{"id":"F2006B08869","name":"AD/DH 104/27 - Pneumatic System - Main Air Reservoirs","slug":"ad-dh-104-27-pneumatic-system-main-air-reservoirs","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":52290,"registerId":"commonwealth-F2006B08869-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/DH 104/27 - Pneumatic System - Main Air Reservoirs","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 - 105 CIVIL AVIATION SAFETY AUTHORITY\n\nSCHEDULE OF AIRWORTHINESS DIRECTIVES\n\n \n\n![](image.001.png)  DH 104 (Dove) Series Aeroplanes\n\n \n\nAD/DH 104/27 Pneumatic System - Main Air Reservoirs 8/71\n\nApplicability: All models.\n\n \n\nDocument: Hawker Siddeley TNS CT(104) No. 223 Issue 1. Compliance: Before 31 December 1971.\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\n \n\n \n","sortOrder":0}],"analysis":{"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":false,"description":"The text provided sets clear scope: applicability to all DH 104 (Dove) models and mandatory compliance with Hawker Siddeley TNS CT(104) No. 223 Issue 1 before 31 December 1971. The AD text does not indicate any expansion, contraction, or amendment to that scope; there is no information in this source to conclude the scope has changed from the instrument’s original stated terms."},"complexity_factors":["Short, single-action directive referencing an external technical document rather than listing corrective steps directly (Document).","Applicability to all models increases the number of affected operators (Applicability).","Mandatory deadline imposes scheduling and operational constraints (Compliance).","Absence of detail in the AD text requires operators to obtain and interpret the referenced Hawker Siddeley document, adding administrative and interpretative complexity (Document).","No explicit statement of the defect, required parts, or follow-up obligations in the AD increases uncertainty for implementers (Header; Document)."],"plain_english_summary":"This AD requires all DH 104 (Dove) operators to obtain and carry out the Hawker Siddeley TNS CT(104) No.223 Issue 1 technical instructions for the pneumatic system main air reservoirs, with work to be completed before 31 December 1971. It binds aircraft owners/operators and their maintenance organisations, who bear the cost, downtime and logistical burden of complying."},"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This is a discrete, time-limited safety directive focused on a specific aircraft type and system. It has not expanded beyond its original purpose of mandating a safety modification to DH 104 Dove air reservoirs."},"complexity_factors":["Extremely short document (under 200 words)","No defined terms section — uses plain aviation terminology","No cross-references to other legislation beyond the enabling Civil Aviation Regulations 1998","Simple conditional structure: applicability statement + single compliance requirement","Single technical reference to external manufacturer document rather than detailed technical specifications within the text itself"],"plain_english_summary":"**What this is:** This is an **Airworthiness Directive (AD)** — a mandatory safety order issued by Australia's Civil Aviation Safety Authority (CASA) under the Civil Aviation Regulations 1998.\n\n**What it does:** It requires owners and operators of **DH 104 \"Dove\" series aeroplanes** (a British twin-engine aircraft from the 1940s-60s) to inspect or modify the **main air reservoirs** (the large tanks that store compressed air for the plane's pneumatic systems, such as brakes and landing gear) according to a specific technical document.\n\n**Who it affects:** Anyone who owns, operates, or maintains a DH 104 Dove aircraft in Australia.\n\n**Why it matters:** Air reservoirs can fail due to corrosion, fatigue, or manufacturing defects. A failure could lead to loss of braking power or other critical systems, potentially causing accidents. This directive ensures a specific safety fix is applied before a deadline (31 December 1971) to prevent catastrophic failures.\n\n**Key details:**\n- **Compliance deadline:** Before 31 December 1971 (historical deadline — this AD is long past but remains on the books for record-keeping)\n- **Technical reference:** Hawker Siddeley TNS CT(104) No. 223 Issue 1 (the manufacturer's service bulletin specifying the exact work required)"}},"importantCases":[],"_links":{"self":"/api/acts/ad-dh-104-27-pneumatic-system-main-air-reservoirs","history":"/api/acts/ad-dh-104-27-pneumatic-system-main-air-reservoirs/history","analysis":"/api/acts/ad-dh-104-27-pneumatic-system-main-air-reservoirs/analysis","conflicts":"/api/acts/ad-dh-104-27-pneumatic-system-main-air-reservoirs/conflicts","importantCases":"/api/acts/ad-dh-104-27-pneumatic-system-main-air-reservoirs/important-cases","documents":"/api/acts/ad-dh-104-27-pneumatic-system-main-air-reservoirs/documents"}}