{"id":"F2006L03504","name":"AD/JT8D/42 Amdt 1 - 8th Stage High Pressure Compressor Discs","slug":"ad-jt8d-42-amdt-1-8th-stage-high-pressure-compressor-discs","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":61034,"registerId":"commonwealth-F2006L03504-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"Pratt and Whitney Turbine Engines - JT8D","sectionType":"division","heading":"Pratt and Whitney Turbine Engines - JT8D Series","content":"### Pratt and Whitney Turbine Engines - JT8D Series\n\n| AD/JT8D/42 Amdt 1 | 8th Stage High Pressure Compressor Discs. | 13/2006 DM |\n| ----------------- | ----------------------------------------- | ---------- |\n\n| Applicability: | Pratt & Whitney (PW) JT8D-1, -1A, -1B, -7, -7A, -7B, -9, -9A, -11, -15, -15A, -17,-17A, -17R and -17AR turbofan engines, with 8th stage high pressure compressor (HPC) front hubs as listed in Table 1 of FAA AD 2006-17-07R1.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                               |\n| -------------- | -------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |\n| Requirement:   | Action in accordance with FAA AD 2006-17-07R1 with a revised effective date of26 October 2006.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                               |\n| Compliance:    | As detailed in FAA AD 2006-17-07R1 with a revised effective date of26 October 2006.Any engine with a HPC front hub that has been inspected in accordance with AD/JT8D/29 Amdt 2 (FAA AD 2003-12-07) counts as an inspection towards compliance with this AD.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                 |\n|                | This Amendment becomes effective on 26 October 2006.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                         |\n| Background:    | This AD requires either replacing HPC front hubs and HPC disks that have operated at any time with PWA 110-21 coating and that operated in certain engine models, or, visually inspecting and FMPI for cracking of those parts and re-plating them if they pass inspection. This AD results from an investigation by PW, which concluded that any HPC front hub or HPC disk coated with PWA 110-21 that ever operated on JT8D-15, -15A, -17, -17A, -17R, -17AR, -209, -217, -217A, -217C, and -219 turbofan engines, could crack before reaching their published life limit.This AD requires the same actions, but makes necessary corrections to inadvertent reference errors and omissions found in FAA AD 2006-17-07, and relaxes some of the compliance times in Table 5.The original issue of this AD became effective 26 October 2006. |\n\n![](image.001.png)  \nJames Coyne  \nDelegate of the Civil Aviation Safety Authority\n\n23 October 2006","sortOrder":0},{"sectionNumber":"AD/JT8D/42 Amdt 1","sectionType":"part","heading":"AD/JT8D/42 Amdt 1","content":"## AD/JT8D/42 Amdt 1","sortOrder":1},{"sectionNumber":"8th","sectionType":"part","heading":"Stage High Pressure Compressor Discs.","content":"## 8th Stage High Pressure Compressor Discs.","sortOrder":2},{"sectionNumber":"13/2006 DM","sectionType":"part","heading":"13/2006 DM","content":"## 13/2006 DM","sortOrder":3}],"analysis":{"flash_summary":{"complexity_score":4,"scope_assessment":{"changed":true,"description":"The amendment does not change the core actions required (inspect, re‑plate, or replace affected HPC hubs/disks) but corrects reference errors/omissions in the original FAA AD and relaxes some compliance times in Table 5. Applicability remains limited to listed JT8D engine models and the hubs identified in Table 1 of the FAA AD (Background; Applicability; Requirement; Compliance)."},"complexity_factors":["Cross-reference to external FAA AD (FAA AD 2006-17-07R1) creates dependence on another instrument for full requirements (Requirement).","Technical scope limited to parts with specific coating (PWA 110-21) and particular JT8D models, increasing technical specificity but narrowing applicability (Applicability; Background).","Interplay with prior ADs: inspections performed under AD/JT8D/29 Amdt 2 are creditable toward compliance, requiring operators to track historical maintenance records (Compliance).","Amendment corrects inadvertent reference errors and omissions and relaxes some compliance times (Table 5), which introduces small interpretive adjustments rather than new substantive duties (Background).","Operational burden falls on operators to fund inspections, re‑plating or replacement and to schedule compliance within revised times (Requirement; Compliance)."],"plain_english_summary":"Requires operators of specified Pratt & Whitney JT8D engines to inspect, re‑plate, or replace 8th‑stage high‑pressure compressor front hubs and disks that ever had PWA 110‑21 coating, following FAA AD 2006‑17‑07R1 (Requirement). Operators pay for inspections, re‑plating or replacement and may count prior inspections under AD/JT8D/29 Amdt 2 toward compliance (Compliance). The amendment corrects reference errors and relaxes some compliance times while keeping the same core actions (Background)."},"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":4,"scope_assessment":{"changed":false,"description":"This is a standard aviation safety directive (Airworthiness Directive) that maintains its original narrow scope: addressing a specific mechanical defect in specific engine models. The amendment does not expand beyond the original safety purpose; it merely corrects reference errors and adjusts compliance timelines."},"complexity_factors":["Heavy reliance on external document: requires compliance with FAA AD 2006-17-07R1, meaning the full requirements are not contained in this document","Technical aviation terminology throughout (HPC, FMPI, turbofan, PWA 110-21 coating)","Multiple nested conditions: applicability depends on specific engine model numbers AND coating type AND operational history","Cross-reference to prior Australian directive AD/JT8D/29 Amdt 2 for partial compliance credit","Table references (Table 1, Table 5) that are not reproduced in this document","Amendment structure creates layered history: this is Amendment 1 correcting an original issue that itself corrected an FAA AD"],"plain_english_summary":"This Australian Airworthiness Directive requires operators and maintenance organisations to either replace or inspect (by FMPI) and re-plate 8th-stage high-pressure compressor front hubs and discs on specified Pratt & Whitney JT8D engine models if those parts were coated with PWA 110-21. It responds to early-life cracking discovered by the manufacturer and mirrors an FAA directive (with a revised effective date of 26 October 2006), addressing a potential in-flight engine-failure safety risk."}},"importantCases":[],"_links":{"self":"/api/acts/ad-jt8d-42-amdt-1-8th-stage-high-pressure-compressor-discs","history":"/api/acts/ad-jt8d-42-amdt-1-8th-stage-high-pressure-compressor-discs/history","analysis":"/api/acts/ad-jt8d-42-amdt-1-8th-stage-high-pressure-compressor-discs/analysis","conflicts":"/api/acts/ad-jt8d-42-amdt-1-8th-stage-high-pressure-compressor-discs/conflicts","importantCases":"/api/acts/ad-jt8d-42-amdt-1-8th-stage-high-pressure-compressor-discs/important-cases","documents":"/api/acts/ad-jt8d-42-amdt-1-8th-stage-high-pressure-compressor-discs/documents"}}