Ballooning and characteristics

Ballooning and characteristics commonly refer to the practice of marking engineering drawings or models with numbered “balloons” and defining each unique, inspectable requirement as a discrete characteristic. This is widely used in first article inspection (FAI), production inspection, and ongoing quality control in regulated manufacturing such as aerospace.

What ballooning is

Ballooning is the process of visually annotating an engineering drawing or 3D model so that every requirement that must be verified is identified with a unique reference number (the balloon). Each balloon typically corresponds to a specific line item in an inspection report.

In practice, ballooning may include:

• Dimension callouts (linear, angular, GD&T features)
• Notes and specifications that require verification (material, finish, treatments)
• Hole sizes, locations, patterns, and thread details
• Form, fit, and function requirements that can be inspected
• Referenced standards or process requirements that must be confirmed

Ballooning can be performed manually on paper, in 2D CAD/PDF, or through digital tools that link the balloons directly to a characteristic database or FAI software.

What characteristics are

Characteristics are the individual, measurable or otherwise verifiable requirements extracted from the drawing or model and associated with a balloon number. In AS9102 and similar frameworks, these are often called inspection characteristics or product characteristics.

A characteristic definition usually includes:

• The balloon or item number
• Description of the requirement (for example, diameter of hole, surface finish)
• Nominal value and tolerances, or acceptance criteria
• Units of measure
• Associated drawing zone or reference
• Type of characteristic (for example, key, critical, major, minor) when applicable
• Planned inspection method and frequency where defined

Characteristics provide the structure needed to build inspection plans, first article inspection forms, and ongoing in-process or final inspection records.

Role in AS9102 and FAI

In aerospace, ballooning and characteristics are tightly linked to AS9102 first article inspection:

• The ballooned drawing defines the complete set of product requirements that must be verified.
• Each ballooned item is translated into a characteristic line on the AS9102 Form 3 (characteristic accountability and verification list) or equivalent digital record.
• Inspection results, tools used, and any nonconformances are recorded per characteristic, enabling traceable evidence of conformance to drawing requirements.

Digital FAI systems typically use structured characteristic data to automate form population, result capture, and traceability back to specific drawing requirements and revisions.

Operational use in manufacturing systems

In day-to-day operations, ballooning and characteristics may feed multiple systems:

• PLM/CAD: Source of the design, where requirements originate.
• FAI or quality systems: Store and manage the characteristic list, inspection results, and evidence.
• MES: Use characteristics to drive in-process inspection steps and operator checks.
• ERP/QMS: Reference characteristics for nonconformance records, deviations, and certificates of conformance.

Consistent ballooning and characteristic definitions help align what is designed, what is manufactured, and what is inspected across different systems and locations.

Common confusion

• Ballooning vs. general markup: Ballooning is a structured, numbered system tied to inspection characteristics, not just informal comments or highlights on a drawing.
• Characteristics vs. process parameters: Characteristics are typically product requirements on the drawing or model. Process parameters (for example, machine settings) may be controlled and recorded, but are not always defined as characteristics unless they appear as specific requirements.
• Characteristics vs. critical characteristics only: While some organizations focus on key or critical characteristics, ballooning and characteristic listing usually cover all inspectable requirements, not only the critical subset.

Relation to digital FAI preparation

When preparing for advanced digital FAI capabilities, manufacturers often focus on cleaning and standardizing ballooning practices and characteristic data. This can include using consistent numbering rules, ensuring every inspectable requirement is captured as a characteristic, and structuring the data so it can be exchanged between PLM, ERP, MES, and quality systems without rework.