{"id":"F2006B09276","name":"AD/DHE/26 - Induction Manifold - Pressure Test","slug":"ad-dhe-26-induction-manifold-pressure-test","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":53312,"registerId":"commonwealth-F2006B09276-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/DHE/26 - Induction Manifold - Pressure Test","content":"---\nmeta-content-style-type: text/css\nmeta-content-type: application/xhtml+xml; charset=utf-8\nmeta-generator: Aspose.Words for .NET 22.10.0\n---\n\n?xml version=\"1.0\" encoding=\"utf-8\" standalone=\"no\"?>\n\nCOMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 106 CIVIL AVIATION SAFETY AUTHORITY\n\nSCHEDULE OF AIRWORTHINESS DIRECTIVES\n\n \n\n![](image.001.png)  De Havilland Piston Engines\n\n \n\nAD/DHE/26 Induction Manifold - Pressure Test 8/74\n\nApplicability: All Gipsy Major series.\n\n \n\nDocument: 1. R. Royce Gipsy TNS G No. 77; or\n\n \n\n2. R. Royce Gipsy TNS GM 10 No. 47.\n\n \n\nCompliance: Within 100 hours time in service after 30 August 1974 and thereafter at intervals not exceeding 100 hours time in service.\n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n","sortOrder":0}],"analysis":{"flash_summary":{"complexity_score":2,"scope_assessment":{"changed":false,"description":"The source text sets a specific, limited requirement (pressure test of induction manifold for all Gipsy Major series engines) with defined timing (within 100 hours after 30 August 1974 and every 100 hours thereafter). There is no language in the provided text indicating any change in the population covered or the nature of the test requirement from its stated terms."},"complexity_factors":["Narrow technical scope limited to Gipsy Major engine series (Applicability)","Single, fixed compliance interval (every 100 hours) is straightforward (Compliance)","References external technical documents for procedural detail rather than embedding steps (Document) — creates dependency on document availability and interpretation","No alternative compliance paths or exemptions stated in the text — binary compliance requirement (Compliance)","Absence of procedural detail and enforcement language in this excerpt increases reliance on the wider regulatory framework (Schedule header)"],"plain_english_summary":"What this instrument changes mechanically\n\n- It requires owners/operators of aircraft powered by Gipsy Major series piston engines to carry out a pressure test of the induction manifold. The required test procedure is the one set out in either R. Royce Gipsy TNS G No. 77 or R. Royce Gipsy TNS GM 10 No. 47 (\"Document\"). (Document)\n- The first test must be completed within 100 hours time in service after 30 August 1974 and then repeated at intervals not exceeding 100 hours time in service. (Compliance)\n- The directive is recorded in the Schedule of Airworthiness Directives issued under Part 39 - 106 (Civil Aviation Safety Authority). (Schedule header)\n\nWho the requirement affects\n\n- Applies to all installations of the Gipsy Major engine series (\"Applicability\"). Owners, operators, maintenance organisations and certificated engineers who maintain or operate aircraft with those engines are the parties that must ensure the tests are done. (Applicability; Compliance)\n\nOfficial purpose-claims stated in the source\n\n- The source text is a Schedule of Airworthiness Directives and identifies the test requirement and timing. The document itself does not include an explicit statement of policy rationale or objectives beyond specifying the mandatory test and intervals. (Schedule header; Document; Compliance)\n\nPractical effects, costs and incentives (mechanical analysis)\n\n- Who pays: the owner/operator of the affected aircraft pays for the pressure test, any inspection labour and any repairs or parts found necessary by the test. The instrument does not provide funding or exemptions. (Applicability; Compliance)\n- Who decides: the directive sets a mandatory requirement (timing and referenced procedure). Discretion for how to comply is limited to following one of the two referenced documents; no alternative procedures are specified in the text. (Document; Compliance)\n- Behaviour change: operators must schedule recurring maintenance events at 100-hour intervals and retain or follow the referenced procedure documents when performing the test. (Compliance; Document)\n- Compliance burden: recurring inspections at fixed intervals create ongoing maintenance planning and cost; the frequency (every 100 hours) determines opportunity cost in maintenance scheduling and aircraft availability. (Compliance)\n- Implementation risk and operational trade-offs: reliance on two external documents means availability and interpretive clarity of those documents affect execution. The directive does not set out what to do if a referenced document is unavailable or if a tested manifold fails the prescribed test — operators must follow normal maintenance and airworthiness procedures outside this text. (Document)\n- Effects on private enterprise: the directive imposes a recurring regulatory compliance cost on operators and maintenance providers for affected engines. It also creates demand for certified inspections and repairs for these engines. (Applicability; Compliance)\n\nConcrete limits of the instrument as written\n\n- The instrument prescribes the test and the interval but does not describe the test steps in full in the text; it points to two external technical documents for procedure. (Document)\n- The directive sets a mandatory interval but does not describe enforcement mechanism or penalties in this excerpt; enforcement will depend on the broader regulatory framework under which the Schedule is issued. (Schedule header)\n\nKey citations in the source text: (Applicability); (Document); (Compliance)."},"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This is a discrete, single-issue airworthiness directive focused solely on induction manifold testing for one engine series. There is no evidence of scope creep; it remains tightly bounded to its original safety purpose."},"complexity_factors":["Single, specific maintenance task with clear interval","Only two defined applicability criteria (engine series and two technical documents)","No nested exceptions, conditional logic, or cross-references to other legislation","Straightforward compliance timeline (100 hours time in service)","Document appears to be a historical directive from 1974 with minimal regulatory machinery"],"plain_english_summary":"This is a **Civil Aviation Safety Authority (CASA) Airworthiness Directive** — essentially a mandatory safety order for aircraft maintenance.\n\n**What it does:**\nRequires owners and operators of aircraft with **De Havilland Gipsy Major engines** to perform a **pressure test on the induction manifold** (the part of the engine that delivers the fuel-air mixture to the cylinders).\n\n**Who it affects:**\nAnyone operating or maintaining aircraft fitted with **any model in the Gipsy Major engine series** — these are vintage piston engines commonly found in older light aircraft like the Tiger Moth.\n\n**What must be done:**\n- **First test:** Within 100 hours of flying time after 30 August 1974\n- **Ongoing:** Repeat the test at least every 100 hours of flying time thereafter\n\n**Why it matters:**\nInduction manifold leaks can cause engine failure, power loss, or dangerous backfires. This directive ensures potential cracks or leaks are caught before they cause accidents.\n\n**Technical references:**\nThe tests must follow specific Rolls-Royce technical instructions (TNS G No. 77 or TNS GM 10 No. 47)."}},"importantCases":[],"_links":{"self":"/api/acts/ad-dhe-26-induction-manifold-pressure-test","history":"/api/acts/ad-dhe-26-induction-manifold-pressure-test/history","analysis":"/api/acts/ad-dhe-26-induction-manifold-pressure-test/analysis","conflicts":"/api/acts/ad-dhe-26-induction-manifold-pressure-test/conflicts","importantCases":"/api/acts/ad-dhe-26-induction-manifold-pressure-test/important-cases","documents":"/api/acts/ad-dhe-26-induction-manifold-pressure-test/documents"}}