{"id":"F2006B02728","name":"AD/B727/28 - Emergency Brake System - Modification","slug":"ad-b727-28-emergency-brake-system-modification","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":42044,"registerId":"commonwealth-F2006B02728-current","compilationNumber":null,"startDate":"2026-04-01","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/B727/28 - Emergency Brake System - Modification","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)  Boeing 727 Series Aeroplanes\n\n \n\nAD/B727/28 Emergency Brake System - Modification 7/66\n\nApplicability: All models. Document: Boeing SB No. 29-22. Compliance: Forthwith.\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":{"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":false,"description":"The AD text presents a single, immediate requirement applying to all Boeing 727 models and references Boeing SB No. 29-22 for the technical modification. The text contains no indication that the scope has been altered from any prior statement; there is no amendment language or narrowings/expansions noted in this instrument itself."},"complexity_factors":["Very short directive with a single clear obligation (low textual complexity).","Immediate compliance requirement ('Forthwith') increases operational urgency and scheduling complexity for operators.","Technical method and details are delegated to an external document (Boeing SB No. 29-22), requiring operators to obtain and interpret that bulletin.","No details in the AD about cost allocation, enforcement, exemptions or verification, creating practical ambiguity that must be resolved outside the text.","Broad scope (applies to all Boeing 727 models) increases the number of affected parties and potential aggregate operational impact."],"plain_english_summary":"What this directive does\n\n- The document is an Airworthiness Directive (AD) that requires a modification to the emergency brake system on Boeing 727 series aeroplanes. (Document: Boeing SB No. 29-22)\n- It applies to all Boeing 727 models. (Applicability: All models)\n- The required action is to be complied with immediately. (Compliance: Forthwith)\n\nWho is affected and what they must do\n\n- Owners and operators of Boeing 727 series aeroplanes are the parties affected because the AD applies to “all models.” (Applicability: All models)\n- The AD directs that the modification be carried out according to Boeing Service Bulletin No. 29-22. The AD itself contains no technical steps; those are in the referenced Boeing service bulletin. (Document: Boeing SB No. 29-22)\n- Compliance must occur without delay because the AD sets the compliance time as “forthwith.” (Compliance: Forthwith)\n\nWhat the instrument says about purpose and what is left unstated\n\n- The AD text does not state a rationale, safety assessment, cost allocation, or enforcement detail. The only operative content is the requirement to make the modification per the referenced Boeing document and the immediacy of compliance. (Document: Boeing SB No. 29-22; Compliance: Forthwith)\n- Because the AD does not specify who bears costs, timelines beyond “forthwith,” inspection or verification procedures, or any exemptions, those matters are not addressed in the text and must be resolved by operators, maintenance organisations, and the regulator using other authorities or practices.\n\nMechanics, incentives and implementation considerations (source-grounded)\n\n- Who pays: The AD does not specify payment or cost allocation. The text requires the modification but contains no provision allocating costs. (no cost provision present in the AD)\n- Who decides/has discretion: The AD sets the mandatory requirement and references a Boeing service bulletin for the technical method; the AD text itself does not provide discretion or exemptions. The practical discretion (for timing, work scheduling, or interpretation of the service bulletin) will fall to the operator and the maintenance organisation unless the regulator issues further directions. (Compliance: Forthwith; Document: Boeing SB No. 29-22)\n- Compliance burden: The AD creates an immediate operational requirement to implement the referenced modification for every affected aeroplane. The AD does not quantify labour, parts, or downtime. (Compliance: Forthwith; Document: Boeing SB No. 29-22)\n- Reliance on external document: The AD’s technical content is delegated to Boeing SB No. 29-22. Operators must obtain and follow that service bulletin to meet the AD’s requirement. (Document: Boeing SB No. 29-22)\n- Enforcement and verification: The AD does not describe enforcement mechanisms or required evidence of compliance in this text.\n\nTrade-offs, risks and tradeable costs (conditional and source-grounded)\n\n- The AD creates a clear, immediate legal obligation to modify equipment; the directive itself does not state its benefits or costs. Any trade-off assessment (for example, repair cost versus safety benefit) is not in the AD and would require external documentation or regulatory materials.\n- The broad applicability (all models) concentrates the operational task on all owners/operators of Boeing 727s; the AD text does not indicate phased compliance or exemptions. (Applicability: All models; Compliance: Forthwith)\n\nBottom line\n\n- Mechanically, this AD mandates that all Boeing 727 series aeroplanes be modified in accordance with Boeing Service Bulletin No. 29-22, and that compliance be carried out immediately. The directive is short and procedural: it sets the obligation and points to the service bulletin for technical details, but it does not address costs, enforcement mechanics, exemptions, or a stated rationale. (Applicability: All models; Document: Boeing SB No. 29-22; Compliance: Forthwith)"},"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This is a discrete, single-issue safety directive. It has not expanded beyond its original purpose of mandating a specific modification to the emergency brake system of Boeing 727 aircraft. The scope remains precisely as intended: targeted, aircraft-specific, and limited to one technical modification."},"complexity_factors":["Extremely short document — only 4 substantive lines of regulatory text","No defined terms section — relies entirely on external references (Boeing SB No. 29-22)","No conditional logic or exceptions — single universal applicability ('All models')","Single cross-reference to external technical document (Boeing Service Bulletin)","Simple imperative structure: applicability + document reference + compliance deadline","No nested provisions, subsections, or interpretive provisions"],"plain_english_summary":"This is an **Airworthiness Directive (AD)** — essentially a mandatory safety order issued by Australia's Civil Aviation Safety Authority (CASA) for aircraft.\n\n**What it does:**\nRequires owners and operators of **Boeing 727 series aeroplanes** to modify the emergency brake system on their aircraft.\n\n**Who it affects:**\nAnyone who owns, operates, or maintains any model of Boeing 727 aircraft in Australia.\n\n**What must be done:**\nOperators must follow the technical instructions in **Boeing Service Bulletin No. 29-22** (the official manufacturer guidance on how to make this fix).\n\n**When:**\n**\"Forthwith\"** — meaning immediately, without delay. This isn't optional and there's no grace period.\n\n**Why it matters:**\nAirworthiness Directives are legally binding safety requirements. If an aircraft doesn't comply, it cannot legally fly. This particular directive addresses a specific safety issue with the emergency brake system — a critical component for safe landing and ground operations. Non-compliance grounds the aircraft."}},"importantCases":[],"_links":{"self":"/api/acts/ad-b727-28-emergency-brake-system-modification","history":"/api/acts/ad-b727-28-emergency-brake-system-modification/history","analysis":"/api/acts/ad-b727-28-emergency-brake-system-modification/analysis","conflicts":"/api/acts/ad-b727-28-emergency-brake-system-modification/conflicts","importantCases":"/api/acts/ad-b727-28-emergency-brake-system-modification/important-cases","documents":"/api/acts/ad-b727-28-emergency-brake-system-modification/documents"}}