{"id":"F2006B06552","name":"AD/RB211/21 Amdt 2 - Radial Drive Steady Bearing","slug":"ad-rb211-21-amdt-2-radial-drive-steady-bearing","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":48276,"registerId":"commonwealth-F2006B06552-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/RB211/21 Amdt 2 - Radial Drive Steady Bearing","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 \\- RB211 Series\n\nAIRWORTHINESS DIRECTIVE\n\n![](image.002.png)\n\nFor the reasons set out in the background section, the CASA delegate whose signature appears below revokes Airworthiness Directive (AD) AD/RB211/21 Amdt 1 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\n![](image.003.png)AD/RB211/21\n\nAmdt 2\n\n  \nRadial Drive Steady Bearing 7/2001\n\nApplicability: RB211-535C-37, \\-535E4-37, \\-535E4-B-37 and \\-535E4-B-75 series engines not incorporating Rolls Royce Service Bulletin (SB) RB.211-72-C925 Revision 2.\n\nRequirement: 1. Aircraft configuration: To ensure no aircraft is fitted with both engines incorporating pre SB 72-C925 bearings with a bearing time in service of concern, compliance is required with Rolls Royce SB RB.211-72-D176.\n\n    2. Oil filter inspection: To detect evidence of radial drive steady bearing failure, inspect the oil scavenge filter for evidence of bronze and/or bearing steel debris in accordance with Rolls Royce Service Bulletin RB.211-72-C815 Revision 3.\n\n    3. Bearing replacement: Remove from service any radial drive steady bearing, P/N LK76084, IPC 72-62-01 Fig/Item 01 260, identified with prefixes DLJO, DLJP, DLOQ, DLSK or DMBA in accordance with the procedures in Rolls Royce Service Bulletin RB.211-72-C930.\n\nNote: UK CAA ADs’ 004-12-99, 004-09-2000 and FAA AD 2000-09-14 refer.\n\nCompliance: 1. Within 100 hours time in service from the effective date of this Directive.\n\n    2. From the effective date of this Directive.\n\n    3. From the effective date of this Directive.\n\nThis Amendment becomes effective on 12 July 2001.\n\nBackground: This Directive was originally issued to require a visual inspection of the oil scavenge filter for evidence of radial drive steady bearing debris indicating bearing failure may be imminent. This amendment provides a terminating action by limiting engines applicable to those incorporating a pre mod. 72-C925 bearing. This amendment also adds a requirement to ensure no aircraft is fitted with both engines incorporating pre SB 72-C925 bearings with a bearing time in service of concern.\n\nCOMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 \\- 106 CIVIL AVIATION SAFETY AUTHORITY\n\nSCHEDULE OF AIRWORTHINESS DIRECTIVES\n\n![](image.004.png)The original issue of this Airworthiness Directive became effective on 7 October 1999.\n\nAmendment 1 of this Airworthiness Directive became effective on 10 August 2000.\n\n![Signature of Eugene Paul Holzapfel Delegate of the Civil Aviation Safety Authority](image.005.png)  \n\nEugene Paul Holzapfel\n\nDelegate of the Civil Aviation Safety Authority 28 May 2001\n\n![](image.002.png)  \n\nThe above AD is notified in the Commonwealth of Australia Gazette on 13 June 2001.","sortOrder":0}],"analysis":{"flash_summary":{"complexity_score":4,"scope_assessment":{"changed":true,"description":"This amendment narrows and clarifies applicability compared with the original AD by limiting affected engines to those incorporating pre‑mod (pre‑SB RB.211‑72‑C925) bearings and by adding a terminating action and a requirement to ensure no aircraft is fitted with both engines having pre‑SB 72‑C925 bearings with a bearing time in service of concern. (Background and Requirement text)"},"complexity_factors":["Technical identification requirement: bearings specified by part number (P/N LK76084) and limited to certain serial-prefixes (DLJO, DLJP, DLOQ, DLSK, DMBA), requiring detailed parts tracking.","Multiple referenced service documents and regulatory actions (Rolls Royce SBs RB.211‑72‑C925 Rev 2, RB.211‑72‑D176, RB.211‑72‑C815 Rev 3, RB.211‑72‑C930; UK CAA and FAA ADs) that operators must consult.","Differing compliance windows: a 100‑hour time‑in‑service deadline for the configuration check versus immediate applicability for inspections and removals, creating scheduling and operational impacts.","Recordkeeping and maintenance-history review burden to establish whether SB RB.211‑72‑C925 Rev 2 was incorporated and to confirm bearing time in service.","Operational interruption risk if both engines on an aircraft are found to have pre‑mod bearings of concern, potentially leading to grounding or part replacements.","Inspection uncertainty: oil scavenge filter visual inspections for bronze/steel debris rely on detection sensitivity and may produce false negatives/positives."],"plain_english_summary":"This Airworthiness Directive requires operators of certain Rolls‑Royce RB211‑535 series engines that have not had Service Bulletin RB.211‑72‑C925 (Rev 2) applied to check engine configuration, inspect oil scavenge filters for bearing debris, and replace specified radial drive steady bearings identified by part number and serial prefixes. The stated purpose is to detect and remove bearings at risk of imminent failure; compliance includes a 100‑hour deadline for the configuration check and immediate inspection/replacement actions to remove the unsafe parts from service."},"kimi_summary":{"content_quality":"ok","complexity_score":4,"scope_assessment":{"changed":true,"description":"The original directive (October 1999) required only oil filter inspections to detect bearing debris. Amendment 2 significantly expanded the scope by: (1) adding a terminating action that narrows applicability to pre-modification bearings only, (2) introducing a new aircraft-level configuration requirement preventing dual-engine risk, and (3) adding mandatory bearing replacement for specific serial numbers. The directive evolved from a simple inspection requirement to a comprehensive risk mitigation strategy addressing both detection and prevention."},"complexity_factors":["Multiple cross-references to external Rolls-Royce Service Bulletins (SB RB.211-72-D176, SB RB.211-72-C815 Rev 3, SB RB.211-72-C930) — operators must obtain and follow separate technical documents","Specific part number and serial number prefix identification required (P/N LK76084 with prefixes DLJO, DLJP, DLOQ, DLSK, DMBA)","Nested applicability criteria: applies only to specific engine models AND only those not incorporating a specific service bulletin revision","Three distinct compliance streams with different timing requirements (immediate vs. 100 hours)","Technical aviation terminology throughout (IPC references, time in service, scavenge filters, etc.)","Reference to overseas regulatory equivalents (UK CAA ADs and FAA AD) for additional context"],"plain_english_summary":"This CASA Airworthiness Directive updates mandatory safety actions for Rolls‑Royce RB211‑535 series engines to address failures of the radial drive steady bearing. It requires operators to avoid having both engines fitted with at‑risk, pre‑Service Bulletin bearings, inspect oil filters for metal debris, and remove specified bearing serials from service.\n\nThe rule affects aircraft (notably many Boeing 757s) with the listed RB211 variants and aims to prevent bearing degradation that can lead to dual‑engine failure."},"flash_summary_failed":{"failed":true,"reason":"Unauthenticated. Configure AI_GATEWAY_API_KEY or use a provider module. Learn more: https://ai-sdk.dev/unauthenticated-ai-gateway","source":"analysis-cron"}},"importantCases":[],"_links":{"self":"/api/acts/ad-rb211-21-amdt-2-radial-drive-steady-bearing","history":"/api/acts/ad-rb211-21-amdt-2-radial-drive-steady-bearing/history","analysis":"/api/acts/ad-rb211-21-amdt-2-radial-drive-steady-bearing/analysis","conflicts":"/api/acts/ad-rb211-21-amdt-2-radial-drive-steady-bearing/conflicts","importantCases":"/api/acts/ad-rb211-21-amdt-2-radial-drive-steady-bearing/important-cases","documents":"/api/acts/ad-rb211-21-amdt-2-radial-drive-steady-bearing/documents"}}