{"id":"F2006L01350","name":"AD/AL501/3 - First Stage Turbine Wheels","slug":"ad-al501-3-first-stage-turbine-wheels","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":58874,"registerId":"commonwealth-F2006L01350-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/AL501/3 | First Stage Turbine Wheels | 6/2006 |\n| ---------- | -------------------------- | ------ |\n\n| Applicability: | Rolls Royce (formerly DETROIT DIESEL ALLISON) Model 501-D13, 501-D13A, 501-D13D, 501-D13E, and 501-D13H engines equipped with 1st stage turbine wheels with part numbers 6844061 and 6847111. |\n| -------------- | --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |\n| Requirement:   | Remove from service first stage turbine wheels in accordance with the schedule detailed in FAA AD 80-14-13.Note: FAA AD 80-14-13 Amdt 39-3820 refers.                                         |\n| Compliance:    | As detailed in FAA AD 80-14-13 with a revised effective date of 8 June 2006.                                                                                                                  |\n|                | This Airworthiness Directive becomes effective on 8 June 2006.                                                                                                                                |\n| Background:    | This AD is intended to prevent disc failures due to fatigue. The schedule for removal is based upon the dimension of the spline fit.                                                          |\n\n![](image.001.png)  \nJames Coyne  \nDelegate of the Civil Aviation Safety Authority\n\n28 April 2006","sortOrder":0},{"sectionNumber":"AD/AL501/3","sectionType":"part","heading":"AD/AL501/3","content":"## AD/AL501/3","sortOrder":1},{"sectionNumber":"First Stage Turbine Wheels","sectionType":"part","heading":"First Stage Turbine Wheels","content":"## First Stage Turbine Wheels","sortOrder":2},{"sectionNumber":"6/2006","sectionType":"part","heading":"6/2006","content":"## 6/2006","sortOrder":3}],"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"},"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This is a standard, narrow airworthiness directive targeting a specific mechanical defect in specific engine models. It has not expanded beyond its original safety purpose."},"complexity_factors":["Very short document (under 300 words)","Only 2 defined part numbers and 5 engine models in applicability","Single operative requirement: remove parts per external FAA directive","No nested exceptions or conditional logic beyond the applicability criteria","Cross-reference to one external document (FAA AD 80-14-13) rather than internal legislative structure","No interpretation section or defined terms"],"plain_english_summary":"This CASA Airworthiness Directive requires owners/operators of Rolls‑Royce (formerly Detroit Diesel Allison) 501‑D13 series engines with turbine wheels P/N 6844061 or 6847111 to remove those first‑stage wheels before reaching specified flight hours/cycles, determined by measured spline‑fit clearance. It mirrors FAA AD 80‑14‑13 with an effective date of 8 June 2006. Compliance is mandatory to prevent fatigue cracks that could cause catastrophic engine failure."},"flash_summary":{"complexity_score":4,"scope_assessment":{"changed":false,"description":"The directive adopts the removal schedule and requirements set out in FAA AD 80‑14‑13 (Amdt 39‑3820) for first‑stage turbine wheels (see 'Requirement' and 'Compliance'). The only change signalled in this instrument is a revised effective date of 8 June 2006; no broader or narrower applicability is stated in the source text."},"complexity_factors":["Cross‑reference to an external instrument (FAA AD 80‑14‑13 / Amdt 39‑3820) — requires users to consult another document for the full compliance schedule, increasing procedural complexity.","Technical criterion tied to spline‑fit dimensions — compliance timing depends on measured part geometry rather than a simple hours/cycles threshold, requiring technical measurement and recordkeeping.","Narrow applicability (specific engine models and two part numbers) — lowers scope complexity but requires precise parts tracking in operator maintenance records.","Regulatory update limited to a revised effective date (8 June 2006) — minimal substantive change but introduces a specific compliance start date that operators must observe.","Compliance burden concentrated on operators/owners (removal, inspection, replacement costs) rather than on the regulator; potential operational scheduling and downtime costs.","Limited regulatory discretion — directive prescribes removal per FAA AD, reducing interpretive leeway but increasing reliance on correct implementation of the external AD."],"plain_english_summary":"Requires owners/operators of Rolls Royce (Allison) Model 501‑D13 engines fitted with first‑stage turbine wheels P/N 6844061 or 6847111 to remove those wheels from service on the schedule set out in FAA AD 80‑14‑13 (Amdt 39‑3820). CASA issued the directive effective 8 June 2006 to prevent turbine‑disc fatigue failures; operators pay for removal, inspection and replacement and must follow the spline‑fit‑based removal intervals."}},"importantCases":[],"_links":{"self":"/api/acts/ad-al501-3-first-stage-turbine-wheels","history":"/api/acts/ad-al501-3-first-stage-turbine-wheels/history","analysis":"/api/acts/ad-al501-3-first-stage-turbine-wheels/analysis","conflicts":"/api/acts/ad-al501-3-first-stage-turbine-wheels/conflicts","importantCases":"/api/acts/ad-al501-3-first-stage-turbine-wheels/important-cases","documents":"/api/acts/ad-al501-3-first-stage-turbine-wheels/documents"}}