Engineering Drawings, Diagrams & Standards
Drawing types, symbols and tolerances; first- and third-angle projection and the title block; the ATA Specification 100 chapter system; AN, MS, NAS and ISO standards.
Engineering drawings, summary notes
- Drawings communicate shape, size and tolerance through orthographic views. The two conventions for arranging those views are first-angle and third-angle projection.
- In THIRD-angle projection each view sits on the same side as the face it represents, right-hand view to the right, top view above. In FIRST-angle projection the views sit on the opposite side, right-hand view to the left, top view below.
- The projection in use is shown by the truncated-cone symbol in the title block. Misreading it inverts the interpretation of every view, so it is checked before any work.
- The title block also carries the drawing number, issue/revision status, scale and units, the issue must be confirmed current before the drawing is worked to.
- ATA Specification 100 numbers technical documentation by system in a chapter-section-subject format: Chapter 24 Electrical Power, 27 Flight Controls, 28 Fuel, 32 Landing Gear. It lets any manufacturer's manuals be navigated consistently.
- Common standards seen on parts and drawings: AN (Air Force-Navy), MS (Military Standard), NAS (National Aerospace Standard), MIL and ISO.
- Diagram types: block (functional overview), schematic (how it works, not physical layout), wiring (actual connections and wire numbers), and pictorial or exploded views for assembly.
- ⚠ Exam trap: third angle = same side, first angle = opposite side. A schematic shows FUNCTION, not physical position.
- Third-angle
- view placed on the SAME side as the face it represents
- First-angle
- view placed on the OPPOSITE side
- ATA 100
- chapter · section · subject, e.g. 32-41-00
A drawing shows the right-hand view positioned to the left of the front view. Which projection is in use?
First-angle. The views are placed on the side opposite the face they represent, the truncated-cone symbol in the title block will confirm it.
Which ATA chapter covers the landing gear, and what does the rest of a reference like 32-41-00 mean?
Chapter 32 is Landing Gear. The second pair is the section (41, wheels and brakes within that chapter) and the third the subject, giving a unique, type-independent address for the topic.
Engineering drawings concept map
Drawings & Standards
Engineering drawings quiz
Engineering Drawings & Standards, quiz
1. In third-angle projection each view is placed:
On the same side as the face it representsOn the opposite sideAlways below the front view2. The projection in use is identified by:
A truncated-cone symbol in the title blockThe paper sizeThe title block colour3. ATA Specification 100 organises documentation by:
Chapter and system numberingAlphabetical part nameSupplier code4. ATA Chapter 32 covers:
Landing gearElectrical powerFuel5. ATA Chapter 24 covers:
Electrical powerFlight controlsLanding gear6. A schematic diagram shows:
How the system functions, not its physical layoutThe exact physical position of every partOnly the wire numbers7. A wiring diagram gives:
Actual connections and wire identificationA functional overview onlyStructural dimensions8. Before working to a drawing you must confirm:
Its issue or revision status is currentThe draughtsman's nameThe paper size9. In first-angle projection the right-hand view appears:
To the left of the front viewTo the right of the front viewAbove the front view10. AN, MS and NAS on a drawing are:
Part and material standardsATA chaptersProjection symbols