{"id":"F2005L02424","name":"AD/BAe 146/91 Amdt 3 - Flap Structure and Machined Ribs","slug":"ad-bae-146-91-amdt-3-flap-structure-and-machined-ribs","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":36965,"registerId":"commonwealth-F2005L02424-current","compilationNumber":null,"startDate":"2026-04-01","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"British Aerospace BAe 146 Series Aeropla","sectionType":"division","heading":"British Aerospace BAe 146 Series Aeroplanes","content":"### British Aerospace BAe 146 Series Aeroplanes\n\n| AD/BAe 146/91 Amdt 3 | Flap Structure and Machined Ribs | 10/2005 |\n| -------------------- | -------------------------------- | ------- |\n\n| Applicability: | All Models BAe 146 and AVRO RJ series aircraft.                                                                                                                                                                                                                                                                                                                                                                                             |\n| -------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |\n| Requirement:   | Inspect in accordance with BAE Systems Service Bulletin ISB. 57-066 Revision 2, or later EASA approved revision.Note: UK CAA AD G-2005-0018 refers.                                                                                                                                                                                                                                                                                         |\n| Compliance:    | As specified in the Requirement document.                                                                                                                                                                                                                                                                                                                                                                                                   |\n|                | This Amendment becomes effective on 29 September 2005.                                                                                                                                                                                                                                                                                                                                                                                      |\n| Background:    | Evidence of corrosion has been found at various locations within the flap structure and machined ribs.Amendment 1 amended an Appendix 1 Procedure instruction.Amendment 2 introduced the latest revision of the Requirement document.Amendment 3 is issued to introduce a new CAA AD issue, with no change to the technical content of this Directive.The original issue of this Airworthiness Directive became effective on 9 August 2001. |\n\n![](image.001.png)  \nDavid Villiers  \nDelegate of the Civil Aviation Safety Authority\n\n9 August 2005","sortOrder":0},{"sectionNumber":"AD/BAe 146/91 Amdt 3","sectionType":"part","heading":"AD/BAe 146/91 Amdt 3","content":"## AD/BAe 146/91 Amdt 3","sortOrder":1},{"sectionNumber":"Flap Structure and Machined Ribs","sectionType":"part","heading":"Flap Structure and Machined Ribs","content":"## Flap Structure and Machined Ribs","sortOrder":2},{"sectionNumber":"10/2005","sectionType":"part","heading":"10/2005","content":"## 10/2005","sortOrder":3}],"analysis":{"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This amendment explicitly states it introduces 'no change to the technical content of this Directive.' It is purely administrative — updating the reference to match a new UK CAA AD issue. The scope remains limited to corrosion inspection of flap structures on BAe 146/AVRO RJ aircraft, unchanged since the original 2001 issue."},"complexity_factors":["Very short document (under 300 words)","Only 1 substantive requirement (inspect per specified service bulletin)","No defined terms section","No nested conditional logic or exceptions","Single cross-reference to external technical document (BAE Systems Service Bulletin)","Administrative amendment only — no new technical content"],"plain_english_summary":"This CASA Airworthiness Directive mandates inspection of flap structure and machined ribs for corrosion on BAe 146 and AVRO RJ series aircraft, following BAE Systems Service Bulletin ISB.57-066 Rev 2 (or later). It applies to Australian operators and maintenance organisations to prevent corrosion-related structural failure of critical flight controls.\n\nThis Amendment 3 only updates the administrative reference to align with a UK CAA directive; the technical inspection and corrective requirements are unchanged."},"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":false,"description":"Amendment 3 does not change the technical scope of the directive. It introduces a new CAA AD issue number but retains the same technical requirement: inspections of flap structure and machined ribs per BAE Systems Service Bulletin ISB.57-066 (or later EASA-approved revisions). The directive remains narrowly focused on corrosion inspection and corrective action for the BAe 146 / Avro RJ fleet."},"complexity_factors":["Short directive text (single mandatory requirement)","One primary external reference: BAE Systems Service Bulletin ISB.57-066 Rev 2 (or later EASA-approved revision)","Cross-reference to an externally controlled approval process (EASA approval of later revisions)","Administrative layering: original AD plus two prior amendments (Amendment 1 and 2) and this Amendment 3","No detailed inspection intervals, thresholds or procedures contained in the AD itself — those are delegated to the service bulletin"],"plain_english_summary":"**What this directive does (in simple terms)**\n\n- This Airworthiness Directive (AD) requires operators of BAe 146 / Avro RJ aircraft to inspect the flap structure and machined ribs for corrosion according to a specified BAE Systems service bulletin. (See \"Requirement\".)\n\n**Who is affected**\n\n- All owners and operators of BAe 146 and Avro RJ series aeroplanes (\"Applicability\").\n- Maintenance organisations and mechanics who perform the inspections and any required repairs.\n\n**How it works, mechanically**\n\n- The AD directs operators to carry out inspections in accordance with BAE Systems Service Bulletin ISB.57-066 Revision 2, or any later revision that has been approved by EASA (European Aviation Safety Agency) (\"Requirement\").\n- The AD has an effective date for compliance (this amendment became effective 29 September 2005) and refers operators to the service bulletin for the detailed inspection procedures and corrective actions (\"Compliance\" and \"Requirement\").\n\n**Why the AD was issued (stated purpose)**\n\n- The stated reason is that evidence of corrosion was found at various locations within the flap structure and machined ribs (\"Background\"). The inspections are intended to detect and allow repair of corrosion before it affects structural integrity.\n\n**What changed with this amendment**\n\n- Amendment 3 introduces a new Civil Aviation Authority (CAA) AD issue number but does not change the technical requirements of the directive. Earlier amendments updated procedural details and the referenced service bulletin revision (\"Background\").\n\n**Practical implications, costs and incentives**\n\n- Who pays: aircraft operators (airlines, lessors) pay for inspections, any required repairs, parts and labor, and for aircraft downtime while maintenance is performed. Maintenance organisations may also incur costs to obtain the service bulletin and train staff on the procedure.\n- Who decides: the regulator (Civil Aviation Safety Authority delegate) enforces the AD; BAE Systems provides the technical inspection procedure; EASA approval determines which later revisions are acceptable (\"Requirement\").\n- Behaviour change required: operators must adopt the inspection schedule and procedures in the specified service bulletin and carry out corrective work where corrosion is found.\n\n**Trade-offs and risks**\n\n- Trade-off: the AD imposes direct maintenance cost and downtime on operators in return for reduced risk of structural failure associated with corrosion. The directive delegates the technical detail to the BAE service bulletin (mechanism: mandatory reference).\n- Compliance burden: reliance on a manufacturer service bulletin and on EASA approval means operators must obtain and follow that external document; if the bulletin specifies complex inspections or specialised tooling, independent MROs (maintenance organisations) may incur additional setup costs.\n- Implementation risk: effectiveness depends on the thoroughness of the service bulletin and on timely compliance. The AD text does not reproduce inspection intervals or thresholds; those are in the service bulletin, so the AD’s practical clarity depends on that external document.\n\n**Effects on markets and private choice (brief, concrete)**\n\n- Competition and independent businesses: independent MROs can perform the work but must have access to the service bulletin and any specialised tooling or approvals the bulletin requires; this could create modest fixed costs for smaller shops.\n- Prices and productivity: operators face increased maintenance costs and potential short-term aircraft downtime which can affect productivity and unit costs; the AD does not alter ownership or operating rights.\n\n**Source references inside the AD text**\n- Applicability: \"All Models BAe 146 and AVRO RJ series aircraft.\" (Applicability)\n- Mandatory action: \"Inspect in accordance with BAE Systems Service Bulletin ISB.57-066 Revision 2, or later EASA approved revision.\" (Requirement)\n- Rationale/background: \"Evidence of corrosion has been found at various locations within the flap structure and machined ribs.\" (Background)\n- Administrative note: Amendment 3 introduces a new CAA AD issue with no change to technical content; original AD effective 9 August 2001; this amendment effective 29 September 2005. (Background / Compliance)\n\n\n"},"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"}},"importantCases":[],"_links":{"self":"/api/acts/ad-bae-146-91-amdt-3-flap-structure-and-machined-ribs","history":"/api/acts/ad-bae-146-91-amdt-3-flap-structure-and-machined-ribs/history","analysis":"/api/acts/ad-bae-146-91-amdt-3-flap-structure-and-machined-ribs/analysis","conflicts":"/api/acts/ad-bae-146-91-amdt-3-flap-structure-and-machined-ribs/conflicts","importantCases":"/api/acts/ad-bae-146-91-amdt-3-flap-structure-and-machined-ribs/important-cases","documents":"/api/acts/ad-bae-146-91-amdt-3-flap-structure-and-machined-ribs/documents"}}