AS9102 Balloon Drawing to Dimensional Results Linking: A Complete Guide

AS9102 balloon drawing to dimensional results linking is the process of assigning a unique sequential number to every characteristic on a marked engineering drawing and referencing that same number in the dimensional results section (Form 3) of an AS9102 First Article Inspection report. This one-to-one correspondence — balloon on drawing, row in report — is what gives an FAI package its end-to-end traceability. The link typically spans 40–60 words in the standard's own language but has significant audit consequences when broken.

When the Numbers Don't Match, the Whole Package Falls Apart

Picture a DQE at a Tier-1 aerospace supplier opening an FAI package submitted by a machine shop. The marked drawing shows balloon 47 on a critical bore diameter. Form 3 jumps from row 46 to row 48. Balloon 47 is nowhere in the report. The FAI is rejected on the spot, the production hold extends another two weeks, and the root cause is a simple sequencing mistake made in the first ten minutes of ballooning.

This scenario is far more common than most quality teams admit. The link between a balloon number on a marked drawing and its corresponding row on the dimensional results report is the backbone of AS9102 traceability. Get it wrong and every measurement — even perfect ones — becomes inadmissible.

What Is Actually at Stake

AS9102 Rev C Section 4.2 states clearly that each characteristic shall be identified with a unique reference number on the design documentation, and that same number shall appear on the inspection records. A missing or duplicated balloon number is not a minor paperwork error. It is a formal nonconformance that triggers corrective action, delays first-flight clearance, and, in some programmes, triggers a full delta FAI. For quality engineers managing multiple active part numbers, one numbering inconsistency can cascade across an entire FAI log.

Beyond AS9102, the same traceability logic applies in PPAP dimensional results submissions under AIAG's PPAP manual (4th edition), where each characteristic on the part print must map to a numbered row on the dimensional results spreadsheet. The discipline is identical; only the form format changes. For a side-by-side view of the two standards, see the AS9102 vs PPAP comparison on CadNexa.

How AS9102 Balloon-to-Result Linking Works: Step by Step

The process has three distinct phases: marking the drawing, building the inspection report, and verifying the link. Each phase must be completed in sequence and cross-checked before the package is submitted.

1. Obtain the released revision of the drawing. Always work from the design authority's released revision. Confirm the revision letter, drawing number, and any applicable change notices before placing a single balloon. Ballooning a superseded revision is one of the most expensive mistakes in FAI preparation.
2. Identify every characteristic requiring measurement. Walk through every dimension, tolerance, GD&T frame, surface finish callout, thread specification, and note that carries a measurable requirement. AS9102 Rev C uses the term "design characteristic" — any attribute defined by the design authority that can be verified by measurement or examination qualifies. Refer to SAE AS9102 Rev C (SAE International) for the normative definition.
3. Assign balloon numbers sequentially, starting at 1. Number from 1 upward with no gaps. The direction — left-to-right and top-to-bottom is the industry convention — matters less than consistency. If the drawing has multiple sheets, continue numbering sequentially across sheets rather than restarting at 1 on each page. This is the most common source of numbering gaps in multi-sheet drawings.
4. Place the balloon symbol on the drawing adjacent to each characteristic. A balloon (circle with number inside and a leader line pointing to the feature) must be placed so there is no ambiguity about which feature it references. For GD&T feature control frames, the balloon leader should point to the frame itself, not the surface. For a detailed primer on reading feature control frames, see the Feature Control Frame guide on CadNexa.
5. Record the nominal value and tolerance for each balloon number. Before measuring anything, transcribe the nominal dimension and its tolerance directly from the drawing into Form 3, column by column. The nominal, upper tolerance limit (UTL), and lower tolerance limit (LTL) must match the drawing exactly — no rounding, no unit conversion without documentation.
6. Enter measured results against each balloon number row. Each measured value occupies its own row, identified by the balloon number in the first column. The column structure of AS9102 Form 3 is fixed: Balloon Number | Characteristic Description | Nominal | Tolerance | Actual Measurement | Result (Pass/Fail). At this point, using the CadNexa FAI Report Generator to auto-populate Form 3 from balloon data eliminates the manual re-keying where most numbering errors occur.
7. Cross-check the complete list for gaps and duplicates. After completing Form 3, sort by balloon number and confirm: (a) no number is missing, (b) no number appears twice, (c) the highest balloon number on Form 3 equals the total count of characteristics on the marked drawing. Any mismatch must be resolved before submission.
8. Attach the marked drawing to the FAI package as a controlled document. The marked drawing is not optional. It is a required exhibit under AS9102 Rev C. The submitted copy must be legible, revision-stamped, and match the form in every balloon number.

The AS9102 Form 3 Column Structure

Understanding the exact column layout removes ambiguity about where each data point belongs. The table below shows the standard Form 3 structure with a single worked example for a turned bore diameter.

Balloon 12 on the marked drawing points to the bore. Row 12 on Form 3 carries the same characteristic, the nominal 25.000 mm, the tolerance band, the CMM-measured actual of 25.011 mm, and the pass result. The link is complete and auditable. For tolerance band values across the full range of ISO 286 fits, refer to the ISO 286-1 standard (ISO Online Browsing Platform) rather than transcribing tables here.

Numbering Convention Details That Auditors Check

Several numbering decisions that seem minor become significant during a DQE audit or AS9100 surveillance. The table below summarises the most common convention questions and the accepted practice.

Linking Balloon Numbers to Measurement Results in FAI: Special Cases

GD&T Characteristics

A feature control frame contains multiple data elements: the geometric tolerance symbol, the tolerance value, the datum references, and any material condition modifiers. Each frame receives one balloon number. On Form 3, the characteristic description column should spell out the full callout — for example, "True Position Ø0.1 (M) A B C" — so the auditor can match it to the drawing without ambiguity. For a worked true position example, the true position formula post on CadNexa is a useful companion.

Surface Finish Callouts

Surface roughness (Ra or Rz) callouts are measurable characteristics and must be ballooned. Place the balloon adjacent to the finish symbol. In the Form 3 description column, record the parameter and value — for example, "Ra 1.6 µm" — and enter the profilometer reading as the actual result. ASME Y14.36M and ISO 1302 govern the drawing symbols; the measured value must use the same parameter as the callout.

Thread Characteristics

A threaded feature typically carries two measurable characteristics: the thread form/class (verified by go/no-go gauge) and sometimes the thread depth or engagement length. Assign a separate balloon number to each measurable element. On Form 3, the result for a go/no-go check is recorded as "GO: PASS / NO-GO: PASS" rather than a numeric actual, which is acceptable practice when a variable measurement is not required by the drawing.

AS9102 Inspection Report Balloon Reference Traceability: The Audit Trail

Traceability in an FAI package means an auditor can start at any row on Form 3, read the balloon number, and find the corresponding balloon on the marked drawing within seconds. Three documents must be consistent simultaneously: the released drawing (with revision), the marked/ballooned copy of that drawing, and Form 3. If any one of the three diverges — a different revision, a missing balloon, an extra row — the package fails.

Customer quality requirements often add a fourth element: the measurement system record. CMM reports, gauge calibration certificates, and surface profilometer printouts must reference the same balloon numbers used on Form 3. When a CMM report uses its own internal feature numbering, add a cross-reference column that maps CMM feature IDs to AS9102 balloon numbers. This cross-reference becomes part of the FAI package and must be retained for the life of the programme. For measurement uncertainty considerations that affect how close an actual can be to a tolerance limit before it needs additional analysis, the JCGM 100:2008 GUM (NIST hosted) is the authoritative reference.

Common Mistakes and Pitfalls

• Ballooning from memory rather than a fresh review. Engineers who have worked with a part for months sometimes assume they know every characteristic. A systematic, feature-by-feature walk of the drawing always catches callouts that familiarity obscures.
• Restarting the balloon sequence on each sheet. Sheet 1 ends at balloon 38, sheet 2 starts at balloon 1 again. Form 3 then has two rows numbered 1, two rows numbered 2, and so on. This is an automatic rejection.
• Failing to balloon general tolerance notes. A title block note reading "Unless otherwise specified: ±0.1 mm" is a design characteristic. Every dimension controlled by that note is potentially measurable. Common practice is to assign one balloon number to the note itself and reference it in the Form 3 description for all affected dimensions.
• Using different balloon numbers on the controlled drawing versus the working copy. Teams sometimes mark up a working PDF for planning and then submit a separately ballooned copy for the FAI package, with slightly different numbering. Always use one master balloon file.
• Leaving gaps after deleting a misplaced balloon. Deleting balloon 23 and leaving 22 followed by 24 creates an unexplained gap. Re-sequence the entire drawing before submission, and update Form 3 to match.
• Not recording the actual measurement for every instance of a repeated feature. If 6 holes share balloon 14, all 6 actual measurements must appear in Form 3 — either as six sub-rows or in a supporting measurement sheet cross-referenced to balloon 14.

How CadNexa Helps

CadNexa's PDF Balloon Tool (live) handles the mechanical discipline of sequential numbering directly in the browser. It supports Click, Leader, and Box+Balloon modes across PDF, TIFF, PNG, JPG, and BMP drawings, with 13 balloon colours, adjustable size, and continuous numbering across multiple pages. When a balloon is deleted, the gap-filling feature flags the break so engineers can re-sequence before the package is locked.

The Box+Balloon OCR feature (live) lets quality engineers draw a box around a dimension on the drawing; the tool reads the value, tolerance, and characteristic type — diameter, radius, thread, GD&T — and pre-fills the balloon data. The Smart Detect Dimensions feature (live) scans the entire drawing in one click to auto-detect dimensions, tolerances, and GD&T frames for review and approval, dramatically reducing the time spent on manual identification.

Once ballooning is complete, the FAI Report Generator (live) at cadnexa.com/app.html builds the AS9102 Rev C Form 3 directly from the balloon data — same numbers, same sequence, same characteristic descriptions — eliminating the manual transcription step where most numbering errors occur. The report exports as interactive HTML, PDF, or CSV, with no separate re-keying step between the marked drawing and the inspection report.

Frequently Asked Questions

What is the correct balloon numbering convention for AS9102 Form 3?

AS9102 Rev C requires each characteristic on the drawing to receive a unique sequential balloon number starting from 1. That same number appears in the "Balloon Number" column of Form 3 (Characteristic Accountability), creating a direct, traceable link between the marked drawing and the measured result.

Does AS9102 require a specific starting number or sequence direction for balloons?

AS9102 Rev C does not mandate a fixed starting point or direction, but aerospace customer supplements — such as Boeing D1-9000 or Airbus AIPS 04-01-003 — often prescribe left-to-right, top-to-bottom sequencing. Always check the applicable customer quality requirement before ballooning.

Can the same balloon number appear twice on an AS9102 drawing?

No. Each balloon number must be unique. If the same dimension appears in multiple views, use the same balloon number in all views, but record only one row on Form 3. Duplicate numbers are a common audit finding that triggers immediate rejection.

What happens if a balloon number on Form 3 does not match the marked drawing?

A mismatch breaks traceability and is a nonconformance under AS9102 Rev C Section 4.2. The FAI package will be rejected by the customer DQE. Every balloon number in the inspection report must trace back to an identifiable feature on the marked drawing.

How many parts must be measured for the dimensional results section of an AS9102 FAI?

AS9102 Rev C Section 4.2 requires dimensional results from one first article part. Some customers require three to five samples; always verify the purchase order or customer quality plan for additional sample requirements before finalising the measurement plan.

Conclusion

The link between a balloon number on a marked drawing and its corresponding row on the AS9102 Form 3 dimensional results report is the single most audited element of an FAI package. Sequential numbering with no gaps, consistent cross-sheet continuation, and a controlled marked drawing submitted alongside the report — these three disciplines resolve the vast majority of FAI rejections caused by traceability failures.

Getting the balloon-to-result link right the first time saves weeks of rework, prevents production holds, and protects the supplier's standing with aerospace customers who review FAI packages against every clause of AS9102 Rev C. The AS9102 Forms 1, 2 and 3 explainer on CadNexa and the FAI checklist guide are good companions to this process.