{"id":"F2006B09894","name":"AD/F50/65 - Aileron Hinge Bolt and Spring-Tab Balance Unit","slug":"ad-f50-65-aileron-hinge-bolt-and-spring-tab-balance-unit","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":55045,"registerId":"commonwealth-F2006B09894-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/F50/65 - Aileron Hinge Bolt and Spring-Tab Balance Unit","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 F50 (F27 Mk 50) Series Aeroplanes\n\n \n\nAD/F50/65 Aileron Hinge Bolt and Spring-Tab Balance Unit 5/94\n\nApplicability: Model F27 Mk 050 Series aircraft, serial numbers 20103 through 20266, 20270\n\nthrough 20292, and 20294 through 20304.\n\n \n\nRequirement: Action in accordance with Fokker Service Bulletin F50-27-036.\n\n \n\nNote: RLD AD 94-025 (A) refers.\n\n \n\nCompliance: Prior to 1 July 1995.\n\n \n\nBackground: The RLD received two separate reports of damage to the ailerons of F50 aircraft, while the aircraft were parked in heavy and gusty tailwind conditions. In both cases, the wind force on the ailerons was sufficient to cause the failure of the gustlock mechanism of the spring tab balance units of both ailerons.\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":{"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":false,"description":"The directive applies only to the listed F27 Mk 050 serial numbers and requires action per the referenced Fokker service bulletin before the stated date. There is no text indicating an enlargement or narrowing of scope beyond those specified aircraft and the service-bulletin requirement."},"complexity_factors":["Narrow applicability to defined serial-number ranges reduces policy breadth but requires accurate aircraft identification (Applicability).","Mandates work by reference to an external technical document (Fokker Service Bulletin F50-27-036), so practical compliance depends on that document's technical detail and parts/labour needs (Requirement).","Fixed deadline for compliance creates a time-bound enforcement burden for operators (Compliance).","Safety-critical technical work implied by background incident reports increases need for qualified maintenance and verification (Background).","Cross-reference to another authority's directive (RLD AD 94-025 (A)) introduces coordination and possible duplicate-check obligations (Note)."],"plain_english_summary":"This airworthiness directive requires owners/operators of specific Fokker F27 Mk 050 series aircraft (listed serial numbers) to carry out the work described in Fokker Service Bulletin F50-27-036 to address the aileron hinge bolt and spring‑tab balance unit. Compliance had to be completed before 1 July 1995. The measure targets aircraft affected by reports of aileron damage when parked in heavy, gusty tailwinds; the immediate cost and work fall on the aircraft owners/operators who must follow the service bulletin."},"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This is a discrete, time-bound safety directive with a narrow, specific scope (particular serial numbers, particular component, particular failure mode). It has not expanded beyond its original purpose of addressing gustlock failures in parked F50 aircraft."},"complexity_factors":["Very short document (under 200 words)","Only 4 defined elements: applicability (serial number ranges), requirement (single reference to service bulletin), compliance date, and background","No nested conditional logic or exceptions","Single cross-reference to Fokker Service Bulletin and Dutch aviation authority (RLD) directive","Straightforward command structure: identify affected aircraft → specify required action → set deadline"],"plain_english_summary":"**What this is:** This is an Airworthiness Directive (AD) — a mandatory safety order issued by Australia's Civil Aviation Safety Authority (CASA). Think of it as a \"recall notice\" for aircraft, but legally binding.\n\n**What it does:** It requires owners and operators of specific Fokker F50 aircraft to inspect and fix a problem with the **aileron hinge bolts** and **spring-tab balance units** (parts that help control the plane's roll and stability).\n\n**Who it affects:** Only specific Fokker F50 planes — those with serial numbers 20103-20266, 20270-20292, and 20294-20304.\n\n**Why it matters:** Two aircraft suffered aileron damage while parked in strong, gusty tailwinds. The wind was so powerful it broke the \"gustlock\" mechanism (a device that locks control surfaces when the plane is on the ground). This could lead to control surface damage or failure, potentially affecting flight safety.\n\n**What must be done:** Operators must follow the instructions in **Fokker Service Bulletin F50-27-036** — a technical repair guide from the manufacturer — before **1 July 1995**.\n\n**Key point:** This is a **time-critical safety mandate**. Non-compliance means the aircraft cannot legally fly."}},"importantCases":[],"_links":{"self":"/api/acts/ad-f50-65-aileron-hinge-bolt-and-spring-tab-balance-unit","history":"/api/acts/ad-f50-65-aileron-hinge-bolt-and-spring-tab-balance-unit/history","analysis":"/api/acts/ad-f50-65-aileron-hinge-bolt-and-spring-tab-balance-unit/analysis","conflicts":"/api/acts/ad-f50-65-aileron-hinge-bolt-and-spring-tab-balance-unit/conflicts","importantCases":"/api/acts/ad-f50-65-aileron-hinge-bolt-and-spring-tab-balance-unit/important-cases","documents":"/api/acts/ad-f50-65-aileron-hinge-bolt-and-spring-tab-balance-unit/documents"}}