{"id":"F2006B04246","name":"AD/BEECH 90/58 - Wing Fatigue Life Limitation","slug":"ad-beech-90-58-wing-fatigue-life-limitation","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":44027,"registerId":"commonwealth-F2006B04246-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/BEECH 90/58 - Wing Fatigue Life Limitation","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)  Beechcraft 90 and 65-90 (King Air) Series Aeroplanes\n\n \n\nAD/BEECH 90/58 Wing Fatigue Life Limitation 3/81\n\nApplicability: All model F90 Series.\n\n \n\nRequirement:  Retire the wing main spar and wing centre section carry-thru spar lower cap. Compliance:              Before exceeding 10,300 hours in service.\n\nNote 1: This life may be revised following the completion of further tests and analysis currently being carried out by the manufacturer.\n\n \n\nNote 2: On the basis of currently available fatigue substantiating data only one spar replacement is permitted. This will allow a single lifetime extension from spar cap replacement.\n\n \n\nBackground: Analysis and test data supplied by the manufacturer has established the above retirement life for the wing spar.\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\n \n\n \n\n \n\n \n\n \n\n \n\n \n","sortOrder":0}],"analysis":{"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":false,"description":"The instrument sets a specific retirement life (10,300 hours) and permits a single spar replacement extension; it also allows for future revision by the manufacturer (Notes 1 & 2). The AD establishes these limits rather than expanding or narrowing the affected aircraft beyond its stated applicability (All model F90 Series), so no change of scope from the instrument itself is indicated."},"complexity_factors":["Numeric retirement threshold: 10,300 hours — a single clear compliance trigger (Requirement; Compliance: \"Before exceeding 10,300 hours in service\").","Parts specified: wing main spar and wing centre‑section carry‑thru spar lower cap — narrows scope to critical structural components (Requirement).","Replacement limit: only one spar replacement permitted, allowing a single lifetime extension — requires lifetime tracking of parts and creates future planning constraints (Note 2).","Potential revision: manufacturer may revise the retirement life after further tests and analysis — adds regulatory uncertainty and need to monitor updates (Note 1).","Applicability: all model F90 Series — affects the entire fleet of that model, concentrating costs on those operators (Applicability).","Operational burden: operators must record hours-in-service and schedule retirements before the threshold — adds maintenance planning and potential downtime (Requirement/Compliance).","Technical detail omission: the Directive mandates retirement but does not set out the detailed replacement procedure or engineering approvals — may require additional maintenance/engineering guidance."],"plain_english_summary":"This airworthiness directive requires owners/operators of Beechcraft F90-series aeroplanes to retire the wing main spar and the wing centre‑section carry‑thru spar lower cap before those parts exceed 10,300 hours in service. It applies to all F90 models and obliges replacement planning and parts tracking by operators. The manufacturer may revise the life limit after further testing (Note 1), and only one spar replacement is permitted to extend lifetime once (Note 2), so operators must plan around that single permitted extension."},"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This is a discrete, targeted safety directive addressing a specific fatigue issue in a specific aircraft model. It has not expanded beyond its original purpose of establishing a hard life limit for critical wing structure components."},"complexity_factors":["Single, unambiguous applicability clause (one aircraft model series)","One clear quantitative compliance threshold (10,300 hours)","Only two defined technical terms requiring domain knowledge (spar, carry-thru spar lower cap)","Minimal conditional logic — no nested exceptions or alternative compliance methods","Two advisory notes providing context rather than creating legal complexity","No cross-references to other legislation, regulations, or ADs","Extremely short document (under 200 words of substantive content)"],"plain_english_summary":"This is an **Airworthiness Directive (AD)** — essentially a mandatory safety order issued by Australia's Civil Aviation Safety Authority (CASA) for specific aircraft.\n\n**What it does:**\n- **Targets:** Beechcraft F90 King Air series aircraft (a type of twin-turboprop plane).\n- **Requires:** Owners/operators must **permanently retire (replace)** two critical structural parts — the wing main spar and the wing centre section carry-thru spar lower cap — before the aircraft reaches **10,300 flight hours**.\n\n**Why these parts matter:**\nThe \"spar\" is the backbone of the wing — the main structural beam that carries flight loads. The \"carry-thru spar\" connects the wings through the fuselage. The \"lower cap\" is the bottom flange of this beam, typically under tension during flight. If these crack or fail due to metal fatigue, the wing can separate from the aircraft.\n\n**Key details:**\n- **Compliance deadline:** Before hitting 10,300 hours total time in service.\n- **One replacement allowed:** You can replace these parts once to extend the aircraft's life, but only once based on current data.\n- **Future changes possible:** The 10,300-hour limit might be revised if the manufacturer completes more testing.\n\n**Why it matters:**\nThis AD prevents catastrophic structural failure. Metal fatigue accumulates with every pressurisation cycle and flight hour. Without this directive, high-time aircraft could suffer wing separation with no warning. It's a \"hard life limit\" — unlike inspections that look for cracks, this mandates retirement before cracks become likely."}},"importantCases":[],"_links":{"self":"/api/acts/ad-beech-90-58-wing-fatigue-life-limitation","history":"/api/acts/ad-beech-90-58-wing-fatigue-life-limitation/history","analysis":"/api/acts/ad-beech-90-58-wing-fatigue-life-limitation/analysis","conflicts":"/api/acts/ad-beech-90-58-wing-fatigue-life-limitation/conflicts","importantCases":"/api/acts/ad-beech-90-58-wing-fatigue-life-limitation/important-cases","documents":"/api/acts/ad-beech-90-58-wing-fatigue-life-limitation/documents"}}