AS9100D and the PCB Manufacturer — Where We Plug Into the Quality System

AS9100D is the quality management standard for aerospace and defence. Most prime contractors and Tier-1 suppliers in those sectors are certified to it, and they expect their PCB and assembly partners to either be certified themselves or to integrate cleanly into their own AS9100D framework as a controlled supplier. The standard is large, but the PCB partner's footprint inside it is well defined: counterfeit-parts prevention, configuration management, special-process control, first-article inspection, and traceability. Get those right and the rest of the AS9100D conversation is your customer's problem, not yours.

The clauses that touch the PCB manufacturer most directly

• Clause 8.1.4 — Prevention of counterfeit parts. Inspection, supplier qualification, and chain-of-custody discipline.
• Clause 8.5.1.3 — Control of production process changes. What you can change without notifying the customer, and what triggers re-qualification.
• Clause 8.5.1.2 — Validation and control of special processes. Soldering, conformal coating, and any process whose result cannot be fully verified by inspection.
• Clause 8.5.2 — Identification and traceability. Per-board, per-component, full audit trail for the life of the deliverable.
• Clause 8.5.6 — Control of changes. Configuration management discipline against released revisions.

"The first AS9100D audit we ever supported was for a UAV avionics customer. The audit team did not ask about our SMT line. They asked about our counterfeit-parts plan, our process FMEA, and how we tied a serial number on the board to the reel of MLCCs it was built from. Every audit since has followed the same script." — Pioneer Horizon aerospace audit team

The rest of this article walks through each of those clauses from the manufacturer's side of the table.

Clause 8.1.4 of AS9100D requires a documented counterfeit-parts prevention plan that addresses six elements: supplier control, inspection, reporting, training, escalation, and disposition. AS6174 and AS5553 are the companion standards that the aerospace world uses to flesh out the inspection side. The plan is not optional; it is one of the first documents an aerospace customer's quality engineer will ask to see when qualifying us as a supplier.

What our plan contains

1. Authorised distributor first. Aerospace BOMs are sourced through franchised distributors wherever possible. Grey-market sourcing is permitted only with documented customer approval and an enhanced inspection regime.
2. Tiered inspection at incoming. Optical, X-ray, and decapsulation in three tiers, with criteria for moving a lot up the tiers. The full framework is in our counterfeit-detection guide; the aerospace overlay is that any grey-market lot is automatically Tier 2 minimum.
3. Reference-image library. X-ray reference images for the high-value parts on aerospace BOMs, maintained internally and shared with customer quality teams.
4. Escalation procedure. A suspect lot is quarantined, the customer is notified within 24 hours, and the disposition is decided jointly. Suspect lots are never silently re-stocked or returned to the distributor without record.
5. Training. Incoming inspectors are trained against AS6171 inspection criteria with refresher training every 18 months.

Records the audit will demand

• Counterfeit-parts plan document with revision history.
• Inspection records by lot for the past three years minimum.
• Supplier qualification records and audit reports for any non-franchised source.
• Suspect-lot incident log, including dispositions.

The audit will not just confirm that the plan exists. The auditor will pull a specific board's serial number, trace it back to the components used, and verify the inspection record on those reels existed at the time of the build. The traceability has to be intact end-to-end.

Configuration management is where AS9100D differs most sharply from commercial manufacturing. Every released revision of every drawing — Gerbers, fab notes, BOM, assembly drawing, programming files — is under formal control. A change requires an engineering change order, a customer notification if the change affects the controlled characteristics, and re-qualification of any affected first-article requirement. The discipline is not heavy by itself; the failures come from teams treating it as bureaucratic overhead.

What we control as the build partner

• Released revision baseline. Every customer programme has a baseline package: Gerbers Rev X, BOM Rev Y, assembly drawing Rev Z. The baseline is the only version that can be built without further authorisation.
• Process recipe lock. The reflow profile, the AOI inspection program, the X-ray void thresholds — all locked to the customer programme. Changes require an internal change control board sign-off and customer notification per the supply agreement.
• Software and firmware. If the board ships with programmed firmware or configuration data, the file used at programming is under the same configuration control as the hardware revisions. Build records capture the file version.

What requires customer notification

The supply agreement spells this out, but the typical aerospace triggers are: any change to a critical-to-quality dimension, any change to a special process, any change in component manufacturer or part number, any change in process step sequence. We have seen programmes pause for a quarter while a customer's quality engineering reviews a notification we issued for a paste-chemistry change; the cost of issuing the notice is small, the cost of not issuing it and being found at audit is programme-ending.

The change-control records the audit will look for

1. Engineering change order log with originator, reviewer, approver, and date.
2. Customer notification record for each external change.
3. Re-qualification evidence — first-article inspection on the changed configuration.
4. As-built record per panel ID stating the exact baseline revision used.

The principle behind all of it is simple: an aerospace customer needs to be able to look at a board built four years ago and know, with certainty, which release of every input went into that exact build. Configuration management is how that certainty is produced.

A special process under AS9100D is one whose output cannot be fully verified by subsequent inspection. Soldering qualifies because you cannot see inside a finished joint without destructive testing. Conformal coating qualifies because coverage and thickness, once cured, are partially obscured. Plating, brazing, and welding all qualify. The standard requires that special processes be validated, the operators qualified, and the validation maintained — and AS9100D points to industry-specific qualifications like NADCAP for the soldering side.

What validation means in practice

• Documented process specification. Reflow profile by zone, paste rheology spec, soldering iron temperature for hand work, coating thickness target.
• Initial validation. First production lot characterised against the specification with statistical sampling; result documented.
• Ongoing monitoring. Control charts on the parameters that drift — peak reflow temperature, oven zone variance, paste viscosity at the printer.
• Operator qualification. Hand-solder operators qualified against J-STD-001 with periodic re-test every 24 months.

First-article inspection (FAI)

AS9102 is the standard format for FAI in aerospace. For a new PCB programme, the FAI on the first article covers every controlled dimension on the assembly drawing, every BOM substitution, the firmware version, and the special-process records that produced that first article. The report runs to dozens of pages on a complex board. The deliverable is signed by us, reviewed by the customer's quality engineering, and stored against the programme for the programme's life.

What the auditor will probe

• Show me the FAI report for serial number XYZ.
• Show me the reflow profile log for the date that board ran.
• Show me the operator qualification card for the hand-solder technician who closed that joint.
• Show me the calibration record for the X-ray that inspected the BGA.

The audit is not a paper exercise. The auditor is checking whether the system you describe is the system you live. Records that exist but are incomplete fail just as cleanly as records that do not exist at all.

Audit day on an AS9100D programme is usually one full day, sometimes two, on our floor — with the customer's quality engineer or a third-party auditor walking the line, reading records, and interviewing the people who do the work. The audits that go well are the ones we have rehearsed; the audits that go poorly are the ones where a record is missing because nobody anticipated it would be asked for. Three things we do to keep the second kind from happening.

1. Quarterly internal audit against the standard

Our internal quality team runs a mock audit every quarter on a programme selected at random. The audit follows the AS9100D clauses and the customer's specific quality plan. Findings are logged, corrective actions assigned with due dates, and verified at the next audit. The mock audit's job is not to pass; its job is to surface gaps before the real audit does.

2. Per-programme audit pack ready at all times

Every aerospace programme has an audit pack — a folder of documents that an auditor would expect to see. We maintain it in a state where, if the customer called tomorrow and said the auditor arrives Friday, we could produce the entire pack inside an hour. The pack contains the configuration baseline, the FAI report, the special-process validations, the operator qualifications, the calibration records on the line equipment, the counterfeit-parts plan, the supplier qualification records, and the per-board traceability for a representative sample.

3. Floor walk-through preparation

The floor is not staged for audits; it runs the same way every day. What we do prepare is the conversation. The operators and technicians who will be interviewed are briefed on what the auditor is likely to ask and trained to answer in their own words against the standard. An operator who can describe, in their own language, what they would do if the AOI flagged a defect — and where they would record that — is the strongest evidence of a quality system in actual use.

What we have learned from real audits

• The auditor will spend more time on traceability than any other topic.
• The auditor will pick a board off the shipping shelf and trace it backwards to the BOM and the operators; have that path clean.
• The auditor will look for the change-control evidence on a recent process change; do not let any process change skip the documentation.
• The auditor will interview people on the line; they have to know what they do and how it ties to the documented system.

If you are preparing for a first AS9100D customer audit on a programme we build for you, share the audit scope with our quality team ahead of time. We will assemble the audit pack and walk through it with your quality engineering before the auditor arrives.