FAA Aviation Mechanic General (AMG)Aircraft Drawings, Weight and BalanceHard
On a detail drawing of a long wing spar, a middle portion of the part is omitted to conserve drawing space, shown using a jagged or S-shaped break line, while both remaining ends retain their true dimensions and features. What is this line called?
- ASection line
- BBreak line
- CPhantom line
- DHidden line
Show answer & explanationAnswer & explanation
Correct answer: B. Break line
A break line (long break) is a jagged or S-shaped line used to show that a uniform middle portion of a long part has been omitted from the drawing to save space, while the true dimension is still noted for the full length.
Why the other options are wrong
- A. A section line (hatching) indicates the material cut in a sectional view, not an omitted length.
- C. A phantom line shows alternate positions of a moving part or adjacent parts, not an omitted section.
- D. A hidden line is a series of short dashes showing edges not visible from the current view.
Break Line
A line, often drawn jagged or S-shaped, used on a drawing to indicate that a uniform middle portion of a long part has been left out to conserve space, while overall length is still dimensioned.
- Used for long, uniform parts like spars, shafts, tubing
- Jagged (freehand) or S-shaped (long break) style
- True overall dimension is still specified despite the omission
Memory trick: Break line — imagine literally snapping the part in the middle and pushing the ends together to save paper.