting flowcharts are used for detecting faulty components through a series of yes or no questions.
What is a logic flowchart?
Logic flowcharts analyse digitally controlled components and systems using standardised symbols to indicate logic gates.
What do schematic drawings illustrate?
Schematic drawings illustrate a principle of operation and indicate the location of objects in relation to each other.
What is the difference between electronic schematic diagrams and pictorial diagrams?
Electronic schematic diagrams use symbols for components, while pictorial diagrams show the actual layout of components on a circuit board.
What is the purpose of schematic diagrams?
Schematic diagrams provide an overview representation of the complete aircraft system for fault diagnosis.
What are the types of projection in illustrated representations?
The types of projection refer to orientation with respect to how it is viewed on a flat plane.
What is orthographic projection?
Orthographic projection is a method used to produce detailed part construction drawings, requiring several views to show the exact size and shape of complex objects.
What are the six possible views in orthographic projection?
The six possible views are: Front, Rear, Top, Bottom, Left side, Right side.
What does an orthographic projection drawing represent?
An orthographic projection drawing represents a three-dimensional object using several two-dimensional views.
What is the arrangement of views in orthographic projection?
The arrangement is generally shown with the front view as the principal view.
What are the two types of angle projections?
The two types of angle projections are first angle projection and third angle projection.
What is first angle projection?
First angle projection is a method where each view represents the side of the object that is remote from it in the adjacent view.
What is third angle projection?
Third angle projection is a method where each view represents the side of the object that is nearest to it in the adjacent view.
What is the common use of third angle projection?
Most drawings produced for aircraft purposes show the parts in third angle projection.
What is a sketch?
A sketch is a simple drawing that is drawn quickly and without much detail.
What are the steps to make a sketch?
Determine necessary views, block in views using light construction, add details, darken object view lines, add dimension lines, and include a title, date, and sketcher’s name.
What is an isometric view?
An isometric view combines views of an orthographic projection and tilts the object forward to show portions of all three views.
What are the characteristics of isometric drawings?
In isometric drawings, lines are parallel, distances are the same length as the actual sides, and they help visualize a part.
What is an oblique drawing?
An oblique drawing is an isometric drawing with one object face parallel to the drawing plane and the depth axis at a convenient angle, usually about 45°.
What are perspective drawings?
Perspective drawings show an object as it appears to the observer, resembling how an object would look in a photograph.
Do aircraft engineers need to be accomplished in making drawings?
No, aircraft engineers do not necessarily need to be accomplished in making drawings.
What must aircraft engineers have a working knowledge of?
They must have a working knowledge of the information conveyed to them.
When do aircraft engineers most frequently encounter drawings?
They encounter drawings for the construction of components, assembly of new aircraft, during modifications, and when making repairs.
How should a drawing be read effectively?
Follow a systematic procedure: read the drawing number, description, model affected, latest change letter, and next assembly listed.
What is the first step when reading a multi-view drawing?
Get a general idea of the object’s shape by scanning all the views.
What should be done after scanning all views of a multi-view drawing?
Select one view for a more careful study and refer back and forth to adjacent views.
What does each line on a view represent?
Each line represents a change in the direction of a surface.
What must be consulted to determine what a circle represents in a view?
Another view must be consulted to determine what the change is.
What is indicated by dimension lines?
Dimension lines indicate the origin and termination of a measurement.
What is the customary practice for giving part dimensions?
It is customary to give part dimensions and an overall dimension that gives the greatest length of the part.
What unit is commonly used for drawings of new aircraft and components?
Millimetre (mm) is commonly used for these drawings.
How are dimensions indicated in drawings?
Dimensions may be given in decimals or fractions, especially for tolerances.
What do extension lines do?
Extension lines extend the line showing the side or edge of a figure for placing a dimension.
What do sectioning lines indicate?
Sectioning lines indicate the exposed surfaces of an object in a sectional view.
What do phantom lines indicate?
Phantom lines indicate the alternate position of parts of the object or the relative position of a missing part.
What do break lines indicate?
Break lines indicate that a portion of the object is not shown on the drawing.
What do leader lines indicate?
Leader lines indicate a part or portion that a note, number, or other reference applies.
What do hidden lines indicate?
Hidden lines indicate invisible edges or contours.
What are outline lines used for?
Outline lines are used for all lines on the drawing representing visible lines on the object.
What do stitch lines indicate?
Stitch lines are used to indicate the stitching or sewing lines on an article.
What do cutting plane lines indicate?
Cutting plane lines indicate the plane where a sectional view of the object is taken.
What do viewing plane lines indicate?
Viewing plane lines indicate the plane from where a surface is viewed.
What do material symbols show?
Material symbols show the kind of material from which the part is to be constructed.
What do finish marks indicate?
Finish marks indicate the surface that must be machine finished.
What does surface texture measure?
Surface texture measures the smoothness of the surface finish.
What do holes in drawings represent?
Holes can be plain-drilled, reamed, or threaded.
What is a counterbore?
A counterbore is a larger diameter hole, concentric to the primary hole, with a flat shoulder.
What is a spotface?
A spotface is effectively a shallow counterbore to provide a flat, smooth seating for a mating part.
What do countersunk holes accept?
Countersunk holes accept the tapered head of a fastener.
What is the purpose of a title block in a print?
A title block provides means of identification for the print.
What information is typically included in a title block?
The title block includes a drawing number, name of the part or assembly, scale, date, name of the firm, and names of the drafter, checker, and approver.
Where is the title block usually located on a print?
The title block is usually located in the lower right-hand corner of the print.
What is the purpose of a drawing number?
The drawing number identifies the print for filing and prevents confusion with other prints.
How is the drawing size specified?
The drawing size is usually specified by a letter.
What are the dimensions of an A-size drawing?
A-size drawing measures 8 ½ x 11 in (22 x 28 cm).
What is the scale of drawings made to the same size as the drawn part?
Drawings made to the same size as the drawn part have a scale of 1:1.
What does the tolerance in a technical drawing indicate?
Tolerance indicates the allowable variation in a given dimension.
How is tolerance represented when plus and minus allowances are the same?
Tolerance is represented as ± followed by the allowance value.
What names are included on the title block?
The title block includes the firm’s name, engineer, drafter, checker, and approver.
Where are revisions recorded in a drawing?
Revisions are recorded in a block on the upper-right hand corner of a drawing.
What does a zone in aircraft drawings indicate?
A zone is indicated by a combination of a vertical letter and a horizontal number.
What is a Bill of Materials?
A Bill of Materials is a list of materials and parts necessary for fabrication or assembly.
What is the purpose of electronic schematic drawings?
Electronic schematic drawings provide detailed information about a circuit, including component ratings.
What was the primary method of creating aircraft drawings in the early days of aviation?
Aircraft drawings were created on a drawing board using a pen or pencil and paper.
How were early aircraft drawings preserved?
They were developed as microfilm/microfiche to prevent damage to the paper drawing.
What technological advancement in the 1980s changed aircraft drawing creation?
The introduction and advancement of computers allowed for the creation and storage of drawings digitally.
What is Computer Aided Design (CAD)?
CAD is the use of computers to aid in the creation, modification, and analysis of a design.
What are the benefits of using CAD software?
It increases productivity, improves design quality, enhances communication through documentation, and creates a manufacturing database.
What does Computer Aided Manufacturing (CAM) refer to?
CAM refers to the use of computers in the manufacturing of a part or product.
What is an example of a software package used for aircraft design?
Computer Aided Three Dimensional Interactive Application (CATIA) is commonly used for aircraft design.
What is microfilm and microfiche?
They are analog storage systems using film reels developed into photographic records.
What are the two formats of microfilm?
Microfilm is available as 16 mm or 35 mm film.
What has largely replaced microfilm and microfiche in aircraft manufacturing?
Digital storage methods using CDs, DVDs, and other data storage devices have replaced microfilm and microfiche.
How do digital images assist aircraft maintenance engineers?
Digital images provide instant pictures of defects/damage that can be shared for quicker responses.
What can be used in a digital image to emphasize the size of damage?
A rule or a coin can be placed near the area of concern before taking the picture.
How can digital images be transmitted?
They can be rapidly transmitted over the internet as email attachments.
What is ATA Spec 100?
ATA Spec 100 is the original specification issued by the Air Transport Association of America to standardise the format for presenting aircraft maintenance information in Aircraft Maintenance Manuals (AMM).
How is maintenance data organised in ATA Spec 100?
Maintenance data is classified by standardised numbered chapters and a sub-system numbering system within each chapter.
What is the purpose of the standardised numbering system in maintenance manuals?
The standardised numbering system allows aircraft personnel to find relevant information without needing to learn each manufacturer’s data organisation.
What chapter number is assigned to fire-protection systems under ATA 100?
Chapter 26 is designated for all technical information on the fire-protection system.
What does the numbering format XX-XX-XX represent?
The format XX-XX-XX divides material into chapters, sections, and subjects.
What does the first two digits in the ATA Specification 100 number represent?
The first two digits represent the System/Chapter Identification.
What is the significance of the last two digits in the ATA Specification 100 number?
The last two digits represent the Subject within the specified Sub-Section.
What is ATA iSpec 2200?
ATA iSpec 2200 is the latest organisation standard that combines ATA Spec 100 and ATA Spec 2100 for electronic documentation.
What does the page block number indicate?
The page block number provides information on how to perform a specific maintenance task.
What are the page block numbers for ‘Fault Isolation’?
The page block numbers for Fault Isolation range from 101 to 199.
Why is it important to consult aircraft maintenance manuals?
It is important to consult aircraft maintenance manuals for a complete description of the subsystems and the page block numbers used in them.
What is ATA spec 100?
ATA spec 100 is a standard for the organisation of data in the aerospace industry.
Why are standards important in component manufacturing?
Standards ensure that the aircraft performs as designed when a component is replaced.
What role do government-controlled institutions play in standard development?
They develop standards for various industries, facilitating business and technology.
What is the pressure on countries regarding international standards?
Countries with independent standards are pressured to adapt to universal worldwide standards.
What is EASA’s role in standardisation?
EASA is moving towards the benefits of standardisation in certification and craft.
What is the International Organization for Standardisation (ISO)?
ISO is one of the world’s largest developers of global standards, comprised of national standards organisations from 156 member countries.
How does ISO develop standards?
ISO works through technical committees with expert representatives, gathering consensus and conducting public reviews before adoption.
Are ISO published standards mandatory?
ISO published standards are voluntary, but members comply due to the benefits they provide.
What benefits do ISO standards offer?
ISO standards make development, manufacturing, and supply more efficient, safer, and cleaner, ease trade, provide a technical base for legislation, aid technology transfer, and safeguard consumers.
What is the AN system?
The AN system is a widely used standard in aircraft hardware developed by the US military.
What is the MS/MIL standard?
The MS/MIL standard was developed by the military and incorporates most hardware from the AN system, allowing for cross-referencing.
What is NAS (National Aerospace Standard)?
NAS is based on the approval of military hardware for use in the civilian aerospace industry.
What are British Standards (BS)?
British Standards are controlled by the British Standards Institution (BSI), which represents the UK in ISO matters.
What are diagrams?
Diagrams are a graphic representation of an assembly or system, illustrating various parts and expressing methods or principles of operation.
What is a schematic?
A schematic shows the plan and function for an electrical circuit, without concern for physical layout and in-depth detail of the cables.
What does a wiring diagram show?
A wiring diagram shows how wires are connected and their locations in the actual system, including physical connections between components.
What are the three types of schematic diagrams?
The three types of schematic diagrams are block diagrams, simplified schematics, and system schematics.
What is a block diagram?
Block diagrams provide a general overview of a system, showing major functions, components, functional groups, and relevant interfaces.
What is a simplified schematic?
Simplified schematics provide a broader view of functions, components, and interfaces, showing more detail than a block diagram.
What is a system schematic?
System schematics show sufficient depth and detail for fault isolation to the Line Replacement Unit (LRU) level, linking function and physical implementation.
What information do schematic diagrams provide?
Schematic diagrams identify and locate all LRUs, show functional internal circuitry, and provide signal flow for primary functions.
What is the preferred schematic layout?
The preferred schematic layout is power on the left and load on the right, with signal source on the left and signal destination/indication on the right.
What do wiring diagrams show?
Wiring diagrams show detailed wiring of the system, including wire size and type of terminals, and relate to connectivity and interface of interdependent systems.
What do wiring diagrams typically identify?
Wiring diagrams typically identify each component within a system by its part number and serial number, including production changes.
What is the purpose of the Standard Wiring Practices Manual (SWPM)?
The SWPM contains important data and tables concerning wiring necessary for repairs of connectors and wiring specified within the manual.
What is a home diagram?
A home diagram indicates all connections on a termination used for three or more wires shown on three or more wiring diagrams.
What does effectivity refer to in wiring diagrams?
Effectivity refers to the applicability of a wiring diagram manual to specific aircraft listed on the effective aircraft page.
What is diagram sheet numbering?
If diagrams cannot be shown on one sheet, they are shown on additional sheets with the same title, diagram number, and page number.
What are equipment item numbers?
Customer assigned and manufacturer assigned equipment item numbers are used within drawings and diagrams, referencing effectivity data.
