{"id":"F2006B07571","name":"AD/VAT/37 - Wing Ribs - Inspection and Modification","slug":"ad-vat-37-wing-ribs-inspection-and-modification","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":50174,"registerId":"commonwealth-F2006B07571-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/VAT/37 - Wing Ribs - Inspection and Modification","content":"COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY\n\nSCHEDULE OF AIRWORTHINESS DIRECTIVES\n\nVicta and A.E.S.L. Airtourer Series Aeroplanes\n\nAD/VAT/37 Wing Ribs \\- Inspection and Modification 6/72\n\nApplicability: All models not modified to AESL SB No. 019.\n\nRequirement: Remove the walkway top skin sufficiently for wing ribs P/Nos. 10217/1 and /2 and 102109/1 to be inspected for cracks. Particular attention should be paid to the lower flange to web radius in the vicinity of the attachment points for the landing gear legs.\n\nPrior to further flight defective ribs shall be repaired in accordance with AESL SB No. 019 or to a scheme approved by the Secretary.\n\nCompliance: For aircraft which have exceeded 3500 hours time in service as at 30 June 1972 - within 300 hours time in service and thereafter at intervals not exceeding 3500 hours time in service.\n\nFor aircraft which have not exceeded 3500 hours time in service at 30 June 1972 - before achieving 3800 hours time in service and thereafter at intervals not exceeding 3500 hours time in service.","sortOrder":0}],"analysis":{"kimi_summary":{"content_quality":"ok","complexity_score":3,"scope_assessment":{"changed":false,"description":"This is a discrete, single-issue airworthiness directive from 1972 addressing a specific structural fatigue concern in a particular aircraft type. It has not expanded beyond its original purpose of ensuring wing rib integrity in Victa/A.E.S.L. Airtourer aircraft."},"complexity_factors":["Single, specific technical requirement with clear applicability criteria","Only 4 defined references (part numbers, service bulletin numbers, and regulatory citations)","Simple conditional compliance structure based on aircraft flight hours as of a fixed historical date (30 June 1972)","No nested exceptions or cross-references to other legislation beyond the parent Civil Aviation Regulations 1998","Straightforward repair pathway: either follow the manufacturer's service bulletin or seek regulatory approval","Length: approximately 150 words — very short and focused"],"plain_english_summary":"This is an **Airworthiness Directive** — a mandatory safety order issued by Australia's aviation safety regulator (CASA) that requires owners of specific aircraft to inspect and potentially repair their planes.\n\n**What it does:**\n- Targets **Victa and A.E.S.L. Airtourer series aeroplanes** — small, single-engine aircraft popular in Australia\n- Requires inspection of specific **wing ribs** (internal structural supports inside the wing) for cracks\n- Focuses on areas near where the landing gear attaches to the wing — a high-stress point\n- If cracks are found, the ribs must be repaired before the aircraft can fly again\n\n**Who it affects:**\n- Owners and operators of these specific aircraft models\n- Only applies to planes that **haven't already been modified** according to a specific service bulletin (AESL SB No. 019)\n\n**Why it matters:**\nCracks in wing ribs near landing gear attachments could lead to **structural failure** — potentially causing the wing to fail during flight or landing. This directive prevents catastrophic accidents by catching fatigue damage before it becomes dangerous.\n\n**When to comply:**\n- **High-time aircraft** (over 3,500 flight hours as of June 1972): Inspect within next 300 flight hours, then every 3,500 hours after that\n- **Lower-time aircraft** (under 3,500 hours as of June 1972): Inspect before hitting 3,800 total hours, then every 3,500 hours after that"},"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":false,"description":"The directive's stated scope — inspect and, if necessary, repair specified wing ribs on affected Airtourer series aeroplanes unless already modified per AESL SB No. 019 — matches the operative requirements in the text. The AD sets who must comply (owners/operators of non-modified aircraft), what must be done (inspection, attention to a specific rib area, repair per SB No. 019 or Secretary-approved alternative), and when to do it (initial and recurring hours-in-service thresholds) without indicating an expansion or contraction of scope beyond those elements."},"complexity_factors":["Different initial compliance triggers based on an aircraft's hours-in-service as at a fixed historical date (30 June 1972) (Compliance).","Technical specificity of parts to inspect (three part numbers) and the precise inspection location (lower flange-to-web radius near landing-gear attachment points) (Requirement).","Physical access requirement: removal of walkway top skin to perform the inspection increases maintenance scope and downtime (Requirement).","Mandatory repair-before-flight condition for defects and requirement to follow a particular service bulletin or obtain Secretary approval for alternatives creates a compliance-and-approval pathway (Requirement).","Exemption for aircraft already modified to AESL SB No. 019 creates a dichotomy in applicability and an incentive/operational choice for operators (Applicability)."],"plain_english_summary":"This directive requires owners/operators of Victa and A.E.S.L. Airtourer aeroplanes (unless already modified per AESL SB No.019) to remove the walkway top skin to inspect three specific wing ribs for cracks around the lower flange-to-web radius near the landing-gear attachments, and to repair any defects per SB No.019 or a Secretary‑approved alternative before flight.\n\nInspections follow an initial timing tied to aircraft hours and recur every 3,500 hours; owners/operators bear inspection and repair costs, creating downtime and an incentive to adopt SB No.019."}},"importantCases":[],"_links":{"self":"/api/acts/ad-vat-37-wing-ribs-inspection-and-modification","history":"/api/acts/ad-vat-37-wing-ribs-inspection-and-modification/history","analysis":"/api/acts/ad-vat-37-wing-ribs-inspection-and-modification/analysis","conflicts":"/api/acts/ad-vat-37-wing-ribs-inspection-and-modification/conflicts","importantCases":"/api/acts/ad-vat-37-wing-ribs-inspection-and-modification/important-cases","documents":"/api/acts/ad-vat-37-wing-ribs-inspection-and-modification/documents"}}