{"id":"F2006B06238","name":"AD/PITTS S-2/1 - Horizontal Stabiliser - Modification","slug":"ad-pitts-s-2-1-horizontal-stabiliser-modification","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":47185,"registerId":"commonwealth-F2006B06238-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/PITTS S-2/1 - Horizontal Stabiliser - 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)  Pitts S-1 and S-2 Series Aeroplanes\n\n \n\nAD/PITTS S-2/1 Horizontal Stabiliser - Modification 6/73\n\nApplicability: All model S-2A.\n\n \n\nRequirement: Modify horizontal stabiliser structure in accordance with Pitts SB No. 7 dated 12 March 1973.\n\n \n\nCompliance: Before issue of a Certificate of Airworthiness.\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":"The directive, as written, applies to all Pitts S-2A aircraft and mandates a specific modification to the horizontal stabiliser to be completed before issuance of a Certificate of Airworthiness. The instrument itself does not state any change from an earlier scope or intent; there is no text indicating an expansion or contraction of scope compared with a prior instrument within the document. (Applicability, Requirement, Compliance)"},"complexity_factors":["Single, model-specific requirement (applies to all Pitts S-2A) reduces scope complexity (Applicability).","Single prescriptive action: modify horizontal stabiliser per a named Service Bulletin simplifies compliance content (Requirement).","Reliance on an external technical document (Pitts SB No. 7) introduces implementation dependency and potential variation in interpretation (Requirement).","Timing tied to Certificate of Airworthiness issuance concentrates enforcement at certification but leaves retrospective scope ambiguous (Compliance).","No additional inspection schedules, alternatives, or exemptions in the text reduces legal complexity but may increase operational uncertainty for existing certificated aircraft (Applicability, Compliance)."],"plain_english_summary":"Summary of the Directive\n\n- What the directive does mechanically: The Airworthiness Directive AD/PITTS S-2/1 requires that the horizontal stabiliser structure of Pitts model S-2A aeroplanes be modified in accordance with Pitts Service Bulletin No. 7 dated 12 March 1973. (Requirement)\n\n- Who it applies to: The directive is stated to apply to all Pitts S-2A aircraft. (Applicability)\n\n- When it must be done: The modification must be completed before a Certificate of Airworthiness is issued for an affected aeroplane. (Compliance)\n\nWho pays, who decides, and what changes in behaviour\n\n- Who pays: Aircraft owners or operators (and their maintenance providers) will bear the direct cost of performing the physical modification and any associated inspections, parts procurement and labour. (Requirement)\n- Who decides and enforces compliance: The directive is issued by the civil aviation authority and compliance is enforced through the certification process because the modification is required before a Certificate of Airworthiness can be issued. That means the authority responsible for issuing the Certificate of Airworthiness will withhold the certificate until the required modification is completed. (Compliance)\n- Behaviour change required: Owners/operators seeking certification for S-2A aircraft must obtain Pitts SB No. 7 and carry out the modification to the horizontal stabiliser structure before final airworthiness certification. Maintenance organisations will need to schedule and perform the modification and keep records to demonstrate compliance.\n\nCosts, incentives, trade-offs and implementation considerations (sourced to the directive text)\n\n- Cost and timing: The text requires the modification be done before CoA issuance (Compliance). That creates an incentive for owners/operators to complete the work during the certification process; it may increase the time and expense of bringing an S-2A into service. (Compliance)\n- Dependency on an external technical document: The modification must follow Pitts SB No. 7 (Requirement). That means affected parties must obtain that Service Bulletin and rely on its instructions and parts lists; availability, clarity and completeness of the SB affect implementation risk and cost. (Requirement)\n- Enforcement lever: The directive uses the Certificate of Airworthiness as the compliance trigger (Compliance). This ties enforcement to the certification process rather than specifying ongoing in-service inspection intervals or retrospective mandatory modifications for already certificated aircraft (the directive does not state any retroactive enforcement beyond the CoA requirement). (Applicability, Compliance)\n- Compliance burden and resources: The modification is structural work on the horizontal stabiliser (Requirement). It will generally require maintenance facilities with appropriate skills, possible parts procurement, and recordkeeping to show the authority that the SB has been complied with. (Requirement)\n- Possible operational effects: By requiring modification prior to CoA, the directive may delay entry to service for affected aircraft until the modification is done. The text does not specify funding, timeframes beyond the CoA condition, or exemptions. (Compliance)\n\nNotes on stated purpose and testing that claim against costs and incentives\n\n- The directive text does not include an explicit statement of the safety deficiency or event that prompted the AD. The document only prescribes the required action (Requirement) and timing (Compliance). (Requirement, Compliance)\n- If the underlying purpose is to address a structural or safety issue in the horizontal stabiliser, then the concrete mechanism here is to force the structural modification as a condition of certification. That mechanism imposes concentrated costs on S-2A owners/operators (who must pay for and schedule the work) while concentrating the authority to permit operation in the hands of the certification authority (who enforces through the CoA). The directive leaves the magnitude of those costs and the precise implementation burden to the SB and to operators/maintenance organisations that must execute it. (Requirement, Compliance)\n\nPotential sources of ambiguity or implementation risk (based on the text)\n\n- The AD references an external Service Bulletin (Pitts SB No. 7 dated 12 March 1973) but does not reproduce its contents; parties must obtain and rely on that SB. (Requirement)\n- The AD requires compliance before issue of a Certificate of Airworthiness but does not state whether aircraft already holding a CoA are affected. The text therefore ties enforceability clearly to the certification process but leaves retrospective effect unclear. (Applicability, Compliance)\n\nRelevant sections cited: (Applicability) “All model S-2A.”; (Requirement) “Modify horizontal stabiliser structure in accordance with Pitts SB No. 7 dated 12 March 1973.”; (Compliance) “Before issue of a Certificate of Airworthiness.”"},"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This is a discrete, single-issue safety directive focused specifically on the horizontal stabiliser modification for one aircraft model. It has not expanded beyond its original purpose."},"complexity_factors":["Extremely short document (under 200 words)","Only 1 defined term implicitly referenced (Certificate of Airworthiness)","No cross-references to other legislation beyond the enabling regulation (Civil Aviation Regulations 1998, Part 39)","Single, unconditional requirement with clear compliance deadline","No exceptions, exemptions, or conditional logic","Technical implementation delegated to external document (Service Bulletin) rather than detailed in the AD itself"],"plain_english_summary":"**What this is:** This is an **Airworthiness Directive (AD)** — a mandatory safety order issued by Australia's Civil Aviation Safety Authority (CASA) under the Civil Aviation Regulations 1998.\n\n**What it does:** It requires owners and operators of **Pitts S-2A aeroplanes** (a type of aerobatic biplane) to modify the **horizontal stabiliser** (the small wing at the tail that keeps the plane level) according to a specific manufacturer's service bulletin (Pitts SB No. 7, dated 12 March 1973).\n\n**Who it affects:** Anyone who owns, operates, or maintains a Pitts S-2A aircraft in Australia.\n\n**Why it matters:** The modification must be completed **before the aircraft can be issued a Certificate of Airworthiness** — meaning the plane cannot legally fly until this safety fix is done. Airworthiness Directives are legally binding safety requirements designed to prevent accidents caused by known design flaws or wear issues.\n\n**Key requirement:** The actual technical details of the modification aren't spelled out in this document — operators must follow the manufacturer's Service Bulletin No. 7 from March 1973."}},"importantCases":[],"_links":{"self":"/api/acts/ad-pitts-s-2-1-horizontal-stabiliser-modification","history":"/api/acts/ad-pitts-s-2-1-horizontal-stabiliser-modification/history","analysis":"/api/acts/ad-pitts-s-2-1-horizontal-stabiliser-modification/analysis","conflicts":"/api/acts/ad-pitts-s-2-1-horizontal-stabiliser-modification/conflicts","importantCases":"/api/acts/ad-pitts-s-2-1-horizontal-stabiliser-modification/important-cases","documents":"/api/acts/ad-pitts-s-2-1-horizontal-stabiliser-modification/documents"}}