AS9102 Form 3 fields, column by column
Form 3 is a wide table. If you have been handed one and are not sure what a column is asking for, this page maps the data the form holds and what each field is for. It is a guide to the form, not a substitute for the standard.
What Form 3 is for
Form 3, Characteristic Accountability, exists to show that every design characteristic on a part was identified and measured. Each row is one characteristic. Each column is one piece of evidence about it.
That is why the form is wide. A measurement is meaningless without knowing which feature it belongs to, what the requirement was, what tolerance applied, and what instrument produced the number.
The characteristic itself
| Field | What it holds |
|---|---|
| Characteristic number | The balloon number. Matches the numbered callout on the ballooned drawing and ties the row back to a feature. |
| Reference location | Where on the drawing or model the characteristic is found — a sheet, zone or view reference. |
| Characteristic designation | Whether the feature is classified, for example as Key or Critical, where the drawing or contract says so. |
| Specification / requirement | The drawing or specification requirement the characteristic must meet. |
The requirement and the tolerance
| Field | What it holds |
|---|---|
| Nominal / basic dimension | The stated design value the tolerance is applied to, such as a diameter of 12.000 mm. |
| Tolerance plus | The upper allowable deviation from nominal. It may be zero, and it may come from a general tolerance block rather than being written on the dimension. |
| Tolerance minus | The lower allowable deviation. Not always symmetrical with the plus tolerance. |
The measurement result
| Field | What it holds |
|---|---|
| Actual / measured result | The value the inspection produced. Often more than one value where a feature is measured at several points. |
| Pass / fail determination | The conformity result for that characteristic. On a completed form this is a recorded outcome, not something calculated while transcribing. |
| Nonconformance reference | Where a characteristic failed, the reference linking it to the nonconformance record. |
How it was measured
| Field | What it holds |
|---|---|
| Inspection method | The method used for that characteristic — a gage, a CMM, a visual check, a functional test. |
| Gage / equipment ID | The identifier of the instrument, which is what links the measurement to its calibration record. |
The gage identifier is easy to treat as a formality. It is not. Without it a measured value cannot be traced to a calibrated instrument, and the evidence chain breaks.
Who did the work, and when
| Field | What it holds |
|---|---|
| Inspector / prepared by | The person who performed or recorded the inspection. |
| Inspection date | When the inspection took place. |
| Approval / signature | Sign-off, where the form or your quality system requires it. |
Why the form is laid out this way
Every column answers one of four questions: which feature, what was required, what was measured, and how do we know the measurement is trustworthy. A row missing any of those four is an incomplete record.
That structure is also why a number pasted out of a CMM report is not a Form 3 row. On its own it has no balloon, no requirement, no tolerance and no gage behind it.
Frequently asked questions
What does the characteristic number mean on AS9102 Form 3?
It is the balloon number, the numbered callout on the ballooned drawing that identifies which feature the row refers to. It ties a measurement back to a specific location on the drawing or model.
What is the difference between nominal and tolerance on Form 3?
The nominal is the stated design value, such as a 12.000 mm diameter. The plus and minus tolerances are the allowable deviations from that value. They are separate fields because a measurement cannot be judged without both.
Why does Form 3 ask for a gage ID?
The gage identifier links the measured value to the calibration record of the instrument that produced it. Without it the measurement cannot be traced to a calibrated source, which breaks the evidence chain.
Does Form 3 calculate pass or fail?
On a completed Form 3 the pass or fail determination is a recorded result for each characteristic. If you are transcribing an existing form into a spreadsheet you are copying that determination, not recomputing it.
Sources
- IAQG — AS9102 forms and supporting form instructions
- IAQG — Form 3 Characteristic Accountability (9102B)
- SAE International — AS9102C, Aerospace First Article Inspection
Standards are revised. Always work from the current published edition of AS9102 from SAE International. This page is orientation only and is not a substitute for the standard.