What Is a First Article Inspection?
A first article inspection is a structured, documented comparison between the first production-ready unit built from recovered design files and the original reference board. It answers one question: does this copy function, fit, and perform identically to the source? The inspection covers dimensional accuracy, component placement, solder quality, electrical continuity, and functional behavior — all measured against defined tolerances before a single production lot ships.
In a PCB reverse engineering service, FAI is not optional. Recovered Gerbers and BOMs are only as trustworthy as the physical board they produce. Without a formal first article inspection, errors in layer registration, trace impedance, or BOM substitution can propagate silently into hundreds or thousands of units.
Why First Article Inspection Matters After Reverse Engineering
When you work from OEM documentation, your Gerber files have a known pedigree. When files are recovered from a physical sample, every data point was extracted — not authored. That extraction introduces risk at every stage:
- Layer imaging: Copper features recovered from cross-section photography may carry ±0.5 mil dimensional drift per layer.
- Drill mapping: Hole positions measured optically can shift 1–2 mil from true center, especially on boards with 8+ layers.
- BOM recovery: Passive values read from markings (e.g., 0402 resistors) occasionally mismatch datasheets by one E-series step.
- Stackup reconstruction: Dielectric thicknesses estimated from cross-section micrographs carry ±0.5 mil uncertainty, affecting impedance.
First article inspection catches these issues on one board, not a batch of 500.
What Does a First Article Inspection Check?
Our engineers apply a 12-point FAI protocol. The table below shows each checkpoint, the measurement method, and the pass/fail tolerance we hold.
| Checkpoint | Method | Pass Tolerance |
|---|---|---|
| Board outline dimensions | CMM / caliper | ±4 mil (±0.1 mm) |
| Hole position accuracy | Optical comparator | ±2 mil (±0.05 mm) |
| Hole diameter | Pin gauge | ±1 mil (±0.025 mm) |
| Trace width / spacing | Microscope + calibrated reticle | ±0.5 mil on fine-pitch; ±1 mil standard |
| Layer-to-layer registration | X-ray or microsection | ±3 mil |
| Impedance (controlled lines) | TDR coupon | ±10 % of target Z₀ |
| Solder joint quality | IPC-A-610 Class 2 visual | No Class 3 defects |
| Component placement | AOI vs. centroid file | ≤50 % of pad width offset |
| Component value / part number | LCR meter + visual | Exact match to recovered BOM |
| Net continuity | Flying probe vs. recovered netlist | 0 opens, 0 shorts |
| Functional test | Power-on golden-board compare | Voltage rails ±3 %, signal timing ±5 % |
| Marking / silkscreen | Visual | Legible, correctly oriented |
Not every board requires all 12 checks. A 2-layer FR4 with through-hole parts may skip impedance testing. A 10-layer HDI with 4 mil trace/space needs every line in the table — plus non-destructive X-ray imaging to verify buried via registration without destroying the article.
How We Run a First Article Inspection — Step by Step
1. Build the first article
The board is fabricated and assembled using the exact recovered Gerber set, drill files, and BOM that will go to volume production. No “engineering tweaks” are allowed at this stage — the point is to validate the production data package, not a hand-modified prototype. If you need a prototype built directly from a sample board, that happens upstream; FAI comes after the data package is frozen.
2. Dimensional and visual inspection
Board outline, mounting-hole positions, and slot dimensions are measured against the original on a coordinate measuring machine. Copper features are spot-checked under a calibrated microscope at 50×–200× magnification. Solder joints are graded per IPC-A-610 Class 2 (or Class 3 where the customer specifies).
3. Electrical verification
A flying-probe test runs the full netlist extracted during reverse engineering. Every net must pass — a single open or short sends the article back for root-cause analysis. Controlled-impedance lines are verified by TDR on dedicated test coupons panelized alongside the board.
4. Functional comparison
The first article is powered alongside the original reference board. Our engineers measure supply rails, clock frequencies, and key signal waveforms at defined test points. We use a golden-board functional comparison methodology: if the copy’s output deviates beyond the tolerance window, the specific net is traced back through the schematic to isolate the discrepancy.
5. Documentation and sign-off
The FAI report is delivered as a PDF package containing:
- Dimensional inspection data with pass/fail per checkpoint
- AOI placement report (images + offset data)
- Flying-probe continuity results (net count, pass count, fail count)
- TDR impedance traces (if applicable)
- Functional test waveforms and voltage measurements
- Disposition: PASS, CONDITIONAL PASS (with noted deviations), or FAIL
A conditional pass means the board works but one or more measurements fell outside nominal tolerance while remaining within functional limits. The report flags the deviation and recommends whether to proceed or re-spin.
First Article Inspection vs. Quality Inspection — What’s the Difference?
FAI validates the data package by testing one board before production. Ongoing quality inspection validates the production process by sampling boards during and after a run. Think of FAI as the gate that proves “we can build this correctly,” while quality inspection proves “we are still building it correctly on unit 500.”
Common Failure Modes Found During First Article Inspection
Over hundreds of reverse-engineered boards, these are the issues our FAI process catches most often:
- Annular ring violation: Drill-to-pad misregistration on inner layers causes the annular ring to drop below IPC Class 2 minimums (≥5 mil). Root cause is usually a 1–2 mil systematic offset in the recovered NC drill file.
- Impedance miss: A 6 % dielectric thickness deviation in the fab stackup pushes a 50 Ω line to 54 Ω. The TDR coupon catches this before signal-integrity problems appear in the field.
- BOM substitution error: A 10 kΩ resistor marked “103” is read correctly, but the recovered BOM specifies 1 % tolerance while the assembled part is 5 %. Functional test reveals excess ripple on a voltage regulator feedback divider.
- Solder bridge on fine-pitch QFP: 0.5 mm pitch leads bridged during reflow. AOI flags it; rework resolves it before the production run.
When Should You Request a First Article Inspection?
Always — if the board will enter volume production. Specifically:
- After any reverse engineering engagement where files were recovered, not authored.
- When switching fabrication vendors for an existing cloned design.
- After an obsolete component replacement changes the BOM, even if only one part number is swapped.
- When a board revision adds or removes layers, changes the stackup, or modifies controlled-impedance routes.
What a First Article Inspection Costs and How Long It Takes
FAI cost depends on board complexity and the number of checkpoints required. Typical ranges:
| Board Class | Layers | FAI Turnaround | Typical FAI Cost Range |
|---|---|---|---|
| Simple consumer | 1–2 | 2–3 working days | $150–$350 |
| Mid-complexity industrial | 4–6 | 3–5 working days | $350–$800 |
| High-density / HDI | 8–16+ | 5–8 working days | $800–$1,800 |
These ranges cover inspection and reporting only — fabrication and assembly of the first article are separate line items. Turnaround starts when we receive the assembled first article, not when the fab order ships.
Check feasibility for your project
Send the chip marking or board details and tell us what you need to recover. Add clear photos if available.
Request a feasibility reviewIs first article inspection the same as AS9102?
AS9102 is the aerospace-specific FAI standard that requires detailed form-based reporting (Forms 1, 2, and 3). Our standard FAI protocol covers the same dimensional and functional checks but uses a streamlined report format. If your program requires AS9102-compliant documentation, let us know at quoting — we can deliver the required forms at additional cost.
Can you perform FAI on a board we assembled ourselves?
Yes. If you fabricated and assembled the board from our recovered data package, ship us the first article along with the original reference board. We run the same 12-point inspection and return a formal report. This is common when customers use their own contract manufacturer but want independent verification.
What happens if the first article fails inspection?
We issue a failure report identifying every out-of-tolerance measurement and its probable root cause. If the issue traces back to the recovered data (e.g., a drill offset), we correct the files and re-release the package at no additional engineering charge. If the issue is a fabrication or assembly defect, the report gives your manufacturer the data needed to adjust their process before re-building.
Do you inspect firmware behavior during FAI?
Functional testing during FAI covers power-on behavior, voltage rails, and signal waveforms — essentially, does the board boot and operate like the original? Deep firmware validation (protocol-level communication, edge-case behavior) falls under extended functional testing and is scoped separately.
How does first article inspection relate to a sample duplication order?
A sample duplication project typically includes FAI as the final gate before delivering cloned boards. The first article proves the recovered files produce a board that matches the original you sent us. If you order duplication, FAI is built into the workflow — you don’t need to request it separately.
Working on a board like this?
Send the chip marking or two photos. You get feasibility, lead time and price within 24 hours, and the check costs nothing.
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