{"id":"F2006B03478","name":"AD/BAe 146/27 Amdt 1 - Passenger and Service Door Mechanism","slug":"ad-bae-146-27-amdt-1-passenger-and-service-door-mechanism","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":43032,"registerId":"commonwealth-F2006B03478-current","compilationNumber":null,"startDate":"2026-04-01","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/BAe 146/27 Amdt 1 - Passenger and Service Door Mechanism","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 146/27\n\nAmdt 1\n\n  \nPassenger and Service Door Mechanism 9/91\n\nApplicability: Models & Constructors numbers; as specified in BAe 146 SB 52-89-00668H, J, K & L Revision 2.\n\nRequirement: Action in accordance with BAe Mandatory SB 52-89-00668H, J, K & L Revision 2\\. Compliance: Prior to 31 October 1991.\n\nBackground: Constant high outward force on the door during opening sequence may prevent the side baulk blade from retracting, this hindering emergency evacuation. Modifications required by the initial issue of this Directive introduced stronger springs to increase tension at the side baulk blade.\n\nThis amendment requires additional work for aircraft already modified, due to a dimension error. Compliance date required by the UK CAA is extended by three months.","sortOrder":0}],"analysis":{"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This is a standard technical amendment to an airworthiness directive. It adds a specific corrective action for aircraft already modified under the original directive, but does not expand beyond the original safety purpose (fixing door mechanisms to ensure emergency evacuation capability)."},"complexity_factors":["Very short document (under 200 words)","Only 1 defined term implicitly referenced (the Service Bulletin)","Single compliance action with clear deadline","No nested exceptions or conditional logic","Cross-reference to external technical document (BAe Service Bulletin) rather than internal legislative complexity","Straightforward amendment: adds one additional requirement and extends deadline"],"plain_english_summary":"This is an **Airworthiness Directive** — essentially a mandatory safety order issued by Australia's Civil Aviation Safety Authority (CASA) for specific aircraft.\n\n**What it does:**\n- Orders owners and operators of **British Aerospace BAe 146 series aircraft** to inspect and modify the passenger and service door mechanisms.\n- The problem: A design flaw means that if someone pushes hard on the door while opening it, a safety component called the \"side baulk blade\" can get stuck. This could block the door during an emergency evacuation.\n\n**Who it affects:**\n- Operators of BAe 146 aircraft with specific serial numbers listed in British Aerospace Service Bulletin 52-89-00668H, J, K & L (Revision 2).\n\n**What must be done:**\n- Follow the instructions in the British Aerospace Mandatory Service Bulletin mentioned above.\n- **Deadline:** Before 31 October 1991.\n\n**Why this amendment exists:**\n- The original directive (from September 1991) required installing stronger springs to fix the door problem.\n- This update (**Amendment 1**) adds extra work because the original modification had a **dimension error** — the parts didn't quite fit right.\n- It also gives Australian operators **3 extra months** to comply compared to the UK deadline.\n\n**Why it matters:**\nDoor mechanisms that jam during emergencies can trap passengers inside a burning or damaged aircraft. This directive closes a safety gap that could cost lives."},"flash_summary":{"complexity_score":2,"scope_assessment":{"changed":true,"description":"This amendment modifies the earlier directive's operational scope by (1) requiring additional corrective work for aircraft that had already received the initial modification because a dimension error was discovered, and (2) altering the compliance timetable referenced by the UK CAA (extending that compliance date by three months). The directive continues to apply only to the BAe 146 models listed in the BAe Mandatory SB, but it expands the set of required actions for affected aircraft (see: \"Background\" and \"Requirement\")."},"complexity_factors":["Narrow technical scope limited to specified BAe 146 models (\"Applicability\")","Mandates compliance with an external BAe Mandatory Service Bulletin rather than setting out detailed technical steps in the directive (\"Requirement\")","Short, fixed compliance timeframe (must be completed prior to 31 October 1991) adds scheduling pressure (\"Compliance\")","Amendment requires additional rework due to a dimension error, creating follow-up logistics and potential re-inspection (\"Background\")","Cross-jurisdictional note: reference to the UK CAA compliance date being extended by three months requires operators to track multiple regulators (\"Background\")"],"plain_english_summary":"### What this directive does\n\nThis airworthiness directive requires certain British Aerospace BAe 146 series aeroplanes to have their passenger and service door mechanism modified in a specific way. The modification work must be carried out in accordance with BAe Mandatory Service Bulletin (SB) 52-89-00668 (Revisions H, J, K & L Revision 2). (See: \"Applicability\" and \"Requirement\".)\n\n### Who it affects\n\n- Aircraft operators/owners of the BAe 146 models listed in BAe SB 52-89-00668H/J/K/L Revision 2. (See: \"Applicability\".)\n- Maintenance organisations or contractors who carry out the mandatory SB instructions.\n- The Civil Aviation Safety Authority as the issuing authority under the Civil Aviation Regulations schedule. (Header: Part 39 - Schedule of Airworthiness Directives.)\n\n### Why it matters and how it works mechanically\n\n- Mechanism of the safety issue: During the door opening sequence, a constant high outward force on the door can stop the side baulk blade from retracting, which can hinder emergency evacuation. (See: \"Background\".)\n- Initial fix: The original directive required installing stronger springs to increase tension at the side baulk blade so the blade would retract reliably. (See: \"Background\".)\n- What this amendment changes: Because a dimension error was discovered in the earlier modification, this amendment requires additional corrective work even for aircraft that already had the earlier modification. It also extends the compliance date imposed by the UK CAA by three months. (See: \"Background\".)\n- Timing: Under this Australian directive, the required action must be completed before 31 October 1991. (See: \"Compliance\" and \"Requirement\".)\n\n### Who pays, who decides, and what behaviour changes\n\n- Who pays: Aircraft operators or their maintenance providers pay for the modification work and any rework required by the amendment (costs of parts, labour, and aircraft downtime). (Implied by \"Requirement\" to implement SB instructions.)\n- Who decides: The Civil Aviation Safety Authority issues the directive; the technical content and corrective steps are set out in the BAe Mandatory Service Bulletin that the directive mandates. Operators must follow the SB to comply. (See: header and \"Requirement\".)\n- Behaviour change required: Operators must schedule and carry out the specified modification/rework on affected aircraft before the compliance date. Maintenance organisations must apply the additional corrective steps where the earlier fix used the incorrect dimension. (See: \"Requirement\" and \"Background\".)\n\n### Costs, incentives and implementation issues (mechanical and administrative)\n\n- Compliance burden: Operators face direct costs of parts, labour and aircraft downtime to carry out the SB instructions and any additional rework required by this amendment. (See: \"Requirement\" and \"Background\".)\n- Implementation risk: The amendment exists because a dimension error in the earlier fix was found, so there is a technical risk that earlier work did not fully resolve the safety concern and requires rework. That creates schedule and logistics demands for operators who already completed the initial fix. (See: \"Background\".)\n- Coordination across jurisdictions: The UK CAA had its own compliance date; this amendment notes an extension of that UK date by three months. Operators with internationally registered fleets will need to track both CASA and UK CAA requirements. (See: \"Background\".)\n- Incentives: The directive imposes a mandatory compliance obligation. Operators have an incentive to complete the work promptly to restore compliance and maintain airworthiness certification; maintenance providers have an incentive to identify affected aircraft and perform the corrective work. (See: \"Requirement\" and \"Compliance\".)\n\n### Trade-offs and limited effects on broader markets\n\n- The directive is narrowly targeted to a defined set of BAe 146 models (see \"Applicability\"), so its direct effects on competition, prices, and industry-wide productivity are limited to the costs borne by affected operators and their maintenance suppliers. (See: \"Applicability\" and \"Requirement\".)\n- There is no change to ownership, contract freedom or speech rights in the text. The action is a technical airworthiness requirement enforced through the service bulletin mechanism. (Entire directive.)\n\nReferences to source text: Applicability; Requirement; Compliance; Background (AD/BAe 146/27 Amdt 1)."}},"importantCases":[],"_links":{"self":"/api/acts/ad-bae-146-27-amdt-1-passenger-and-service-door-mechanism","history":"/api/acts/ad-bae-146-27-amdt-1-passenger-and-service-door-mechanism/history","analysis":"/api/acts/ad-bae-146-27-amdt-1-passenger-and-service-door-mechanism/analysis","conflicts":"/api/acts/ad-bae-146-27-amdt-1-passenger-and-service-door-mechanism/conflicts","importantCases":"/api/acts/ad-bae-146-27-amdt-1-passenger-and-service-door-mechanism/important-cases","documents":"/api/acts/ad-bae-146-27-amdt-1-passenger-and-service-door-mechanism/documents"}}