A customer sends a new part number and asks for "FAI with the first lot". Another customer, an automotive OEM, asks for "layout inspection results" with the PPAP. Many shops treat these as the same job, fill a generic inspection sheet, and get the file sent back. They overlap, but they are not the same, and knowing the difference saves a second round of measuring.

What a first article inspection proves

A first article inspection (FAI) checks the first parts made by your planned process against every requirement on the drawing and the purchase order. It is common in aerospace and defence supply chains, where it is governed by AS9102.

A supplier requirements document from Lockheed Martin RMS, based on AS9102, says FAI provides objective evidence that all engineering, design, contractual and specification requirements are "correctly understood, accounted for, verified and recorded". It also says: "All characteristics on the face of a drawing must be documented and verified."

The AS9102 report has three forms:

  • Form 1 – part number accountability: part number, name, drawing number and revision, PO, and whether the FAI is full or partial.
  • Form 2 – product accountability: materials, special processes (heat treatment, plating, NDT) and functional tests, with the specification and certificate for each.
  • Form 3 – characteristic accountability: every design characteristic, its requirement, the measured result, and any non-conformance number.

What a layout inspection is

Layout inspection is the automotive term. In PPAP it appears as the Dimensional Results element. Quality-One's PPAP guide describes it as a "dimensional layout of sample parts" to validate that the product meets the print, with each dimension on the drawing measured and the results recorded in the submission.

PPAP is required for a new part and for approval of any change to an existing part or process, and the customer may ask for it at any time. Your customer's supplier manual may also ask for a periodic layout inspection on running parts, so check it for frequency and the number of parts to measure.

FAI vs layout inspection: the real differences

  • Industry and standard: FAI usually follows AS9102 (aerospace). Layout inspection follows the customer's PPAP requirements (automotive).
  • Scope: FAI covers dimensions plus materials, special processes and functional tests on separate forms. Layout inspection is mainly the dimensional record; material and performance results are separate PPAP elements.
  • Trigger: both start with a new part. AS9102-based rules also ask for a partial or delta FAI after changes to design, process, tooling, material, location or NC program, and after a lapse in production of two years or as the customer specifies.
  • Repeat: FAI is mostly event-driven. Layout inspection may also be repeated on a schedule if the customer's requirements ask for it.
Both reports fail for the same reason: a characteristic on the drawing that nobody numbered, so nobody measured.

Balloon the drawing first

Whichever report you owe, start with a ballooned drawing. Number every dimension, tolerance, GD&T frame, surface finish symbol and note, including notes like "break sharp edges 0.2–0.5" or "thread to 6H". The Lockheed Martin document calls ballooning recommended "to ensure accuracy and completeness", and asks for reference locations when the drawing is not ballooned.

Practical tips from the shop floor:

  • Balloon general notes and title-block tolerances too. A default ±0.1 on unmarked dimensions is still a requirement.
  • Split multi-part callouts. A hole note like "4x Ø8.5 thru, ⌀15 C'bore 8 deep" is several characteristics, and each needs a result.
  • Record actual values, not "OK". Write 25.012, not a tick.
  • Note the gauge or instrument for each line, so the customer can see that a 0.01 mm tolerance was not checked with a vernier.
  • Attach mill test certificates and plating or heat-treatment certificates where the drawing calls for them.

An illustrative example

For example, a turned and milled bracket might have 46 balloons: 31 dimensions, 6 GD&T controls, 4 surface finish callouts, a thread, a material spec, a hardness requirement, a plating note and a deburr note. A layout report lists all 46 with readings. An AS9102 FAI puts the 43 measurable characteristics on Form 3 and the material, hardness and plating on Form 2 with their certificates. (Illustrative numbers only.)

Common reasons the report is rejected

  • Drawing revision on the report does not match the PO.
  • Notes and title-block requirements left out.
  • Readings outside tolerance marked as accepted without a deviation.
  • Missing certificates for material or special processes.
  • Parts measured from a trial setup rather than the production process.

How SpecReview helps

Upload the drawing PDF, the STEP model, or both, and SpecReview builds a layout inspection plan that lists the characteristics to check, along with spec gaps and unclear notes worth clarifying before the first part is cut. For automotive work it also prepares a PPAP document set, with each item tagged as coming from the spec, the geometry or an assumption.