{"id":"F2006B08493","name":"AD/CF6/55 - Vertical Link And Pylon Attachment Bolts","slug":"ad-cf6-55-vertical-link-and-pylon-attachment-bolts","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":51190,"registerId":"commonwealth-F2006B08493-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"AIRWORTHINESS DIRECTIVE","sectionType":"part","heading":"AIRWORTHINESS DIRECTIVE","content":"# ![](image.001.png)  \nAIRWORTHINESS DIRECTIVE\n\nFor the reasons set out in the background section, the CASA delegate whose signature appears below issues the following Airworthiness Directive (AD) under subregulation 39.1 (1) of CASR 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.001.png)  \n\nGeneral Electric Turbine Engines \\- CF6 Series","sortOrder":0},{"sectionNumber":"AD/CF6/55 Vertical Link And Pylon Attach","sectionType":"part","heading":"AD/CF6/55 Vertical Link And Pylon Attachment Bolts 7/2004","content":"# AD/CF6/55 Vertical Link And Pylon Attachment Bolts 7/2004\n\nApplicability: General Electric Company (GE) CF6-80E1A2 and \\-80E1A4 turbofan engines with left vertical link bolts part number (P/N) 1304M26P02 installed, and pylon attachment bolts originally torqued to 450-500 lb ft.\n\nNote 1: These engines are installed on, but not limited to Airbus Industrie A330-200 and A330-300 aeroplanes.\n\nRequirement: 1. Reduce the pylon attachment bolt torque on each of the five bolts to 400-450 lb ft in accordance with paragraph 3 of the Accomplishment Instructions of Alert Service Bulletin (ASB) No. CF6- 80E1 S/B 72-A0184, Revision 1, dated February 26, 2002.\n\n2. Remove the three left vertical link bolts, P/N 1304M26P02, and replace with three left vertical link bolts, P/N 1304M26P05.\n\nNote 2: Bolts P/N 1304M26P05 are serialized and have a calculated life limit published in the Life Limits section of Chapter 5 of the engine manual.\n\nNote 3: FAA AD 2003-26-11 Amdt 39-13409 refers.\n\nCompliance: For Requirement 1:\n\nFor CF6-80E1A2 engines, before exceeding 7,160 cycles-since-new (CSN) or before exceeding 5,120 cycles-since- last-installation (CSLI), whichever is later.\n\nFor CF6-80E1A4 engines before exceeding 6,520 CSN or before exceeding 4,480 CSLI, whichever is later.\n\nFor Requirement 2:\n\nAt the next shop visit.\n\nThis Airworthiness Directive becomes effective on 8 July 2004.","sortOrder":1}],"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"},"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":false,"description":"This AD remains focused on a narrowly defined unsafe condition affecting specific hardware (pylon attachment bolts and left vertical link bolts) on CF6‑80E1A2 and CF6‑80E1A4 engines. It does not broaden the class of affected parts or engines beyond the stated applicability. The only notable extension of obligations beyond the immediate physical corrective actions is the requirement to use serialized, life‑limited replacement bolts (P/N 1304M26P05), which creates an ongoing tracking requirement but does not change the AD’s substantive scope."},"complexity_factors":["Short instrument with two main mandatory actions (Requirement 1 and Requirement 2).","Two engine variants (CF6‑80E1A2 and CF6‑80E1A4) with different CSN/CSLI compliance thresholds (Compliance section).","Cross‑reference to GE Alert Service Bulletin No. CF6‑80E1 S/B 72‑A0184 Rev 1 (procedural detail located outside the AD).","Replacement part is serialized and life‑limited, with the life limit published in the engine manual (Note 2) — creates ongoing recordkeeping obligations beyond immediate compliance.","Reference to an FAA AD (2003‑26‑11), adding an external regulatory cross‑reference.","Compliance timing uses two metrics (CSN and CSLI) and a ‘whichever is later’ conditional, adding a small layer of conditional logic."],"plain_english_summary":"**What this Airworthiness Directive (AD) actually requires — mechanically**\n\n- Reduce the torque on each of the five pylon‑to‑engine attachment bolts from 450–500 lb·ft to 400–450 lb·ft, following paragraph 3 of the Accomplishment Instructions of GE Alert Service Bulletin (ASB) No. CF6‑80E1 S/B 72‑A0184, Revision 1 (Requirement 1).\n- Remove the three left vertical link bolts currently fitted with part number (P/N) 1304M26P02 and replace them with left vertical link bolts P/N 1304M26P05 (Requirement 2).\n\n(See the AD’s “Requirement” section for these two mandated actions.)\n\n**Who is affected**\n\n- Operators and maintenance organisations responsible for General Electric CF6‑80E1A2 and CF6‑80E1A4 turbofan engines that have: (a) left vertical link bolts P/N 1304M26P02 installed; and (b) pylon attachment bolts that were originally torqued to 450–500 lb·ft.  The AD notes these engines are installed on — but not limited to — Airbus A330‑200 and A330‑300 aeroplanes.\n\n**When the work must be done (compliance timing)**\n\n- Torque reduction (Requirement 1):\n  - For CF6‑80E1A2 engines, before exceeding 7,160 cycles‑since‑new (CSN) or before exceeding 5,120 cycles‑since‑last‑installation (CSLI), whichever is later.\n  - For CF6‑80E1A4 engines, before exceeding 6,520 CSN or before exceeding 4,480 CSLI, whichever is later.\n- Bolt replacement (Requirement 2): at the next shop visit.\n\n(See the AD’s “Compliance” section for these specific thresholds.)\n\n**Other technical points the AD makes**\n\n- Replacement bolts P/N 1304M26P05 are serialized and have a calculated life limit published in the engine manual (Note 2). That creates an ongoing tracking and life‑limit compliance obligation after replacement.\n- The AD points maintenance personnel to GE’s ASB for the torque‑reduction procedure and references an FAA AD on the same subject (FAA AD 2003‑26‑11) (Notes and Requirement text).\n\n**Why the AD exists (stated purpose) and what that implies in practical terms**\n\n- The AD is presented as corrective action for an unsafe condition related to the pylon/vertical link attachment hardware: changing the torque specification and replacing specific left vertical link bolts is intended to reduce the safety risk that prompted the directive (this is stated in the AD background and requirement structure).\n\nPractical implications, trade‑offs and implementation considerations:\n\n- Direct costs to operators: labour to check and retorque five pylon bolts per engine; cost of three replacement bolts (P/N 1304M26P05) and associated installation at the next shop visit. (Requirement 1–2; Compliance.)\n- Ongoing administrative cost: replacement bolts are serialized with published life limits, so operators must record serial numbers and track remaining life against the engine manual’s limits (Note 2). That increases maintenance recordkeeping and inventory control obligations beyond the immediate replacement.\n- Scheduling impact: the torque change has explicit CSN/CSLI thresholds that may force earlier maintenance events for some engines; replacement is deferred until the next shop visit, which gives operators some scheduling flexibility but requires shop capacity planning (Compliance; Requirement 2).\n- Dependence on OEM technical material: the AD requires following a GE ASB procedure for torque reduction (Requirement 1). Operators need access to that document and must apply its detailed steps; independent MROs can perform the work if they comply with the ASB and recordkeeping requirements.\n- Market effects: demand for the serialized replacement bolt (P/N 1304M26P05) may rise among affected operators, with potential short‑term price and supply implications. The serialized nature may concentrate aftermarket supply and tracking around the OEM and authorised parts distributors (Note 2).\n- Safety benefit concentration and cost diffusion: the primary safety benefit accrues to operators of the affected engine models (a concentrated beneficiary group). The compliance cost is borne directly by those operators rather than a wider group (Requirements and Compliance).\n- Implementation risk: enforcing correct torque values requires calibrated tools and competent personnel; failure to follow the ASB procedure correctly could leave the unsafe condition uncorrected. The AD’s clear torque band and ASB cross‑reference reduce but do not eliminate that risk (Requirement 1).\n\n**Concrete behavioural changes required of affected parties**\n\n- Maintenance teams must inspect pylon attachment torque and retorque to 400–450 lb·ft per the ASB (Requirement 1).\n- Operators must remove and replace specific left vertical link bolts at the next shop visit and start life‑limit tracking for the new serialized bolts (Requirement 2; Note 2).\n\n**Where the AD points for further technical detail**\n\n- GE Alert Service Bulletin CF6‑80E1 S/B 72‑A0184, Revision 1 (for torque procedure).\n- Engine manual Chapter 5, Life Limits section (for replacement bolt life limits).\n- FAA AD 2003‑26‑11 is referenced for related regulatory context (Note 3)."},"kimi_summary":{"content_quality":"ok","complexity_score":3,"scope_assessment":{"changed":false,"description":"This Airworthiness Directive maintains its original narrow scope as a targeted safety intervention for specific bolt issues on specific engine models. The document reflects the standard AD format with clear applicability, requirement, and compliance sections consistent with its original regulatory purpose."},"complexity_factors":["Multiple applicability conditions requiring cross-checking of engine model, bolt part numbers, and original torque specifications","Two distinct requirements with different compliance timelines and methods","Technical compliance thresholds involving two different metrics (cycles-since-new vs cycles-since-last-installation) with 'whichever is later' logic","Reference to external technical documents (Alert Service Bulletin CF6-80E1 S/B 72-A0184) for detailed accomplishment instructions","Cross-reference to FAA AD 2003-26-11 indicating international regulatory coordination","Specific part number tracking and serialized component lifecycle management requirements"],"plain_english_summary":"The CASA safety order requires operators and maintenance crews to reduce bolt preload on certain GE CF6‑80E1 engines fitted to Airbus A330‑200/300s and to replace flawed left vertical link bolts with improved, serialized parts at overhaul.  \n\nIt targets aircraft using those engines to prevent bolt failure that could lead to engine separation in flight, mandating corrective work before unsafe service-life limits are reached."}},"importantCases":[],"_links":{"self":"/api/acts/ad-cf6-55-vertical-link-and-pylon-attachment-bolts","history":"/api/acts/ad-cf6-55-vertical-link-and-pylon-attachment-bolts/history","analysis":"/api/acts/ad-cf6-55-vertical-link-and-pylon-attachment-bolts/analysis","conflicts":"/api/acts/ad-cf6-55-vertical-link-and-pylon-attachment-bolts/conflicts","importantCases":"/api/acts/ad-cf6-55-vertical-link-and-pylon-attachment-bolts/important-cases","documents":"/api/acts/ad-cf6-55-vertical-link-and-pylon-attachment-bolts/documents"}}