{"id":"F2006B03595","name":"AD/BEA 121/3 - Engine Bearers","slug":"ad-bea-121-3-engine-bearers","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":43186,"registerId":"commonwealth-F2006B03595-current","compilationNumber":null,"startDate":"2026-04-01","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/BEA 121/3 - Engine Bearers","content":"---\nmeta-content-style-type: text/css\nmeta-content-type: application/xhtml+xml; charset=utf-8\nmeta-generator: Aspose.Words for .NET 22.10.0\n---\n\n?xml version=\"1.0\" encoding=\"utf-8\" standalone=\"no\"?>\n\nCOMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY\n\nSCHEDULE OF AIRWORTHINESS DIRECTIVES\n\n \n\n![](image.001.png)  Beagle B121 (Pup) Series Aeroplanes\n\n \n\nAD/BEA 121/3 Engine Bearers 1/70\n\nApplicability: All Series 2 and 3 models prior to S/No. B121/107 which have 300 hours time in service.\n\n \n\nRequirement: Action in accordance with Beagle SB B121/11 (Mod. BE349). Compliance:  Within 100 hours time in service from 31 January 1970.\n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n","sortOrder":0}],"analysis":{"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This is a discrete, time-bound safety directive issued in 1970 with a narrow, specific scope (particular aircraft models with defined serial numbers and flight hours). It has not expanded beyond its original purpose of addressing a specific airworthiness concern with engine bearers on early-production Beagle B121 aircraft."},"complexity_factors":["Very short document (approximately 150 words)","Only 4 defined applicability criteria (model series, serial number, flight hours, effective date)","Single mandatory action with clear reference to external technical standard (Beagle SB B121/11)","Simple compliance deadline (100 hours from fixed date)","No nested exceptions, conditional logic, or cross-references to other legislation","Straightforward scope limited to specific aircraft type and manufacturing batch"],"plain_english_summary":"**What this is:** This is an **Airworthiness Directive (AD)** — a mandatory safety order issued by Australia's Civil Aviation Safety Authority (CASA) under the Civil Aviation Regulations 1998.\n\n**What it does:** It requires owners and operators of specific **Beagle B121 (Pup) Series aeroplanes** to carry out a mandatory inspection or modification to the **engine bearers** (the structural mounts that hold the engine to the airframe).\n\n**Who it affects:** \n- **Aircraft models:** All Series 2 and 3 Beagle B121 aircraft\n- **Serial number cutoff:** Only those with serial numbers **before B121/107**\n- **Flight hours:** Only aircraft that have accumulated **300 hours or more** of \"time in service\" (actual flying hours)\n\n**What must be done:**\n- Follow the instructions in **Beagle Service Bulletin B121/11** (specifically Modification BE349)\n- This likely involves inspecting, reinforcing, or replacing the engine mounts to prevent structural failure\n\n**When it must be done:**\n- Within **100 hours of flying time** after **31 January 1970**\n\n**Why it matters:** Engine bearers are critical safety components. If they fail, the engine could detach from the aircraft in flight. This AD addresses a known defect or wear pattern discovered in these specific aircraft models before a certain manufacturing point."},"flash_summary":{"complexity_score":4,"scope_assessment":{"changed":false,"description":"The text of the AD states the applicability, required action (by reference to Beagle SB B121/11 (Mod. BE349)) and a compliance deadline. The instrument does not indicate any alteration to scope compared with an earlier version within the text itself; there is no language in this document showing a change of scope from an original intent."},"complexity_factors":["Narrow, technical applicability tied to model series, serial-number cut-off and a specific time-in-service threshold (\"All Series 2 and 3 models prior to S/No. B121/107 which have 300 hours time in service\").","Mandates compliance by reference to an external technical document (Beagle SB B121/11 (Mod. BE349)), requiring operators to obtain and interpret another source to know the required work.","A definite but short compliance window (\"Within 100 hours time in service from 31 January 1970\") that creates scheduling pressure.","Lack of technical detail in the AD itself forces reliance on the service bulletin for scope, parts lists and procedures, increasing implementation uncertainty.","Applies to vintage aircraft where parts, tooling or specialist labour may be limited, creating potential practical delays not addressed in the AD text."],"plain_english_summary":"This AD mandates that owners/operators of Beagle B121 Series 2 and 3 aircraft (prior to S/No. B121/107 with 300 hrs TIS) carry out the engine-bearer work specified in Beagle Service Bulletin B121/11 (Mod. BE349) within 100 hours TIS from 31 January 1970. Operators are responsible for arranging and funding the work; the SB supplies technical detail. The short compliance window may affect scheduling, parts sourcing and aircraft availability."}},"importantCases":[],"_links":{"self":"/api/acts/ad-bea-121-3-engine-bearers","history":"/api/acts/ad-bea-121-3-engine-bearers/history","analysis":"/api/acts/ad-bea-121-3-engine-bearers/analysis","conflicts":"/api/acts/ad-bea-121-3-engine-bearers/conflicts","importantCases":"/api/acts/ad-bea-121-3-engine-bearers/important-cases","documents":"/api/acts/ad-bea-121-3-engine-bearers/documents"}}