{"id":"F2005L01361","name":"AD/CF6/57 Amdt 1 - HPT S2 NGV Distress","slug":"ad-cf6-57-amdt-1-hpt-s2-ngv-distress","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":35179,"registerId":"commonwealth-F2005L01361-current","compilationNumber":null,"startDate":"2026-04-01","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"General Electric Turbine Engines - CF6 S","sectionType":"division","heading":"General Electric Turbine Engines - CF6 Series","content":"### General Electric Turbine Engines - CF6 Series\n\n| AD/CF6/57 Amdt 1 | HPT S2 NGV Distress | 7/2005 |\n| ---------------- | ------------------- | ------ |\n\n```html\n

Applicability:

This AD applies to General Electric Company (GE) CF6-80C2A1, -80C2A2,
-80C2A3, -80C2A5, -80C2A5F, -80C2A8, -80C2B1, -80C2B1F, - 80C2B2,
-80C2B2F, -80C2B4, -80C2B4F, -80C2B5F, -80C2B6, -80C2B6F, - 80C2B6FA,
-80C2B7F, -80C2B8F, and -80C2D1F turbofan engines, with the part numbers (P/Ns) of high pressure turbine (HPT) stage 2 nozzle guide vanes (HPT S2 NGVs) listed in the following Table 1, installed:

Table 1. -Affected HPT S2 NGVs

HPT S2 NGV:

Provided that:

P/N 1347M66G03, P/N 1347M66G04, and P/Ns 1815M81G01 through 1815M81G07.

Insert, P/N 1957M40G01 or P/N 1957M40G02, was installed during repair.

P/Ns 9373M80G07 through 9373M80G22, and P/Ns 9373M80G25 through 9373M80G32.

Insert, P/N 1957M40G01 or P/N 1957M40G02, was installed during repair, or NGV was repaired by GE between 1 April 1998 through 30 September 1999.

P/Ns 9373M80G33 through 9373M80G36

Part was repaired.

P/Ns 2080M38G01 through 2080M38G16, and P/Ns 2080M38G19 through 2080M38G24.

Insert, P/N 1957M40G01 or P/N 1957M40G02, was installed during modification or repair.

P/Ns 2080M19G01 through 2080M19G04, P/Ns 2080M19G07 through 2080M19G16, P/Ns 2080M19G19 through 2080M19G46, P/Ns 2080M19G49 through 2080M19G70, and P/Ns 2080M19G73 through 2080M19G80.

Insert, P/N 1957M40G01 or P/N 1957M40G02, was installed during modification or repair.

\n```\n\n| | Note 1: These engines are installed on, but not limited to, Airbus A300, Airbus A310, Boeing 747, Boeing 767, and McDonnell Douglas MD-11 aeroplanes. |\n| ------------ | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |\n| Requirement: | 1. Initial InspectionFlex-boroscope inspect the NGVs following paragraph 3.B.(3) through 3.B.(5) of Accomplishment Instructions of GE Service Bulletin (SB) No. CF6-80C2 S/B 72-0952, Revision 6 dated 5 May 2003.For NGVs installed in engines operated as more than one engine model configuration (thrust level), use the lowest applicable initial inspection threshold, and use the reinspection intervals associated with the current engine model.2. Reinspection or removal.Reinspect or remove from service NGVs as detailed in GE SB No. CF6-80C2 S/B 72-0952, Revision 6.For NGVs installed in engines operated as more than one engine model configuration (thrust level), use the lowest applicable initial inspection threshold, and use the reinspection intervals associated with the current engine model.Note 2: FAA AD 2004-22-07 Amdt 39-13835 refers. |\n| Compliance: | Initial Inspection Thresholds1. Remains unchanged as detailed in the original issue of this Directive as: For all P/N NGVs, initial-inspect after 20 January 2005 (the effective date of the original issue of this Directive) at the following applicable initial inspection thresholds:(a) For CF6-80C2A2, -80C2B2, and -80C2B2F engines, inspect at or before accumulating 1,600 HPT cycles-since-overhaul (CSO).(b) For CF6-80C2A1, -80C2A3, -80C2A5, -80C2A5F, -80C2A8, - 80C2B1, -80C2B1F, -80C2B4, -80C2B4F, -80C2B5F, -80C2B6, -80C2B6F, - 80C2B6FA, -80C2B7F, -80C2B8F, and -80C2D1F engines, inspect at or before accumulating 800 CSO.(c) For engines listed in compliance paragraphs (1)(a) and (1)(b) of this Directive that are already beyond the initial inspection thresholds, inspect at or before accumulating an additional 200 CSO after 20 January 2005 (the effective date of the original issue of this Directive). |\n\n| | Reinspection or removal.2. In accordance with the Conditions and Reinspection intervals listed in the \"Inspection Table for Cracking in the Airfoil Outer Fillet\", Figure 5, Sheets 1 and 2, of GE SB No. CF6-80C2 S/B 72-0952 Revision 6.(a) If the recommendation contained in Figure 5, Sheets 1 and 2, of GE SB No. CF6-80C2 S/B 72-0952, Revision 6, states \"reinspect at next regular S2 Blade inspection,\" then for the purposes of this Directive, the next regular S2 Blade Inspection must be within the following intervals:(i) For CF6-80C2D1F engines with 5.0 or more hours per flight leg, the next regular S2 Blade inspection means within 250 cycles-since-last-inspection (CSLI).(ii) For all other engines applicable to this Directive, the next regular S2 Blade inspection means within 400 CSLI. |\n| ----------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------ |\n| | This Amendment becomes effective on 7 July 2005. |\n| Background: | The Directive requires GE CF6-80C2 turbofan engines with certain part number HPT S2 NGV’s installed to undertake flex boroscope inspections of the HPT S2 NGV’s. This Directive results from an uncontained engine failure due to HPT S2 NGV distress. The actions detailed in this Directive are to prevent blade separation from HPT S2 NGV distress, which could result in an uncontained engine failure.This amendment makes correction to paragraph 2(a)(i) of the compliance section of this Directive to read 5.0 or more hours per flight leg instead of 5.0 or more cycles per flight leg. There are no other changes to the Directive.The original issue of this Directive became effective on 20 January 2005. |\n\n![](image.001.png) \nJames Coyne \nDelegate of the Civil Aviation Safety Authority\n\n19 May 2005","sortOrder":0},{"sectionNumber":"AD/CF6/57 Amdt 1","sectionType":"part","heading":"AD/CF6/57 Amdt 1","content":"## AD/CF6/57 Amdt 1","sortOrder":1},{"sectionNumber":"HPT S2 NGV Distress","sectionType":"part","heading":"HPT S2 NGV Distress","content":"## HPT S2 NGV Distress","sortOrder":2},{"sectionNumber":"7/2005","sectionType":"part","heading":"7/2005","content":"## 7/2005","sortOrder":3}],"analysis":{"flash_summary":{"complexity_score":7,"scope_assessment":{"changed":false,"description":"This Amendment makes a narrow correction to the original Directive: it changes the phrase in Compliance paragraph 2(a)(i) to read \"5.0 or more hours per flight leg\" instead of \"5.0 or more cycles per flight leg.\" The correction alters unit wording to reduce ambiguity but does not expand the set of affected engines, the inspection requirements, or the remedial actions. No substantive scope expansion beyond the original safety objective is introduced."},"complexity_factors":["Large list of affected part numbers across multiple ranges and conditional subsets (several dozen P/Ns listed in the Applicability table).","Cross‑reference to an external technical document: GE Service Bulletin CF6-80C2 S/B 72-0952 Revision 6 (specific paragraphs and Figure 5 Sheets 1–2).","Different timing metrics used: cycles‑since‑overhaul (CSO), cycles‑since‑last‑inspection (CSLI), and flight hours per leg — and a corrected unit in this amendment (hours, not cycles).","Conditional logic for engines operated in multiple configurations: requirement to use the lowest applicable initial inspection threshold and the reinspection intervals of the current engine model.","Nested outcomes in the SB's inspection table (remove, repair, or reinspect) with reinspection sometimes tied to the next regular S2 Blade inspection, which the AD then defines differently for one engine sub‑group.","Applicability depends not only on part number but on repair/modification history (e.g. whether an insert was installed or whether GE repaired the NGV in a given date range).","Multiple engine model subgroups with distinct thresholds (e.g. 800 CSO vs 1,600 CSO) and a transitional clause for engines already beyond initial thresholds (additional 200 CSO)."],"plain_english_summary":"**What this instrument requires (in simple terms)**\n\n- This is an airworthiness directive that requires targeted inspections of the high-pressure turbine stage 2 nozzle guide vanes (HPT S2 NGVs) on certain General Electric CF6-80C2 turbofan engines. The inspections must follow the specified steps in GE Service Bulletin CF6-80C2 S/B 72-0952, Revision 6 (paragraphs 3.B.(3)–3.B.(5) and Figure 5 Sheets 1–2).\n\n- The directive applies only to CF6-80C2 engines that have particular HPT S2 NGV part numbers installed. Some of those part numbers are further limited to cases where a specified insert (P/N 1957M40G01 or 1957M40G02) was fitted during repair or modification, or where the NGV was repaired by GE in a specified period. (See the Applicability table for the affected P/N ranges and the conditions that make them subject to the AD.)\n\n- The stated safety problem is HPT S2 NGV distress that can lead to blade separation and an uncontained engine failure. The AD says that the inspections and the follow-up actions in the GE Service Bulletin are intended to prevent that outcome. (Background and Requirement sections.)\n\n**Who it affects**\n\n- Airlines and other aircraft operators who fly aeroplanes fitted with the listed GE CF6-80C2 engine variants and affected NGV part numbers. Note 1 lists likely aeroplane types where these engines are installed (for example, Airbus A300/A310, Boeing 747/767, MD-11), but the directive applies wherever an affected engine/part combination is in service.\n\n- Maintenance organisations and engineers who must perform the flex‑boroscope inspections and any required reinspection, repair, removal or replacement work according to the GE Service Bulletin and the AD.\n\n**What operators must do and when**\n\n- Initial inspection: Perform a flex‑boroscope inspection of the HPT S2 NGVs per GE SB paragraphs referenced. The timing is driven by cycles‑since‑overhaul (CSO) and is different by engine model group:\n - For CF6-80C2A2, -80C2B2 and -80C2B2F: inspect at or before 1,600 HPT CSO. (Compliance ¶1(a))\n - For the other listed engine models (CF6-80C2A1, A3, A5, etc.): inspect at or before 800 HPT CSO. (Compliance ¶1(b))\n - If an engine is already past its initial threshold as of 20 January 2005, the engine must be inspected within an additional 200 CSO. (Compliance ¶1(c))\n\n- Reinspection / removal: Follow the Conditions and Reinspection intervals set out in Figure 5 (\"Inspection Table for Cracking in the Airfoil Outer Fillet\") of GE SB Revision 6. That table tells you whether to remove the NGV, repair it, or reinspect and at what interval.\n\n- If the table tells you to \"reinspect at next regular S2 Blade inspection,\" the AD defines the interval for that next regular inspection as:\n - For CF6-80C2D1F engines that are operated with 5.0 or more hours per flight leg: within 250 cycles‑since‑last‑inspection (CSLI). (Corrected by this amendment.)\n - For all other applicable engines: within 400 CSLI.\n\n- All inspections and follow-up actions must be done in accordance with GE SB No. CF6-80C2 S/B 72-0952 Revision 6; the AD enforces that SB as mandatory for the listed engines/parts.\n\n**Why it matters and how it changes behaviour**\n\n- The AD makes a specific maintenance action mandatory (inspection and possible repair/removal) for a subset of CF6-80C2 engines. Operators must track part numbers, repair histories (e.g. whether a particular insert was fitted or the NGV was repaired by GE in a specified date range), cycles‑since‑overhaul, cycles‑since‑last‑inspection and, for one threshold, average hours per flight leg.\n\n- Who pays: the operators pay the inspection labour and borescope equipment/contractor costs, and they bear repair/replacement costs and aircraft downtime if NGVs are found serviceable or need removal.\n\n- Who decides day‑to‑day: operators and their maintenance providers must follow the GE service instructions and the AD's specific timing rules; the regulator enforces compliance.\n\n**Costs, incentives and trade-offs**\n\n- Direct costs: labour for borescope inspections, potential NGV removal, repair or replacement, and aircraft out‑of‑service time.\n\n- Incentives: operators may choose to inspect earlier than required, to replace affected NGVs proactively, or to adjust operational deployment (e.g. avoid long‑leg utilisation for certain engines) to manage inspection timing thresholds tied to hours/cycle usage.\n\n- Compliance burden and implementation risk: the AD requires careful record keeping because applicability depends on specific part numbers and repair history, and inspection timing differs by engine model and by whether an engine operates long sectors (hours per flight leg). The amendment corrects a unit (\"hours\" not \"cycles\") in one rule, reducing the risk of misapplication for that threshold.\n\n- Opportunity costs: time and resources spent on these inspections reduce availability for other maintenance priorities; if many engines need immediate inspection/repair, scheduling pressure may concentrate downtime.\n\n**Mechanisms to watch operationally**\n\n- The AD makes a GE Service Bulletin mandatory. That shifts from recommended practice (SB) to regulatory requirement (AD), removing operator discretion to ignore the SB for affected parts.\n\n- The AD uses conservative logic for engines that can operate at multiple thrust/configurations: it requires operators to apply the lowest applicable initial inspection threshold across the configurations, which pushes inspections earlier in multi‑config usage scenarios. (Requirement ¶1 and Note in Applicability.)\n\n**Citation pointers in the instrument**\n\n- Applicability: table of affected HPT S2 NGV P/Ns and conditional notes about inserts/repair dates.\n- Requirement/Initial inspection: Compliance paragraphs 1(a)–(c).\n- Reinspection/removal: Compliance paragraph 2 and GE SB Figure 5 Sheets 1–2.\n- Amendment purpose: correction of paragraph 2(a)(i) to read \"5.0 or more hours per flight leg\" (not cycles).\n\n**Net effect**\n\n- The AD compels targeted inspections and follow‑up actions for a defined set of NGV parts on CF6-80C2 engines, with specific timing rules that vary by engine model and usage. The immediate purpose is stated as preventing blade separation and uncontained engine failure; operationally, it imposes inspection and potential repair/replacement costs and requires precise record keeping to determine applicability and inspection timing."},"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":6,"scope_assessment":{"changed":false,"description":"This is a minor amendment (Amendment 1) that corrects a single technical error in the compliance section — changing 'cycles' to 'hours' for the CF6-80C2D1F engine configuration regarding flight leg duration. The scope remains identical to the original January 2005 directive. No expansion of affected engines, part numbers, or inspection requirements occurred."},"complexity_factors":["Multiple nested conditions based on engine model variants (19 different CF6-80C2 sub-models listed)","Complex applicability matrix requiring cross-referencing between Table 1 and specific part numbers (P/Ns)","Conditional logic for repaired vs. unmodified parts — some rules only apply if specific insert parts (P/N 1957M40G01/G02) were installed during repair","Dual threshold system: different inspection deadlines based on engine thrust configuration (800 vs 1,600 cycles-since-overhaul)","Cross-reference dependency on external GE Service Bulletin (SB No. CF6-80C2 S/B 72-0952, Revision 6) for detailed inspection procedures","Nested exception for engines operated at multiple thrust levels requiring use of 'lowest applicable threshold'","Special interval calculation for high-utilisation engines (5.0+ hours per flight leg) vs standard operations (250 vs 400 cycles-since-last-inspection)","Technical aviation terminology throughout (CSO, CSLI, flex-boroscope, NGV, HPT) requiring domain knowledge"],"plain_english_summary":"This is an **Airworthiness Directive (AD)** — a mandatory safety order issued by Australia's Civil Aviation Safety Authority (CASA). It requires airlines and aircraft operators to inspect specific General Electric jet engines for a dangerous defect.\n\n**What it does:**\n- **Targets:** GE CF6-80C2 series turbofan engines (used on Airbus A300/A310, Boeing 747/767, and MD-11 aircraft)\n- **The problem:** Certain high-pressure turbine nozzles (HPT S2 NGVs — basically, stationary blades that guide hot gases onto rotating turbine blades) can crack and break apart. If this happens, pieces can fly out of the engine uncontrollably, potentially damaging the aircraft or causing engine failure.\n- **The fix:** Operators must use a flexible camera (flex-boroscope) to inspect these nozzles for cracks. Depending on what they find, they must either reinspect regularly or replace the damaged parts.\n\n**Who must comply:**\n- Airlines and maintenance organisations operating aircraft with the affected engine models\n- Specific part numbers are listed in a detailed table — the rules vary slightly depending on which exact nozzle part is installed and whether it has been repaired previously\n\n**Why it matters:**\nThis directive prevents catastrophic engine failures. An \"uncontained engine failure\" means debris escapes the engine casing — this can cut fuel lines, damage flight controls, or injure passengers. The amendment corrects a technical error in the original directive (changing \"cycles\" to \"hours\" for one specific engine configuration) to ensure inspections happen at the right time.\n\n**Key dates:**\n- Initial inspections needed by specific cycle counts (engine use measurements) after January 2005\n- This amended version took effect in July 2005"}},"importantCases":[],"_links":{"self":"/api/acts/ad-cf6-57-amdt-1-hpt-s2-ngv-distress","history":"/api/acts/ad-cf6-57-amdt-1-hpt-s2-ngv-distress/history","analysis":"/api/acts/ad-cf6-57-amdt-1-hpt-s2-ngv-distress/analysis","conflicts":"/api/acts/ad-cf6-57-amdt-1-hpt-s2-ngv-distress/conflicts","importantCases":"/api/acts/ad-cf6-57-amdt-1-hpt-s2-ngv-distress/important-cases","documents":"/api/acts/ad-cf6-57-amdt-1-hpt-s2-ngv-distress/documents"}}