{"id":"F2006B08381","name":"AD/CESSNA 400/97 Amdt 1 - Wing Front Spar Under Cap","slug":"ad-cessna-400-97-amdt-1-wing-front-spar-under-cap","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":115809,"registerId":"commonwealth-F2006B08381-current","compilationNumber":null,"startDate":"2026-04-03","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/CESSNA 400/97 Amdt 1 - Wing Front Spar Under Cap","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 400 Series Aeroplanes\n\nAD/CESSNA 400/97\n\nAmdt 1\n\n  \nWing Front Spar Under Cap 1/95\n\nApplicability: Models 421C S/N 421C0801 to 421C1807, and 425 S/N 425-0002 to 425-0236.\n\nRequirement: 1. Inspect in accordance with Cessna SB CQB 91-8 Rev.1 or MEB 91-7 Rev.1, as applicable.\n\n    2. Install SK421-142 or SK425-44 as applicable.\n\n    3. Install a repair scheme acceptable to the Authority that has been validated by the Cessna Aircraft Company.\n\n    4. Remove from service any repair scheme:\n\n    installed as a result of the initial issue of this Directive that is not in accordance with Paragraphs 2. or 3. above; and\n\n    b. that does not have an inspection schedule incorporated into the aircraft’s approved System of Maintenance that reflects the actual repair carried out, and the requirements of the following Compliance.\n\nNote: FAA AD 91-25-08 R1 refers.\n\nCompliance: 1. Unless already accomplished in the previous 300 hours time in service, inspect prior to 3000 hours total time in service or within the next 50 hours time in service after 08 December 1994, whichever is the later; thereafter if cracking is:\n\n    less than 50mm (2.00\"), at intervals not exceeding 50 hours time in service until the applicable service kit is installed. Following installation of the the Service Kit inspect in accordance with the requirements of Paragraph 2; or\n\n    b. not detected - reinspect at intervals not exceeding 300 hours time in service until applicable Service Kit is installed. Installation of the applicable Service Kit prior to any detectable cracking terminates the inspection requirements of this Directive.\n\n    2. If crack length is:\n\n    equal to or less than 50mm (2.00\") \\- within the next 200 hours time in service, then re-inspect at intervals not exceeding 600 hours time in service;\n\n    b. greater than 50mm (2.00\") and less than 63.5mm (2.50\") \\- within 50 hours time in service, then re-inspect at intervals not exceeding 600 hours time in service\n\n    3. Where any crack:\n\n    length is greater than 63.5mm \\- prior to further flight, and/or\n\nCOMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 \\- 105 CIVIL AVIATION SAFETY AUTHORITY\n\nSCHEDULE OF AIRWORTHINESS DIRECTIVES\n\n    b. is detected that is not parallel to the grain structure; i.e. inboard to outboard along the spar cap, irrespective of length \\- prior to further flight; then re-inspect in accordance with the intervals and procedures specified in the acceptable repair scheme.\n\n    4. Within 300 hours time in service since the last inspection.\n\nBackground: Cracks have been found in the wing front spar upper cap adjacent to the landing gear actuator. If not rectified wing failure could occur.\n\nAmendment 1 includes acceptable repair schemes that will ameliorate the inspections or provide terminating action.","sortOrder":0}],"analysis":{"flash_summary":{"complexity_score":7,"scope_assessment":{"changed":true,"description":"Amendment 1 expands the directive’s practical options by adding Authority‑acceptable, Cessna‑validated repair schemes that can reduce or terminate recurring inspections, and it tightens enforcement by requiring removal of earlier repairs that do not comply or lack an inspection schedule (see Amendment note; Requirements 2–4). The core safety focus (addressing spar cap cracking) remains, but the amendment changes compliance pathways and record‑keeping obligations."},"complexity_factors":["Serial‑number limited applicability creates narrow population and tracking needs (Applicability).","Multiple technical crack‑length thresholds with different mandated actions and inspection intervals (Compliance: 1–3).","Different timing triggers: initial deadlines tied to total hours and a fixed calendar reference, plus recurring hour‑based intervals (Compliance: 1).","Multiple remedial options: fit specific service kits (SK421‑142, SK425‑44) or install an Authority‑acceptable repair validated by Cessna (Requirement: 2–3).","Obligation to remove earlier repairs that don't meet new requirements or lack an inspection schedule; requires updating the aircraft’s approved System of Maintenance (Requirement: 4).","Cross‑references to manufacturer service documents and FAA AD increase procedural dependencies (Requirement: 1; Note).","Regulatory discretion: Authority must accept repair schemes and validate conformity, creating administrative review and compliance‑certainty costs (Requirement: 3)."],"plain_english_summary":"**What it does:** Requires owners/operators of specified Cessna 421C (S/N 421C0801–421C1807) and 425 (S/N 425‑0002–425‑0236) aircraft to inspect the wing front spar upper cap, install an approved service kit (SK421‑142 or SK425‑44) or a Cessna‑validated repair, and remove earlier non‑compliant repairs. It responds to cracking found adjacent to the landing‑gear actuator that could lead to wing failure.\n\nWho pays/acts: Owners/operators must fund and carry out inspections, kits or validated repairs and record inspection schedules in the aircraft’s approved maintenance system."},"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":4,"scope_assessment":{"changed":false,"description":"This amendment stays within the original scope of addressing wing spar cracking in specific Cessna models. Amendment 1 adds acceptable repair schemes as terminating actions, which is a natural evolution of the original safety intent rather than scope creep. The applicability (affected aircraft serial numbers) and core safety objective remain unchanged from the original directive."},"complexity_factors":["Multiple conditional compliance paths based on crack size (four distinct scenarios: no cracks, <50mm, 50-63.5mm, >63.5mm)","Cross-references to external documents (Cessna Service Bulletins CQB 91-8 Rev.1, MEB 91-7 Rev.1, FAA AD 91-25-08 R1)","Nested conditional logic: compliance intervals change based on both crack detection status AND crack dimensions AND repair kit installation status","Specific measurement thresholds requiring precise assessment (50mm, 63.5mm, 2.00\", 2.50\")","Dual measurement systems (metric and imperial) creating potential conversion ambiguity","Time-based triggers using two different metrics ('hours time in service' vs 'total time in service')","Retroactive provisions affecting repairs done under earlier versions of the directive","Requirement for integration with aircraft's 'approved System of Maintenance' (a defined aviation term)"],"plain_english_summary":"This Airworthiness Directive orders owners/operators and maintenance engineers of specified Cessna 421C (S/N 421C0801–421C1807) and 425 (S/N 425‑0002–425‑0236) aeroplanes to inspect the wing front spar at the landing-gear attachment for cracking, require timely repairs, and impose grounding for serious defects. \n\nAmendment 1 adds approved repair options and kits that can remove or reduce ongoing inspection obligations to prevent catastrophic wing failure."}},"importantCases":[],"_links":{"self":"/api/acts/ad-cessna-400-97-amdt-1-wing-front-spar-under-cap","history":"/api/acts/ad-cessna-400-97-amdt-1-wing-front-spar-under-cap/history","analysis":"/api/acts/ad-cessna-400-97-amdt-1-wing-front-spar-under-cap/analysis","conflicts":"/api/acts/ad-cessna-400-97-amdt-1-wing-front-spar-under-cap/conflicts","importantCases":"/api/acts/ad-cessna-400-97-amdt-1-wing-front-spar-under-cap/important-cases","documents":"/api/acts/ad-cessna-400-97-amdt-1-wing-front-spar-under-cap/documents"}}