{"id":"F2006B04227","name":"AD/BEECH 90/36 Amdt 1 - Wing Structural Fatigue Limitation","slug":"ad-beech-90-36-amdt-1-wing-structural-fatigue-limitation","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":43985,"registerId":"commonwealth-F2006B04227-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/BEECH 90/36 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)  \nBeechcraft 90 and 65-90 (King Air) Series Aeroplanes\n\nAD/BEECH 90/36\n\nAmdt 1\n\n  \nWing Structural Fatigue Limitation 5/79\n\nApplicability: All Model E90 aircraft with centre-section and outer wing main spar lower caps exceeding 13000 hours’ time in service.\n\nRequirement: Retire from service the centre-section and outer wing main spar lower caps including the centre-section to the outer wing attachment fittings.\n\nThis life limitation assumes an average mean flight cruise weight of 9300 pounds and one landing per hour. Should the mean cruise weight, averaged over the life of the aircraft be greater than 9350 pounds or should landings occur on average at a greater frequency than one every 45 minutes, the Secretary must be advised.\n\nNote: On the basis of the currently available fatigue substantiation for the aircraft, only one spar cap replacement is permitted. Any proposal for a further extension in life incorporating a second spar change must be supported by a substantiation covering all the remaining primary structure including empennage, control surface hinge arms etc. This substantiation must incorporate a safe life assessment, or a sufficiently rigorous revised inspection schedule to ensure that any fatigue cracking which could occur in service will be detected before the aircraft is endangered. A third spar change will not be permitted.\n\nEffective: 30 April 1975.","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 a narrow, technical airworthiness directive focused specifically on wing spar fatigue limitations for a single aircraft model. It has not expanded beyond its original safety purpose."},"complexity_factors":["Single, specific applicability criterion (Model E90 aircraft with >13,000 hours on specific components)","Clear, unambiguous operative requirement (retire from service)","Two conditional adjustments based on operational parameters (cruise weight and landing frequency)","One substantive note clarifying replacement limitations and future extension requirements","No cross-references to other legislation or regulations within the text","Short length (approximately 200 words)","Minimal defined terms (only 'Secretary' requires external context — refers to Secretary of the Department responsible for civil aviation)"],"plain_english_summary":"This Airworthiness Directive mandates permanent removal and replacement of the centre‑section and outer wing main spar lower caps (and their attachment fittings) on Beechcraft Model E90 King Air aeroplanes once those parts reach 13,000 flight hours. It affects owners, operators and maintenance personnel; operators with heavier or more frequent flights must notify the regulator because increased use accelerates fatigue. Only one replacement is permitted per aircraft (further life extension requires extreme analysis; a third replacement is prohibited)."},"flash_summary":{"complexity_score":4,"scope_assessment":{"changed":true,"description":"This instrument is titled as an amendment (Amdt 1) and sets a specific life limit (13,000 hours on defined spar caps) plus operational assumptions and strict limits on the number of permitted spar-cap replacements. The amendment therefore narrows and specifies the service-life and extension pathway for the affected structural parts compared with a non-amended or unspecified regime (text: Applicability; Requirement; Note)."},"complexity_factors":["Applicability threshold: applies only to Model E90 aircraft when centre-section and outer wing main spar lower caps exceed 13,000 hours’ time in service (Applicability).","Mandatory retirement: requires removal/retirement of specified structural components, creating direct replacement cost and maintenance scheduling obligations (Requirement).","Operational-assumption conditionality: life limit is tied to assumed average mean cruise weight (9300 lb) and landing frequency (one landing per hour), with an obligation to advise the Secretary if averages exceed the stated values — monitoring and recordkeeping burden (Requirement).","Limit on spare changes: permits only one spar cap replacement under current substantiation; any further extension requires comprehensive structural substantiation covering primary structure, empennage, hinge arms etc., or a rigorous inspection regime (Note).","Burden of proof for extensions: further life extension demands a safe-life assessment or sufficiently rigorous revised inspection schedule; administrative and technical cost to prepare and gain acceptance of substantiation (Note).","Regulatory discretion and notification: operator must notify the Secretary where operational parameters differ from assumptions, introducing a point of regulator discretion and potential for case-by-case assessment (Requirement).","Absolute prohibition: a third spar change is expressly not permitted, creating a hard technical limit on lifecycle management options (Note)."],"plain_english_summary":"This airworthiness directive requires Beechcraft Model E90 (King Air) aeroplanes to have the centre-section and outer wing main spar lower caps removed from service once those parts exceed 13,000 hours’ time‑in‑service. It affects aircraft owners/operators who must replace those spar caps, track average cruise weight and landing frequency, and notify the regulator if operational loads exceed the stated assumptions. The rule also limits spare-cap replacements and requires detailed structural substantiation for any further life extension."}},"importantCases":[],"_links":{"self":"/api/acts/ad-beech-90-36-amdt-1-wing-structural-fatigue-limitation","history":"/api/acts/ad-beech-90-36-amdt-1-wing-structural-fatigue-limitation/history","analysis":"/api/acts/ad-beech-90-36-amdt-1-wing-structural-fatigue-limitation/analysis","conflicts":"/api/acts/ad-beech-90-36-amdt-1-wing-structural-fatigue-limitation/conflicts","importantCases":"/api/acts/ad-beech-90-36-amdt-1-wing-structural-fatigue-limitation/important-cases","documents":"/api/acts/ad-beech-90-36-amdt-1-wing-structural-fatigue-limitation/documents"}}