{"id":"F2006B09687","name":"AD/F27/120 - Inner/Outer Wing Joint Stringer Coupling Rods","slug":"ad-f27-120-inner-outer-wing-joint-stringer-coupling-rods","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":115837,"registerId":"commonwealth-F2006B09687-current","compilationNumber":null,"startDate":"2026-04-03","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/F27/120 - Inner/Outer Wing Joint Stringer Coupling Rods","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)  Fokker F27 Series Aeroplanes\n\n \n\nAD/F27/120 Inner/Outer Wing Joint Stringer Coupling Rods 7/90\n\nApplicability: F27 models with serial numbers 10102, and 10105 to 10624 inclusive. Requirement:  Action in accordance with Fokker SB F27/57-64 Rev 1, Parts 1, 2 and 3.\n\nNote: Netherlands AD BLA 89-148 Issue 2 refers.\n\n \n\nCompliance: For Part 1: Prior to 31 October 1990. Parts 2 and 3 in accordance with the Requirement Document.\n\n \n\nBackground: Country of origin AD. Stress corrosion cracking can occur in the coupling rods.\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\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":{"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This is a discrete, single-issue airworthiness directive focused on a specific structural defect in a specific aircraft model. It has not expanded beyond its original safety purpose."},"complexity_factors":["Very short document (approximately 150 words)","Only 1 defined applicability criterion (specific serial number range)","Single cross-reference to manufacturer service bulletin and Netherlands AD","No nested conditional logic or exceptions","Straightforward compliance deadline structure","Technical content assumes aviation engineering knowledge but legislative structure is simple"],"plain_english_summary":"This is an **Airworthiness Directive (AD)** — essentially a mandatory safety notice issued by Australia's Civil Aviation Safety Authority (CASA) for aircraft.\n\n**What it does:**\nOrders owners and operators of specific **Fokker F27 aircraft** to inspect and fix a structural problem in the wing joints. The issue involves \"coupling rods\" — metal components that connect parts of the wing — which can develop **stress corrosion cracking** (tiny cracks caused by a combination of tension and chemical corrosion that can weaken the metal over time).\n\n**Who it affects:**\n- Owners and operators of Fokker F27 aeroplanes with serial numbers **10102, and 10105 through to 10624**\n- Maintenance engineers working on these aircraft\n\n**What must be done:**\nOperators must follow a specific technical bulletin from the manufacturer (Fokker Service Bulletin F27/57-64 Revision 1) which has three parts:\n- **Part 1:** Must be completed before 31 October 1990\n- **Parts 2 and 3:** Must be done according to the timelines set out in the technical document\n\n**Why it matters:**\nStress corrosion cracking in wing structure components is serious — if left unchecked, it could lead to structural failure in flight. This directive ensures potentially dangerous aircraft are identified and repaired before they become unsafe."},"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":false,"description":"The AD's scope is limited to specified Fokker F27 serial numbers and requires actions as set out in the manufacturer's Service Bulletin. The text references the country-of-origin AD but does not expand or narrow the set of affected aircraft beyond the serial numbers listed, so there is no change in scope apparent within this instrument (Applicability; Requirement; Note)."},"complexity_factors":["Narrow, serial-numbered applicability reduces scope but requires precise fleet identification (Applicability).","Substantive technical and procedural detail is delegated to an external manufacturer Service Bulletin, requiring operators to consult that document (Requirement).","Compliance timing is split (Part 1 with a fixed deadline; Parts 2 and 3 tied to SB instructions), adding scheduling complexity (Compliance).","Technical subject (stress corrosion cracking) requires specialised inspection and repair competence, implying reliance on specialised maintenance providers (Background; Requirement).","Reference to a foreign (Netherlands) AD as related material implies cross-jurisdictional alignment that operators may need to review (Note)."],"plain_english_summary":"This directive requires owners/operators of specified serial‑numbered Fokker F27 aircraft to perform inspections, repairs or replacements set out in Fokker Service Bulletin F27/57‑64 Rev 1 (with Part 1 done by 31 Oct 1990 and Parts 2–3 per the SB) to address stress‑corrosion cracking in wing joint coupling rods. Compliance costs, downtime and scheduling burdens fall to those operators, who must follow the manufacturer’s bulletin for technical details and timing."}},"importantCases":[],"_links":{"self":"/api/acts/ad-f27-120-inner-outer-wing-joint-stringer-coupling-rods","history":"/api/acts/ad-f27-120-inner-outer-wing-joint-stringer-coupling-rods/history","analysis":"/api/acts/ad-f27-120-inner-outer-wing-joint-stringer-coupling-rods/analysis","conflicts":"/api/acts/ad-f27-120-inner-outer-wing-joint-stringer-coupling-rods/conflicts","importantCases":"/api/acts/ad-f27-120-inner-outer-wing-joint-stringer-coupling-rods/important-cases","documents":"/api/acts/ad-f27-120-inner-outer-wing-joint-stringer-coupling-rods/documents"}}