How to fill in AS9102 Form 3 without errors
The aerospace prime contractor wants the complete FAI package before it authorises delivery of the first production batch. At the heart of this approval package is AS9102 Form 3, the document that records every measurement result, dimension by dimension, balloon by balloon. Filling in this grid by hand invites major approval delays as soon as a balloon number is missed or a tolerance is copied wrongly.
Structure and role of AS9102 Form 3 in the FAI package
Form 3 (Characteristic Accountability, Verification and Compatibility Evaluation) records every geometric and dimensional requirement on the design drawing. Knowing how to fill it in guarantees full traceability between the ballooned drawing, the calibrated gauges and the parts produced.
| Column number | AS9102 title | What to enter | Example entry |
|---|---|---|---|
| Field 5 | Char. No. | Balloon number on the drawing | 14 |
| Field 6 | Reference Location | Drawing zone (grid coordinates) | B3 |
| Field 7 | Characteristic Designator | Key characteristic or critical requirement | Key / Critical |
| Field 8 | Requirement | Drawing requirement with limits or text | ⌀25 H7 (+0.021 / 0) |
| Field 9 | Results | Physical value measured on the part | 25.014 mm |
| Field 10 | Designed / Qualified Tooling | Inspection tooling designed or qualified for the part | Gauge TL-044 |
| Field 11 | Nonconformance Number | Nonconformance report number, if the dimension is out of tolerance | NCR-2026-088 |
| Field 12 | Additional Data / Comments | Remarks, measuring equipment, CMM program | MIC-2024-08 |
Fields 1 to 4 repeat at the top of the page the part number, name, serial number and report identifier.
Each line corresponds strictly to one ballooned dimension. No characteristic may be left out, or the customer’s quality inspector rejects the package at once.
Numbering and locating characteristics on the drawing
The first task is to give each specification on the drawing a unique number (Field 5). That number must match exactly the balloon placed on the mechanical drawing sent to inspection.
Locating the characteristic in Field 6 makes checking easier. By giving the zone coordinates (for example C4 or B2), the reviewer finds the dimension straight away on an A0 drawing with more than two hundred balloons.
Critical requirements and key characteristics (KC) must be flagged in Field 7, to signal to auditors that they need closer statistical monitoring.
Copying the drawing requirements accurately
Column 8 calls for the requirement exactly as written, with its tolerances. Don’t just write the nominal value: the full specification must be there in black and white.
For a ⌀25 H7 dimension, don’t simply write ⌀25. Enter ⌀25 H7 together with the exact numerical limits (+0.021 / 0.000). This removes any ambiguity in a corrective action analysis if there is a dispute.
Title block notes, applicable general tolerances (such as ISO 2768-mK) and surface finish requirements (Ra roughness) must have their own balloons and appear in this same column.
Recording results and identifying the inspection equipment
Field 9 holds the inspection results actually found on the first good machined part. Writing a single word such as “Conforms” or “OK” is strictly forbidden for any measurable dimension. Only qualitative characteristics (no burrs, visual appearance) allow an attribute assessment.
Field 10 identifies the tooling designed or qualified specifically to inspect the characteristic: gauge, plug gauge, inspection fixture, CMM program. It guarantees that the same means can be reused in production.
For general-purpose instruments, metrological traceability goes through Field 12 (Additional Data / Comments). If a dimension is measured on a CMM, give the CMM program reference and the identifier of the probing report attached to the package. For a vernier caliper or a micrometer, enter its asset number, which leads back to its calibration.
Automating the entries with the FAI package export tools removes typing errors between the readings and the final sheet.
Concrete example: an FAI line for an aerospace housing
Consider the inspection of the bearing seat of an aluminium alloy engine accessory housing. Balloon number 18, in zone D2, calls for a ⌀52 H6 bore.
The ISO 286 tables give, for a 52 mm diameter at grade 6, an IT6 interval of 19 microns, i.e. limits from 52.000 mm to 52.019 mm.
- Field 5 (Char #): 18.
- Field 6 (Location): D2.
- Field 7 (Designator): KC (Key Characteristic).
- Field 8 (Requirement):
⌀52 H6 (+0.019 / 0.000 mm). - Field 9 (Results): 52.012 mm.
- Field 10 (Designed / Qualified Tooling): Plain plug gauge METRO-TL-044.
- Field 11 (Nonconformance Number): empty, the dimension conforms.
- Field 12 (Comments): additional check with three-point bore gauge A3T-102.
The measured value of 52.012 mm lies within [52.000 mm; 52.019 mm]. The characteristic is approved as conforming on Form 3.
Classic pitfalls that get Form 3 rejected
The first pitfall is a mismatch between the ballooned drawing and the table. If the drawing carries 145 balloons and Form 3 only has 142 lines, the inspection package is rejected without further review. Every technical note at the bottom of the title block counts as a characteristic in its own right.
The second is using unsuitable or uncalibrated equipment. Entering a general-purpose vernier caliper (0.02 mm resolution) to accept an H6 tolerance of 19 microns is a major methodological mistake. The ratio between the tolerance and the measuring equipment must respect the standard minimum of 4 to 1.
The third comes with drawing changes (revision updates). When the drawing moves from revision A to revision B, every changed or added dimension must be listed with the new revision on the partial Form 3, or the manufacturing history becomes void.
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