{"id":"F2006L01352","name":"AD/AL501/4 - First Stage Compressor Disc","slug":"ad-al501-4-first-stage-compressor-disc","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":58879,"registerId":"commonwealth-F2006L01352-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"Rolls Royce (Allison) Turbine Engines - ","sectionType":"division","heading":"Rolls Royce (Allison) Turbine Engines - AL501 Series","content":"### Rolls Royce (Allison) Turbine Engines - AL501 Series\n\n| AD/AL501/4 | First Stage Compressor Disc | 6/2006 |\n| ---------- | --------------------------- | ------ |\n\n| Applicability: | Rolls Royce (formerly ALLISON GAS TURBINE DIVISION) Models 501-D13 and 501-D22 Series Engines fitted with part numbers (P/Ns) 6738651, 6788581, 6789681, 6805651, 6805701, 6844081, and 6829661 first stage compressor wheels with balance weight pin holes in the front lip of the outer rim. |\n| -------------- | ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |\n| Requirement:   | Action in accordance with FAA AD 69-21-03.Note: FAA AD 69-21-03 Amdt 39-862 refers.                                                                                                                                                                                                            |\n| Compliance:    | As detailed in FAA AD 69-21-03 with a revised effective date of 8 June 2006.                                                                                                                                                                                                                   |\n|                | This Airworthiness Directive becomes effective on 8 June 2006.                                                                                                                                                                                                                                 |\n| Background:    | The requirements detailed in this AD are to ensure an adequate life limit for first stage compressor discs.                                                                                                                                                                                    |\n\n![](image.001.png)  \nJames Coyne  \nDelegate of the Civil Aviation Safety Authority\n\n28 April 2006","sortOrder":0},{"sectionNumber":"AD/AL501/4","sectionType":"part","heading":"AD/AL501/4","content":"## AD/AL501/4","sortOrder":1},{"sectionNumber":"First Stage Compressor Disc","sectionType":"part","heading":"First Stage Compressor Disc","content":"## First Stage Compressor Disc","sortOrder":2},{"sectionNumber":"6/2006","sectionType":"part","heading":"6/2006","content":"## 6/2006","sortOrder":3}],"analysis":{"flash_summary_failed":{"failed":true,"reason":"Unauthenticated. Configure AI_GATEWAY_API_KEY or use a provider module. Learn more: https://ai-sdk.dev/unauthenticated-ai-gateway","source":"analysis-cron"},"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This is a standard, narrow airworthiness directive targeting a specific mechanical component (first stage compressor disc) in specific engine models. It has not expanded beyond its original safety purpose."},"complexity_factors":["Very short document (approximately 200 words)","Only 7 defined part numbers in applicability section","Single requirement: compliance with external FAA directive (AD 69-21-03)","No nested exceptions or conditional logic","No cross-references to other Australian legislation","Simple effective date and compliance structure","Incorporation by reference to foreign (US) standard rather than detailed technical specifications in text"],"plain_english_summary":"This CASA Airworthiness Directive mandates that operators of Rolls‑Royce (Allison) 501‑D13 and 501‑D22 turbine engines comply with FAA AD 69‑21‑03 to impose life limits on first‑stage compressor discs. It targets discs with balance‑weight pin holes in the outer rim (specific part numbers) to prevent catastrophic disc failure.\n\nThe AD took effect 8 June 2006 and applies to affected engine owners and operators."},"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":false,"description":"The directive adopts the requirements of FAA AD 69‑21‑03 for the specified AL501 engine parts and sets an Australian effective date (Requirement; Compliance). The instrument does not expand applicability beyond the listed models/part numbers or add new obligations beyond those in the referenced FAA AD (Applicability; Requirement)."},"complexity_factors":["Cross-reference to an external document (FAA AD 69-21-03) creates dependency on another instrument for full compliance (Requirement; Compliance).","Narrow technical applicability defined by specific engine models and multiple part numbers, requiring verifiable parts records (Applicability).","A revised effective date (8 June 2006) fixes the compliance start and can affect scheduling and backlog (Compliance).","Mandated life‑limit/inspection actions are technical and may require specialised maintenance, parts replacement or engineering judgement (Background; Requirement).","Limited textual detail in this instrument increases reliance on FAA AD content for procedural specifics (Requirement).","Enforcement and compliance cost fall to operators who must alter maintenance programs and possibly remove/replace parts (Applicability; Compliance)."],"plain_english_summary":"This Airworthiness Directive tells operators of Rolls Royce (Allison) AL501‑D13 and AL501‑D22 engines with certain first‑stage compressor wheels to follow the inspection and life‑limit requirements in FAA AD 69‑21‑03, adopted by CASA with effect 8 June 2006. It applies to engines fitted with the listed part numbers and requires owners/operators to change maintenance and retirement schedules to meet the mandated life limits (Applicability; Requirement; Compliance)."}},"importantCases":[],"_links":{"self":"/api/acts/ad-al501-4-first-stage-compressor-disc","history":"/api/acts/ad-al501-4-first-stage-compressor-disc/history","analysis":"/api/acts/ad-al501-4-first-stage-compressor-disc/analysis","conflicts":"/api/acts/ad-al501-4-first-stage-compressor-disc/conflicts","importantCases":"/api/acts/ad-al501-4-first-stage-compressor-disc/important-cases","documents":"/api/acts/ad-al501-4-first-stage-compressor-disc/documents"}}