{"id":"F2006B04755","name":"AD/BN-2/44 - Main Undercarriage Leg - Conversion","slug":"ad-bn-2-44-main-undercarriage-leg-conversion","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":44519,"registerId":"commonwealth-F2006B04755-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/BN-2/44 - Main Undercarriage Leg - Conversion","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)  Pilatus Britten-Norman BN-2 Series Aeroplanes\n\n \n\nAD/BN-2/44 Main Undercarriage Leg - Conversion 1/80\n\nApplicability: All models.\n\n \n\nDocument: 1. Britten Norman SB No. BN-2/SB.134; and\n\n \n\n2. A.P. Precision Hydraulics SB No. 32-277. Compliance: Before 1 June 1980.\n\nBackground: A number of undercarriage leg assemblies P/N AIR83002 not cleared for installation on BN-2A aircraft must be converted to the original design standard in accordance with the referenced Service Bulletin. Failure to promptly carry out the conversion may result in transmission of higher than normal landing loads to the airframe.\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’s scope is limited and consistent with its stated purpose: it applies to all BN‑2 models and requires conversion of specific undercarriage leg assemblies (P/N AIR83002) using the referenced Service Bulletins, to be completed by a set date. There is no textual indication in the instrument that it expands or narrows scope beyond that original corrective objective (Applicability; Background; Documents; Compliance)."},"complexity_factors":["Clear, narrow technical requirement (convert P/N AIR83002 legs to original design) reduces legal complexity (Background)","Fixed, early compliance deadline creates urgency but not regulatory layering (Compliance)","Single aircraft family scope (all BN‑2 models) keeps applicability simple (Applicability)","Reliance on two external Service Bulletins for the technical method requires maintenance organisations to follow and interpret separate technical documents (Documents)","Some operational complexity in execution: locating affected parts, arranging modification work, managing aircraft downtime (Background; Compliance)"],"plain_english_summary":"What this directive does (mechanical change)\n\n- Requires conversion of certain main undercarriage leg assemblies (part number P/N AIR83002) to the original design standard using the procedures set out in two manufacturer/service documents. (Background; Documents)\n- Sets a firm completion deadline for that conversion: before 1 June 1980. (Compliance)\n\nWho is affected\n\n- Applies to all Pilatus Britten‑Norman BN‑2 series aeroplanes. Operators of those aircraft must ensure any affected undercarriage legs are converted. (Applicability; Background)\n\nWhy the change is required (stated purpose)\n\n- The directive states the conversion is needed because some AIR83002 undercarriage leg assemblies are not cleared for installation on BN‑2A aircraft, and, if not converted, may transmit higher‑than‑normal landing loads to the airframe. The referenced Service Bulletins give the required conversion method. (Background; Documents)\n\nWho decides and who carries out work\n\n- The Civil Aviation Safety Authority issued this airworthiness directive (header). The conversion must be done in accordance with the Britten Norman and A.P. Precision Hydraulics Service Bulletins listed in the directive. That fixes the method to be followed. (header; Documents; Background)\n\nPractical effects, incentives and costs\n\n- Operators (aircraft owners/operators) will need to identify any installed AIR83002 legs and arrange for their conversion to the original design standard before the compliance date. This will create direct costs: labour, parts or modification work, and aircraft downtime while the conversion is performed. (Applicability; Background; Compliance)\n- The directive reduces the operator’s exposure to the risk described (higher landing loads being transmitted to the airframe) by requiring the conversion method specified in the Service Bulletins. Compliance therefore trades immediate modification costs and downtime for a reduced risk of the stated structural loading issue. (Background; Documents)\n\nCompliance and implementation notes\n\n- The directive is prescriptive about the method: conversion must follow the referenced Service Bulletins (Britten Norman SB No. BN‑2/SB.134 and A.P. Precision Hydraulics SB No. 32‑277). That limits technical discretion; operators and maintenance organisations must follow those procedures. (Documents; Background)\n- Failure to complete the conversion by the stated date is implied to leave the aircraft subject to the stated loading risk; the directive sets a deadline rather than a recurring inspection regime. (Compliance; Background)\n\nTrade‑offs, administration and risk\n\n- The conversion centralises the technical solution in the two referenced Service Bulletins; this simplifies enforcement (one defined method) but concentrates dependence on those documents for correct workmanship. (Documents)\n- The cost of compliance will be borne by operators in the short term; the directive’s stated benefit is reducing the risk of excess landing loads being transmitted to the airframe. The directive does not itself state how compliance will be verified or enforced beyond setting the conversion requirement and deadline. (Compliance; Background)"},"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This is a discrete, time-bound safety directive with a narrow technical scope (specific part number on specific aircraft type). It has not expanded beyond its original purpose of mandating a specific mechanical conversion."},"complexity_factors":["Very short document (approximately 150 words)","Only 2 defined references (the Service Bulletins)","Single, unambiguous compliance deadline","No nested conditions or exceptions","No cross-references to other legislation or regulations beyond the parent Civil Aviation Regulations 1998","Straightforward applicability (all models)"],"plain_english_summary":"This is an **Airworthiness Directive** — a mandatory safety order issued by Australia's Civil Aviation Safety Authority (CASA) for aircraft.\n\n**What it does:**\nOrders owners and operators of **Pilatus Britten-Norman BN-2 series aircraft** (all models) to modify their main landing gear (undercarriage legs) before 1 June 1980.\n\n**The problem:**\nSome aircraft had undercarriage leg assemblies (part number AIR83002) installed that weren't actually approved for the BN-2A model. These need to be converted back to the original design standard.\n\n**Why it matters:**\nIf not fixed, these unapproved parts could transmit excessive landing forces into the airframe, potentially causing structural damage or failure.\n\n**What must be done:**\n- Follow the instructions in two specific Service Bulletins (technical repair notices from the manufacturer)\n- Complete the work before the deadline: **1 June 1980**\n\n**Who it affects:**\nAnyone operating or maintaining Pilatus Britten-Norman BN-2 aircraft in Australia."}},"importantCases":[],"_links":{"self":"/api/acts/ad-bn-2-44-main-undercarriage-leg-conversion","history":"/api/acts/ad-bn-2-44-main-undercarriage-leg-conversion/history","analysis":"/api/acts/ad-bn-2-44-main-undercarriage-leg-conversion/analysis","conflicts":"/api/acts/ad-bn-2-44-main-undercarriage-leg-conversion/conflicts","importantCases":"/api/acts/ad-bn-2-44-main-undercarriage-leg-conversion/important-cases","documents":"/api/acts/ad-bn-2-44-main-undercarriage-leg-conversion/documents"}}