Ballooning (or "drawing ballooning") is the process of annotating every characteristic on an engineering drawing with a sequentially numbered circle (balloon), so that each dimension and tolerance can be uniquely referenced in the FAI Form 3.
The balloon number creates a direct cross-reference between the drawing and the measurement record. Balloon 1 on the drawing corresponds to row 1 in Form 3, ensuring traceability and eliminating ambiguity when multiple characteristics share similar nominal values.
Ballooning is typically performed by quality engineers or FAI specialists. On a complex drawing with hundreds of characteristics, the process can take several hours per drawing. The result must be reviewed and approved before the FAI measurement campaign begins.
Automated ballooning tools — such as BullePlan — use AI to detect and extract all dimensions, GD&T symbols, and tolerances from a PDF drawing, assign balloon numbers, and pre-populate Form 3, reducing a multi-hour task to minutes.
Concrete example
A turbine blade drawing with 85 dimensions is ballooned by the quality engineer: each dimension receives a circled number (1 to 85), and these numbers are listed in sequence in Form 3 alongside the measured values.