{"id":"F2006B04777","name":"AD/BN-2/65 - NLG Leg Cylinder Bearing Surfaces","slug":"ad-bn-2-65-nlg-leg-cylinder-bearing-surfaces","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":44553,"registerId":"commonwealth-F2006B04777-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/BN-2/65 - NLG Leg Cylinder Bearing Surfaces","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)  \nPilatus Britten-Norman BN-2 Series Aeroplanes\n\nAD/BN-2/65 NLG Leg Cylinder Bearing Surfaces 5/99\n\nApplicability: Model BN2, BN2A, BN2B, and BN2T Islander aircraft.\n\nRequirement: Action in accordance with Britten Norman Mandatory Service Bulletin BN2/SB.249.\n\nNote: FHL Service Bulletin 32-19 Issue 1 refers.\n\nCompliance: Before further flight if stiffness or restriction is found in the function of the rudder and nose wheel steering system, or at the next 100 hour inspection, whichever event occurs first.\n\nThis Airworthiness Directive becomes effective on 20 May 1999.\n\nBackground: There has been an occurrence where the chrome plating, added by the embodiment of Repair FHR2067 to either or both of the upper and lower bearing surfaces of the cylinder assembly Part No 61757, has delaminated causing stiffness in the operation of the rudder and nose wheel steering.","sortOrder":0}],"analysis":{"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":false,"description":"The AD is narrowly targeted to address a specific failure mode (delamination of chrome plating on cylinder assembly Part No. 61757) affecting a defined set of BN‑2 series models. It requires operators to follow a named mandatory service bulletin and sets conditional timing for compliance. The directive does not broaden applicability beyond those models or introduce new regulatory powers; it prescribes corrective action for a stated, identified defect."},"complexity_factors":["Limited number of affected aircraft models (BN2, BN2A, BN2B, BN2T) narrows technical scope (Applicability).","Key technical detail (what to do) is delegated to an external document (Britten Norman Mandatory Service Bulletin BN2/SB.249), increasing reliance on another source for procedural specifics (Requirement).","Conditional compliance timing (before next flight if stiffness is found, otherwise at next 100‑hour inspection) adds a simple decision branch for operators (Compliance).","Specific part and repair references (Part No. 61757; Repair FHR2067) make the AD narrowly targeted but require accurate maintenance records to identify affected items (Background).","Cross-reference to an additional service bulletin (FHL Service Bulletin 32‑19 Issue 1) adds a minor layer of documentary complexity (Requirement — Note)."],"plain_english_summary":"Operators of Pilatus Britten‑Norman Islander BN2/BN2A/BN2B/BN2T aircraft must carry out the work in Britten Norman Mandatory Service Bulletin BN2/SB.249 to inspect and, if needed, repair cylinder assembly Part No. 61757 bearing surfaces after reported chrome‑plating delamination that can cause rudder and nose‑wheel steering stiffness.\n\nIf stiffness is found the work is required before the next flight; if not, complete it at the next 100‑hour inspection. Costs and downtime fall to the aircraft owners/operators."},"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 a specific aircraft type. It has not expanded beyond its original purpose of mandating inspection/repair of nose landing gear bearing surfaces."},"complexity_factors":["Very short document (under 200 words)","Only 1 defined term implicitly referenced (FHL Service Bulletin)","Single, clear compliance trigger (stiffness found OR next 100-hour inspection)","No nested exceptions or conditional logic","Straightforward cross-reference to single external technical document (Britten Norman Mandatory Service Bulletin BN2/SB.249)","Narrow applicability (4 specific aircraft models only)"],"plain_english_summary":"This is a **safety order for specific aircraft**.\n\n**What it does:**\nThis document is an **Airworthiness Directive (AD)** — a mandatory safety instruction issued by Australia's Civil Aviation Safety Authority (CASA). It requires owners and operators of certain **Pilatus Britten-Norman Islander aircraft** (models BN2, BN2A, BN2B, and BN2T) to inspect and potentially repair the nose landing gear (NLG).\n\n**The problem:**\nThe chrome plating on bearing surfaces in the nose landing gear cylinder can **peel off (delaminate)**. This causes the rudder and nose wheel steering to become stiff or restricted — a serious safety risk during takeoff, landing, and taxiing.\n\n**What must be done:**\n- **Immediately** if pilots notice stiffness or restriction in the rudder or nose wheel steering, **or**\n- **At the next routine 100-hour maintenance inspection** (whichever comes first)\n\nThe work must follow the manufacturer's specific instructions in **Service Bulletin BN2/SB.249**.\n\n**Who it affects:**\n- Owners and operators of BN-2 series Islander aircraft\n- Licensed aircraft maintenance engineers\n- Flying schools, charter operators, and private owners using these aircraft\n\n**Why it matters:**\nSteering problems on the ground can lead to runway excursions, loss of directional control, or accidents during critical flight phases. This directive prevents accidents by catching a known manufacturing defect before it causes system failure."}},"importantCases":[],"_links":{"self":"/api/acts/ad-bn-2-65-nlg-leg-cylinder-bearing-surfaces","history":"/api/acts/ad-bn-2-65-nlg-leg-cylinder-bearing-surfaces/history","analysis":"/api/acts/ad-bn-2-65-nlg-leg-cylinder-bearing-surfaces/analysis","conflicts":"/api/acts/ad-bn-2-65-nlg-leg-cylinder-bearing-surfaces/conflicts","importantCases":"/api/acts/ad-bn-2-65-nlg-leg-cylinder-bearing-surfaces/important-cases","documents":"/api/acts/ad-bn-2-65-nlg-leg-cylinder-bearing-surfaces/documents"}}