{"id":"F2006B02544","name":"AD/AT/15 Amdt 1 - Wing Attachment Tube Bushings","slug":"ad-at-15-amdt-1-wing-attachment-tube-bushings","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":41800,"registerId":"commonwealth-F2006B02544-current","compilationNumber":null,"startDate":"2026-04-01","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/AT/15 Amdt 1 - Wing Attachment Tube Bushings","content":"COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 \\- 105 CIVIL AVIATION SAFETY AUTHORITY\n\nSCHEDULE OF AIRWORTHINESS DIRECTIVES\n\n![](image.001.png)  \nAirtractor AT-300, 400 and 500 Series Aeroplanes\n\nAD/AT/15\n\nAmdt 1\n\n  \nWing Attachment Tube Bushings 10/95\n\nApplicability: Airtractor AT-501 serial numbers up to 510-0128 and Airtractor AT-502 serial numbers up to 502-0128 with unreinforced bushings in the fuselage wing attachment tubes.\n\nRequirement: 1. Visually inspect for cracks around the unreinforced bushings in the fuselage wing attachment tubes. Inspect in accordance with Snow Engineering Co. Service Letter No 92.\n\n2. a. Remove the wing gap covers, detachable side skins and wing attachment angles from the wing attachment tubes. Thoroughly clean the area around the unreinforced bushing in the wing attachment tubes, rinse thoroughly with water and air dry.\n\nNote: It is advisable not to use paint strippers and volatile cleaning agents in confined areas since they may react with the chemical residue remaining from agricultural operations.\n\n2. b. Remove the paint and perform a fluorescent dye penetrant inspection accordance with CAO 108.10. If no cracks are detected repaint the wing attachment tube.\n\nCompliance: 1. Inspect before 5 hours time in service after 22 June 1995.\n\n2. At the next 100 hourly inspection or annual inspection, whichever occurs first.\n\nReinspect at intervals not to exceed 500 hours or each annual inspection, whichever occurs first.\n\nThis Amendment is effective from the 14 September 1995.\n\nNote: Installation of reinforcement gussets P/N 10803-1 (or equivalent) cancels the Requirement of this AD.\n\nBackground: The manufacturer reports finding cracks in the tubing around an unreinforced bush in the wing attachment tube. This Amendment revises the preparation procedure for inspection, allows a terminating modification and increases the interval for the repeat inspections.","sortOrder":0}],"analysis":{"flash_summary_failed":{"failed":true,"reason":"A positive credit balance is required for all requests, including BYOK, so fallback providers remain available. Add credits at https://vercel.com/d?to=%2F%5Bteam%5D%2F%7E%2Fai%3Fmodal%3Dtop-up to continue.","source":"analysis-cron"},"kimi_summary":{"content_quality":"ok","complexity_score":3,"scope_assessment":{"changed":false,"description":"This is an amendment to an existing Airworthiness Directive (AD/AT/15). The scope remains tightly focused on the original safety issue (cracked wing attachment tube bushings). The amendment refines the inspection preparation procedure, adds a terminating modification option, and adjusts inspection intervals — all within the original purpose of ensuring structural integrity of the wing attachment points. No scope creep detected."},"complexity_factors":["Short, single-purpose document (1 page)","Only 2 defined applicability criteria (aircraft model and serial number ranges)","Clear sequential requirements (1, 2a, 2b)","Single cross-reference to CAO 108.10 (Civil Aviation Order specifying inspection standards)","Single cross-reference to manufacturer service letter (Snow Engineering Co. Service Letter No 92)","Simple conditional logic: compliance deadlines based on 'whichever occurs first' formulas","Explicit terminating action (installation of P/N 10803-1 gussets cancels the AD requirements)"],"plain_english_summary":"This CASA Airworthiness Directive requires owners/operators of certain Airtractor AT‑501 and AT‑502 agricultural aircraft with unreinforced bushings to inspect the wing‑to‑fuselage attachment tubes for cracks. It mandates an initial visual check, a detailed dye‑penetrant inspection at the next 100‑hour or annual maintenance, and repeat inspections every 500 flight hours or annually.\n\nThe unsafe condition is wing separation if tubes fail; installing reinforcement gussets (PN 10803‑1 or equivalent) removes the need for ongoing inspections."},"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":false,"description":"This amendment does not broaden the AD’s subject matter beyond its original safety purpose (detecting and preventing cracks around unreinforced wing-attachment bushings). It modifies implementation details: it revises preparation procedures for inspection, introduces a stated terminating modification (reinforcement gussets), and increases the repeat-inspection interval. Those are adjustments to the compliance regime rather than an expansion of the AD’s substantive scope or expansion to additional aircraft/components."},"complexity_factors":["Targeted applicability by aircraft model and serial-number ranges (narrow scope but specific).","Two-step inspection regime (initial 5‑hour visual, then cleaned/dye-penetrant at next 100‑hour/annual).","Repeat inspection interval that is conditional (not to exceed 500 hours or each annual inspection, whichever occurs first).","Terminating modification option (installation of P/N 10803-1 or equivalent) that cancels the AD requirements.","References to external documents (Snow Engineering Co. Service Letter No. 92 and CAO 108.10) which practitioners must consult.","A cautionary note on cleaning methods (avoid volatile solvents in confined agricultural-residue environments) adding procedural constraint.","Short text length with limited definitions and few cross-referenced legislative provisions (keeps overall complexity low)."],"plain_english_summary":"**What this directive does**\n\n- This is an Airworthiness Directive (AD) that requires specific inspections and possible repair for certain Airtractor agricultural aeroplanes (AT-501 and AT-502) that have unreinforced bushings in the fuselage wing attachment tubes. (Applicability)\n\n- It instructs operators to inspect the area around those unreinforced bushings for cracks, using a visual check and, where required, a fluorescent dye penetrant test. It sets out how to gain access, how to clean the area before inspection, and how to proceed if no cracks are found. (Requirement 1 & 2)\n\n- It gives precise compliance timing: an initial inspection within 5 hours time-in-service after the specified date, a follow-up at the next 100‑hour or annual check (whichever comes first), and repeat inspections at intervals not exceeding 500 hours or each annual inspection. (Compliance)\n\n- It allows a one-time modification (installation of reinforcement gussets, part number 10803-1 or an equivalent) that cancels the inspection requirements for that aircraft — i.e. the modification terminates the need for the AD’s repetitive inspections. (Note)\n\n- The directive also revises preparation procedures for inspection and increases the repeat-inspection interval compared with the prior version. (Background)\n\n\nWho this affects\n\n- Owners and operators of Airtractor AT-501 and AT-502 aeroplanes with unreinforced bushings in the fuselage wing attachment tubes and with serial numbers within the stated ranges. (Applicability)\n\n- Maintenance organisations and mechanics who will perform the inspections, cleaning and dye-penetrant tests. They must follow the referenced service and inspection procedures. (Requirement)\n\n\nWhy it matters (mechanics and trade-offs)\n\n- Purpose claimed by the source: to find and address cracks that have been reported around unreinforced bushings in the wing attachment tube, reducing the risk of structural failure. (Background)\n\n- Who pays: aircraft operators pay the direct costs — labour for access and inspection, possible downtime for the aircraft, consumables for cleaning and testing, and the cost of reinforcement gussets and installation if they choose the terminating modification. (Requirement; Note)\n\n- Behaviour change required: operators must (a) perform an early visual inspection, (b) remove covers/skins/angles to access the bushing area for a more thorough cleaning and dye-penetrant inspection, (c) repaint if no cracks, and (d) repeat inspections at the stated intervals unless they install the terminating modification. (Requirement; Compliance)\n\n- Incentives and trade-offs: installing the reinforcement gussets imposes an upfront cost but eliminates recurring inspection costs and downtime thereafter (the AD explicitly states the modification cancels the AD requirement). Operators must weigh the one-off modification cost against ongoing inspection costs and operational disruption. (Note)\n\n- Compliance and implementation risk: the AD relies on visual and fluorescent dye-penetrant inspection techniques and on following external documents (Snow Engineering Service Letter No. 92; CAO 108.10). Missed defects are possible if inspections are poorly performed or access is inadequate. The AD reduces inspection frequency (longer repeat interval) compared with the prior version, which lowers operator burden but increases the time window for an undetected crack to develop. (Requirement; Compliance; Background)\n\n- Practical constraints: the AD cautions against using paint strippers and volatile cleaning agents in confined areas because residues from agricultural chemicals may react — this constrains cleaning methods and may increase cleaning time or cost. (Requirement, Note)\n\n- Market effects and third-party activity: maintenance providers and parts suppliers (for gussets, inspection services and consumables) capture the market created by the directive. Operators retain the choice to either accept the recurring inspection regime or pay for the terminating modification. (Note)\n\n\nKey procedural points to note (mechanical summary)\n\n- Applicability limited to AT-501 and AT-502 aircraft up to specified serial numbers with unreinforced bushings.\n- Initial visual inspection required within 5 hours time-in-service after the effective date.\n- More detailed cleaning and fluorescent dye-penetrant inspection at next 100‑hour or annual inspection.\n- Repeat inspections at intervals no greater than 500 hours or each annual inspection.\n- Installing reinforcement gussets P/N 10803-1 (or an equivalent) cancels the AD’s inspection requirements.\n\n(References in parentheses indicate the part of the AD where each requirement appears.)"}},"importantCases":[],"_links":{"self":"/api/acts/ad-at-15-amdt-1-wing-attachment-tube-bushings","history":"/api/acts/ad-at-15-amdt-1-wing-attachment-tube-bushings/history","analysis":"/api/acts/ad-at-15-amdt-1-wing-attachment-tube-bushings/analysis","conflicts":"/api/acts/ad-at-15-amdt-1-wing-attachment-tube-bushings/conflicts","importantCases":"/api/acts/ad-at-15-amdt-1-wing-attachment-tube-bushings/important-cases","documents":"/api/acts/ad-at-15-amdt-1-wing-attachment-tube-bushings/documents"}}