{"id":"F2006B02720","name":"AD/B727/20 - Thrust Reverser Lockout Actuator Piston - Replacement","slug":"ad-b727-20-thrust-reverser-lockout-actuator-piston-replacement","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":42036,"registerId":"commonwealth-F2006B02720-current","compilationNumber":null,"startDate":"2026-04-01","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/B727/20 - Thrust Reverser Lockout Actuator Piston - Replacement","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/B727/20 Thrust Reverser Lockout Actuator Piston - Replacement\n\n\n2/66\n\n \n\nApplicability: All models.\n\nDocument: Boeing Alert SB No. 78-18. 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\n \n","sortOrder":0}],"analysis":{"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This is a discrete, targeted safety directive addressing a specific mechanical component on a specific aircraft type. It has not expanded beyond its original purpose of mandating a safety-critical replacement."},"complexity_factors":["Extremely short document (approximately 100 words of substantive content)","No defined terms section","No cross-references to other legislation beyond the parent Civil Aviation Regulations 1998","Single, unambiguous compliance requirement (replace the part)","No conditional logic, exceptions, or nested provisions","Clear applicability (all Boeing 727 models)"],"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) for aircraft.\n\n**What it does:** It requires the **replacement of the thrust reverser lockout actuator piston** on all Boeing 727 series aircraft.\n\n**Why it matters:** A thrust reverser is the part of a jet engine that redirects thrust forward to help slow the plane after landing. The \"lockout actuator piston\" is a mechanical component that helps control this system. If this part fails, it could prevent the thrust reverser from working properly — potentially causing runway overruns or loss of control during landing.\n\n**Who must comply:** All operators of Boeing 727 aircraft (all models).\n\n**When:** Immediately (\"forthwith\"). This is urgent — no grace period.\n\n**Source:** Based on Boeing Alert Service Bulletin No. 78-18."},"flash_summary":{"complexity_score":2,"scope_assessment":{"changed":false,"description":"The text supplied contains no statement that changes the scope from an original intent. The directive applies to all Boeing 727 models and requires replacement of the thrust reverser lockout actuator piston by reference to Boeing Alert SB No. 78-18, with compliance required forthwith. There is no language in the document indicating an expansion or narrowing of scope relative to any earlier instrument within the supplied text."},"complexity_factors":["Short, single‑issue directive: mandates one specific replacement task (thrust reverser lockout actuator piston).","Applicability is broad but simple: applies to all Boeing 727 models (no model‑by‑model distinctions).","Relies on an external technical document (Boeing Alert SB No. 78-18) for procedural detail, requiring operators to consult that bulletin.","Immediate compliance requirement (\"Forthwith\") increases operational urgency despite simple substantive requirement.","No detailed timeline, exemptions, or alternative compliance paths set out in the text supplied, so operators must seek guidance in the service bulletin or from the regulator."],"plain_english_summary":"This directive requires operators of all Boeing 727 models to replace the thrust reverser lockout actuator piston immediately, using the procedure in Boeing Alert Service Bulletin No. 78-18.  \n\nIt affects aircraft owners and their maintenance providers, who must fund and perform the work forthwith; compliance is enforceable under CASA’s Part 39 airworthiness directive authority."}},"importantCases":[],"_links":{"self":"/api/acts/ad-b727-20-thrust-reverser-lockout-actuator-piston-replacement","history":"/api/acts/ad-b727-20-thrust-reverser-lockout-actuator-piston-replacement/history","analysis":"/api/acts/ad-b727-20-thrust-reverser-lockout-actuator-piston-replacement/analysis","conflicts":"/api/acts/ad-b727-20-thrust-reverser-lockout-actuator-piston-replacement/conflicts","importantCases":"/api/acts/ad-b727-20-thrust-reverser-lockout-actuator-piston-replacement/important-cases","documents":"/api/acts/ad-b727-20-thrust-reverser-lockout-actuator-piston-replacement/documents"}}