{"id":"F2006B09821","name":"AD/F28/86 - Fuselage Butt Joint at Stringers 27/48","slug":"ad-f28-86-fuselage-butt-joint-at-stringers-27-48","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":54763,"registerId":"commonwealth-F2006B09821-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"AIRWORTHINESS DIRECTIVE","sectionType":"part","heading":"AIRWORTHINESS DIRECTIVE","content":"# AIRWORTHINESS 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 issues the following Airworthiness Directive (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.","sortOrder":0},{"sectionNumber":"AD/F28/86 Fuselage Butt Joint at Stringe","sectionType":"part","heading":"AD/F28/86 Fuselage Butt Joint at Stringers 27/48 2/2001","content":"# AD/F28/86 Fuselage Butt Joint at Stringers 27/48 2/2001\n\nApplicability: Model F28 Mk. 1000 through 4000 series aircraft, all serial numbers. Requirement: Inspect in accordance with Fokker Service Bulletin F28/53-148.\n\nNote: RLD AD 2000-151 refers.\n\nCompliance: Before accumulating 30,000 total flight cycles since new, or within 12 months after 22 February 2001, whichever occurs later.\n\nThis Airworthiness Directive becomes effective on 22 February 2001.\n\nBackground: The RLD received a report of a crack in the fuselage skin between STA.9805 and STA.10305 on the right side of the aircraft in a bonded doubler at stringer 48.\n\nSubsequent investigation revealed that the crack initiated at a scratch, possibly present from production, at the edge of the bonded lower skin. This Directive requires a one- time eddy current inspection of the affected fuselage skin areas.\n\n![](image.003.png)  \n\nDavid Alan Villiers\n\nDelegate of the Civil Aviation Safety Authority 12 January 2001\n\n![](image.002.png)  \n\nThe above AD is notified in the Commonwealth of Australia Gazette on 24 January 2001.","sortOrder":1}],"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 Airworthiness Directive maintains its original narrow scope — addressing a specific structural defect in a specific aircraft type. There is no evidence of scope creep; it remains a targeted safety intervention for the identified unsafe condition."},"complexity_factors":["Very short document (approximately 250 words)","Only 1 defined term implicitly referenced (\"flight cycles\" — understood in aviation context)","No cross-references to other legislation beyond a single note referencing a Dutch aviation directive (RLD AD 2000-151)","Single, clear requirement with straightforward compliance timing","No nested exceptions or conditional logic — simple 'whichever occurs later' timing rule","Technical content limited to specific aircraft model and inspection procedure reference (Fokker Service Bulletin)"],"plain_english_summary":"This mandatory CASA safety order requires owners and operators of Fokker F28 (1000–4000 series) to perform a one‑time eddy‑current inspection of fuselage skin joints near stringers (positions 27 and 48). The action responds to a discovered crack originating from a manufacturing scratch that could cause structural failure. Compliance is required before 30,000 total flight cycles or within 12 months of 22 February 2001, whichever is later."},"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":false,"description":"The Directive imposes a targeted, one‑time inspection for the identified fuselage area on all F28 Mk.1000–4000 aircraft; it does not expand ongoing monitoring, operational limits, or certification conditions. Applicability, the single-action Requirement, and the specified Compliance window set the intervention's scope (Applicability; Requirement; Compliance)."},"complexity_factors":["Technical inspection method and location require specialist non-routine maintenance capability (Requirement; Background).","Dependence on an external service document for the inspection procedure creates an implementation dependency outside the AD text (Requirement: Fokker Service Bulletin F28/53-148).","The compliance timing formula ('before accumulating 30,000 total flight cycles since new, or within 12 months after 22 February 2001, whichever occurs later') requires operators to verify historical flight-cycle records (Compliance).","Broad applicability to all serial numbers across multiple model variants increases the number of affected aircraft and administrative burden (Applicability).","Use of technical terms and structural references (STA coordinates, bonded doubler, stringer numbering) requires engineering interpretation to locate and assess the defect (Background)."],"plain_english_summary":"This Airworthiness Directive requires operators of Fokker F28 Mk.1000–4000 aircraft to carry out a one‑time eddy‑current inspection of the fuselage skin at the specified stringer area in accordance with Fokker Service Bulletin F28/53‑148. Compliance must occur before an aircraft reaches 30,000 total flight cycles since new, or within 12 months after 22 February 2001, whichever is later. The inspection targets a crack found in a bonded doubler that likely began at a production scratch."}},"importantCases":[],"_links":{"self":"/api/acts/ad-f28-86-fuselage-butt-joint-at-stringers-27-48","history":"/api/acts/ad-f28-86-fuselage-butt-joint-at-stringers-27-48/history","analysis":"/api/acts/ad-f28-86-fuselage-butt-joint-at-stringers-27-48/analysis","conflicts":"/api/acts/ad-f28-86-fuselage-butt-joint-at-stringers-27-48/conflicts","importantCases":"/api/acts/ad-f28-86-fuselage-butt-joint-at-stringers-27-48/important-cases","documents":"/api/acts/ad-f28-86-fuselage-butt-joint-at-stringers-27-48/documents"}}