{"id":"F2006B10561","name":"AD/HS 748/26 - Underfloor Flying Control Circuits Forward of STA 252F","slug":"ad-hs-748-26-underfloor-flying-control-circuits-forward-of-sta-252f","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":116385,"registerId":"commonwealth-F2006B10561-current","compilationNumber":null,"startDate":"2026-04-03","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"AIRWORTHINESS DIRECTIVE","sectionType":"part","heading":"AIRWORTHINESS DIRECTIVE","content":"# AIRWORTHINESS DIRECTIVE\n\n![](image.002.png)\n\n![](image.002.png)  \nFor the reasons set out in the background section, the CASA delegate whose signature appears below issues the following Airworthiness Directive (AD) under subregulation 39.1 (1) of CAR 1998. The AD requires that the action set out in the requirement section (being action that the delegate considers necessary to correct the unsafe condition) be taken in relation to the aircraft or aeronautical product mentioned in the applicability section: (a) in the circumstances mentioned in the requirement section; and (b) in accordance with the instructions set out in the requirement section; and (c) at the time mentioned in the compliance section.","sortOrder":0},{"sectionNumber":"AD/HS 748/26 Underfloor Flying Control C","sectionType":"part","heading":"AD/HS 748/26 Underfloor Flying Control Circuits","content":"# AD/HS 748/26 Underfloor Flying Control Circuits\n\nForward of STA 252F\n\nApplicability: All HS 748 series aircraft.","sortOrder":1},{"sectionNumber":"4/2000","sectionType":"part","heading":"4/2000","content":"# AD/HS 748/26 Underfloor Flying Control Circuits\n\nForward of STA 252F\n\nApplicability: All HS 748 series aircraft.\n\n#   \n4/2000","sortOrder":2}],"analysis":{"flash_summary":{"complexity_score":4,"scope_assessment":{"changed":false,"description":"The supplied text does not indicate a change in scope from an earlier instrument. The applicability remains stated as 'All HS 748 series aircraft' and the AD continues to require action to correct an unsafe condition under the CASA delegate’s authority (Applicability; first paragraph). No modification to the stated scope is evident in the material provided."},"complexity_factors":["Applicability is broad (applies to all HS 748 series aircraft), which increases operational reach but is simple to state (Applicability).","Key operational details (requirement and compliance sections) are absent from the supplied text, creating uncertainty about implementation and cost.","Legal authority is delegated to the CASA delegate under subregulation 39.1(1) of CAR 1998 — introduces administrative discretion but the extract does not show limits or criteria.","Potentially technical subject matter (flying control circuits forward of STA 252F) implies specialised maintenance/inspection work, though specifics are not provided.","Uniform legal obligation (mandatory AD) simplifies legal compliance expectations but may generate variable practical burdens depending on the missing technical requirements."],"plain_english_summary":"This Airworthiness Directive requires mandatory, time‑bound corrective action on underfloor flying control circuits forward of STA 252F for all HS 748 series aircraft.\n\nIt is issued by a CASA delegate under subregulation 39.1(1) of the CAR 1998 and creates a legal obligation for owners/operators to comply; the specific technical actions and deadlines are not included here."},"kimi_summary":{"content_quality":"ok","complexity_score":3,"scope_assessment":{"changed":false,"description":"This appears to be a standard, targeted airworthiness directive focused on a specific safety issue (underfloor control circuits) for a specific aircraft type. There is no evidence of scope creep; it maintains the original purpose of ensuring airworthiness for the HS 748 fleet."},"complexity_factors":["Very short document (approximately 200 words)","Only one defined term implicitly referenced (STA 252F — a standard structural station reference)","Single applicability clause covering entire aircraft series","No nested exceptions or conditional logic visible in the excerpt","Standardised AD format with predictable structure (Applicability/Requirement/Compliance/Background)","Missing the actual Requirement and Compliance sections in the provided text, which would contain the specific technical instructions"],"plain_english_summary":"This is an **Airworthiness Directive (AD)** — essentially a mandatory safety order issued by the Civil Aviation Safety Authority (CASA) for aircraft.\n\n**What it does:**\nThis directive requires owners and operators of **HS 748 series aircraft** (a British-built twin-turboprop regional airliner) to take specific safety action regarding the **underfloor flying control circuits** located **forward of STA 252F** (a specific structural reference point on the aircraft).\n\n**Who it affects:**\n- Anyone who owns, operates, or maintains HS 748 aircraft\n- Airlines, charter operators, or private owners flying this aircraft type in Australia\n\n**Why it matters:**\nFlying control circuits are the mechanical or electronic systems that connect the pilot's controls (like the yoke or rudder pedals) to the actual control surfaces on the wings and tail. If these circuits fail or are damaged — especially in the underfloor area where they might be exposed to corrosion, wear, or damage — the pilots could lose control of the aircraft. This AD mandates inspection or repair to prevent that unsafe condition.\n\n**Key point:** This is a **mandatory compliance** document. Ignoring it means the aircraft cannot legally fly in Australian airspace."}},"importantCases":[],"_links":{"self":"/api/acts/ad-hs-748-26-underfloor-flying-control-circuits-forward-of-sta-252f","history":"/api/acts/ad-hs-748-26-underfloor-flying-control-circuits-forward-of-sta-252f/history","analysis":"/api/acts/ad-hs-748-26-underfloor-flying-control-circuits-forward-of-sta-252f/analysis","conflicts":"/api/acts/ad-hs-748-26-underfloor-flying-control-circuits-forward-of-sta-252f/conflicts","importantCases":"/api/acts/ad-hs-748-26-underfloor-flying-control-circuits-forward-of-sta-252f/important-cases","documents":"/api/acts/ad-hs-748-26-underfloor-flying-control-circuits-forward-of-sta-252f/documents"}}