--- title: "Tungsten Blog — EASA Certification Insights | Tungsten" description: "Practical guidance for Part 21J design offices on certification workflows, document control, compliance, and how to get more done with less overhead." canonical_url: "https://www.tungsten.aero/blog" meta: author: "Altus Aeronautica Ltd" keywords: "EASA Part 21J, certification software, aerospace compliance, document control, airworthiness, design office" "og:description": "Practical guidance for Part 21J design offices on certification workflows, document control, compliance, and how to get more done with less overhead." "og:image": "https://www.tungsten.aero/img/og-image.png" "og:image:alt": "Tungsten — Aerospace Certification Software for EASA Part 21J Design Offices" "og:image:width": "1200" "og:title": "Tungsten Blog — EASA Certification Insights" "twitter:description": "Purpose-built certification software that replaces spreadsheets and manual approval chains. Structured document workflows, audit trails, and compliance automation for airworthiness engineers." "twitter:image": "https://www.tungsten.aero/img/og-image.png" "twitter:title": "Tungsten — Certification Software for EASA Part 21J Design Offices" --- > Index of every page on this site: [llms.txt](https://www.tungsten.aero/llms.txt) **Insights for Part 21J teams** # **Tungsten Blog** Practical guidance for Part 21J design offices on certification workflows, document control, and compliance. [Book a Demo](https://www.tungsten.aero/contact) [Start Free Trial](https://app.tungsten.aero) **Document control****Approval workflows****Audit readiness** ## **Featured article** Start with the latest practical guidance from the Tungsten team. Each piece is written for design offices that need cleaner approvals, clearer records, and less admin drag. **Latest post **15 October 2026By Tungsten ## **Supplier Design Data in Part 21J: Closing the Compliance Gap Between Your DOA and External Partners** External partners deliver drawings and analyses your DOA must own for certification. This guide explains why email handoffs create unowned revisions and unprovable approvals — and how to run an intake model that survives authority sampling. [**Read featured article **](https://www.tungsten.aero/blog/supplier-design-data-compliance-part-21j) [**Ask about Tungsten **](https://www.tungsten.aero/contact) **Why this blog exists ** ### **Less theory. More operational clarity. ** The editorial focus is practical: what slows certification teams down, what causes avoidable rework, and what structured workflows change in real operations. **Coverage ** **13 published articles** **Written for ** **Part 21J design offices ** **Focus ** **Compliance without admin sprawl ** ## **Archive** Browse the full library of guidance, analysis, and workflow notes for certification teams. **Archive**1 October 2026 ### **The Q4 Certification Rush: Why Part 21J Design Offices Lose Control in the Last Quarter** Year-end milestones, leave, and parallel programmes turn temporary shortcuts into the real process. This guide explains why Q4 breaks document and approval control in Part 21J offices — and how to keep gates intact when schedule pressure peaks. [**Read article **](https://www.tungsten.aero/blog/q4-certification-rush-part-21j) **Archive**15 September 2026 ### **When Minor Isn’t Minor: Getting Change Classification Right in Part 21J Design Offices** A change treated as minor that the authority later treats as major is one of the most expensive failures in Part 21J work. This guide explains why classification drifts, what it actually costs, and how to make major/minor decisions at initiation — with criteria the system can enforce. [**Read article **](https://www.tungsten.aero/blog/change-classification-major-minor-part-21j) **Archive**3 September 2026 ### **Designing for Compliance: How Part 21J Teams Prevent Certification Delays Before They Start** Most certification delays are not engineering failures — they are compliance discoveries made too late. This guide explains how to embed compliance visibility into design work from the first requirement, so findings surface during design instead of at submission. [**Read article **](https://www.tungsten.aero/blog/designing-for-compliance-prevent-certification-delays-part-21j) **Archive**14 August 2026 ### **How to Evaluate Document Control Software for a Part 21J Design Office: A Buyer's Guide** Generic document management tools and aerospace-specific platforms look similar in demos and behave very differently in audits. This guide gives design offices a structured evaluation framework: the capabilities that are non-negotiable, the questions that expose weak products, and the total-cost traps to avoid. [**Read article **](https://www.tungsten.aero/blog/choosing-document-control-software-part-21j) **Archive**2 August 2026 ### **Who Can Approve What? Fixing the Authority Matrix Problem in Part 21J Design Offices** Most design offices have an authority matrix on paper and a very different reality on the shared drive. This guide covers why signatory authority drifts, what it costs in audits, and how to make the matrix something the system enforces rather than a document people are supposed to remember. [**Read article **](https://www.tungsten.aero/blog/authority-matrix-access-control-part-21j) **Archive**15 July 2026 ### **Requirement-to-Evidence Traceability in Part 21J: Building a Compliance Matrix That Doesn't Rot** Most compliance matrices are accurate on the day they are built and wrong within a month. This guide explains why spreadsheet-based traceability decays, what a living compliance matrix requires, and how to migrate without re-keying years of data. [**Read article **](https://www.tungsten.aero/blog/requirement-evidence-traceability-part-21j) ```json {"@context":"https://schema.org","@graph":[{"@id":"https://www.tungsten.aero/#website","@type":"WebSite","description":"Purpose-built certification software for EASA Part 21J design offices. 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