{"id":"F2006B08389","name":"AD/CESSNA 500/15 - Wing Main Spar - Inspection and Modification","slug":"ad-cessna-500-15-wing-main-spar-inspection-and-modification","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":115826,"registerId":"commonwealth-F2006B08389-current","compilationNumber":null,"startDate":"2026-04-03","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/CESSNA 500/15 - Wing Main Spar - Inspection and 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)  Cessna 500 (Citation) Series Aeroplanes\n\n \n\n# AD/CESSNA 500/15 Wing Main Spar - Inspection\n\nand Modification\n\nApplicability: All models 500 and 501 with unit numbers 0001 to 0520.\n\n# 4/81\n\n \n\nRequirement:  1. Inspect the wing spar upper and lower cap in the area of wing section 37 in accordance with Cessna SL No. 57-2 Rev. 3 dated 15 May 1980. FAA AD 79-12-06 also refers.\n\n \n\n2.    Inspect and modify in accordance with :\n\n \n\n(a)     Cessna SB No. 57-10 Rev. 1 dated 28 March 1980 for aircraft unit Nos. 0001 to 0349.\n\n \n\n(b)     Cessna SB No. 57-11 rev. 1 dated 28 March 1980 for aircraft unit Nos. 0350 to 0520.\n\n \n\n3.    Visually inspect for further cracks the wing main spar upper and lower caps of aircraft modified in accordance with SB No. 57-10 Rev. 1 or SB No. 57-11 Rev. 1, in the area of the W.S. 37 modification.\n\n \n\nCompliance: For Para. 1 - As detailed in the requirement document.\n\n \n\nFor Para. 2 - In accordance with the requirement documents when any crack monitored under the provisions of Para. 1 reaches or exceeds 0.30 inches in length.\n\n \n\nNote: The modification may be carried out at any time (i.e. not necessarily at crack detection) and thus exempt the aircraft from the inspections under Para.1.\n\n \n\nFor Para. 3 - At or prior to exceeding 1,200 hours after modification and thereafter at intervals not exceeding 1,200 hours or 1,200 landings whichever occurs first.\n\n \n\nBackground:  The results of full-scale fatigue testing and the inspection of several high time Citation aircraft have revealed small fatigue cracks in the main spar upper and lower caps at W.S. 37. In service cracks were found in 8 instances in the upper cap and in 1 instance in the lower cap.\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":{"kimi_summary":{"content_quality":"ok","complexity_score":3,"scope_assessment":{"changed":false,"description":"This is a discrete airworthiness directive addressing a specific fatigue cracking issue in a defined aircraft population. It has not expanded beyond its original safety purpose."},"complexity_factors":["Short, single-purpose document (one specific airworthiness issue)","Only 3 main requirements with clear sequential logic (inspect → modify if cracked → re-inspect after modification)","Limited applicability (specific aircraft models and serial number range)","References to external technical documents (Cessna Service Bulletins and Service Letter) rather than reproducing complex technical specifications inline","Simple conditional trigger (crack length ≥ 0.30 inches) with an optional early compliance path","No nested definitions, interpretation sections, or extensive cross-referencing to other legislation"],"plain_english_summary":"This CASA Airworthiness Directive mandates owners/operators of Cessna 500/501 Citations (S/N 0001–0520) inspect the wing spar (wing section 37) for fatigue cracks and, if cracks reach 0.30 in (≈7.6 mm), apply specified Cessna modification SBs. Early modification is allowed and removes the need for repeated inspections. After modification, visual checks are required every 1,200 flight hours or landings. It’s mandatory to prevent catastrophic wing failure; non‑compliance grounds the aircraft in Australian airspace."},"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"},"flash_summary":{"complexity_score":5,"scope_assessment":{"changed":false,"description":"The AD's scope is limited to Cessna 500 and 501 aircraft with unit numbers 0001–0520 as stated under 'Applicability'. The text shows no alteration or expansion of that applicability within the instrument."},"complexity_factors":["Technical nature: fatigue inspection and structural modification of the wing main spar upper/lower caps requires engineering assessment and precise crack measurement (Requirement Paras 1–3; Background).","Cross-references to multiple external documents increase implementation complexity (Cessna SL No.57-2 Rev.3; SB No.57-10 Rev.1; SB No.57-11 Rev.1; FAA AD 79-12-06) (Requirement Para.1–2).","Conditional compliance triggers: modification becomes mandatory when monitored cracks reach 0.30 inches, but modification may be carried out earlier to exempt inspections (Compliance Para.2; Note).","Recurring inspection schedule after modification: visual checks at or before 1,200 hours and then at intervals not exceeding 1,200 hours or 1,200 landings (Para.3), requiring ongoing operator tracking.","Limited applicability by aircraft unit numbers (0001–0520) requires operators to identify affected airframes accurately (Applicability).","Multiple compliance pathways and timing options (inspect now, modify later; or modify now to remove inspections) create operational decision points and recordkeeping needs (Requirement, Compliance, Note).","Enforcement and operational costs fall on owners/operators: inspections, potential repairs/modification and recurrent checks (Requirement & Compliance sections)."],"plain_english_summary":"Requires owners/operators of Cessna 500/501 aeroplanes (unit nos. 0001–0520) to inspect and, where necessary, modify the wing main spar upper and lower caps near wing station 37 using specified Cessna service documents and a referenced FAA AD. Inspections are mandatory as detailed in the AD; modification is required when monitored cracks reach 0.30 inches and, after modification, recurring visual inspections are required every 1,200 hours or 1,200 landings (modification may be done earlier to avoid the inspection schedule)."}},"importantCases":[],"_links":{"self":"/api/acts/ad-cessna-500-15-wing-main-spar-inspection-and-modification","history":"/api/acts/ad-cessna-500-15-wing-main-spar-inspection-and-modification/history","analysis":"/api/acts/ad-cessna-500-15-wing-main-spar-inspection-and-modification/analysis","conflicts":"/api/acts/ad-cessna-500-15-wing-main-spar-inspection-and-modification/conflicts","importantCases":"/api/acts/ad-cessna-500-15-wing-main-spar-inspection-and-modification/important-cases","documents":"/api/acts/ad-cessna-500-15-wing-main-spar-inspection-and-modification/documents"}}