{"id":"F2006B06803","name":"AD/SC7/3 - Flap - Aileron Shroud Attach Lugs - Modification","slug":"ad-sc7-3-flap-aileron-shroud-attach-lugs-modification","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":114661,"registerId":"commonwealth-F2006B06803-current","compilationNumber":null,"startDate":"2026-04-03","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/SC7/3 - Flap - Aileron Shroud Attach Lugs - 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)  Short SC7 (Skyvan) Series Aeroplanes\n\n \n\nAD/SC7/3 Flap - Aileron Shroud Attach Lugs - Modification 12/69\n\nApplicability: All models of Series 3. Document: Short SB No. 57-51.\n\nCompliance: Within 100 hours time in service after 23 January 1970.\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\n \n","sortOrder":0}],"analysis":{"flash_summary":{"complexity_score":2,"scope_assessment":{"changed":false,"description":"Based on the text supplied, the directive’s scope is to require the specified modification for all Short SC7 Series 3 aeroplanes within the stated 100-hour window and to reference Short SB No. 57-51 for the technical procedure (Applicability / Document / Compliance). The instrument as presented contains no language indicating an expansion or narrowing of that scope from an earlier or different intent; therefore no change in scope is evident from the supplied text."},"complexity_factors":["Narrow and clearly stated applicability: applies to all Short SC7 Series 3 aircraft (Applicability).","Single clear compliance deadline expressed in operating hours and a calendar reference (Compliance).","Technical execution delegated to an external service bulletin (Short SB No. 57-51), requiring operators to obtain and follow a separate technical document (Document).","Regulatory instrument is short and prescriptive but lacks procedural detail, creating reliance on the service bulletin for technical complexity (Document).","Operational complexity for owners: scheduling, parts, trained maintenance personnel and downtime despite simple regulatory wording (Compliance)."],"plain_english_summary":"What this instrument requires\n\n- This is an airworthiness directive issued under the Commonwealth civil aviation regulatory framework that requires a specific modification to Short SC7 (Series 3) aeroplanes. The directive title identifies the affected part as the \"Flap - Aileron Shroud Attach Lugs\" and the action as a \"Modification\" (Title / Header).\n\nWho it applies to\n\n- It applies to all models of the Short SC7 Series 3 (Applicability).\n\nWhat must be done and when\n\n- Operators or owners must carry out the modification shown in Short Service Bulletin No. 57-51 (Document). The work must be completed within 100 hours time in service after 23 January 1970 (Compliance).\n\nHow it works mechanically\n\n- The directive does not itself set out repair steps; it makes compliance conditional on following the referenced service bulletin (Short SB No. 57-51) (Document). The AD creates a legal obligation to implement the modification within the stated time window (Compliance).\n\nWho pays, who decides, and what changes\n\n- Who pays: The operator or aircraft owner bears the direct costs of arranging, performing and certifying the modification, including parts, labour and any downtime. This follows because the AD imposes the obligation on owners/operators to comply (Applicability / Compliance).\n- Who decides: The Civil Aviation Safety Authority (as the issuing aviation safety regulator identified in the header) sets the requirement and enforces compliance. The detailed technical method is delegated to the service bulletin (Document), which operators must follow to meet the AD.\n- Behaviour changes required: Owners/operators must plan and schedule maintenance to perform the modification within the stated 100-hour window, obtain and implement Short SB No. 57-51, and keep records showing compliance.\n\nImplementation, compliance burden and risks\n\n- Compliance burden: The AD imposes a definite maintenance obligation to be completed in a short operating-hours window. That creates immediate scheduling, parts procurement and labour costs for each affected aeroplane (Compliance). The AD itself does not include the step-by-step procedure; operators must obtain and follow Short SB No. 57-51 (Document), which may add time and administrative steps.\n- Discretion and enforcement: The regulator prescribes the outcome and deadline; discretion over the exact technical means is constrained by the service bulletin referenced (Document). The AD gives the regulator a clear enforcement point (the 100-hour deadline) but does not describe tolerance, exemptions or alternative methods in the text provided.\n- Opportunity costs and operational effects: Aircraft may be taken out of service for the modification, producing lost flying hours and potential short-term revenue impact for operators. These are costs borne by operators because the AD makes completion a compliance requirement (Compliance).\n\nTrade-offs and incentives (source-grounded)\n\n- The AD concentrates the cost and operational disruption on the owners/operators of Series 3 aircraft because they must implement the modification (Applicability / Compliance).\n- The technical specification and acceptability of the modification are determined by the referenced service bulletin; anyone wishing to use a different method would need an alternative approved route but the AD text supplied does not describe such an alternative (Document).\n\nWhat the text does not say (limits of the instrument)\n\n- The AD text supplied does not state the technical reason for the modification, the estimated cost, how long the work takes, whether spares are provided, or whether there are approved alternatives to the service bulletin. It also does not describe enforcement processes, penalties, or record-keeping requirements beyond the compliance date and reference to the service bulletin."},"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This is a discrete, single-issue airworthiness directive from 1969/1970 addressing a specific structural defect in a specific aircraft series. It has not expanded beyond its original purpose of mandating a safety modification to flap-aileron shroud attachment lugs."},"complexity_factors":["Extremely short document — only 4 substantive lines of regulatory text","No defined terms section — all terminology is standard aviation maintenance language","Single, unambiguous compliance requirement (100 hours time in service)","No cross-references to other legislation beyond the enabling Civil Aviation Regulations 1998","No conditional logic, exceptions, or alternative compliance methods","References only one external technical document (Short SB No. 57-51)"],"plain_english_summary":"**What this is:** An Airworthiness Directive (AD) — essentially a mandatory safety order — issued by Australia's Civil Aviation Safety Authority (CASA) for a specific type of aircraft.\n\n**What it does:** Requires owners and operators of **Short SC7 Skyvan Series 3 aeroplanes** to modify the attachment lugs (the metal brackets that hold parts together) where the **flap-aileron shroud** connects to the wing. This modification must be done according to **Short Service Bulletin No. 57-51** (the manufacturer's official repair instructions).\n\n**Who it affects:** Anyone who owns, operates, or maintains a Short SC7 Skyvan Series 3 aircraft — a twin-turboprop utility aircraft used for cargo, skydiving, and regional transport.\n\n**Why it matters:** The flap-aileron shroud is a protective covering over the gap between the wing's flaps (the moving surfaces that help slow the plane down for landing) and ailerons (the surfaces that control roll). If the attachment lugs fail, the shroud could detach in flight, potentially damaging the aircraft or causing loss of control. This AD mandates a fix to prevent structural failure.\n\n**Deadline:** The modification had to be completed within **100 hours of flight time** after 23 January 1970."}},"importantCases":[],"_links":{"self":"/api/acts/ad-sc7-3-flap-aileron-shroud-attach-lugs-modification","history":"/api/acts/ad-sc7-3-flap-aileron-shroud-attach-lugs-modification/history","analysis":"/api/acts/ad-sc7-3-flap-aileron-shroud-attach-lugs-modification/analysis","conflicts":"/api/acts/ad-sc7-3-flap-aileron-shroud-attach-lugs-modification/conflicts","importantCases":"/api/acts/ad-sc7-3-flap-aileron-shroud-attach-lugs-modification/important-cases","documents":"/api/acts/ad-sc7-3-flap-aileron-shroud-attach-lugs-modification/documents"}}