{"id":"F2006B05537","name":"AD/PA-24/38 - Aileron Spar - Inspection and Modification","slug":"ad-pa-24-38-aileron-spar-inspection-and-modification","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":46448,"registerId":"commonwealth-F2006B05537-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/PA-24/38 - Aileron Spar - Inspection and 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)  Piper PA-24 (Comanche) Series Aeroplanes\n\n \n\nAD/PA-24/38 Aileron Spar - Inspection and Modification 2/77\n\nApplicability: All models PA-24, PA-24-250, PA-24-260 and PA-24-400 with S/Nos. 24-1 to 24- 5047 and 26-2 to 26-148 not incorporating Piper Kit No. 760914.\n\n \n\nDocument: Piper SL No. 787.\n\n \n\nCompliance: Inspection within 100 hours time in service after 28 February 1977 and thereafter at intervals not exceeding 100 hours time in service until modified.\n\n \n","sortOrder":0}],"analysis":{"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This is a discrete, time-bound safety directive issued in 1977 (as indicated by '2/77' in the reference number). It addresses a specific airworthiness concern for a specific aircraft type. There is no indication of scope creep; it remains tightly focused on aileron spar integrity for the identified Piper Comanche models."},"complexity_factors":["Very short document (approximately 150 words)","Only 4 defined elements: applicability (aircraft models/serial numbers), document reference, compliance deadline, and recurring interval","No cross-references to other legislation or regulations beyond the enabling authority (Civil Aviation Regulations 1998, Part 39)","Single conditional exception: aircraft with Piper Kit No. 760914 are exempt","Straightforward temporal logic: one-time initial deadline + recurring interval until modification"],"plain_english_summary":"This is an **Airworthiness Directive (AD)** — a mandatory safety order issued by Australia's Civil Aviation Safety Authority (CASA). It applies to specific **Piper PA-24 Comanche aircraft** (a type of single-engine propeller plane).\n\n**What it requires:**\n- Owners and operators must **inspect the aileron spar** (a structural beam that supports the aileron, which is the hinged flap on the wing that controls rolling) for cracks or damage.\n- The first inspection must happen **within 100 hours of flying time** after 28 February 1977.\n- After that, inspections must continue **every 100 hours of flying time** until a permanent modification is installed.\n\n**Who it affects:**\n- Owners and operators of PA-24, PA-24-250, PA-24-260, and PA-24-400 model aircraft with specific serial numbers (24-1 to 24-5047 and 26-2 to 26-148), **unless** the aircraft already has Piper Kit No. 760914 installed.\n\n**Why it matters:**\nAileron spar failures can cause loss of control of the aircraft. This AD was issued to prevent accidents by catching fatigue cracks before they become catastrophic. It references **Piper Service Letter No. 787**, which contains the technical details of what to look for and how to do the modification."},"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":false,"description":"The AD text as provided sets a narrow, time‑based inspection requirement for a defined set of PA‑24 series serial numbers and excludes aircraft with Piper Kit No. 760914 (Applicability; Compliance). The excerpt contains no amendment history or indication that the scope in this text departs from an earlier stated intent, so based on the supplied text the scope has not changed."},"complexity_factors":["Narrow, clearly stated applicability based on specific aircraft models and serial-number ranges (Applicability)","Simple, fixed inspection interval and start date (Compliance: 100 hours after 28 Feb 1977, then every 100 hours)","Dependence on an external technical document for procedures (Piper SL No. 787) which requires access and technical interpretation (Document)","Binary compliance end-point: requirement continues until aircraft is modified, creating an economic decision for operators (Compliance)","Need for operators to identify incorporation of a particular kit (Piper Kit No. 760914) to determine applicability (Applicability)"],"plain_english_summary":"What this instrument does (mechanically)\n\n- It requires regular inspections of the aileron spar on specified Piper PA-24 (Comanche) series aeroplanes until those aeroplanes are modified. The inspections must start within 100 hours time-in-service after 28 February 1977 and then be repeated at intervals not exceeding 100 hours time-in-service until the aeroplane has been modified (Compliance section).\n- The detailed inspection and modification procedures are referenced to a Piper service document: Piper SL No. 787 (Document section).\n\nWho is covered\n\n- Owners and operators of all PA-24, PA-24-250, PA-24-260 and PA-24-400 aeroplanes with serial numbers 24-1 to 24-5047 and 26-2 to 26-148, except those aeroplanes that already incorporate Piper Kit No. 760914 (Applicability section).\n\nWhy it matters (stated and practical consequences)\n\n- The AD imposes a recurring maintenance obligation on identified aircraft until they are modified. The AD text itself sets the mechanical rule (inspect every 100 hours until modified) but does not include an explicit description of the underlying hazard in the excerpt provided (Compliance; Applicability).\n\nPractical effects, costs and incentives\n\n- Who pays: Owners/operators pay for each inspection and ultimately for the modification if they choose to eliminate the recurring inspections (Compliance; Applicability). The AD does not specify cost amounts.\n- Behavioural incentive: Because inspections are required repeatedly “until modified,” operators face a trade-off: pay recurring inspection costs and downtime, or invest once in the modification (Compliance). That creates an incentive to evaluate the one-off cost of modification against cumulative inspection costs and operational disruption.\n- Compliance burden and administration: Operators must track flight hours to meet the 100‑hour inspection schedule and follow the procedures set out in Piper SL No. 787 (Compliance; Document). The Civil Aviation Safety Authority is the issuing authority for airworthiness directives and is the entity responsible for listing this requirement (header). The AD text does not set out enforcement mechanisms or penalties in this excerpt.\n- Effects on third parties and markets: Maintenance organisations and technicians will perform the inspections and modifications; demand for their services rises for affected serial-numbered aircraft until those aircraft are modified (Document; Compliance). The AD places a contractual and operational constraint on owners/operators of the specified fleet until modification.\n\nTrade-offs, risks and implementation notes\n\n- Opportunity cost: Time and resources used for inspections and modifications cannot be used for other maintenance or operations (Compliance).\n- Substitution effect: Operators may choose to accelerate modification to avoid repeated inspections, or defer modification and continue periodic inspections, depending on cost and operational priorities (Compliance).\n- Information and procedural dependence: The AD refers operators to Piper SL No. 787 for procedural details; the effectiveness and clarity of the AD therefore depends on that external document (Document).\n\nSource citations\n\n- Applicability: lists affected models, serial-number ranges and the exception for Piper Kit No. 760914 (Applicability section).\n- Document: points to Piper SL No. 787 for the procedures to follow (Document section).\n- Compliance: sets the inspection timing requirement (within 100 hours after 28 February 1977 and at intervals not exceeding 100 hours until modified) (Compliance section)."}},"importantCases":[],"_links":{"self":"/api/acts/ad-pa-24-38-aileron-spar-inspection-and-modification","history":"/api/acts/ad-pa-24-38-aileron-spar-inspection-and-modification/history","analysis":"/api/acts/ad-pa-24-38-aileron-spar-inspection-and-modification/analysis","conflicts":"/api/acts/ad-pa-24-38-aileron-spar-inspection-and-modification/conflicts","importantCases":"/api/acts/ad-pa-24-38-aileron-spar-inspection-and-modification/important-cases","documents":"/api/acts/ad-pa-24-38-aileron-spar-inspection-and-modification/documents"}}