{"id":"F2006B06681","name":"AD/RRT-S/13 Amdt 1 - Low Pressure Turbine Stage 2 NGV Seal Support","slug":"ad-rrt-s-13-amdt-1-low-pressure-turbine-stage-2-ngv-seal-support","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":48688,"registerId":"commonwealth-F2006B06681-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/RRT-S/13 Amdt 1 - Low Pressure Turbine Stage 2 NGV Seal Support","content":"COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 \\- 106 CIVIL AVIATION SAFETY AUTHORITY\n\nSCHEDULE OF AIRWORTHINESS DIRECTIVES\n\n![](image.001.png)  \n![](image.002.png)  \nRolls Royce Turbine Engines \\- Spey Series\n\nAIRWORTHINESS DIRECTIVE\n\n![](image.002.png)\n\n![](image.002.png)  \nFor the reasons set out in the background section, the CASA delegate whose signature appears below revokes Airworthiness Directive (AD) AD/RRT-S/13 and issues the following AD under subregulation 39.1 (1) of CAR 1998. The AD requires that the action set out in the requirement section (being action that the delegate considers necessary to correct the unsafe condition) be taken in relation to the aircraft or aeronautical product mentioned in the applicability section: (a) in the circumstances mentioned in the requirement section; and (b) in accordance with the instructions set out in the requirement section; and (c) at the time mentioned in the compliance section.\n\nAD/RRT-S/13\n\nAmdt 1\n\n  \nLow Pressure Turbine Stage 2 NGV Seal Support 9/2000\n\nApplicability: Rolls Royce Spey 555-15, \\-15H, \\-15N, and \\-15P engines.\n\nRequirement: Modify low pressure turbine stage 2 nozzle guide vane and seal support assemblies in accordance with Rolls Royce Spey Service Bulletin Sp72-1053 Revision 3 (Mod 6403).\n\nNote 1: CAA (UK) AD 008-08-97 also refers.\n\nNote 2: Compliance with earlier revisions of SB Sp72-1053 satisfies the intent of this amendment to the AD.\n\nCompliance: No later than 20 January 2001.\n\nThis amendment becomes effective on 7 September 2000.\n\nBackground: This Directive is prompted by reports of stiff rotors and engine seizure associated with thermally induced locking of stage 2 LPT nozzle guide vanes to the vane support and seal assembly, which can lead to the inability of the seal to centralise resulting in excessive eccentricity and unsatisfactory seal rubs or rotor seizure.\n\nThis amendment extends the compliance period.\n\nThe original issue of this Airworthiness Directive became effective on 26 March 1998.\n\n![Signature of Eugene Paul Holzapfel Delegate of the Civil Aviation Safety Authority](image.003.png)  \n\nEugene Paul Holzapfel\n\nDelegate of the Civil Aviation Safety Authority 31 July 2000\n\n![](image.002.png)  \n\nThe above AD is notified in the Commonwealth of Australia Gazette on 9 August 2000.","sortOrder":0}],"analysis":{"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":true,"description":"The amendment does not change the required modification or the engines to which it applies (Requirement), but extends the compliance timing: compliance must be completed no later than 20 January 2001 (Compliance). The amendment explicitly revokes the earlier AD and notes that compliance with earlier revisions of SB Sp72‑1053 also satisfies the AD (Background; Note 2)."},"complexity_factors":["Technical subject matter (turbine NGV and seal assemblies) requiring specialised maintenance and parts knowledge.","Cross-reference to a manufacturer Service Bulletin (Sp72‑1053 Rev 3) — compliance requires access to and interpretation of that SB.","Interaction with prior AD: revocation of an earlier AD and note that earlier SB revisions also satisfy the requirement.","A single, fixed compliance deadline that affects maintenance scheduling and operational availability.","Limited applicability to specific engine models (Spey 555‑15 variants) — concentrates burden on a narrow group of operators."],"plain_english_summary":"This directive requires operators of Rolls‑Royce Spey 555‑15, ‑15H, ‑15N and ‑15P engines to modify the low‑pressure turbine stage‑2 nozzle‑guide‑vane and seal‑support assemblies in line with Rolls‑Royce Service Bulletin Sp72‑1053 Rev 3 (Mod 6403). CASA’s delegate set a compliance deadline of no later than 20 January 2001; operators must arrange and pay for the modification to mitigate thermal locking that can cause stiff rotors, seal eccentricity, rubs or engine seizure."},"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This amendment maintains the original scope. It is purely administrative — extending the compliance deadline without expanding the affected engine models, the required modification, or the safety rationale."},"complexity_factors":["Single, specific technical requirement referencing an external service bulletin","Only 4 engine models listed in applicability","Simple compliance deadline with no conditional logic or exceptions","No defined terms section — uses standard aviation terminology","Straightforward amendment purpose (deadline extension only)","Total length under 400 words"],"plain_english_summary":"This CASA Airworthiness Directive legally requires operators of Rolls‑Royce Spey 555‑15, ‑15H, ‑15N and ‑15P engines to carry out a modification (per Rolls‑Royce Service Bulletin Sp72‑1053 Rev 3) to prevent stage‑2 low‑pressure turbine nozzle guide vanes from locking and causing stiff rotors or engine seizure. \n\nThis Amendment 1 only extends the compliance date to 20 January 2001; the required safety fix itself is unchanged."},"flash_summary_failed":{"failed":true,"reason":"A positive credit balance is required for all requests, including BYOK, so fallback providers remain available. Add credits at https://vercel.com/d?to=%2F%5Bteam%5D%2F%7E%2Fai%3Fmodal%3Dtop-up to continue.","source":"analysis-cron"}},"importantCases":[],"_links":{"self":"/api/acts/ad-rrt-s-13-amdt-1-low-pressure-turbine-stage-2-ngv-seal-support","history":"/api/acts/ad-rrt-s-13-amdt-1-low-pressure-turbine-stage-2-ngv-seal-support/history","analysis":"/api/acts/ad-rrt-s-13-amdt-1-low-pressure-turbine-stage-2-ngv-seal-support/analysis","conflicts":"/api/acts/ad-rrt-s-13-amdt-1-low-pressure-turbine-stage-2-ngv-seal-support/conflicts","importantCases":"/api/acts/ad-rrt-s-13-amdt-1-low-pressure-turbine-stage-2-ngv-seal-support/important-cases","documents":"/api/acts/ad-rrt-s-13-amdt-1-low-pressure-turbine-stage-2-ngv-seal-support/documents"}}