{"id":"F2006B03469","name":"AD/BAe 146/15 Amdt 1 - Additional Riveted Attachment - Stringer 21P","slug":"ad-bae-146-15-amdt-1-additional-riveted-attachment-stringer-21p","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":43023,"registerId":"commonwealth-F2006B03469-current","compilationNumber":null,"startDate":"2026-04-01","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/BAe 146/15 Amdt 1 - Additional Riveted Attachment - Stringer 21P","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)  \nBritish Aerospace BAe 146 Series Aeroplanes\n\nAD/BAe 146/15\n\nAmdt 1\n\n  \nAdditional Riveted Attachment \\- Stringer 21P 12/89\n\nDM\n\nApplicability: Series 200 and 200A: S/No. E2103, E2106, E2107, E2108, E2110, E2111, E2115\n\nand E2121.\n\nSeries 300 and 300A: S/No. E3120, E3122, E3123, E3126 and E3132.\n\nRequirement: Action in accordance with BAe S.B. 53-84-00737D Revision 1\\. Compliance: Prior to achieving 3000 flight cycles.\n\nBackground: On some aircraft stringer 21P which is attached to the lower L.H. skin panel has not been riveted at the end termination area adjacent to frame 39X. This S.B. introduces eight rivet positions to the stringer and termination area. Amendment 1 corrects original Service Bulletin number, and further references Revision 1 of the Service Bulletin, which adds an aircraft serial number to the applicable aircraft.","sortOrder":0}],"analysis":{"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":true,"description":"Amendment 1 altered the AD's scope and references by correcting the original Service Bulletin number and by referencing Revision 1 of the Service Bulletin, which added an aircraft serial number to the list of applicable aircraft. This change clarifies which serial numbers are covered and which exact Service Bulletin revision operators must follow. (Amendment 1)"},"complexity_factors":["Technical installation of eight rivet positions per BAe S.B. 53-84-00737D Revision 1 (Requirement; Background)","Limited applicability to a small set of specific serial numbers, requiring per-aircraft tracking (Applicability; Amendment 1)","Compliance deadline tied to flight cycles (must be done prior to 3000 flight cycles) requiring utilisation monitoring (Compliance)","Dependence on an external technical document (Service Bulletin) for the detailed procedure (Requirement)","Amendment that corrected the Service Bulletin reference and added a serial number creates a need to verify the correct SB revision before performing work (Amendment 1)"],"plain_english_summary":"What this instrument changes, mechanically\n\n- This Airworthiness Directive (AD) requires installation of an additional riveted attachment at the termination area of stringer 21P on certain British Aerospace BAe 146 aeroplanes. The work must be done in accordance with BAe Service Bulletin (S.B.) 53-84-00737D Revision 1. (Requirement)\n- The AD applies only to the BAe 146 serial numbers listed under “Applicability.” (Applicability)\n- The modification must be completed before the affected aeroplane reaches 3000 flight cycles. (Compliance)\n\nWho it affects and who decides\n\n- The Civil Aviation Safety Authority (CASA) issued the AD as part of the Schedule of Airworthiness Directives. The AD imposes an obligation on the operators/owners of the listed BAe 146 aircraft to carry out the work. (heading; Applicability; Requirement)\n\nWhy it matters (official claim and mechanical test)\n\n- The AD states the reason: inspection found that on some aeroplanes stringer 21P was not riveted at the end termination area adjacent to frame 39X. The Service Bulletin adds eight rivet positions to correct that condition. (Background; Requirement)\n- Mechanically, the AD prescribes a physical repair (adding rivets) to a specific structural attachment. The stated objective is to ensure the specified attachment has the rivet pattern set out in the BAe Service Bulletin. (Background; Requirement)\n\nPractical implications, costs and incentives (concrete mechanisms)\n\n- Who pays: The aircraft operator or owner must arrange and pay for the rivet installation and any associated maintenance work required by the Service Bulletin. (Requirement)\n- What must be done: Obtain and follow BAe S.B. 53-84-00737D Revision 1 and install the eight rivet positions at stringer 21P per that document. The AD ties mandatory compliance to that external technical document, so operators must access the Service Bulletin. (Requirement)\n- When it must be done: The work must be completed prior to the aeroplane reaching 3000 flight cycles, so operators must track flight cycles and schedule the work accordingly. Failure to comply by that threshold is a breach of the AD. (Compliance)\n- Compliance burden and operational cost: The requirement imposes a discrete maintenance task (rivet installation) with labour, parts and downtime costs. The AD does not specify time-in-service relief or alternative means of compliance; it directs operators to the Service Bulletin for technical detail. (Requirement)\n- Administrative/implementation risk: Amendment 1 corrects the original Service Bulletin number and references Revision 1 of the Service Bulletin, and it adds a serial number to the list of applicable aircraft. Operators must ensure they use the corrected SB number and correct revision to avoid performing incorrect work or missing an applicable aircraft. (Amendment 1)\n\nTrade-offs and decision points for operators\n\n- Operators weigh the immediate maintenance cost and aircraft downtime against the regulatory requirement to complete the installation before 3000 flight cycles. The AD creates a clear compliance deadline tied to utilisation (flight cycles), so higher-utilisation aircraft will need the work scheduled sooner. (Compliance; Applicability)\n- The AD constrains operator choice about how to address this specific structural condition: the AD prescribes the fix via the Service Bulletin rather than leaving method selection to individual operators, so the primary decisions for operators are scheduling, procuring parts and performing the work to the SB standard. (Requirement)\n\nConcentration of effects and potential for confusion\n\n- The requirement is narrowly targeted: it applies only to the specific serial numbers listed under Applicability. That concentrates costs on the listed aircraft’ operators while leaving other operators unaffected. (Applicability)\n- Because Amendment 1 corrects the Service Bulletin reference and adds a serial number, there is a potential for confusion if operators relied on the original text; checking the amended SB reference and revision is a necessary compliance step. (Amendment 1)\n\nKey source citations\n\n- Applicability: lists the affected BAe 146 serial numbers. (Applicability)\n- Requirement: mandates action in accordance with BAe S.B. 53-84-00737D Revision 1. (Requirement)\n- Compliance: sets the deadline “Prior to achieving 3000 flight cycles.” (Compliance)\n- Background: describes the missing rivets and that the Service Bulletin introduces eight rivet positions. (Background)\n- Amendment 1: corrects the original Service Bulletin number and adds an aircraft serial number to the applicability. (Amendment 1)\n"},"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This is a minor amendment to an existing Airworthiness Directive. The scope remains tightly focused on the specific structural modification to stringer 21P. Amendment 1 makes only technical corrections: fixing the Service Bulletin number and adding one aircraft to the applicability list. No expansion of regulatory scope or purpose."},"complexity_factors":["Very short document (under 200 words)","Only 1 substantive requirement with clear compliance deadline","No defined terms section","No cross-references to other legislation","Simple conditional logic: if serial number matches, then modification required","Single amendment limited to correcting a Service Bulletin reference and adding one aircraft serial number"],"plain_english_summary":"This is a **safety order for specific British Aerospace BAe 146 aircraft**.\n\n**What it does:**\nTells owners and operators of certain BAe 146 planes they must add extra rivets (metal fasteners) to a specific structural part called \"stringer 21P\" — a support beam on the left-hand side of the fuselage near frame 39X.\n\n**Who it affects:**\nOnly 12 specific aircraft by serial number:\n- **Series 200/200A:** E2103, E2106, E2107, E2108, E2110, E2111, E2115, E2121\n- **Series 300/300A:** E3120, E3122, E3123, E3126, E3132\n\n**What must be done:**\n- Follow British Aerospace Service Bulletin 53-84-00737D Revision 1\n- Install 8 additional rivets where stringer 21P meets the skin panel\n- **Deadline:** Before the aircraft reaches 3,000 flight cycles (takeoff-landing cycles)\n\n**Why it matters:**\nThe original manufacturing missed rivets at a critical stress point. Without this fix, the structure could weaken over time, potentially compromising airframe integrity. This amendment corrects a paperwork error in the original directive and adds one more aircraft to the affected list."}},"importantCases":[],"_links":{"self":"/api/acts/ad-bae-146-15-amdt-1-additional-riveted-attachment-stringer-21p","history":"/api/acts/ad-bae-146-15-amdt-1-additional-riveted-attachment-stringer-21p/history","analysis":"/api/acts/ad-bae-146-15-amdt-1-additional-riveted-attachment-stringer-21p/analysis","conflicts":"/api/acts/ad-bae-146-15-amdt-1-additional-riveted-attachment-stringer-21p/conflicts","importantCases":"/api/acts/ad-bae-146-15-amdt-1-additional-riveted-attachment-stringer-21p/important-cases","documents":"/api/acts/ad-bae-146-15-amdt-1-additional-riveted-attachment-stringer-21p/documents"}}