{"id":"F2006B03477","name":"AD/BAe 146/26 - Parking Brake","slug":"ad-bae-146-26-parking-brake","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":43031,"registerId":"commonwealth-F2006B03477-current","compilationNumber":null,"startDate":"2026-04-01","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/BAe 146/26 - Parking Brake","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 146/26 Parking Brake 3/91 Applicability:              Model 146 with Constructor’s numbers listed in BAe SB 32-104-01159A. Requirement:               Action in accordance with BAe Mandatory SB 32-104-01159A.\n\nCompliance: As specified in the Requirement Document.\n\n \n\nBackground:  This Directive is raised to introduce a modification that installs a special washer in the park brake selector assembly. This prevents the cable tensioning spring in the selector assembly from inadvertently selecting the park brake.\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":{"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":false,"description":"The directive's stated action — introducing a modification (installation of a special washer) to prevent inadvertent park-brake selection — matches the stated background purpose. The instrument is narrowly targeted by constructor number and delegates procedural detail to BAe Mandatory Service Bulletin 32-104-01159A, so there is no indication in the text that the scope departs from its original stated intent (Applicability; Requirement; Background; Compliance)."},"complexity_factors":["Narrow applicability — applies only to BAe 146 airframes listed by constructor’s number, reducing scope complexity (Applicability).","Delegation of technical detail to an external Mandatory Service Bulletin (BAe SB 32-104-01159A) — the directive is short but requires consulting another document for procedural steps and timing (Requirement; Compliance).","Safety-critical but mechanically simple fix — the modification (installing a washer) is straightforward technically, but correct installation is essential for the intended safety effect (Background).","Unspecified timing in the directive text — the compliance timing is contained in the Requirement Document rather than in the directive itself, which creates operational planning uncertainty (Compliance).","Regulatory mandatory nature — reduces operator choice about the technical remedy, though scheduling discretion may remain (Requirement; Compliance)."],"plain_english_summary":"What this instrument does (mechanics)\n\n- Requires fitting a special washer into the parking-brake selector assembly on certain BAe 146 aeroplanes. The washer prevents the selector assembly's cable-tensioning spring from inadvertently putting the aircraft into the park-brake position (Background).\n- The directive applies only to BAe 146 models with the constructor’s numbers listed in BAe Service Bulletin 32-104-01159A (Applicability).\n- The required work is to be carried out exactly as set out in BAe Mandatory Service Bulletin 32-104-01159A (Requirement). The timing and other procedural details are those set out in that Requirement Document (Compliance).\n\nWho is affected and who pays\n\n- Affected parties are operators/owners of BAe 146 aircraft identified by the constructor numbers referenced in the Service Bulletin (Applicability).\n- Those operators are responsible for having the modification carried out per the mandatory Service Bulletin. That implies they pay for parts, labour and any aircraft downtime required to install the washer (Requirement; Compliance).\n\nWhy it matters (official purpose and practical implications)\n\n- The stated purpose is to reduce the risk that the park-brake is selected accidentally by the selector assembly’s cable-tensioning spring (Background).\n- Mechanically, the modification changes the selector assembly to block an unintended movement of the cable-tensioning spring. The intended effect is a lower likelihood of unintended park-brake engagement (Background).\n\nPractical trade-offs, incentives and implementation points\n\n- Cost and burden: The directive creates a compliance cost (parts, maintenance labour, and aircraft time out of service) for the limited set of affected BAe 146 aircraft. The text ties the exact scope of work and timing to the BAe Mandatory Service Bulletin, so operators must follow that external document to know detailed cost and scheduling implications (Requirement; Compliance).\n- Concentration of benefits and costs: Benefits (reduced risk of inadvertent park-brake selection) accrue to operators of the listed aircraft; costs fall on the same, relatively concentrated group because applicability is limited to specific constructor numbers (Applicability; Background).\n- Discretion and enforcement: The directive is prescriptive — it requires action “in accordance with” the Mandatory Service Bulletin. That reduces operator discretion about the technical solution; remaining discretion is mainly when and by whom to schedule and perform the mandated work, subject to the timing in the Requirement Document (Requirement; Compliance).\n- Implementation risk and compliance burden: Effective risk reduction depends on correct installation per the Service Bulletin. The directive does not itself set the technical steps or timing in this text; operators must consult BAe Mandatory SB 32-104-01159A for the procedural detail and timeframe (Requirement; Compliance).\n\nNet effect in plain terms\n\n- Operators of the listed BAe 146 aircraft must install a specified washer in the park-brake selector assembly, following BAe’s mandatory service instructions. The action is intended to prevent accidental park-brake selection; it imposes direct compliance costs and scheduling requirements on those operators and relies on correct implementation to achieve the stated safety improvement (Applicability; Requirement; Compliance; Background)."},"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This is a discrete, targeted safety directive addressing a specific mechanical defect in a specific aircraft type. It has not expanded beyond its original purpose of mandating a parking brake modification."},"complexity_factors":["Extremely short document (under 200 words)","Only 1 substantive requirement: comply with an external technical document","No defined terms section","No conditional logic or nested exceptions","Single applicability criterion (specific aircraft serial numbers)","Cross-reference to only one external document (BAe SB 32-104-01159A)"],"plain_english_summary":"**What this is:** An Airworthiness Directive (AD) — essentially a mandatory safety notice issued by Australia's Civil Aviation Safety Authority (CASA) for specific aircraft.\n\n**What it does:** Requires owners or operators of certain British Aerospace BAe 146 model aircraft to install a special washer in the parking brake system. This washer stops a spring in the brake selector from accidentally engaging the parking brake during flight.\n\n**Who it affects:** Anyone who owns, operates, or maintains BAe 146 aircraft with specific serial numbers (constructor's numbers) listed in the referenced British Aerospace service bulletin.\n\n**Why it matters:** If the parking brake engages unexpectedly during flight, it could cause serious safety problems — potentially affecting control of the aircraft or causing damage. This directive prevents that mechanical failure.\n\n**What must be done:** Follow the instructions in British Aerospace Mandatory Service Bulletin 32-104-01159A (the \"Requirement Document\") by the deadlines specified in that document."}},"importantCases":[],"_links":{"self":"/api/acts/ad-bae-146-26-parking-brake","history":"/api/acts/ad-bae-146-26-parking-brake/history","analysis":"/api/acts/ad-bae-146-26-parking-brake/analysis","conflicts":"/api/acts/ad-bae-146-26-parking-brake/conflicts","importantCases":"/api/acts/ad-bae-146-26-parking-brake/important-cases","documents":"/api/acts/ad-bae-146-26-parking-brake/documents"}}