MRO certification vs. stockist distributor certification — how to tell which AS91XX standard applies to your operation
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Confusing These Two Standards Can Cost You a Contract
A prime contractor asks if you’re “AS certified.” You say yes — but you say it without knowing which AS certification they mean. That gap shows up fast in a supplier qualification review, and understanding AS9110 vs AS9120 before that conversation happens is what keeps you from losing a bid before you ever quote a price.
AS9110 and AS9120 are both aerospace quality management system standards built on the same ISO 9001 foundation as AS9100. But they exist for two completely different kinds of operations. AS9110 governs maintenance, repair, and overhaul (MRO) organizations. AS9120 governs stockist distributors — companies that buy, store, and resell aerospace parts without altering them. Certify to the wrong one, or assume one covers what the other requires, and you’ll fail a customer audit or lose a contract before the certificate is even printed.
If you’re evaluating which standard applies to your operation — or a supplier is asking which one you hold — this guide breaks down the real differences: scope, clause focus, cost, and how to know which one is actually right for you.
From the Floor: I’ve sat at the table with a smaller machine shop during an onboarding audit with a much larger aerospace manufacturer who assumed AS9100 covered their distribution operation — it didn’t, and it cost them weeks in corrective action before we could approve them as a source. The standard has to match what you actually do on the floor, not what sounds closest to what your customer asked for.
Before you go further, know exactly where your QMS stands. Run your operation against the AS9100 Rev D Gap Assessment Checklist — a 74-item, clause-by-clause tool that also flags where MRO- and distribution-specific requirements diverge from base AS9100. Most gap findings are found six weeks too late. Don’t be one of them.
In This Guide
- What AS9110 covers and who needs it
- What AS9120 covers and who needs it
- Side-by-side clause and scope comparison
- Certification cost and timeline differences
- How to know which standard — or standards — your operation needs
- What’s changing in the 2026 IAQG standards revision
- FAQs on dual certification, transition, and audit prep
Table of Contents
👉 Start Here (Top Resources)
- Building your documentation from scratch or closing gaps fast? 9001Simplified’s documentation kits give you a QMS framework built around ISO 9001 that you can adapt to AS9110 or AS9120’s additional clauses — without hiring a consultant.
- Need the actual standard text? AS9110 — ANSI Webstore and AS9120 — ANSI Webstore — both standards are available for direct purchase.
- Shopping for training or a certification body? BSI’s aerospace training catalog covers AS9100-family courses, including MRO and distributor-specific tracks.
What Is AS9110?
Quick Answer: AS9110 is the aerospace quality management system standard for organizations that perform maintenance, repair, and overhaul (MRO) work on aircraft, engines, components, or related equipment. The current edition, AS9110 Rev C (2016), is titled “Quality Management Systems — Requirements for Aviation Maintenance Organizations” and is built on the ISO 9001:2015 clause structure.
AS9110 applies to organizations that touch a product’s airworthiness after it’s already in service — not organizations designing or manufacturing it new. That includes:
- FAA Part 145 certified repair stations
- Engine and component overhaul shops
- Organizations performing continuing airworthiness management
- MRO providers serving commercial, private, or military aircraft
The clause set adds requirements around configuration control of repaired items, release-to-service documentation, component traceability through the repair cycle, and management of customer-supplied product — all specific to the risk profile of returning a used part to service rather than shipping a new one.
If you’re comparing AS9110’s foundation to base ISO 9001, our AS9100 vs ISO 9001 breakdown covers the shared clause structure that AS9110 inherits.
What Is AS9120?
Quick Answer: AS9120 is the aerospace quality management system standard for stockist distributors — companies that procure aerospace parts, materials, or assemblies and resell them without physically modifying the product. The current edition, AS9120 Rev B, is titled “Quality Management Systems — Requirements for Aviation, Space and Defense Distributors.”
AS9120 is intentionally narrow in scope. It’s built for organizations that buy from an approved source, store product under controlled conditions, and ship it back out — sometimes splitting larger lots into smaller quantities, or performing a customer- or regulatory-required inspection before delivery. It is explicitly not intended for organizations that repair, maintain, or perform any process that changes the product’s characteristics or conformity.
That distinction matters because it drives the clause focus. AS9120 emphasizes:
- Purchasing controls and approved source verification
- Prevention of counterfeit and suspect unapproved parts
- Storage, handling, and shelf-life control
- Traceability of parts back to the original manufacturer
If counterfeit parts prevention is a gap area for your operation, our Counterfeit Parts Standards guide covers the AS9100-family clause requirements — including how AS9120 handles it for distributors specifically.
AS9110 vs AS9120: Side-by-Side Comparison
Category AS9110 (MRO) AS9120 (Distributors) Who it applies to Maintenance, repair, and overhaul organizations Stockist distributors, no physical modification of product Current edition Rev C (2016) Rev B Base standard ISO 9001:2015 ISO 9001:2015 Primary risk addressed Airworthiness of returned-to-service parts Traceability and authenticity of resold parts Key added clauses Release-to-service documentation, configuration control, maintenance data control Approved source verification, counterfeit parts prevention, lot control Typical certified organizations FAA Part 145 repair stations, engine overhaul shops Parts distributors, stockist suppliers, kitting operations Physical modification of product Yes — repair, overhaul, alteration No — resale only, with limited exceptions (splitting lots, inspection) Can be held alongside AS9100 Yes, for operations doing both design/production and MRO Yes, though less common — usually a standalone certification
⚠️ Most common finding: Auditors regularly flag distributors who hold AS9120 but perform light processing — such as re-marking, relabeling, repackaging, or other activities that affect traceability documentation — without realizing that activity may push them out of AS9120’s defined scope and into AS9110 or AS9100 territory. Know exactly what your operation does to the product before you pick a standard.
If you are unsure which standard matches your actual operation → map every process step against the AS9110 and AS9120 scope statements before you approach a certification body, not after you’ve already scheduled an audit.
Certification Cost and Timeline
Neither AS9110 nor AS9120 certification is dramatically more expensive than base AS9100 — the cost driver is usually organization size and audit complexity, not which standard you’re certifying to. Expect the same general cost structure: registrar audit fees, any documentation or consulting spend, and internal resource time for gap closure and internal audits.
For a full breakdown of what drives AS9100-family certification cost, see How Much Does AS9100 Certification Cost? — the same cost categories apply to AS9110 and AS9120 audits, with adjustments for scope.
If you are budgeting for certification this year → don’t assume AS9120 is cheaper because the standard is “smaller.” Distributor audits still require full documentation review, internal audit evidence, and a two-stage certification audit through an accredited registrar.
How Long Does Implementation Take?
Timeline follows the same general phases as AS9100: gap assessment, documentation build-out, implementation and internal audit, then the two-stage certification audit. Organizations with an existing ISO 9001 QMS typically move faster because the foundational clause structure is already in place — AS9110 and AS9120 add to that structure rather than replacing it.
For a phase-by-phase breakdown you can apply to either standard, our AS9100 Implementation Timeline walks through the realistic timeline most organizations should plan for.
Most teams miss this step — run a gap check against the specific standard you’re pursuing before you start building documentation. A generic AS9100 gap assessment won’t fully capture AS9110’s release-to-service requirements or AS9120’s distributor-specific traceability and counterfeit-part controls. Check yours before you invest in a documentation build-out you’ll have to redo →
Do You Need Both?
Some organizations legitimately need more than one AS91XX certification — a Tier 1 supplier that manufactures parts and also runs an internal repair operation might hold both AS9100 and AS9110. A distributor that occasionally performs approved rework might need to evaluate whether AS9120 alone still covers their scope, or whether they’ve drifted into AS9110 or AS9100 territory.
If you are already AS9100 certified and expanding into MRO or distribution work → don’t assume your existing certificate covers the new activity. Confirm scope with your registrar before you take on contracts that depend on AS9110 or AS9120 coverage you don’t actually have.
Traceability requirements run through all three standards, just with different emphasis. If you’re building out traceability documentation, our AS9100 Traceability Requirements article covers the clause 8.5.2 requirements that AS9110 and AS9120 both extend from.
Objection: “We’re Small — Do We Really Need to Certify to the Exact Right Standard?”
Yes, and here’s why it’s not just paperwork. Prime contractors and OEMs use your certification scope to determine what work they can flow down to you without additional oversight. If your certificate doesn’t match your actual scope of work, you risk being disqualified from a bid, or worse, passing an audit on paper while operating outside your certified scope — which becomes a much bigger problem the first time there’s a quality escape traced back to your facility.
Small organizations especially benefit from getting this right the first time, because a second certification audit to fix a scope mismatch costs real money and real time you don’t get back.
What’s Changing: The 2026 IAQG Standards Revision
The International Aerospace Quality Group is currently working through a comprehensive revision of the AS9100 series. Current IAQG working materials indicate the standards are expected to transition to the IA9100-series naming convention, although final publication details and transition requirements have not yet been formally released. Planned changes include stronger supplier management requirements, formal cybersecurity risk integration, and expanded counterfeit parts prevention measures for distributors specifically.
⚠️ This revision has not been published as final text as of this writing, and no confirmed transition deadline has been set. Treat any specific 2026 publication date as preliminary until IAQG and SAE International confirm final release. We’ll update this article once the revised editions are formally published.
Quick Audit Checklist: Which Standard Applies to You?
✅ Does your organization physically repair, overhaul, or alter aerospace products after they’ve entered service? → AS9110
✅ Does your organization buy, store, and resell aerospace parts without modification? → AS9120
✅ Does your organization design, develop, or manufacture new aerospace products? → AS9100 — see our What Is AS9100? pillar guide
✅ Does your organization do more than one of the above? → You may need certification to more than one standard — confirm scope with your registrar before proceeding
✅ Have you mapped your actual process steps against the standard’s defined scope statement, not just its title? → Do this before scheduling any certification audit
FAQ
Is AS9110 harder to get certified to than AS9120?
Not inherently. Difficulty depends on how mature your existing quality processes are, not which standard you’re pursuing. AS9110 has more clauses focused on maintenance-specific documentation and release-to-service control, while AS9120 focuses heavily on purchasing and traceability controls. Neither is universally “easier.”
Can a distributor hold AS9100 instead of AS9120?
Technically a distributor could pursue AS9100, but it would include requirements around design and production control that don’t apply to a pure distribution operation. AS9120 is scoped specifically for distributors and avoids that mismatch — which is usually what customers and registrars expect to see.
Does AS9110 or AS9120 replace the need for ISO 9001 certification?
No. Both standards incorporate the full text of ISO 9001:2015 and add aerospace-specific requirements on top of it. You don’t need a separate ISO 9001 certificate in addition to AS9110 or AS9120 — the aerospace standard already contains it — but the underlying quality management principles are the same ones ISO 9001 establishes.
How do I verify a supplier’s AS9110 or AS9120 certification is real?
Check the IAQG’s OASIS database, which lists verified AS9100-family certifications, including AS9110 and AS9120, issued by accredited certification bodies.
What happens if my scope of work doesn’t match my certificate?
You risk failing a customer supplier audit, losing approved-source status with a prime contractor, or facing corrective action findings during your next registrar surveillance audit. If your operation has changed since your last certification cycle, confirm your certificate scope still matches before it becomes a customer’s finding instead of yours.
Is there a bundled cost savings if I need the text of both AS9110 and AS9120?
Is there a bundled cost savings if I need the text of both AS9110 and AS9120?
If you’re evaluating whether your operation needs both standards, buying multiple standards together through ANSI’s bundle packages saves meaningfully compared to purchasing each document separately.
Do AS9110 and AS9120 require the same registrar accreditation as AS9100?
Yes. Certification bodies auditing to any AS91XX standard must be accredited specifically for aerospace scope, not just general ISO 9001 accreditation. Verify your registrar’s aerospace accreditation through ANAB or your relevant national accreditation body before signing a contract.
Will the 2026 IAQG revision require re-certification?
Organizations already certified will go through a transition period once the revised standards (referred to in early IAQG materials as IA9100, IA9110, and IA9120) are formally published. No transition deadline has been confirmed yet — don’t plan around a specific date until IAQG publishes final transition guidance.
📥 Free Resources
- ISO 9001 Roadmap — step-by-step implementation guide for manufacturers building or improving a quality management system
- Manufacturing Compliance Checklist — practical compliance reference covering key ISO, OSHA, and quality requirements for production environments
- Supplier Quality Checklist — evaluation tool for assessing supplier quality controls and flow-down compliance before audits or new contracts
- ISO 13485 Gap Assessment Checklist — free checklist for medical device manufacturers assessing their QMS against ISO 13485 requirements
- AS9100 Rev D Gap Assessment Checklist — 74-item clause-by-clause checklist for aerospace suppliers assessing their QMS before certification
Not Sure What to Do Next?
🔹 Still researching which standard applies to your operation? Run the AS9100 Rev D Gap Assessment Checklist — it flags MRO- and distributor-specific gaps alongside base AS9100 clauses, so you’ll know where you actually stand before talking to a registrar.
🔹 Ready to start building your QMS documentation? 9001Simplified’s documentation kits give you a structured starting point you can adapt to AS9110 or AS9120’s added requirements — no consultant required.
🔹 Need to purchase the standard itself? AS9110 — ANSI Webstore or AS9120 — ANSI Webstore. Use code CC2026 for 5% off through December 31, 2026.
🔹 Shopping for training or picking a certification body? BSI’s aerospace training catalog covers AS9100-family courses relevant to both MRO and distribution operations.
Picking the wrong AS91XX standard doesn’t just slow down your certification timeline — it can cost you a supplier qualification you were counting on. The Standards Navigator covers the full AS9100 family so you can certify to the standard that actually matches what your operation does, not just what sounds closest.
Stay Ahead of Aerospace Compliance Changes
Most operations don’t lose a bid because they can’t meet a requirement — they lose it because they certified to the wrong standard for what they actually do. Organizations that map their real scope of work against AS9110 and AS9120 before choosing a path move through certification once. The ones that guess end up doing it twice.
The Standards Navigator tracks the AS9100 family closely, including the upcoming IAQG revision that will affect every organization certified to AS9110 or AS9120.
👉 Get updates on AS9100-family standards, including AS9110, AS9120, and the 2026 IAQG revision
👉 Be first to access new aerospace gap assessment tools and documentation resources as they’re released
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