{"id":"F2006B05110","name":"AD/CESSNA 185/2 Amdt 4 - Rear Spar","slug":"ad-cessna-185-2-amdt-4-rear-spar","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":45098,"registerId":"commonwealth-F2006B05110-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/CESSNA 185/2 Amdt 4 - Rear Spar","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)  \nCessna 185 Series Aeroplanes\n\nAD/CESSNA 185/2\n\nAmdt 4\n\n  \nRear Spar 12/74\n\nApplicability: All models except those with rear spars P/Nos. 0523400-90 LH and \\-91 RH; 0523400-111 LH and -112 RH.\n\nRequirement: 1. Modify the rear spar root, left and right mainplanes on all agricultural aeroplanes in accordance with Rex Aviation Drawing RA-491 or an alternative scheme approved by the Secretary.\n\n    2. Inspect the mainplane rear spar web for fatigue cracks in the root area. These cracks originate in the radius which is located under the attachment fittings. This inspection shall be carried out using a magnifying glass of at least 4X magnification or alternatively a device such as the “Syte Ade” may be employed.\n\n    3. Inspect the upper flange of the rear spar channel at the outer end of the attachment fitting. This can be done via the flap bay inner inspection panel.\n\n    4. Since the trailing edge root end fits closely to the spar, it may be difficult to detect possible cracks, therefore where doubt exists, the trailing edge root end rib shall be removed for more detailed inspection.\n\nNote: The affected area is illustrated in Rex Aviation Technical Memorandum No. 12 dated 10 May 1960.\n\nCompliance: For Para 1: Forthwith.\n\nFor Paras 2 and 3: Aeroplanes modified to Rex Aviation Drawing RA-491 - at intervals not exceeding 500 hours time in service. All other aeroplanes \\- at intervals not exceeding 100 hours time in service.","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 Amendment 4 to an existing Airworthiness Directive (AD/CESSNA 185/2). The scope remains tightly focused on the original purpose: addressing rear spar fatigue in Cessna 185 agricultural aircraft. The amendment appears to update compliance intervals and inspection methods without expanding beyond the original safety concern."},"complexity_factors":["Short, single-purpose document focused on one aircraft type and specific structural issue","Only 4 defined part numbers in applicability exclusion","Clear, numbered requirements with straightforward compliance intervals","Minimal cross-referencing (only one external document: Rex Aviation Drawing RA-491 and Technical Memorandum No. 12)","Simple conditional logic: modified vs. unmodified aircraft trigger different inspection intervals","Technical aviation terminology requires domain knowledge but is standard for the industry"],"plain_english_summary":"This CASA Airworthiness Directive requires Cessna 185 agricultural aircraft to have a specified rear wing-spar modification and recurring inspections of the rear spar (including access removal when needed) to detect fatigue cracks. It affects owners, operators and maintenance organisations of Cessna 185s, excluding aircraft already fitted with certain reinforced spar part numbers. The measures, with shorter inspection intervals for unmodified planes and immediate mandatory modification, aim to prevent catastrophic in‑flight structural failure."},"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":false,"description":"The directive specifies applicability and prescribes modification plus inspection requirements for Cessna 185 agricultural aeroplanes, excluding certain rear-spar part numbers. The text presents these requirements as definitive; it does not indicate a change from an earlier or different scope within this document."},"complexity_factors":["Technical inspection methods: requires use of at least 4X magnification or approved non-specified devices (e.g. 'Syte Ade'), which demands specialist tools and technique.","Differential compliance intervals: 500-hour interval applies only after compliance with a specific modification drawing (Rex Aviation RA-491), otherwise 100-hour interval applies, creating administrative tracking obligations.","Immediate modification mandate ('Forthwith') for Para 1 increases urgency and potential disruption to operators needing parts and maintenance slots.","Applicability carve-outs: excludes aircraft with particular rear-spar part numbers, requiring operators to verify part numbers to determine applicability.","Potential access difficulty: may require removal of the trailing-edge root rib for adequate inspection, adding labour time and possible downtime.","Discretionary approval path: allows alternative modification schemes but only if approved by the Secretary, introducing a regulatory approval step for deviations."],"plain_english_summary":"Requires immediate modification of the rear spar root on Cessna 185 agricultural aeroplanes (except those with specified rear-spar part numbers) and recurring inspections of the rear-spar web and upper flange for fatigue cracks using at least 4X magnification or an approved device. Modified aeroplanes inspect every 500 hours; unmodified aeroplanes inspect every 100 hours. The rule affects aircraft owners/operators, who must carry out structural work, regular inspections, and remove a trailing-edge root rib for detailed checks when access is doubtful."}},"importantCases":[],"_links":{"self":"/api/acts/ad-cessna-185-2-amdt-4-rear-spar","history":"/api/acts/ad-cessna-185-2-amdt-4-rear-spar/history","analysis":"/api/acts/ad-cessna-185-2-amdt-4-rear-spar/analysis","conflicts":"/api/acts/ad-cessna-185-2-amdt-4-rear-spar/conflicts","importantCases":"/api/acts/ad-cessna-185-2-amdt-4-rear-spar/important-cases","documents":"/api/acts/ad-cessna-185-2-amdt-4-rear-spar/documents"}}