{"id":"F2006B09118","name":"AD/DHC-6/30 - Air Conditioning Compartment - Modification","slug":"ad-dhc-6-30-air-conditioning-compartment-modification","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":115671,"registerId":"commonwealth-F2006B09118-current","compilationNumber":null,"startDate":"2026-04-03","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/DHC-6/30 - Air Conditioning Compartment - Modification","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)  DHC-6 (Twin Otter) Series Aeroplanes\n\n \n\nAD/DHC-6/30 Air Conditioning Compartment - Modification 10/71\n\nApplicability: All models with S/Nos. 1 to 329 and fitted with a JB Systems Series 1000 airconditioner.\n\n \n\nDocument: De Havilland of Canada SB 6/280.\n\n \n\nCompliance: Disconnect electrical power to airconditioner before further flight and until embodiment of additional sealing in accordance with SB 6/280.\n\n \n","sortOrder":0}],"analysis":{"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This is a discrete, targeted safety directive addressing a specific airworthiness issue in a defined aircraft population. It has not expanded beyond its original technical scope."},"complexity_factors":["Very short document (under 150 words)","Only 4 defined elements: applicability (aircraft models/serials), document reference, compliance requirement, and effective directive number","Single unconditional obligation with binary compliance state (disconnected or modified)","No cross-references to other legislation or regulations beyond the parent Civil Aviation Regulations 1998","No nested conditions, exceptions, or discretionary provisions","Clear, imperative language ('before further flight', 'until embodiment')"],"plain_english_summary":"This is an **Airworthiness Directive** — a mandatory safety order issued by Australia's Civil Aviation Safety Authority (CASA). It applies to specific **De Havilland DHC-6 Twin Otter aircraft** (serial numbers 1 to 329) that have a **JB Systems Series 1000 air conditioner** installed.\n\n**What it requires:**\n- **Immediate action:** Owners and operators must **disconnect electrical power to the air conditioner** before the aircraft flies again.\n- **Permanent fix:** They must keep it disconnected until they install **additional sealing** in the air conditioning compartment, following the instructions in **De Havilland Service Bulletin 6/280**.\n\n**Why it matters:**\nThis directive addresses a safety defect in the air conditioning system. Without the fix, there may be risks of electrical hazards, fire, or compromised compartment integrity. The grounding-style requirement (disconnect before further flight) suggests CASA identified a serious or urgent risk.\n\n**Who must comply:**\n- Aircraft owners and operators of affected Twin Otter models\n- Maintenance organisations servicing these aircraft"},"flash_summary":{"complexity_score":2,"scope_assessment":{"changed":false,"description":"The AD, as presented, applies specifically to DHC-6 aircraft serial numbers 1–329 fitted with the named airconditioner and mandates disconnecting the unit until the sealing modification in De Havilland SB 6/280 is embodied. The instrument does not indicate any expansion or narrowing of that applicability compared to the text provided; no change of scope is shown in this document."},"complexity_factors":["Narrow applicability limited to DHC-6 S/Nos. 1–329 fitted with JB Systems Series 1000 airconditioner (Applicability)","Single immediate action mandated (disconnect power before next flight) and a single corrective action (embody sealing per SB 6/280) (Compliance)","Dependence on an external document (manufacturer's service bulletin) for the detailed modification steps (Document)","Operational impacts (airconditioner disabled) and logistical factors (parts, qualified labour, aircraft downtime) increase practical implementation steps despite simple legal text (Compliance)","Regulator prescriptive instruction leaves little procedural discretion to operators, concentrating complexity in execution rather than interpretation (Compliance)"],"plain_english_summary":"This AD requires owners/operators of De Havilland DHC‑6 Twin Otters (S/N 1–329) fitted with JB Systems Series 1000 airconditioners to disconnect the unit immediately and keep it disabled until a sealing modification is embodied per De Havilland of Canada SB 6/280. Maintenance organisations must perform the work; operators bear costs, downtime and operational impact. The Civil Aviation Safety Authority enforces compliance; the AD points to the manufacturer’s bulletin for the modification method."}},"importantCases":[],"_links":{"self":"/api/acts/ad-dhc-6-30-air-conditioning-compartment-modification","history":"/api/acts/ad-dhc-6-30-air-conditioning-compartment-modification/history","analysis":"/api/acts/ad-dhc-6-30-air-conditioning-compartment-modification/analysis","conflicts":"/api/acts/ad-dhc-6-30-air-conditioning-compartment-modification/conflicts","importantCases":"/api/acts/ad-dhc-6-30-air-conditioning-compartment-modification/important-cases","documents":"/api/acts/ad-dhc-6-30-air-conditioning-compartment-modification/documents"}}