{"id":"F2006B10005","name":"AD/FU24/58 Amdt 1 - Wing Structural Fatigue Limitation","slug":"ad-fu24-58-amdt-1-wing-structural-fatigue-limitation","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":55363,"registerId":"commonwealth-F2006B10005-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/FU24/58 Amdt 1 - Wing Structural Fatigue Limitation","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)  \n![](image.002.png)  \nAirparts (NZ) Ltd. FU 24 Series Aeroplanes\n\nAIRWORTHINESS DIRECTIVE\n\n![](image.002.png)\n\n![](image.002.png)  \nFor the reasons set out in the background section, the CASA delegate whose signature appears below revokes Airworthiness Directive (AD) AD/FU24/58 and issues the following AD under subregulation 39.1 (1) of CAR 1998. The AD requires that the action set out in the requirement section (being action that the delegate considers necessary to correct the unsafe condition) be taken in relation to the aircraft or aeronautical product mentioned in the applicability section: (a) in the circumstances mentioned in the requirement section; and (b) in accordance with the instructions set out in the requirement section; and (c) at the time mentioned in the compliance section.\n\nAD/FU24/58\n\nAmdt 1\n\n  \nWing Structural Fatigue Limitation 6/2000\n\nApplicability: All model FU24-950, FU24A-950, FU24-954 and FU24A-954 series aeroplanes which are or have been used in agricultural operations.\n\nRequirement: Retire the wing main spar lower cap from service.\n\nCompliance: Upon or prior to achieving 11000 hours time in service in agricultural operations.\n\nThis Amendment becomes effective on 15 June 2000.\n\nBackground: The wing spar safe fatigue life of 11000 hours in agricultural operations was established on the basis of the manufacturer’s fatigue substantiation in accordance with Australian certification requirements, and with due allowance for Australian requirements and operating conditions.\n\nThe safe fatigue life estimate for Normal Category operations is approximately 130000 hours. This amendment clarifies that the life limitation relates to flight time accumulated in agricultural operations only.\n\nThe initial issue of this directive was issued in September 1980.\n\n![](image.003.png)  \n\nBernard Malcolm Hole\n\nDelegate of the Civil Aviation Safety Authority 5 May 2000\n\n![](image.002.png)  \n\nThe above AD is notified in the Commonwealth of Australia Gazette on 17 May 2000.","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":2,"scope_assessment":{"changed":false,"description":"This amendment does not expand scope beyond the original 1980 directive. It narrows and clarifies the existing requirement by specifying that the 11,000-hour fatigue limit applies only to agricultural operations, not total flight time. This is a technical refinement rather than scope creep."},"complexity_factors":["Very short document (approximately 250 words)","Only 4 defined model variants in applicability section","Single, unambiguous requirement with clear numeric threshold (11,000 hours)","No nested exceptions or conditional logic — straightforward compliance trigger","Minimal cross-referencing (only references the regulation enabling power: CAR 1998 subregulation 39.1(1))","Plain language background section explaining the engineering rationale"],"plain_english_summary":"This AD revokes and replaces the previous directive for Airparts (NZ) FU24 series agricultural aeroplanes and now requires retirement of the wing main spar lower cap after 11,000 hours of time in service in agricultural operations. It affects FU24-950, FU24A-950, FU24-954 and FU24A-954 used for crop spraying and similar work — clarifying the fatigue limit applies only to agricultural, high-stress operations to prevent catastrophic failure."},"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":true,"description":"The amendment narrows and clarifies the life limitation’s scope: it explicitly limits the 11,000‑hour retirement requirement to flight time accumulated in agricultural operations rather than to all operations. The AD also revokes the prior AD/FU24/58 and restates the requirement with that agricultural-only qualification (Background; Applicability; Compliance)."},"complexity_factors":["Single, clear action required: retire the wing main spar lower cap (Requirement).","Narrow technical scope: applies only to specific models FU24-950, FU24A-950, FU24-954 and FU24A-954 used in agricultural operations (Applicability).","Compliance trigger is a measured quantity: 11,000 hours time in service specifically accumulated in agricultural operations (Compliance).","Recordkeeping burden: operators must distinguish and track flight hours in agricultural operations separately from other flying (Compliance/Background).","Safety-critical engineering basis: fatigue life established from manufacturer substantiation under Australian certification rules (Background).","Economic impact concentrated on aircraft owners/operators who must fund retirement and any replacement or repairs (Requirement/Compliance).","Regulatory change mechanism: revokes prior AD/FU24/58 and issues amended AD (opening paragraph), adding administrative complexity for fleet managers tracking regulatory history.","Clarification narrows scope compared with Normal Category life estimate (~130,000 hours) by tying the 11,000-hour limit to agricultural use only (Background).","Implementation timing and notice: amendment effective date specified (becomes effective on 15 June 2000), creating a fixed compliance horizon (last lines)."],"plain_english_summary":"This airworthiness directive mandates that owners/operators of specified Airparts FU24-950 and FU24-954 series aeroplanes used in agricultural work must remove (retire) the wing main spar lower cap from service once it has accumulated 11,000 hours of flight time in agricultural operations. CASA says the limit is based on the manufacturer’s fatigue testing and the amendment clarifies the limit applies only to agricultural flight hours. Operators pay for retirement/replacement and must track hours spent in agricultural operations to comply."}},"importantCases":[],"_links":{"self":"/api/acts/ad-fu24-58-amdt-1-wing-structural-fatigue-limitation","history":"/api/acts/ad-fu24-58-amdt-1-wing-structural-fatigue-limitation/history","analysis":"/api/acts/ad-fu24-58-amdt-1-wing-structural-fatigue-limitation/analysis","conflicts":"/api/acts/ad-fu24-58-amdt-1-wing-structural-fatigue-limitation/conflicts","importantCases":"/api/acts/ad-fu24-58-amdt-1-wing-structural-fatigue-limitation/important-cases","documents":"/api/acts/ad-fu24-58-amdt-1-wing-structural-fatigue-limitation/documents"}}