{"id":"F2006B05542","name":"AD/PA-24/43 - Wing Main Spar Lower Cap - Inspection","slug":"ad-pa-24-43-wing-main-spar-lower-cap-inspection","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":46465,"registerId":"commonwealth-F2006B05542-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/PA-24/43 - Wing Main Spar Lower Cap - Inspection","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)  Piper PA-24 (Comanche) Series Aeroplanes\n\n \n\nAD/PA-24/43 Wing Main Spar Lower Cap - Inspection 9/83\n\nApplicability: All model PA-24-400 with S/Nos. 26-2 and subsequent. All model PA-24-180, PA- 24-250 and PA-24-260 with S/Nos. 24-1 and subsequent.\n\n \n\nDocument: Piper Service Bulletin No. 751.\n\n \n\nCompliance: Within 100 hours time in service after 30th September 1983.\n\n \n\nBackground: The manufacturer reports cases of chafing of the wing main spar lower cap where the spar enters the fuselage.\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 directive's scope is explicit and limited to the listed PA-24 models and serial numbers and sets a single compliance deadline. The source does not indicate any expansion or narrowing beyond those stated applicability and compliance terms (Applicability; Compliance)."},"complexity_factors":["Narrow technical scope limited to specific PA-24 models and serial numbers (Applicability)","Fixed, short compliance window tied to a historical date (Compliance)","Procedural detail delegated to an external manufacturer document (Piper Service Bulletin No. 751) rather than the directive text (Document)","Technical nature of the required inspection (structural spar component) requires qualified maintenance personnel (Background; Document)","Directive text is brief and leaves corrective action details and return-to-service criteria to the service bulletin or maintenance approvals (Document)"],"plain_english_summary":"What this directive requires, mechanically\n\n- This Airworthiness Directive requires an inspection of the wing main spar lower cap where the spar enters the fuselage on specified Piper PA-24 Comanche aeroplanes. The inspection must be done in accordance with Piper Service Bulletin No. 751 (Document). (Document)\n- The instruction applies to: all PA-24-400 aeroplanes with serial numbers 26-2 and subsequent, and all PA-24-180, PA-24-250 and PA-24-260 aeroplanes with serial numbers 24-1 and subsequent. (Applicability)\n- The inspection must be completed within 100 hours time in service after 30 September 1983. (Compliance)\n\nWhy the directive was issued (as stated in the source)\n\n- The manufacturer's report is the stated reason: there have been cases of chafing of the wing main spar lower cap at the point where the spar enters the fuselage. That is the explicit background given for requiring inspection. (Background)\n\nWho pays, who decides, and what changes in behaviour\n\n- Who decides: The directive is issued under the Commonwealth airworthiness framework and is listed by the Civil Aviation Safety Authority. The directive references Piper Service Bulletin No. 751 as the procedural document to follow. (Header; Document)\n- Who pays: Aircraft owners/operators pay for the inspection work, any follow-up repairs, and any associated downtime. The source requires compliance but does not state who bears cost; operational practice is that the registered owner/operator arranges and pays for compliance. (Compliance; Applicability)\n- Behaviour changes: Owners/operators of affected aircraft must schedule and complete the specified inspection within the stated compliance window, and follow the referenced service bulletin for the inspection procedure. If chafing or damage is found, repairs will be required before further flight as per the service document or an authorised maintenance organisation.\n\nPractical trade-offs, compliance burden, and implementation risks (source-grounded)\n\n- Compliance burden: The directive imposes a one-off inspection obligation within a specific time window (100 hours TIS after 30 Sept 1983). This creates direct costs in labour, possible parts and repairs, and aircraft downtime for owners/operators. (Compliance)\n- Technical competence: The inspection concerns a structural component (wing main spar lower cap) and therefore requires qualified maintenance personnel and possibly non-routine maintenance facilities, which is a technical compliance requirement implicit in the nature of the task. The directive itself does not describe inspection technique in detail but points to the service bulletin for procedures. (Document; Background)\n- Reliance on external document: The AD references Piper Service Bulletin No. 751 for the work instructions. That shifts procedural detail to the manufacturer document, so enforceable compliance depends on access to and the content of that bulletin. (Document)\n- Timing and opportunity cost: The compliance deadline (100 hours TIS after 30 Sept 1983) imposes a scheduling constraint; operators must prioritise the inspection within that window, which could displace other maintenance or flight activity. (Compliance)\n- Implementation risk and discretion: The directive prescribes inspection but does not detail follow-up corrective actions within the text provided; those actions will follow the service bulletin or maintenance approval processes. This means some discretion resides with maintenance providers and the approving authority about allowable repairs or return-to-service criteria. (Document)\n\nMarket effects and distribution of costs and benefits (source-grounded)\n\n- Concentrated costs: Costs fall directly on owners/operators of the specified PA-24 aircraft (a concentrated group identifiable by model and serial number). (Applicability; Compliance)\n- Service demand: The directive increases near-term demand for maintenance inspections and any corrective work on the affected aircraft; independent maintenance providers can perform the work under standard approvals, so the directive creates business for those providers. (Document)\n- No direct subsidy or compensation: The source contains no provision for cost-sharing, compensation, or financial relief to owners/operators; the compliance requirement is stated without allocation of funding. (Compliance)\n\nSummary statement\n\nMechanically, this AD orders a time-limited inspection of the wing main spar lower cap on specified Piper PA-24 models (identified by model and serial number) in accordance with Piper Service Bulletin No. 751, to be done within 100 hours TIS after 30 September 1983. The stated reason is manufacturer-reported chafing at the spar/fuselage interface. The immediate effects are an inspection obligation and potential repair costs borne by owners/operators, reliance on the manufacturer service bulletin for procedure, and use of qualified maintenance resources to complete and, if necessary, remedy any damage. (Applicability; Document; Compliance; Background)"},"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This is a discrete, single-issue Airworthiness Directive from 1983 addressing a specific structural defect in specific aircraft models. It has not expanded beyond its original purpose of mandating inspection for wing spar chafing. The scope remains tightly focused on the original safety concern."},"complexity_factors":["Single, specific maintenance task (visual inspection for chafing)","Limited applicability - only 4 specific aircraft models with defined serial number ranges","No defined terms section or complex interpretation provisions","Simple compliance trigger (100 hours time in service after fixed date)","No nested exceptions or conditional logic","Cross-reference to only one external technical document (Piper Service Bulletin No. 751)","Total length is approximately 150 words of substantive content"],"plain_english_summary":"This is an **Airworthiness Directive (AD)** issued by Australia's Civil Aviation Safety Authority (CASA) that mandates a safety inspection for specific Piper Comanche aircraft models.\n\n**What it does:**\n- Requires owners/operators of certain Piper PA-24 series aeroplanes to inspect the wing main spar lower cap (a critical structural component where the wing attaches to the fuselage) for chafing (wear caused by rubbing).\n\n**Who it affects:**\n- Owners and operators of:\n  - Piper PA-24-400 models with serial numbers 26-2 and later\n  - Piper PA-24-180, PA-24-250, and PA-24-260 models with serial numbers 24-1 and later\n\n**Why it matters:**\n- The manufacturer (Piper) reported cases of chafing where the wing spar enters the fuselage. This is a serious safety issue because the main spar is essential to wing structural integrity. If the spar fails, the wing could separate from the aircraft in flight.\n- The directive requires compliance within 100 hours of flight time after 30 September 1983, giving operators a deadline to complete the inspection.\n- Aircraft cannot legally fly unless they comply with Airworthiness Directives (these are mandatory safety orders).\n\n**Key details:**\n- **Compliance deadline:** Within 100 hours \"time in service\" after 30 September 1983\n- **Technical reference:** Piper Service Bulletin No. 751 (this document contains the actual inspection instructions)\n- **Original issue date:** September 1983 (indicated by \"9/83\" in the directive number)"}},"importantCases":[],"_links":{"self":"/api/acts/ad-pa-24-43-wing-main-spar-lower-cap-inspection","history":"/api/acts/ad-pa-24-43-wing-main-spar-lower-cap-inspection/history","analysis":"/api/acts/ad-pa-24-43-wing-main-spar-lower-cap-inspection/analysis","conflicts":"/api/acts/ad-pa-24-43-wing-main-spar-lower-cap-inspection/conflicts","importantCases":"/api/acts/ad-pa-24-43-wing-main-spar-lower-cap-inspection/important-cases","documents":"/api/acts/ad-pa-24-43-wing-main-spar-lower-cap-inspection/documents"}}