{"id":"F2010L02531","name":"AD/PW4000/20 - 15th Stage High Pressure Compressor","slug":"ad-pw4000-20-15th-stage-high-pressure-compressor","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":84465,"registerId":"commonwealth-F2010L02531-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"Pratt and Whitney Turbine Engines - PW40","sectionType":"division","heading":"Pratt and Whitney Turbine Engines - PW4000 Series","content":"### Pratt and Whitney Turbine Engines \\- PW4000 Series\n\n| AD/PW4000/20 | 15th Stage High Pressure Compressor | 19/2010 |\n| ------------ | ----------------------------------- | ------- |\n\n| Applicability: | Pratt and Whitney PW4000 engines as specified by models in FAA AD 2002-09-01.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                     |\n| -------------- | --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |\n| Requirement:   | Unless already accomplished, perform the initial inspections in accordance with the technical requirements of FAA AD 2002-09-01.Repeat the inspections in accordance with the technical requirements of FAA AD 2002-09-01.Ensure the cyclic life limit is established in accordance with the technical requirements of FAA AD 2002-09-01.Later revisions to PW SB PW4G-112-A72-242, dated 1 May 2001, approved by the United States Federal Aviation Administration (FAA) as an Alternate Method of Compliance (AMOC) to FAA AD 2002-09-01, are considered acceptable for compliance with the equivalent Requirements of this AD. |\n| Compliance:    | As specified in the Requirement Document with a revised effective date of17 October 2010.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                         |\n|                | This Airworthiness Directive becomes effective on 17 October 2010.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                |\n| Background:    | This AD is issued as a result of reports of 15th stage High Pressure Compressor (HPC) discs with cracks in the outer rim front rail of the blade loading slots and in the front forward and middle knife edges. The actions in this AD are intended to prevent an uncontained engine failure of the 15th stage HPC disc.                                                                                                                                                                                                                                                                                                          |\n\n![](image.001.png)\n\nCharles Lenarcic  \nDelegate of the Civil Aviation Safety Authority\n\n22 September 2010","sortOrder":0},{"sectionNumber":"AD/PW4000/20","sectionType":"part","heading":"AD/PW4000/20","content":"## AD/PW4000/20","sortOrder":1},{"sectionNumber":"15th","sectionType":"part","heading":"Stage High Pressure Compressor","content":"## 15th Stage High Pressure Compressor","sortOrder":2},{"sectionNumber":"19/2010","sectionType":"part","heading":"19/2010","content":"## 19/2010","sortOrder":3}],"analysis":{"flash_summary":{"complexity_score":5,"scope_assessment":{"changed":false,"description":"The AD’s stated scope aligns with its original corrective purpose: it addresses reported cracks in 15th‑stage HPC discs by mandating inspections and establishment of a cyclic life limit per FAA AD 2002-09-01 (Background; Requirement). The instrument does not broaden or narrow that corrective focus in the text provided; it permits FAA‑approved SB revisions as AMOCs but does not otherwise change affected engines or required actions."},"complexity_factors":["Cross-reference to external FAA AD 2002-09-01 for the technical inspection and compliance requirements (Applicability; Requirement) — dependency on another document increases procedural complexity.","Requirement to perform both initial and repeated inspections and to ‘ensure the cyclic life limit is established’ (Requirement) — involves technical inspection schedules and lifecycle tracking by operators/maintenance organisations.","Acceptance of later revisions to PW SB PW4G-112-A72-242 as an Alternate Method of Compliance (AMOC) (Requirement) — allows flexibility but requires verification that revisions are FAA‑approved.","Applicability tied to models listed in the FAA AD (Applicability) — narrow but conditional scope requires cross‑checking engine serials and models.","Safety‑critical subject matter (Background) — potential for uncontained engine failure imposes high compliance priority and documentation/audit requirements.","Compliance timing and formal effective date (Compliance) — operators must meet timelines tied to the AD’s effective date.","Administrative provenance: issued by CASA delegate (signature block) — formal regulatory enforcement with limited discretion in this text."],"plain_english_summary":"This Airworthiness Directive requires operators of specified Pratt & Whitney PW4000 engines to perform initial and repeated inspections and to establish a cyclic life limit, following the technical procedures in FAA AD 2002-09-01; later FAA‑approved revisions to PW SB PW4G-112-A72-242 are acceptable as alternate methods of compliance. The rule responds to reported cracks in 15th‑stage high pressure compressor discs to reduce the risk of uncontained engine failure. Operators pay for inspections and lifecycle management; compliance follows FAA technical documents and any approved AMOCs."},"kimi_summary":{"content_quality":"ok","complexity_score":3,"scope_assessment":{"changed":false,"description":"This AD maintains its original narrow scope — addressing a specific safety defect in a specific engine component. It does not expand beyond the original FAA safety order it references."},"complexity_factors":["Short, single-purpose instrument (approximately 250 words)","Only 4 defined/model references (FAA AD 2002-09-01, PW SB PW4G-112-A72-242, AMOC, PW4000 series)","Simple conditional structure: 'Unless already accomplished' is the only exception","Heavy reliance on external documents — the actual technical requirements are contained in the referenced FAA AD and manufacturer service bulletin, not reproduced here","No nested exceptions or complex cross-referencing within the instrument itself"],"plain_english_summary":"This CASA Airworthiness Directive requires operators of Pratt & Whitney PW4000 engines to carry out repeated inspections and observe a maximum life limit on the 15th‑stage high‑pressure compressor disc after cracks were found at blade attachments. The rule aims to prevent an uncontained engine failure that could damage the aircraft or injure occupants. It applies to airlines using PW4000‑equipped types (e.g. Boeing 747/767/777, Airbus A300/A310) and adopts the FAA’s 2002 AD (effective Oct 2010); manufacturer‑approved procedures are an acceptable alternative."},"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-pw4000-20-15th-stage-high-pressure-compressor","history":"/api/acts/ad-pw4000-20-15th-stage-high-pressure-compressor/history","analysis":"/api/acts/ad-pw4000-20-15th-stage-high-pressure-compressor/analysis","conflicts":"/api/acts/ad-pw4000-20-15th-stage-high-pressure-compressor/conflicts","importantCases":"/api/acts/ad-pw4000-20-15th-stage-high-pressure-compressor/important-cases","documents":"/api/acts/ad-pw4000-20-15th-stage-high-pressure-compressor/documents"}}