{"id":"F2006B04765","name":"AD/BN-2/53 Amdt 2 - Primary Structure Corrosion","slug":"ad-bn-2-53-amdt-2-primary-structure-corrosion","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":44529,"registerId":"commonwealth-F2006B04765-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/BN-2/53 Amdt 2 - Primary Structure Corrosion","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-2/53\n\nAmdt 2\n\n  \nPrimary Structure Corrosion 4/98\n\nApplicability: All models BN-2 Series Islanders, and BN2T Turbine Islanders.\n\nRequirement: Action in accordance with Pilatus Britten-Norman Mandatory Service Bulletin BN- 2/SB.190 Issue 3.\n\nNote: UK CAA AD 020-02-90 refers.\n\nCompliance: As specified in the requirement document\n\nThe compliance periods of the previous issue of this Directive remain unchanged. This amendment becomes effective on 26 March 1998.\n\nBackground: The manufacturer has determined that the recommended inspections had only been partially successful in controlling major corrosion.\n\nAmendment 1 provided additional information and actions, and incorporated the active parts of earlier service bulletins for the purpose of centralising all effective information relating to corrosion.\n\nAmendment 2 is issued in response to Issue 3 of the requirement document which gives clearer inspection and repair procedures for corrosion control.\n\nAmendment 1 of this airworthiness directive became effective on 4 March 1993.\n\nThe original issue of this airworthiness directive became effective on 30 March 1990.","sortOrder":0}],"analysis":{"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This amendment stays within the original scope of addressing primary structure corrosion in BN-2 aircraft. Amendment 2 simply updates the technical reference to a clearer version of the manufacturer's service bulletin (Issue 3). The scope has not expanded beyond corrosion control for this specific aircraft type."},"complexity_factors":["Very short document (under 300 words)","Only 1 defined applicability criterion (aircraft model series)","Single requirement referencing an external technical document (the Service Bulletin)","No nested conditional logic or exceptions","No cross-references to other legislation beyond a note about a UK aviation directive","Straightforward compliance timeline (inherits previous deadlines)"],"plain_english_summary":"This CASA Airworthiness Directive requires owners, operators and maintainers of Pilatus Britten‑Norman BN‑2 (including BN2T) Islanders to follow Mandatory Service Bulletin BN‑2/SB.190 Issue 3 to inspect for, repair and control corrosion in the aircraft’s primary structure. Corrosion can cause structural failure; previous compliance deadlines remain and the AD took effect 26 March 1998."},"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":false,"description":"Amendment 2 does not expand applicability or change compliance periods. It replaces the requirement document with Issue 3 of the manufacturer’s service bulletin to provide clearer inspection and repair procedures, so the scope remains focused on corrosion control for the same fleet."},"complexity_factors":["Applicability is clear (all BN‑2 Series and BN2T) — low scope ambiguity.","Normative reliance on an external document (Mandatory Service Bulletin BN‑2/SB.190 Issue 3) — requires operators to obtain and interpret the SB.","Chain of prior ADs and service bulletins referenced (original AD, Amendment 1) — necessitates consulting historical material to confirm unchanged compliance periods.","Technical content and repair methods are delegated to the manufacturer’s SB — technical complexity sits with maintenance organisations.","Compliance enforcement and effective date are fixed in the AD — limited administrative discretion for regulators.","Cross‑reference to UK CAA AD 020‑02‑90 indicates parallel international material to consider."],"plain_english_summary":"This airworthiness directive requires owners/operators of all Pilatus Britten‑Norman BN‑2 Series Islanders (including BN2T Turbine Islanders) to carry out inspections and repairs for primary‑structure corrosion in accordance with Pilatus Britten‑Norman Mandatory Service Bulletin BN‑2/SB.190 Issue 3. Compliance follows the service bulletin’s schedules; previous compliance periods remain unchanged and the AD took effect 26 March 1998.\n\nOperators pay for the inspections/repairs and must adopt the SB’s clarified inspection and repair procedures after the manufacturer found earlier measures were only partially successful."}},"importantCases":[],"_links":{"self":"/api/acts/ad-bn-2-53-amdt-2-primary-structure-corrosion","history":"/api/acts/ad-bn-2-53-amdt-2-primary-structure-corrosion/history","analysis":"/api/acts/ad-bn-2-53-amdt-2-primary-structure-corrosion/analysis","conflicts":"/api/acts/ad-bn-2-53-amdt-2-primary-structure-corrosion/conflicts","importantCases":"/api/acts/ad-bn-2-53-amdt-2-primary-structure-corrosion/important-cases","documents":"/api/acts/ad-bn-2-53-amdt-2-primary-structure-corrosion/documents"}}