{"id":"F2008L04130","name":"AD/RB211/38 - Engine - High Pressure Turbine Disc","slug":"ad-rb211-38-engine-high-pressure-turbine-disc","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":76056,"registerId":"commonwealth-F2008L04130-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"Rolls Royce Turbine Engines - RB211 Seri","sectionType":"division","heading":"Rolls Royce Turbine Engines - RB211 Series","content":"### Rolls Royce Turbine Engines - RB211 Series\n\n| AD/RB211/38 | Engine - High Pressure Turbine Disc | 12/2008 |\n| ----------- | ----------------------------------- | ------- |\n\n| Applicability: | Rolls-Royce plc RB211-524, RB211-535C and RB211-535E4 series engines that have High Pressure (HP) Turbine Discs installed, identified by part and serial number in Rolls-Royce Alert Non-Modification Service Bulletin (NMSB) 72-AF996Revision 1 dated 17 July 2008.Note 1: These engines are known to be installed on, but not limited to, Lockheed Martin L-1011 aircraft, Boeing 747, 757 and 767 series aircraft, and Tupolev Tu204 aircraft.                                                                                                                                                                                                                                                                                                                            |\n| -------------- | ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |\n| Requirement:   | 1. Remove from aircraft HP turbine discs identified in Rolls-Royce Alert NMSB 72-AF996 Revision 1 and replace with a serviceable disc. Prior to reinstallation on an engine, inspect each HP turbine disc in accordance with the instructions of the SB.2. HP turbine discs that do not pass the inspection as detailed in Requirement 1 of this AD shall not be reinstalled on an engine and must be returned to Rolls-Royce for further investigation.3. Do not install any HP turbine disc identified in Rolls-Royce Alert NMSB72-AF996 Revision 1 on any engine; unless it has been inspected in accordance with the instructions of Rolls-Royce Alert NMSB 72-AF996 Revision 1 and has passed that inspection.Note 2: EASA AD 2008-0176 dated 18 September 2008 refers. |\n| Compliance:    | For Requirement 1 - After the effective date of this AD, within the applicable time period indicated in Section 1.C “Compliance” of Rolls-Royce Alert Non-Modification Service Bulletin 72-AF996 Revision 1.For Requirements 2 and 3 - From the effective date of this AD.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                   |\n|                | This Airworthiness Directive becomes effective on 20 November 2008.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                          |\n\n| Background: | Rolls-Royce has recently discovered that there may be cracks present in certain HP turbine discs, due to a possible error in an eddy current inspection technique carried out during maintenance. The affected part and serial numbers are identified in Rolls-Royce Alert Non-Modification Service Bulletin 72-AF996 Revision 1 (the SB). This condition, if not corrected, may lead to disc failure and subsequent high-energy debris release.This AD requires the removal from service of the affected HP turbine discs and inspection thereof, prior to reinstallation. |\n| ----------- | --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |\n\n![](image.001.png)  \nCharles Lenarcic  \nDelegate of the Civil Aviation Safety Authority\n\n3 October 2008","sortOrder":0},{"sectionNumber":"AD/RB211/38","sectionType":"part","heading":"AD/RB211/38","content":"## AD/RB211/38","sortOrder":1},{"sectionNumber":"Engine - High Pressure Turbine Disc","sectionType":"part","heading":"Engine - High Pressure Turbine Disc","content":"## Engine - High Pressure Turbine Disc","sortOrder":2},{"sectionNumber":"12/2008","sectionType":"part","heading":"12/2008","content":"## 12/2008","sortOrder":3}],"analysis":{"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"},"kimi_summary":{"content_quality":"ok","complexity_score":3,"scope_assessment":{"changed":false,"description":"This AD maintains its original narrow scope — addressing a specific manufacturing/inspection defect in specific HP turbine discs. There is no evidence of scope creep; it remains targeted at the identified safety-critical defect without expanding to unrelated engine components or operational requirements."},"complexity_factors":["Single, clearly defined mechanical issue (cracked turbine discs) with straightforward remedy","Only 3 numbered requirements with minimal conditional logic","Cross-references only to one external document (Rolls-Royce Service Bulletin 72-AF996 Revision 1) and one related EASA directive","Limited applicability — specific engine series and part numbers only","No nested definitions or interpretation section","Compliance dates reference external document for Requirement 1, but Requirements 2 and 3 use simple 'from effective date' trigger","Document is short (approximately 400 words of substantive content)"],"plain_english_summary":"This mandatory CASA Airworthiness Directive requires operators of Rolls‑Royce RB211‑524, RB211‑535C and RB211‑535E4 engines to remove specified High‑Pressure turbine discs, inspect them per Rolls‑Royce instructions, and replace any unserviceable discs. Discs failing inspection must be returned to Rolls‑Royce; reinstallation is prohibited unless inspected and cleared. This emergency safety measure (effective 20 November 2008) is legally mandatory to prevent in‑flight disc failure and engine debris hazards."},"flash_summary":{"complexity_score":4,"scope_assessment":{"changed":false,"description":"The directive targets HP turbine discs listed in Rolls‑Royce Alert NMSB 72‑AF996 Revision 1 for RB211‑524, ‑535C and ‑535E4 engines and prescribes removal, inspection, replacement and return‑to‑manufacturer procedures. The text gives no indication that the AD’s scope was broadened beyond addressing those identified parts and engines."},"complexity_factors":["Technical specificity: identification of affected parts by part and serial number only via Rolls‑Royce Alert NMSB 72‑AF996 Revision 1 (Applicability).","Cross-reference dependency: mandatory compliance steps refer to an external service bulletin (SB) for inspection instructions and to Section 1.C for timing (Requirement 1; Compliance).","Operational disruption: removal and replacement within specified time windows can affect aircraft availability and maintenance scheduling (Requirement 1; Compliance).","Prohibition and re‑entry conditions: discs listed in the SB are barred from installation unless inspected and passed (Requirement 3).","Traceability and manufacturer return: failed discs must be returned to Rolls‑Royce for further investigation, adding logistical and cost burdens (Requirement 2).","Regulatory linkage: note to EASA AD 2008‑0176 creates parallel international compliance considerations (Note 2 / Background).","Clear effective date and delegated authority: sets an explicit effective date and is issued by CASA’s delegate (effective date; signature)."],"plain_english_summary":"This Airworthiness Directive requires operators to remove specific Rolls‑Royce RB211‑524, RB211‑535C and RB211‑535E4 high‑pressure turbine (HP) discs identified in Rolls‑Royce Alert NMSB 72‑AF996 Revision 1, inspect them to the service bulletin’s instructions, replace any that fail inspection, and not reinstall listed discs unless they pass. It affects aircraft operators and maintenance organisations, who must pay for removal, inspection, replacement and returning failed discs to Rolls‑Royce; compliance times follow Section 1.C of the NMSB and the AD takes effect on 20 November 2008."}},"importantCases":[],"_links":{"self":"/api/acts/ad-rb211-38-engine-high-pressure-turbine-disc","history":"/api/acts/ad-rb211-38-engine-high-pressure-turbine-disc/history","analysis":"/api/acts/ad-rb211-38-engine-high-pressure-turbine-disc/analysis","conflicts":"/api/acts/ad-rb211-38-engine-high-pressure-turbine-disc/conflicts","importantCases":"/api/acts/ad-rb211-38-engine-high-pressure-turbine-disc/important-cases","documents":"/api/acts/ad-rb211-38-engine-high-pressure-turbine-disc/documents"}}