{"id":"F2006B06690","name":"AD/RRT-S/9 - Transply Combustion Liners","slug":"ad-rrt-s-9-transply-combustion-liners","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":48738,"registerId":"commonwealth-F2006B06690-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/RRT-S/9 - Transply Combustion Liners","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 - 106 CIVIL AVIATION SAFETY AUTHORITY\n\nSCHEDULE OF AIRWORTHINESS DIRECTIVES\n\n \n\n![](image.001.png)  Rolls Royce Turbine Engines - Spey Series\n\n \n\nAD/RRT-S/9 Transply Combustion Liners 7/86\n\nApplicability: Spey Mk. 555 Series engines fitted with Mod 6012 or Mod 6123 combustors. Requirement:               Replace Mod 6012 or Mod 6123 combustors in accordance with Rolls Royce SB Sp\n\n72-1001.\n\n \n\nCompliance: Not later than 3,500 hours combustor time since new.\n\n \n\nBackground: This Directive has been issued to require replacement of Transply combustion liners.\n\nRolls Royce advise, service experience with Mod. 6012 standard combustors indicates Transply combustors are experiencing circumferential cracking in the head and barrel sections. Service experience with boroscope inspection of Transply combustors has proven unsatisfactory, therefore a life limit of 3,500 hours is required.\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, single-issue airworthiness directive targeting a specific known defect in specific engine models. It has not expanded beyond its original safety purpose."},"complexity_factors":["Single, unambiguous applicability criterion (two specific modification numbers)","One clear compliance requirement (replacement per specified service bulletin)","Simple time-based compliance trigger (3,500 hours since new)","No defined terms section, no cross-references to other legislation, no conditional exceptions","Total length is approximately 150 words","Background provides straightforward technical rationale without legal caveats"],"plain_english_summary":"This CASA Airworthiness Directive mandates replacement of Transply combustion liners in Rolls‑Royce Spey Mk.555 engines (with Mod 6012 or Mod 6123 combustors) before they reach 3,500 engine hours. It affects any operator of those engines because liners are cracking near the head and barrel; boroscope inspections proved unreliable, so CASA imposed a strict life limit to prevent engine failure, fire, or catastrophic damage."},"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":true,"description":"Imposes a new mandatory life limit and replacement requirement for Mod 6012/6123 Transply combustors — a 3,500 combustor‑hour life limit and compulsory replacement per Rolls‑Royce SB Sp72‑1001 — on the specified engines because of reported circumferential cracking and unreliable borescope inspection (Background; Requirement; Compliance)."},"complexity_factors":["Narrow technical applicability — only Spey Mk.555 engines with Mod 6012 or Mod 6123 combustors (Applicability).","Mandatory replacement tied to an external document — compliance requires following Rolls‑Royce Service Bulletin Sp72‑1001 (Requirement).","Compliance metric requires accurate life tracking — limit set as 3,500 combustor hours since new, imposing record‑keeping and scheduling obligations (Compliance).","Inspection limitation — borescope inspection was judged unsatisfactory, eliminating a less invasive compliance option and increasing replacement rates (Background).","Operational and cost impact concentrated on operators who must procure and fit replacement combustors within the life limit."],"plain_english_summary":"This airworthiness directive requires operators of Rolls‑Royce Spey Mk.555 engines fitted with Mod 6012 or Mod 6123 Transply combustors to replace those combustors per Rolls‑Royce Service Bulletin Sp72‑1001 before they reach 3,500 combustor hours since new (Requirement; Compliance). It cites service experience of circumferential cracking in the head and barrel sections and notes borescope inspection was unsatisfactory; operators bear replacement costs and must keep combustor‑hour records and schedule maintenance to comply (Background)."}},"importantCases":[],"_links":{"self":"/api/acts/ad-rrt-s-9-transply-combustion-liners","history":"/api/acts/ad-rrt-s-9-transply-combustion-liners/history","analysis":"/api/acts/ad-rrt-s-9-transply-combustion-liners/analysis","conflicts":"/api/acts/ad-rrt-s-9-transply-combustion-liners/conflicts","importantCases":"/api/acts/ad-rrt-s-9-transply-combustion-liners/important-cases","documents":"/api/acts/ad-rrt-s-9-transply-combustion-liners/documents"}}