{"id":"F2006B03479","name":"AD/BAe 146/28 - Main Landing Gear Lock Jack","slug":"ad-bae-146-28-main-landing-gear-lock-jack","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":43033,"registerId":"commonwealth-F2006B03479-current","compilationNumber":null,"startDate":"2026-04-01","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/BAe 146/28 - Main Landing Gear Lock Jack","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)  British Aerospace BAe 146 Series Aeroplanes\n\n \n\nAD/BAe 146/28 Main Landing Gear Lock Jack 3/91\n\nApplicability: All BAe 146 aircraft which have an Uplock Jack part number 104275001 installed with the serial number listed in Dowty Rotol SB 146-32-93.\n\n \n\nRequirement: Action in accordance with Dowty Rotol Mandatory SB 146-32-93 Rev 1.\n\n \n\nNote: BAe146 SB 32-103 refers.\n\n \n\nCompliance: As specified in the Requirement Document.\n\n \n\nBackground: A batch of lock jack assemblies have been manufactured with a forging defect in the bodies. A total of forty one units have been identified as being manufactured from the defective material.\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":{"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":false,"description":"The text does not indicate any change in scope from an original intent. The AD identifies a defective batch of uplock jacks and directs operators of BAe 146 aircraft with the listed part number and serial numbers to follow the manufacturer’s mandatory service bulletin. No expansion or narrowing of the affected population or requirements is stated in the document (Applicability; Requirement; Background; Compliance)."},"complexity_factors":["Narrow technical scope limited to one part number and listed serial numbers (Applicability)","Dependence on an external technical document (Dowty Rotol Mandatory SB 146-32-93 Rev 1) for detailed procedures (Requirement)","Small affected population (41 units identified) which simplifies case identification but may complicate logistics for individual operators (Background)","Compliance actions and timing are delegated to the manufacturer’s service bulletin, reducing legal complexity but creating operational dependency (Requirement; Compliance)","Potential operational complexity from scheduling inspections/repairs and sourcing replacement parts, which is logistical rather than legal (Compliance; Background)"],"plain_english_summary":"What this instrument does, mechanically:\n\n- This Airworthiness Directive requires operators of BAe 146 aeroplanes that have a specific main landing gear uplock jack (part number 104275001) with certain serial numbers to carry out the actions set out in a manufacturer mandatory service bulletin, Dowty Rotol Mandatory SB 146-32-93 Rev 1 (Requirement). The AD points operators to that service bulletin for the exact inspection, removal or replacement steps and timing (Requirement; Compliance).\n\nWho is affected and who decides:\n\n- Affected parties are operators/owners of BAe 146 aircraft that have the uplock jack part number 104275001 installed and whose units match the serial numbers listed in Dowty Rotol SB 146-32-93 (Applicability). The issuing authority for the AD is the Commonwealth (Civil Aviation Safety Authority) under the Schedule of Airworthiness Directives header. The specific technical actions to comply are those set out by Dowty Rotol in the referenced mandatory service bulletin (Requirement).\n\nWhy the directive exists (official rationale and its mechanical consequences):\n\n- The background statement says a batch of lock jack assemblies were manufactured with a forging defect in the bodies and 41 units have been identified as coming from that defective material (Background). The AD therefore directs affected aircraft to follow the manufacturer’s mandatory instructions so that defective parts are inspected and dealt with (Requirement). Mechanically, that means inspecting for the listed serial numbers and then performing the corrective work or replacing units as specified in the Dowty Rotol document (Applicability; Requirement; Compliance).\n\nPractical implementation, costs and incentives (tested against trade-offs):\n\n- Who pays: aircraft operators pay for inspections, removals, replacements, and any aircraft downtime required to comply. The AD references a manufacturer mandatory service bulletin as the actions to follow, so the immediate compliance cost is borne by operators who have affected serial-numbered units (Applicability; Requirement; Compliance).\n\n- Behaviour changes required: operators must check their fleet for the listed serial numbers, schedule and carry out the inspection/remedial tasks in the Dowty Rotol SB, and record compliance as required by airworthiness procedures (Applicability; Requirement; Compliance).\n\n- Compliance burden and implementation risk: the AD delegates technical detail to the Dowty Rotol Mandatory SB 146-32-93 Rev 1, so the scope of work, timing and acceptability criteria come from that document (Requirement). That creates dependency on the bulletin’s clarity and on availability of replacement parts or repair capacity. Potential implementation frictions include aircraft downtime for inspections/repairs and the logistics of sourcing replacement jacks if removal is required (Requirement; Compliance; Background).\n\n- Effects on independent service providers and competition: maintenance organisations and third-party MROs that service BAe 146 aircraft must follow the same mandatory steps from the Dowty Rotol SB when they work on affected aircraft. The AD does not itself allocate work to any particular provider, but enforces a technical standard that all providers must meet (Requirement; Compliance).\n\n- Concentrated benefits vs diffuse costs: the safety benefit, as stated, is the mitigation of risk from a defective batch of 41 jack assemblies (Background). The costs—inspection and potential replacement—fall on the operators who have affected units and the MROs who perform the work (Applicability; Background).\n\nTrade-offs, opportunity costs and discretion:\n\n- Opportunity cost: aircraft out of service for inspection/repair means lost flying time and revenue for operators until compliance is completed (Compliance).\n\n- Bureaucratic discretion: the AD points directly to a specific manufacturer mandatory service bulletin for the technical remedy, so regulatory discretion over technical steps is limited; enforcement discretion (timing of audits or approvals) remains with the aviation safety regulator as the issuer (Requirement; Compliance).\n\nKey implementation notes and references to the text:\n\n- Applicability: All BAe 146 aircraft with uplock jack part number 104275001 and serial numbers listed in Dowty Rotol SB 146-32-93 (Applicability).\n- Required action: Follow Dowty Rotol Mandatory SB 146-32-93 Rev 1 (Requirement).\n- Compliance timing and specifics: As specified in the Requirement Document (Compliance).\n- Background reason: A batch of lock jack assemblies were manufactured with a forging defect; 41 units identified (Background)."},"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This is a discrete, targeted safety directive addressing a specific manufacturing defect in a single aircraft component. It has not expanded beyond its original purpose of mandating corrective action for the identified defective batch."},"complexity_factors":["Single, specific applicability criterion (one part number with listed serial numbers)","Single mandatory action referencing an external technical document","No defined terms section","No conditional logic or nested exceptions","Minimal cross-referencing (only one related service bulletin mentioned in a note)","Extremely short document (approximately 150 words of substantive content)"],"plain_english_summary":"This is an **Airworthiness Directive** — a mandatory safety order issued by Australia's Civil Aviation Safety Authority (CASA). It applies to **British Aerospace BAe 146 aircraft** fitted with a specific faulty part.\n\n**What it does:**\n- Orders owners and operators to inspect or replace a defective **main landing gear lock jack** (a hydraulic component that helps secure the landing gear in place)\n- The defect involves a **forging flaw** in the metal body of the part — essentially a manufacturing weakness that could cause the component to fail\n\n**Who it affects:**\n- Operators of BAe 146 aircraft that have the specific part installed (Uplock Jack part number 104275001 with serial numbers listed in Dowty Rotol Service Bulletin 146-32-93)\n- Maintenance organisations servicing these aircraft\n\n**Why it matters:**\nLanding gear failure is catastrophic. This directive prevents potential accidents by grounding or repairing aircraft with the defective batch of 41 identified units before they can fail in service.\n\n**What must be done:**\nFollow the instructions in **Dowty Rotol Mandatory Service Bulletin 146-32-93 Rev 1** — a technical document from the parts manufacturer specifying inspection or replacement procedures."}},"importantCases":[],"_links":{"self":"/api/acts/ad-bae-146-28-main-landing-gear-lock-jack","history":"/api/acts/ad-bae-146-28-main-landing-gear-lock-jack/history","analysis":"/api/acts/ad-bae-146-28-main-landing-gear-lock-jack/analysis","conflicts":"/api/acts/ad-bae-146-28-main-landing-gear-lock-jack/conflicts","importantCases":"/api/acts/ad-bae-146-28-main-landing-gear-lock-jack/important-cases","documents":"/api/acts/ad-bae-146-28-main-landing-gear-lock-jack/documents"}}