First Article Inspection for Cable Assemblies: What to Require Before Production

Published on 10/19/2026

The sample passed incoming inspection on a single piece. Then production started and the next lot behaved differently. First article inspection (FAI) exists to catch this before the lot is built. This page is for quality and procurement teams: what to require on a first article for an RF cable assembly, how to judge the results and how to keep repeat orders identical.

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What an FAI is for

A first article inspection confirms that the supplier's process produces an assembly that meets your drawing, before the full lot is built. It is a record of one piece, measured against every requirement, and a reference for all that follow.

It is different from a routine test report, which records results on each production piece. For what a routine report contains, see cable assembly test report contents. The FAI adds the process evidence: what was built, with what, and how it was checked.

What an FAI should contain

ItemWhat to checkWhy it matters
Dimensional checkOverall length, strip dimensions and connector orientation against the drawingLength error is the most common nonconformance
Materials usedCable type and lot, connector part numbers and lotsConfirms the build matches the spec and can be repeated
Crimp evidenceCrimp height, pull force or a cross-section of a sacrificial pieceA weak crimp passes a bench test and fails in the field
Electrical resultsVSWR, insertion loss and continuity over your frequency bandShows RF performance against your limits
Visual and workmanshipSolder or crimp finish, heat shrink, cleanliness, no cable damageShows process quality
Labelling and markingPart number, revision, date codeNeeded for traceability
PackagingHow the piece was protected and shippedConnectors damaged in transit fail incoming inspection

Key idea

Ask for the FAI measurements against the drawing numbers, not a "passed" stamp. A stamp tells you someone decided it was fine. Numbers tell you by how much.

Need a first article with measured data before you commit to production?

Request a First Article

What to do with the results

  1. Compare to limits. Check every number against the drawing tolerance and the electrical limit, with margin. A result at the edge of a limit is a risk in production.
  2. Decide on tolerances. If a dimension is hard to hold, discuss whether the tolerance is needed before the lot, not after.
  3. Keep a golden sample. Keep the approved piece, or the supplier does, sealed and labelled. Compare later lots against it.
  4. Lock the revision. Record the drawing revision and bill of materials the FAI approved. Any change needs a new approval.
  5. Sign off in writing. A recorded approval prevents later disputes over what was agreed.

Keeping repeat orders identical

The FAI approves one piece. Repeat orders stay identical when the supplier records how that piece was built.

  • A build record: cable type, connector parts, strip dimensions, crimp settings and tools.
  • Lot traceability for cable and connectors on every order.
  • The same test method and band each time, so results compare across lots.
  • A change notice rule: the supplier tells you before changing cable source, connector brand or process.

Ask any supplier for these during qualification. Our 12-point audit includes the questions.

When to demand an FAI and when to skip it

Ask for an FAI when

  • A new supplier is building for you for the first time.
  • The assembly is link-critical or has a tight loss or VSWR budget.
  • You will order the same assembly repeatedly.
  • The drawing has changed in a way that affects electrical performance.

You can skip a full FAI when

  • The part is a standard catalogue assembly used on a bench.
  • You are buying 1 or 2 pieces for a noncritical use and will inspect on receipt.
  • The supplier already shipped the same build to you with data you reviewed.

A middle path for small orders is a first-piece check inside the order: the supplier builds one piece first, sends the measurements and builds the rest after your approval. At SigmaRF every assembly is swept on a VNA for VSWR and insertion loss, so FAI data is the same data we collect on each piece, with the build record added.

FAI checklist

Copy this into your purchase order requirements

  • Drawing number and revision recorded on the FAI.
  • Dimensional results: length, strip dimensions, orientation.
  • Cable and connector part numbers with lot numbers.
  • Crimp evidence: height, pull force or cross-section.
  • VSWR and insertion loss plots over the full band, with the instrument named.
  • Visual and workmanship check recorded.
  • Label, part number and revision confirmed.
  • Written approval before production release.

FAQ: first article inspection

What is a first article inspection for cable assemblies?

A documented check of the first piece built to your drawing, covering dimensions, materials, crimp quality and electrical results, done before full production.

What should a cable assembly FAI report include?

Drawing revision, dimensions, cable and connector lots, crimp evidence, VSWR and insertion loss data, workmanship check and a written approval.

Is an FAI the same as a test report?

No. A test report records electrical results on production pieces. An FAI also records the build process and materials for the first piece.

Do I need PPAP for cable assemblies?

PPAP is a formal automotive approval process. Whether you need it depends on your industry and customer. For most RF assemblies an FAI plus a build record is the working equivalent. Ask your quality team what your customer requires.

How long does an FAI add to lead time?

It adds the time to build, measure and approve one piece, often a few days. Many buyers approve the first piece while the supplier prepares the rest of the lot.

Can SigmaRF provide first article data?

Yes. Request a first article through the contact page and we will send per-unit measurements with the piece.

How do I keep later lots identical to the first article?

Lock the drawing revision, keep a golden sample, ask for lot traceability and require notice of any process or material change.

Bottom Line

A first article turns "it should work" into measured evidence. Require numbers, keep a golden sample, lock the revision and ask the supplier to record the build. Then repeat orders match the piece you approved.

Ready to talk about your build?

Request a first article with per-unit test data and a build record.

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