{"id":"F2006B06149","name":"AD/PC-6/45 - Fuel Return Line Check Valve","slug":"ad-pc-6-45-fuel-return-line-check-valve","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":46948,"registerId":"commonwealth-F2006B06149-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"AIRWORTHINESS DIRECTIVE","sectionType":"part","heading":"AIRWORTHINESS DIRECTIVE","content":"# AIRWORTHINESS DIRECTIVE\n\n![](image.002.png)\n\n![](image.002.png)  \nFor the reasons set out in the background section, the CASA delegate whose signature appears below issues the following Airworthiness Directive (AD) under subregulation 39.1 (1) of CAR 1998. The AD requires that the action set out in the requirement section (being action that the delegate considers necessary to correct the unsafe condition) be taken in relation to the aircraft or aeronautical product mentioned in the applicability section: (a) in the circumstances mentioned in the requirement section; and (b) in accordance with the instructions set out in the requirement section; and (c) at the time mentioned in the compliance section.","sortOrder":0},{"sectionNumber":"AD/PC-6/45 Fuel Return Line Check Valve ","sectionType":"part","heading":"AD/PC-6/45 Fuel Return Line Check Valve 10/2000","content":"# AD/PC-6/45 Fuel Return Line Check Valve 10/2000\n\nApplicability: Pilatus PC-6 Porter aircraft, serial numbers 001 \\- 932 inclusive.\n\nRequirement: Carry out a once only inspection of the fuel return line check valve to determine that it is correctly located on the left hand side of the aircraft behind Frame 1 in accordance with Pilatus Service Bulletin PC-6 No. 179.\n\nIf the check valve is correctly located, no further action is required.\n\nIf the check valve is not correctly located, re-locate it in accordance with Pilatus Service Bulletin PC-6 No. 135 before further flight.\n\nNote: FOCA AD HB 2000-336 also refers.\n\nCompliance: No later than 15 January 2001.\n\nThis Airworthiness Directive becomes effective on 5 October 2000.\n\nBackground: This Directive is prompted by advice the fuel return line check valve installed on some Pilatus Porter aircraft may not be located correctly. The Directive requires a once only inspection of the check valve to ensure it complies with the aircraft’s type design and to relocate it if necessary.\n\n![Signature of Eugene Paul Holzapfel, Delegate of the Civil Aviation Safety Authority.](image.003.png)  \n\nEugene Paul Holzapfel\n\nDelegate of the Civil Aviation Safety Authority 16 August 2000\n\n![](image.002.png)  \n\nThe above AD is notified in the Commonwealth of Australia Gazette on 6 September 2000.","sortOrder":1}],"analysis":{"flash_summary":{"complexity_score":2,"scope_assessment":{"changed":false,"description":"The instrument enforces existing type‑design conformity for a specific subset of aircraft rather than expanding regulatory reach. It imposes a one‑time inspection and corrective obligation on operators of affected PC‑6s but does not create ongoing new operational restrictions or alter the aircraft type design; compliance is required by the stated deadline (Requirement; Compliance)."},"complexity_factors":["Narrow applicability: specific to Pilatus PC‑6 serial numbers 001–932 (Applicability).","Single, one‑time action: a once only inspection with corrective relocation if required (Requirement).","Reliance on external service documents: inspection per Pilatus Service Bulletin PC‑6 No.179 and relocation per Service Bulletin PC‑6 No.135 (Requirement).","\"Before further flight\" corrective standard: relocation must be completed prior to next flight if valve is misplaced (Requirement), which can create immediate operational constraints.","Fixed compliance deadline: must be completed no later than 15 January 2001 (Compliance).","Statutory issuance: AD issued under subregulation 39.1(1) of CAR 1998, creating a regulatory compliance obligation (preamble/background).","Reference to foreign authority advisory: FOCA AD HB 2000-336 is noted (Requirement/Note).","Technical interpretation: verifying \"left hand side behind Frame 1\" may require maintenance judgment and access to structural references."],"plain_english_summary":"This Airworthiness Directive requires a one‑time inspection of the fuel return line check valve on Pilatus PC‑6 Porter aircraft (serial numbers 001–932) to confirm it is located on the left side behind Frame 1. If the valve is misplaced, operators must relocate it in accordance with the Pilatus service instructions before the aircraft flies again. Operators and their maintenance organisations bear the cost and must complete the work by 15 January 2001; CASA issued the AD under CAR 1998 to address a potential unsafe condition."},"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 Airworthiness Directive maintains its original narrow scope. It addresses a specific manufacturing or maintenance error affecting a defined fleet of aircraft (Pilatus PC-6 serial numbers 001-932) and mandates a single, one-time inspection. There is no evidence of scope creep; the directive remains tightly focused on the fuel return line check valve location issue as originally identified."},"complexity_factors":["Single, discrete safety issue addressed (one component on one aircraft type)","Only 3 defined elements: applicability (serial numbers), requirement (inspection/relocation), and compliance deadline","Binary decision tree: correct location = no action; incorrect location = relocate","No nested exceptions or conditional logic","References only 2 external documents (service bulletins) and 1 related foreign directive","Total length: approximately 250 words of substantive text"],"plain_english_summary":"CASA requires a one‑time inspection of the fuel return line check valve on Pilatus PC‑6 Porter aircraft (serials 001–932) to confirm the valve is on the left side behind Frame 1. The check must be completed by 15 January 2001 and affects owners, operators and maintenance engineers.\n\nIf the valve is misplaced it must be relocated before the aircraft next flies to eliminate a potential fuel‑system safety risk."}},"importantCases":[],"_links":{"self":"/api/acts/ad-pc-6-45-fuel-return-line-check-valve","history":"/api/acts/ad-pc-6-45-fuel-return-line-check-valve/history","analysis":"/api/acts/ad-pc-6-45-fuel-return-line-check-valve/analysis","conflicts":"/api/acts/ad-pc-6-45-fuel-return-line-check-valve/conflicts","importantCases":"/api/acts/ad-pc-6-45-fuel-return-line-check-valve/important-cases","documents":"/api/acts/ad-pc-6-45-fuel-return-line-check-valve/documents"}}