{"id":"F2005L03142","name":"AD/JT8D/41 - Compressor Hubs and Disks","slug":"ad-jt8d-41-compressor-hubs-and-disks","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":134345,"registerId":"commonwealth-F2005L03142-current","compilationNumber":null,"startDate":"2026-04-03","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/41 | Compressor Hubs and Disks | 12/2005 |\n| ---------- | ------------------------- | ------- |\n\n| Applicability: | Pratt & Whitney (PW) JT8D-1, -1A, -1B, - 7, -7A, -7B, -9, -9A, -11, -15, -15A, -17,-17A, -17R, -17AR, -209, -217, -217A, -217C, and -219 turbofan engines.Note 1: These engines are installed on, but not limited to, Boeing 727 and 737 series, and McDonnell Douglas DC-9 series and MD-80 series aeroplanes.                                                                                                                                                                                                                                                                                                                                                                                                                   |\n| -------------- | --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |\n| Requirement:   | 1. Remove all coating from the disks and hubs identified in Tables 1 and 2 of FAA Airworthiness Directive (AD) 2005-17-16 and visually, dimensionally and non-destructively inspect the parts using the inspection criteria listed in the Accomplishment Instructions portion of Pratt & Whitney Alert Service Bulletin (ASB) No. JT8D A6442 dated 4 April 2003 or later FAA approved revisions.2. Do not install any disk or hub listed in Table 1 of FAA AD 2005-17-16 that has zero cycles-in-service since 14 May 2001.3. Do not return to service any engine that has a disk or hub listed in Table 1 of FAA AD 2005-17-16 that has zero cycles-in-service since 14 May 2001.Note 2: FAA AD 2005-17-16 Amdt 39-14327 refers. |\n| Compliance:    | 1. At the next shop visit after the effective date of this AD, but no later than 31 March 2008 for all parts listed in Table 1 of FAA AD 2005-17-16 and at next part accessibility for all parts listed in Table 2 of FAA AD 2005-17-16.A shop visit is defined as an engine and/or module removal where engine maintenance entails separation of pairs of major engine flanges or the removal of a disk, hub or spool at a maintenance facility, regardless of the scheduled maintenance action or the reason for engine removal.For the purposes of this AD, accessibility of the HPC rear hub is removing the hub from the engine.2. After the effective date of this AD.3. After the effective date of this AD.               |\n|                | This Airworthiness Directive becomes effective on 24 November 2005.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                               |\n\n| Background: | This AD results from reports that certain JT8D critical life-limited rotating parts have been returned to service with cracks, corrosion pitting, or dimensions outside of manual limits. This AD is intended to prevent failure of critical life-limited rotating engine parts, which could result in an uncontained engine failure and damage to the aeroplane. |\n| ----------- | ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |\n\n![](image.001.png)  \nJayaprakashan Ambali  \nDelegate of the Civil Aviation Safety Authority\n\n7 October 2005","sortOrder":0},{"sectionNumber":"AD/JT8D/41","sectionType":"part","heading":"AD/JT8D/41","content":"## AD/JT8D/41","sortOrder":1},{"sectionNumber":"Compressor Hubs and Disks","sectionType":"part","heading":"Compressor Hubs and Disks","content":"## Compressor Hubs and Disks","sortOrder":2},{"sectionNumber":"12/2005","sectionType":"part","heading":"12/2005","content":"## 12/2005","sortOrder":3}],"analysis":{"flash_summary":{"complexity_score":5,"scope_assessment":{"changed":false,"description":"The directive adopts and applies the requirements of FAA AD 2005-17-16 and the Pratt & Whitney ASB to specified JT8D compressor hubs and disks. It confines action to the listed engine models and parts and does not expand the scope beyond those items (see 'Applicability' and 'Requirement')."},"complexity_factors":["References to external mandatory documents (FAA AD 2005-17-16; Pratt & Whitney ASB JT8D A6442) mean operators must follow multiple texts to comply (Requirement).","Wide applicability across many JT8D engine variants and parts listed in multiple tables increases scope for parts checks and record searches (Applicability; Requirement).","Multiple inspection methods required (visual, dimensional and non‑destructive testing) add technical and tooling complexity to maintenance tasks (Requirement).","Prohibition keyed to a record-based metric — 'zero cycles-in-service since 14 May 2001' — requires reliable historical records and verification procedures (Requirement).","Compliance timing is conditional: ‘next shop visit’ trigger plus an absolute deadline (31 March 2008 for certain parts) creates scheduling and operational-planning complexity (Compliance).","Key definitions (shop visit; HPC rear hub accessibility as removal from the engine) can require engine/module removal, increasing labour and downtime (Compliance).","Enforcement relies on CASA adoption of FAA AD content, creating dependence on foreign-source technical criteria and potentially limited local interpretive guidance (Requirement; Background)."],"plain_english_summary":"This directive forces operators of Pratt & Whitney JT8D-series engines to remove coatings and perform visual, dimensional and non‑destructive inspections on specified compressor hubs and disks, following FAA AD 2005‑17‑16 and Pratt & Whitney ASB JT8D A6442. It also bans fitting or returning to service any listed disk or hub that has had zero cycles-in-service since 14 May 2001.\n\nIt affects airlines and maintenance organisations using JT8D engines (e.g. Boeing 727/737 and DC‑9/MD‑80 types). Operators pay for inspections, repairs or replacements; compliance is required at the next shop visit (and by 31 March 2008 for some parts) and is enforced by CASA."},"kimi_summary":{"content_quality":"ok","complexity_score":4,"scope_assessment":{"changed":false,"description":"This AD maintains its original narrow scope — addressing specific safety defects in specific engine parts. It does not expand beyond the original safety concern of preventing failures in critical life-limited rotating components."},"complexity_factors":["Heavy reliance on external documents — the directive references FAA AD 2005-17-16 and Pratt & Whitney Alert Service Bulletin JT8D A6442 without reproducing their contents","Multiple tables referenced (Tables 1 and 2) but not included in the text","Conditional compliance dates with alternative pathways (\"next shop visit\" vs fixed date of 31 March 2008)","Technical aviation terminology requiring specialised knowledge (\"cycles-in-service\", \"HPC rear hub\", \"major engine flanges\")","Nested applicability covering 17 engine variants across 4 aircraft families","Cross-border regulatory harmonisation requiring familiarity with FAA procedures"],"plain_english_summary":"This AD orders operators and maintenance shops to strip, inspect, and remove specific Pratt & Whitney JT8D compressor hubs and disks used on Boeing 727/737 and McDonnell Douglas DC‑9/MD‑80 series to prevent cracks, corrosion or dimensional defects that could cause uncontained engine failure. It bans returning certain “zero‑time” parts to service and requires defective parts be scrapped by March 31, 2008 or at the next engine shop visit."},"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-jt8d-41-compressor-hubs-and-disks","history":"/api/acts/ad-jt8d-41-compressor-hubs-and-disks/history","analysis":"/api/acts/ad-jt8d-41-compressor-hubs-and-disks/analysis","conflicts":"/api/acts/ad-jt8d-41-compressor-hubs-and-disks/conflicts","importantCases":"/api/acts/ad-jt8d-41-compressor-hubs-and-disks/important-cases","documents":"/api/acts/ad-jt8d-41-compressor-hubs-and-disks/documents"}}