{"id":"F2006B04784","name":"AD/BN-2/71 Amdt 4 - Main Landing Gear Oleo Attachment Bracket","slug":"ad-bn-2-71-amdt-4-main-landing-gear-oleo-attachment-bracket","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":44564,"registerId":"commonwealth-F2006B04784-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/BN-2/71 Amdt 4 - Main Landing Gear Oleo Attachment Bracket","content":"COMMONWEALTH OF AUSTRALIA (Civil Aviation Safety Regulations 1998), PART 39 \\- 105 CIVIL AVIATION SAFETY AUTHORITY\n\nSCHEDULE OF AIRWORTHINESS DIRECTIVES\n\n![](image.001.png)  \n\nAIRWORTHINESS DIRECTIVE\n\n![](image.001.png)\n\nFor the reasons set out in the background section, the CASA delegate whose signature appears below revokes Airworthiness Directive (AD) AD/BN-2/71 Amdt 3 and issues the following AD under subregulation 39.1 (1) of CASR 1998. The AD requires that the action set out in the requirement section (being action that the delegate considers necessary to correct the unsafe condition) be taken in relation to the aircraft or aeronautical product mentioned in the applicability section: (a) in the circumstances mentioned in the requirement section; and (b) in accordance with the instructions set out in the requirement section; and (c) at the time mentioned in the compliance section.\n\n![](image.001.png)  \n\nPilatus Britten-Norman BN-2 Series Aeroplanes\n\nAD/BN-2/71\n\nAmdt 4\n\n  \nMain Landing Gear Oleo Attachment Bracket 7/2004\n\nApplicability: All BN-2, BN2A, BN2B, BN2T, BN2T-4R, and BN2T-4S Islander aircraft. Requirement: Inspect in accordance with B-N Group Ltd. Mandatory Service Bulletin No. 273\n\nIssue 5.\n\nNote: UK CAA AD 005-09-2000 refers.\n\nCompliance: As specified in the Requirement document.\n\nThis Amendment becomes effective on 8 July 2004.\n\nBackground: Several operators reported cracking of the Oleo Attachment Bracket NB-40-0075. If cracking is not detected early, failure of the bracket can occur which could result in detachment of the main landing gear.\n\nAmendment 1 expanded the repeat inspection interval.\n\nAmendment 2 introduced a steel oleo attachment bracket as terminating action for the repeat inspection requirement.\n\nAmendment 3 introduced Mod. NB-M-1712, which embodies an improved fitting for the main landing gear.\n\nAmendment 4 is issued in response to Issue 5 of the Requirement document, which introduces a note to the compliance statement.\n\n![](image.002.png)  \n\nDavid Villiers\n\nDelegate of the Civil Aviation Safety Authority 26 May 2004\n\n![](image.001.png)\n\nThe above AD is notified in the Commonwealth of Australia Gazette on 16 June 2004.\n\n  \n\nPage 1 of 1","sortOrder":0}],"analysis":{"flash_summary_failed":{"failed":true,"reason":"Unauthenticated. Configure AI_GATEWAY_API_KEY or use a provider module. Learn more: https://ai-sdk.dev/unauthenticated-ai-gateway","source":"analysis-cron"},"flash_summary":{"complexity_score":5,"scope_assessment":{"changed":false,"description":"Amendment 4 does not expand or narrow the applicability or the inspection requirement; it revokes Amdt 3 and issues Amdt 4 to incorporate Issue 5 of the Mandatory Service Bulletin by adding a note to the compliance statement. Previously introduced options (steel replacement bracket; Mod NB‑M‑1712) and the requirement to inspect per the Service Bulletin remain in effect."},"complexity_factors":["Cross‑reference to an external Mandatory Service Bulletin (B-N Group No.273 Issue 5) for the substantive inspection procedure and compliance timing — requires operators to obtain and interpret another document.","Multiple aircraft variants nominated in applicability (BN-2 family) — requires fleet-wide identification and tracking.","Amendment history (Amdt 1–3) and revocation of the prior amendment — requires readers to track prior changes (inspection intervals, terminating actions, Mod NB-M-1712) to understand current obligations.","Terminating actions exist (steel bracket, Mod NB‑M‑1712) introduced in earlier amendments — creates choice for operators between ongoing inspections or one‑off modification costs.","Compliance statement refers to Issue 5 changes (Amdt 4 adds a note) rather than altering required actions — minor textual change but increases need to compare issues/editions.","Safety consequence is mechanical failure risk (gear detachment) — requires timely maintenance scheduling and potential parts procurement.","Regulatory discretion is exercised by the CASA delegate under CASR subregulation 39.1(1) — formal legal authority but limited procedural detail in the AD itself."],"plain_english_summary":"Mechanically, this AD requires operators of all Pilatus Britten‑Norman BN‑2 Islander variants to inspect the main landing gear oleo attachment bracket in line with B‑N Group Mandatory Service Bulletin No.273 Issue 5, with timing set in that document. CASA issues the directive because reported cracking can lead to bracket failure and possible main‑gear detachment; operators and maintenance organisations pay for inspections and any repairs, while previously published modifications (a steel bracket or Mod NB‑M‑1712) can be used to end repetitive inspections."},"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This Airworthiness Directive maintains its original scope. It has always been focused on addressing the unsafe condition of the main landing gear oleo attachment bracket in BN-2 series aircraft. The four amendments have refined the technical requirements (inspection intervals, terminating actions, improved parts, and documentation notes) without expanding beyond the original safety purpose."},"complexity_factors":["Single, clearly defined applicability (specific aircraft models)","Single requirement referencing an external technical document (Service Bulletin)","No defined terms section","No nested conditional logic or exceptions","Straightforward compliance timing ('as specified in the Requirement document')","Brief background with clear safety rationale","Document is 1 page with minimal cross-referencing"],"plain_english_summary":"This safety order replaces Amendment 3 with Amendment 4 and requires owners/operators of Pilatus Britten-Norman Islander models (BN-2, BN2A, BN2B, BN2T, BN2T-4R, BN2T-4S) to inspect the oleo attachment bracket per Britten‑Norman Mandatory Service Bulletin No. 273 Issue 5.  \n\nCracks have been found in the bracket; if undetected it can fail and allow the main landing gear to detach during landing. Amendment 4 adds a compliance-note to the service bulletin."}},"importantCases":[],"_links":{"self":"/api/acts/ad-bn-2-71-amdt-4-main-landing-gear-oleo-attachment-bracket","history":"/api/acts/ad-bn-2-71-amdt-4-main-landing-gear-oleo-attachment-bracket/history","analysis":"/api/acts/ad-bn-2-71-amdt-4-main-landing-gear-oleo-attachment-bracket/analysis","conflicts":"/api/acts/ad-bn-2-71-amdt-4-main-landing-gear-oleo-attachment-bracket/conflicts","importantCases":"/api/acts/ad-bn-2-71-amdt-4-main-landing-gear-oleo-attachment-bracket/important-cases","documents":"/api/acts/ad-bn-2-71-amdt-4-main-landing-gear-oleo-attachment-bracket/documents"}}