{"id":"F2006B10173","name":"AD/GAF-N22/26 - Rudder Tab Mass Balance Hinge Pin - Inspection","slug":"ad-gaf-n22-26-rudder-tab-mass-balance-hinge-pin-inspection","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":55815,"registerId":"commonwealth-F2006B10173-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/GAF-N22/26 - Rudder Tab Mass Balance Hinge Pin - Inspection","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)  GAF N22 and N24 Series Aeroplanes\n\n \n\nAD/GAF-N22/26 Rudder Tab Mass Balance Hinge Pin - Inspection\n\n\n5/79\n\n \n\nApplicability: All models N22, N22B, N24 and N24A with Mod. N39 fitted and delivered before 1 March 1979.\n\n \n\nDocument: GAF Alert SB No. ANMD-55-6.\n\n \n\nCompliance: Within 50 hours time in service after 16 March 1979 and thereafter at intervals not exceeding 100 hours time in service until modified in accordance with Alert SB No. ANMD-55-6.\n\n \n\nBackground:  An instance has occurred where the rudder tab mass balance hinge pin seized in its bush and sheared the split pin retaining the hinge pin.\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":{"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":false,"description":"The directive maintains a limited scope: it applies only to GAF N22, N22B, N24 and N24A aeroplanes with Mod. N39 fitted that were delivered before 1 March 1979. It requires inspections at specified intervals until the identified modification in Alert SB ANMD-55-6 is completed. No expansion or narrowing of the stated applicability or requirements is indicated in the provided text."},"complexity_factors":["Narrow technical scope limited to specific aircraft models and a specific modification (Mod. N39) (Applicability).","Cross-reference to an external service bulletin for required inspection/modification procedures (Document).","Mandatory time-based compliance intervals (initial 50 hours after 16 March 1979, then every 100 hours) creating recurring operational scheduling requirements (Compliance).","Safety-critical mechanical failure mode described (seizure and split-pin shearing) requiring practical inspection actions (Background).","Concentrated affected population (older aircraft) which simplifies targeting but creates concentrated compliance load (Applicability)."],"plain_english_summary":"This directive requires owners/operators of GAF N22/N22B/N24/N24A aeroplanes with Mod. N39 (delivered before 1 Mar 1979) to inspect the rudder-tab mass-balance hinge pin per GAF Alert SB ANMD‑55‑6, starting within 50 flight hours from 16 Mar 1979 and then at intervals not exceeding 100 hours until the SB modification is applied. \n\nIt addresses a seized‑pin/split‑pin failure risk, shifts inspection/modification costs to operators, and is enforced by CASA to eliminate the recurring inspection once the SB modification is completed."},"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This is a discrete, targeted safety directive addressing a specific mechanical defect in specific aircraft. It has not expanded beyond its original purpose of ensuring rudder tab hinge pin integrity in affected GAF aircraft models."},"complexity_factors":["Very short document (approximately 150 words)","Only 4 defined applicability criteria (aircraft models, modification status, delivery date)","Single compliance pathway with clear time intervals","No cross-references to other legislation or regulations beyond the parent Civil Aviation Regulations 1998","No conditional logic or exceptions — straightforward mandatory inspection requirement","Single technical reference document (GAF Alert SB No. ANMD-55-6)"],"plain_english_summary":"This is an **Airworthiness Directive** — a mandatory safety order issued by Australia's Civil Aviation Safety Authority (CASA). It requires owners and operators of specific GAF aircraft models to inspect a particular part of the plane's rudder (the moving surface on the tail that helps steer the aircraft).\n\n**What it does:**\n- **Targets:** GAF N22, N22B, N24, and N24A aircraft that have a specific modification (Mod. N39) and were delivered before 1 March 1979.\n- **The problem:** The hinge pin that holds the rudder tab's mass balance (a weight that prevents dangerous vibrations) can seize up in its bush (a sleeve or bearing). This caused at least one incident where the retaining split pin sheared off.\n- **What must be done:** Operators must inspect this hinge pin within 50 flight hours after 16 March 1979, then repeat the inspection every 100 flight hours until the aircraft is modified according to the manufacturer's Alert Service Bulletin ANMD-55-6.\n\n**Why it matters:** A seized or failed hinge pin could cause the rudder tab to malfunction, potentially leading to loss of control or structural damage in flight. This directive prevents accidents by catching the problem before it causes failure."}},"importantCases":[],"_links":{"self":"/api/acts/ad-gaf-n22-26-rudder-tab-mass-balance-hinge-pin-inspection","history":"/api/acts/ad-gaf-n22-26-rudder-tab-mass-balance-hinge-pin-inspection/history","analysis":"/api/acts/ad-gaf-n22-26-rudder-tab-mass-balance-hinge-pin-inspection/analysis","conflicts":"/api/acts/ad-gaf-n22-26-rudder-tab-mass-balance-hinge-pin-inspection/conflicts","importantCases":"/api/acts/ad-gaf-n22-26-rudder-tab-mass-balance-hinge-pin-inspection/important-cases","documents":"/api/acts/ad-gaf-n22-26-rudder-tab-mass-balance-hinge-pin-inspection/documents"}}