{"id":"F2006B03587","name":"AD/BEA 121/22 Amdt 1 - Wing Spar Web","slug":"ad-bea-121-22-amdt-1-wing-spar-web","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":43166,"registerId":"commonwealth-F2006B03587-current","compilationNumber":null,"startDate":"2026-04-01","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/BEA 121/22 Amdt 1 - Wing Spar Web","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)  \nBeagle B121 (Pup) Series Aeroplanes\n\nAD/BEA 121/22\n\nAmdt 1\n\n  \nWing Spar Web 6/91 DM\n\nApplicability: All models not having Modification No. BE. 214 embodied. Requirement: Action in accordance with Mandatory BAe SB B121/79 Revision 1.\n\nCompliance: As specified in the Requirement Document but with a revised accomplishment date of 31 May 1991 for Australian registered aircraft which have exceeded 1300 hours time in service.\n\nBackground: Overseas, cracking has been found on wing spar webs immediately outboard of the root rib. They have occurred on mainplanes which do not have Modification No. BE. 214 embodied.\n\nThis amendment is necessary to introduce the accomplishment of the bulletin at 1300 flying hours in lieu of the present 2000 flying hours, since cracks have been found on an aircraft during preparation for accomplishment of the bulletin at 2000 hours.\n\nCompliance date required by UK CAA extended by two months.","sortOrder":0}],"analysis":{"kimi_summary":{"content_quality":"ok","complexity_score":3,"scope_assessment":{"changed":false,"description":"This amendment maintains the original scope of the Airworthiness Directive. It does not expand applicability to new aircraft types or introduce new categories of requirements. It simply tightens an existing compliance deadline based on new safety evidence (early discovery of cracks). The amendment remains tightly focused on the specific wing spar web cracking issue for Beagle B121 aircraft without the BE.214 modification."},"complexity_factors":["Short, single-purpose instrument (approximately 200 words)","Only 2 defined technical references (Modification No. BE.214 and BAe SB B121/79 Revision 1)","Simple conditional logic: applies to 'all models not having' a specific modification","Single compliance pathway with one amended deadline","No nested exceptions or cross-references to other legislation beyond the parent Civil Aviation Regulations 1998","Clear factual background explaining the safety rationale"],"plain_english_summary":"**What this is:** This is an Airworthiness Directive (AD) — essentially a mandatory safety notice issued by Australia's Civil Aviation Safety Authority (CASA) for a specific type of aircraft.\n\n**Which aircraft:** Beagle B121 \"Pup\" series aeroplanes (small, single-engine planes originally built in the UK).\n\n**What the problem is:** Cracks have been discovered in the wing spar webs (the internal structural \"backbone\" of the wing) on these aircraft, specifically just outside where the wing meets the fuselage. This is a serious safety issue because the wing spar carries the load of the entire wing.\n\n**Who must act:** Owners/operators of Beagle B121 Pup aircraft that do **not** have a specific factory modification called \"Modification No. BE.214\" already installed.\n\n**What they must do:** Follow the instructions in a British Aerospace Service Bulletin (BAe SB B121/79 Revision 1) — a technical repair notice from the manufacturer.\n\n**What changed in this amendment:** Originally, aircraft had to complete this inspection/repair by 2,000 flying hours. This amendment makes it **more urgent** — Australian-registered aircraft that have already flown more than 1,300 hours must now complete the work by **31 May 1991**. This change was made because cracks were found on a plane while it was being prepared for the original 2,000-hour deadline, proving the problem appears earlier than first thought.\n\n**Why it matters:** Wing spar cracks can lead to structural failure and potentially catastrophic loss of the aircraft. This directive forces earlier action to prevent accidents."},"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":true,"description":"The amendment narrows the timing for required action relative to the previous instruction: it reduces the flight-hour threshold for accomplishment from 2,000 hours to 1,300 hours for Australian-registered aircraft that have exceeded 1,300 hours, and specifies an accomplishment date of 31 May 1991 for those aircraft. The amendment also notes an extension of the compliance date required by the UK CAA by two months. (See \"Background\" and \"Compliance\".)"},"complexity_factors":["Narrow technical scope (single aircraft type and specific structural area) reduces breadth of complexity.","Requirement delegates technical detail to an external Mandatory BAe Service Bulletin, so compliance depends on reading that document (adds a layer of reference).","Dependence on whether Modification No. BE.214 is embodied creates a binary applicability condition that operators must check.","Revised compliance threshold and a specific calendar date (31 May 1991) require tracking aircraft hours and scheduling maintenance.","Cross-jurisdiction timing coordination (reference to UK CAA compliance date extension) introduces minor administrative coordination complexity."],"plain_english_summary":"This directive requires Australian-registered Beagle B121 (Pup) aeroplanes without Modification No. BE.214 to inspect and, if needed, repair the wing spar web immediately outboard of the root rib following Mandatory BAe Service Bulletin B121/79 Revision 1, after cracking was found. Compliance is moved earlier—from 2,000 to 1,300 flight hours (deadline 31 May 1991)—and owners/operators bear the inspection/repair costs or may embody Mod BE.214 to remove applicability."}},"importantCases":[],"_links":{"self":"/api/acts/ad-bea-121-22-amdt-1-wing-spar-web","history":"/api/acts/ad-bea-121-22-amdt-1-wing-spar-web/history","analysis":"/api/acts/ad-bea-121-22-amdt-1-wing-spar-web/analysis","conflicts":"/api/acts/ad-bea-121-22-amdt-1-wing-spar-web/conflicts","importantCases":"/api/acts/ad-bea-121-22-amdt-1-wing-spar-web/important-cases","documents":"/api/acts/ad-bea-121-22-amdt-1-wing-spar-web/documents"}}