{"id":"F2006L01464","name":"AD/RB211/35 Amdt 2 - High Pressure Turbine","slug":"ad-rb211-35-amdt-2-high-pressure-turbine","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":59085,"registerId":"commonwealth-F2006L01464-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/RB211/35 Amdt 2 | High Pressure Turbine | 7/2006 DM |\n| ------------------ | --------------------- | --------- |\n\n```html\n

Applicability:

Rolls Royce Model RB211-524 series engines, all marks, installed on Boeing 747 and 767 and Lockheed L1011 aeroplanes fitted with High Pressure (HP) Turbine discs only listed in Table 1 of this AD.

Table 1: Applicable HP Turbine Discs.

Part No

Serial No. to Serial No.

FK24651

LAQDY6061

Single Disc

FK24651

LDRCZ10453

LDRCZ10720 (INCLUSIVE)

FK24651

LQDY9903

Single Disc

FK24651

LQDY9924

Single Disc

FK24790

CRCZ6

CRCZ25 (INCLUSIVE)

FK24790

LDRCZ10717

LDRCZ14022 (INCLUSIVE)

UL23166

LQDY6516

LQDY8718 (INCLUSIVE)

UL24561

LQDY6389

LQDY6438 (INCLUSIVE)

UL24994

LQDY6405

LQDY8727 (INCLUSIVE)

UL29472

LAQDY6013

LAQDY6092 (INCLUSIVE)

UL29472

LDRCZ10029

LDRCZ10821 (INCLUSIVE)

UL29472

LDRCZ6000

LDRCZ6060 (INCLUSIVE)

UL29472

LQDY6592

LQDY9993 (INCLUSIVE)

UL29473

CRCZ24

CRCZ25 (INCLUSIVE)

UL29473

CZ12135

CZ12333 (INCLUSIVE)

UL29473

LAQDY6010

LAQDY6088 (INCLUSIVE)

UL29473

LDRCZ10003

LDRCZ15372 (INCLUSIVE)

UL29473

LDRCZ6001

LDRCZ9995 (INCLUSIVE)

UL29473

LQDY10001

Single Disc

UL29473

LQDY9606

LQDY9989 (INCLUSIVE)

This AD does not apply to HP turbine discs, which are pre modification Service Bulletin (SB) 72-7730, post modification SB72-C109 or post modification
SB72-C762.

Requirement:

Carry out an eddy current inspection of the HP turbine disc in accordance with Section 3 - Accomplishment instructions of Rolls Royce NMSB 72-AE718 original issue or later EASA approved revision.

If a HP turbine disc has previously passed the inspection to Rolls-Royce NMSB
72-C816 or the focussed inspection carried out in accordance with Rolls-Royce TS594-J Overhaul Process Manual Task 70-00-00-200-223 at greater than 700 cycles since new, then either of these inspections meets the requirements of this AD.

Note: UK CAA AD G-2006-0002 EASA approval No. 2006-0034 dated 25 January 2006 refers.

Compliance:

1. For all discs listed in Table 2 that are fitted to RB211-524 engine marks except RB211-524D4 variants:

(a) If the HP turbine disc cycles were greater than 6150 cycles since new on
24 November 2005, inspect the HP turbine disc within 500 cycles from
24 November.

(b) If the HP turbine disc cycles were less than 6150 cycles since new on
24 November 2005, inspect the disc by whichever is the soonest of the conditions below:

(i) Prior to reaching 6650 cycles since new. The HP turbine disc life at inspection must be greater than 700 cycles since new.

(ii) At next shop visit where the HP turbine rotor is removed from the Combustor Outer Case and the HP turbine disc life is greater than 700 cycles since new. If a HP turbine disc that meets these cyclic life criteria is currently at shop visit, and if, at the effective date of this Airworthiness Directive, it has not yet been reinstalled into the Combustion Outer Case, then the HP turbine disc must be inspected in accordance with the requirements of this Airworthiness Directive at the current shop visit.

2. For all discs listed in Table 2 that are fitted to RB211-524D4 engine mark variants:

(a) If the HP turbine disc cycles were greater than 5000 cycles since new on
24 November 2005, inspect the HP turbine disc within 500 cycles from
24 November 2005.

\n```\n\n```html\n

(b) If the HP turbine disc cycles were less than 5000 cycles since new on
24 November 2005, inspect the HP turbine disc by whichever is the soonest of the conditions below:

(i) Prior to reaching 5500 cycles since new. The HP turbine disc life at inspection must be greater than 700 cycles since new.

(ii) At the next shop visit where the HP turbine rotor is removed from the Combustor Outer Case and the HP turbine disc life is greater than 700 cycles since new. If a HP turbine disc that meets these cyclic life criteria is currently at shop visit, and if, at the effective date of this Airworthiness Directive, it has not yet been reinstalled into the Combustion Outer Case, then the HP turbine disc must be inspected in accordance with the requirements of this Airworthiness Directive at the current shop visit.

3. For all other HP turbine discs specified in the Applicability of this Directive but not listed in Table 2 of this AD.

Inspect the HP turbine disc at next shop visit where the HP turbine rotor is removed from the Combustor Outer Case and the HP turbine disc life is greater than 700 cycles since new. If a HP turbine disc that meets these cyclic life criteria is currently at shop visit; and if, at the effective date of this Airworthiness Directive, it has not yet been reinstalled into the Combustion Outer Case, then the HP turbine disc must be inspected in accordance with the requirements of this Airworthiness Directive at the current shop visit.

Table 2

Part No

Serial No

Part No

Serial No

UL29473

LAQDY6043

UL29472

LQDY9125

UL29473

LAQDY6048

UL29472

LQDY9554

UL29473

LAQDY6079

UL29472

LQDY9582

UL29473

LDRCZ10057

UL29472

LQDY9895

UL29473

LDRCZ10264

UL29472

LQDY9910

UL29473

LDRCZ10415

UL29472

LQDY9947

UL29473

LDRCZ11402

UL29472

LQDY9960

UL29473

LDRCZ11425

UL24994

LQDY6777

\n```\n\n```html\n

UL29473

LDRCZ11497

UL24994

LQDY6792

UL29473

LDRCZ11663

UL24994

LQDY6859

UL29473

LDRCZ11679

UL24994

LQDY6860

UL29473

LDRCZ12301

UL24994

LQDY6866

UL29473

LDRCZ12308

UL24994

LQDY6869

UL29473

LDRCZ12316

UL24994

LQDY6934

UL29473

LDRCZ12319

UL24994

LQDY6946

UL29473

LQDY6957

UL24994

LQDY6963

UL29473

LQDY9075

UL23166

LQDY6745

UL29473

LQDY9084

UL23166

LQDY6846

UL29473

LQDY9557

UL23166

LQDY6848

UL29473

LQDY9906

UL23166

LQDY6954

UL29473

LQDY9956

FK24790

LDRCZ12492

UL29473

LQDY9970

FK24790

LDRCZ12694

UL29473

LQDY9985

This Amendment becomes effective on 11 May 2006.

Background:

A population of HP turbine discs that were manufactured between 1989-1999 and which were subject to possible machining anomalies, were believed to have an increased chance of suffering from cooling air hole cracking, compared to the general fleet population of HP turbine discs. As a result of this risk, Rolls-Royce issued Non-Modification Service Bulletin (NMSB) 72-C816, recommending in-service inspections of the subject discs.

Recently an RB211 HP turbine disc has been found with a crack which had propagated further than expected from the risk model that was used to establish the original inspection defined in the above NMSB. This has led to the need for a revision of the original inspection requirements.

An HP turbine disc fracture would be uncontained and create a potential unsafe condition. Accordingly, this AD introduces revised inspection requirements to reflect the increased risk of HP turbine disc cracking and potential disc fracture.

\n```\n\n| | This amendment corrects serial numbers and part numbers detailed in Table 1 and clarifies the compliance statements.The original issue of this AD was to become effective on 11 May 2006. |\n| --- | ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |\n\n![](image.001.png) \nJames Coyne \nDelegate of the Civil Aviation Safety Authority\n\n8 May 2006","sortOrder":0},{"sectionNumber":"AD/RB211/35 Amdt 2","sectionType":"part","heading":"AD/RB211/35 Amdt 2","content":"## AD/RB211/35 Amdt 2","sortOrder":1},{"sectionNumber":"High Pressure Turbine","sectionType":"part","heading":"High Pressure Turbine","content":"## High Pressure Turbine","sortOrder":2},{"sectionNumber":"7/2006 DM","sectionType":"part","heading":"7/2006 DM","content":"## 7/2006 DM","sortOrder":3}],"analysis":{"kimi_summary":{"content_quality":"ok","complexity_score":6,"scope_assessment":{"changed":true,"description":"This is Amendment 2 to an existing Airworthiness Directive, indicating the scope has evolved from the original issue. The amendment specifically 'corrects serial numbers and part numbers detailed in Table 1 and clarifies the compliance statements.' The original AD was prompted by a specific cracked disc discovery that exceeded the risk model used in the initial NMSB 72-C816 inspection requirements. The amendment reflects refined targeting of affected components based on operational experience and updated technical data, narrowing or correcting the population of discs subject to the most stringent compliance timelines (Table 2 discs) versus general applicability."},"complexity_factors":["Multiple nested conditional compliance pathways based on engine variant (RB211-524 vs RB211-524D4), cycle count thresholds (6150, 5000, 6650, 5500, 700), and calendar dates (24 November 2005)","Two detailed tables (Table 1 with 19 rows of part/serial numbers, Table 2 with 32 specific disc entries) requiring cross-referencing to determine applicability","Complex temporal calculations required: 'cycles since new' measured against a fixed historical date (24 November 2005) plus variable future windows (500 cycles, next shop visit)","Alternative compliance pathways: previous inspections under NMSB 72-C816 or TS594-J Overhaul Process Manual may satisfy requirements if performed at >700 cycles","Exemption clauses referencing three separate Service Bulletin modifications (SB 72-7730, SB72-C109, SB72-C762) that must be checked to determine if AD applies","Technical aviation terminology throughout (eddy current inspection, shop visit, Combustor Outer Case, cycles since new) requiring specialised knowledge","Amendment structure (Amdt 2) indicating evolution from original AD, with corrections to serial/part numbers and clarifications to compliance statements"],"plain_english_summary":"This CASA Airworthiness Directive mandates urgent eddy‑current inspections of specific Rolls‑Royce RB211‑524 HP turbine discs (manufactured 1989–1999) installed on certain Boeing 747/767 and Lockheed L1011 aircraft to detect cracking of cooling holes that could cause uncontained engine failure. \n\nIt affects Australian operators and maintenance organisations, requires inspections per Rolls‑Royce NMSB 72‑AE718 within cycle‑based deadlines, and exempts discs already modified by listed Rolls‑Royce service bulletins."},"flash_summary":{"complexity_score":5,"scope_assessment":{"changed":false,"description":"This amendment corrects and clarifies the original AD's part numbers, serial numbers and compliance wording but does not widen the substantive scope of the directive. The core requirement — mandatory inspections of the identified HP turbine discs and the timing/qualification rules — remains the same; the amendment reduces misidentification risk and refines compliance language rather than extending the AD to additional parts or new obligations."},"complexity_factors":["Extensive lists of part numbers and many serial number ranges across Table 1 and Table 2 (large lookup requirement for identification).","Conditional compliance rules that vary by engine mark (RB211‑524 generally vs RB211‑524D4) with different cycle thresholds.","Time‑dependent thresholds referencing a historical date (cycles since new as of 24 November 2005) and absolute cycle windows (e.g. inspect within 500 cycles, or prior to reaching X cycles).","Cross‑references to multiple manufacturer's documents and prior inspections (Rolls‑Royce NMSB 72‑AE718, NMSB 72‑C816, TS594‑J Overhaul Manual), and to EASA/UK approvals.","Exceptions based on modification status (pre‑SB72‑7730; post‑SB72‑C109 or SB72‑C762), creating exclusion logic.","Operational condition requiring inspection only when the disc has >700 cycles since new introduces an additional gating criterion.","Amendment corrects serial/part numbers and clarifies compliance language — adds a layer of change management for operators who adopted the original AD."],"plain_english_summary":"**What this instrument does (mechanically):**\n\n- Mandates targeted non‑destructive inspections (eddy‑current) of specific Rolls‑Royce RB211‑524 high‑pressure (HP) turbine discs listed in the directive (see Applicability and Table 1 / Table 2). (Requirement)\n- Allows certain previously completed inspections (Rolls‑Royce NMSB 72‑C816 or the focused inspection per Rolls‑Royce TS594‑J Overhaul Process Manual Task 70‑00‑00‑200‑223) to satisfy this directive when they were done and the disc has accumulated more than 700 cycles since new. (Requirement)\n- Sets different inspection timing rules depending on engine mark (RB211‑524 generally; RB211‑524D4 variants have earlier cycle thresholds) and on the disc's cycles‑since‑new as of 24 November 2005. Inspections must occur either within specific cycle windows or at the next relevant shop visit when the rotor is removed — provided the disc has >700 cycles since new at inspection. (Compliance)\n- Excludes HP turbine discs that are pre‑modification SB72‑7730 or have post‑modification SB72‑C109 or SB72‑C762. (Applicability)\n- This amendment corrects/clarifies part numbers and serial numbers in the tables and clarifies the compliance language; the AD becomes effective 11 May 2006. (Amendment note / Effective date)\n\n**Who is affected:**\n\n- Aircraft operators and owners using Boeing 747, Boeing 767 and Lockheed L1011 aircraft fitted with RB211‑524 series engines that contain the listed HP turbine discs (Applicability / Tables).\n- Maintenance organisations (MROs) and non‑destructive testing (NDT) technicians who perform eddy‑current inspections in accordance with Rolls‑Royce NMSB 72‑AE718 (Requirement).\n- Parts suppliers and engine overhaul facilities responsible for repair or replacement if cracks are found.\n\n**Why it matters (stated rationale and mechanical implications):**\n\n- Rationale given: a population of HP turbine discs manufactured 1989–1999 was suspected of machining anomalies that increase risk of cooling‑air hole cracking; a recent disc was found with unexpectedly advanced cracking, raising the risk of uncontained disc fracture. The AD revises/clarifies inspection requirements to address that risk. (Background / Requirement)\n- Mechanically, the AD forces earlier or additional inspections for the affected serials/part numbers than would otherwise occur under routine maintenance scheduling. That directly increases immediate maintenance workload and the chance of removing or replacing discs earlier than planned.\n\n**Who pays, who decides, and what behaviour changes:**\n\n- Who pays: aircraft operators (airlines, owners) bear the direct costs — inspection labour, possible additional shop visits, grounding/downtime, and the cost of repair or replacement if cracks are found. Indirect costs may include schedule disruption and parts lead times.\n- Who decides: the Civil Aviation Safety Authority (issuer) requires compliance; the AD delegates method details to Rolls‑Royce NMSB 72‑AE718 (and recognises prior NMSBs/overhaul tasks). That makes regulatory action dependent on manufacturer's service documents and EASA/UK approvals referenced in the AD (Requirement / Note).\n- Behaviour changes: operators must track cycles‑since‑new per disc and serial numbers against the tables, schedule eddy‑current inspections within the defined cycle windows or at the specified shop visits, and comply with the manufacturer's accomplishment instructions.\n\n**Costs, incentives, trade‑offs and implementation risks (practical testing of the stated purpose):**\n\n- Compliance burden: requires accurate record‑keeping of disc serials and cycles, and planned shop visits aligned to the AD windows. The amendment corrects serial/part numbers to reduce misapplication risk (Amendment note).\n- Direct costs: NDT inspection time and expertise (eddy‑current), potential removal and replacement of discs, shop visit timing adjustments, and parts/overhaul costs. These are concentrated on operators of affected aircraft/engines and MROs that service them.\n- Opportunity cost: time and shop capacity used for these inspections displaces other maintenance work.\n- Implementation risk: reliance on Rolls‑Royce service bulletins and approved revisions (and EASA approval) means the detailed inspection method and acceptance criteria are manufacturer‑driven. If service‑bulletin revisions occur, operators must follow the later EASA‑approved revision referenced in the AD, which can create coordination or interpretation issues between regulator, manufacturer and independent MROs.\n- Market effects: increased short‑term demand for authorised NDT and overhaul services (a commercial opportunity for qualified MROs). If parts or authorised repair slots are limited, some operators could face longer aircraft downtime.\n- Capture/rent‑seeking risk: the AD makes compliance dependent on a manufacturer's SB; this creates commercial opportunities for providers authorised to perform the work. The document does not on its face limit work to Rolls‑Royce facilities, provided the MRO can comply with the SB and regulatory approvals.\n\n**Narrowness of benefits and costs:**\n\n- Benefits (safety) are diffuse and accrue to the broader flying public and operators’ staff; costs are relatively concentrated on operators of the affected serial numbers and on MROs performing the inspections. The amendment's correction of serial/part numbers reduces the risk of misidentification (reducing compliance error costs). (Background / Amendment)\n\n**Practical steps operators must take:**\n\n- Check whether any HP turbine disc in their fleet appears in Table 1 or Table 2 and whether it is excluded by the SB modification status. (Applicability / Tables)\n- Calculate cycles‑since‑new as of 24 November 2005 and current cycles, apply the timing rules for their engine mark (RB211‑524 vs RB211‑524D4). (Compliance)\n- Arrange eddy‑current inspection per Rolls‑Royce NMSB 72‑AE718 (or rely on accepted prior inspections if they meet the stated criteria). (Requirement)\n- If cracks are found, follow required repair/replacement and record compliance with the AD.\n\n(References in parentheses indicate the AD sections where these items are addressed: Applicability, Requirement, Compliance, Tables, Background, Amendment note.)"},"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-rb211-35-amdt-2-high-pressure-turbine","history":"/api/acts/ad-rb211-35-amdt-2-high-pressure-turbine/history","analysis":"/api/acts/ad-rb211-35-amdt-2-high-pressure-turbine/analysis","conflicts":"/api/acts/ad-rb211-35-amdt-2-high-pressure-turbine/conflicts","importantCases":"/api/acts/ad-rb211-35-amdt-2-high-pressure-turbine/important-cases","documents":"/api/acts/ad-rb211-35-amdt-2-high-pressure-turbine/documents"}}