FAA Aviation Mechanic General (AMG)Aircraft Drawings, Weight and BalanceMedium
A sheet metal part has a surface inclined at an angle to the front, top, and side projection planes, causing that surface to appear foreshortened in all three standard orthographic views. Which type of view should be added to show the true size and shape of that inclined surface?
- AAuxiliary view
- BSectional view
- CDetail view
- DIsometric view
Show answer & explanationAnswer & explanation
Correct answer: A. Auxiliary view
An auxiliary view is projected from an inclined surface onto a plane parallel to that surface, showing its true size and shape when the standard front, top, and side views distort it. Isometric and sectional views serve different purposes and do not correct foreshortening of an inclined surface.
Why the other options are wrong
- B. A sectional view reveals internal features by cutting through the part, not the true shape of an inclined external surface.
- C. A detail view is an enlarged view of a small area, not specifically for correcting foreshortening of inclined surfaces.
- D. An isometric view gives a 3-D pictorial but still does not show a true, undistorted shape of an inclined surface.
Auxiliary View
A view projected onto a plane parallel to an inclined surface to show that surface's true size and shape, which is distorted in standard orthographic views.
- Used for inclined/slanted surfaces
- Plane of projection is parallel to the inclined feature
- Prevents foreshortening error in dimensioning
Memory trick: Auxiliary = 'aux-help' view for slanted surfaces.