{"id":"F2006B06367","name":"AD/PT6A/31 - Fuel Control Unit","slug":"ad-pt6a-31-fuel-control-unit","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":47617,"registerId":"commonwealth-F2006B06367-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.001.png)\n\n![](image.001.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.\n\nPratt and Whitney Canada Turbine Engines \\- PT6A Series","sortOrder":0},{"sectionNumber":"AD/PT6A/31 Fuel Control Unit 4/2002","sectionType":"part","heading":"AD/PT6A/31 Fuel Control Unit 4/2002","content":"# AD/PT6A/31 Fuel Control Unit 4/2002\n\nApplicability: All Pratt and Whitney Canada (P&WC) PT6A-64, PT6A-65AG, PT6A-65B, PT6A- 66A, PT6A-67AG, and PT6A-67B engines.\n\nRequirement: 1. Inspect the Fuel Control Unit (FCU), and determine whether the part number and the serial number are listed in the effectivity section of P&WC Alert Service Bulletin (ASB) A13341R1 or P&WC ASB A14305R1; and\n\n    2. If the FCU is not listed in the effectivity of P&WC ASB A13341R1 or P&WC ASB A14305R1 no further action is required; or\n\n    3. If the FCU is listed carry out inspection and disposition of the FCU in accordance with P&WC ASB A13341R1 or P&WC ASB A14305R1.\n\nNote: Canadian AD CF-2002-04 refers.\n\nCompliance: 1. Within 200 flight hours; or 120 calendar days; whichever occurs first; from the date this Directive becomes effective; and\n\n2 and 3. Prior to flight after requirement 1 inspection..\n\nThis Airworthiness Directive becomes effective on 18 April 2002.\n\nBackground: Investigation of an in-flight shutdown involving a PT6A-65AG engine revealed that Woodward fuel control units fitted to applicable engines were potentially assembled incorrectly. This situation is considered a safety hazard as the majority of these engines are fitted to single engine aircraft.\n\n![Signature of Eugene Paul Holzapfel, Delegate of the Civil Aviation Safety Authority.](image.002.png)  \n\nEugene Paul Holzapfel\n\nDelegate of the Civil Aviation Safety Authority 10 March 2002\n\n![](image.001.png)","sortOrder":1}],"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 Airworthiness Directive maintains its original narrow scope: addressing a specific manufacturing defect in specific fuel control units for specific engine models. It has not expanded beyond this safety-critical correction."},"complexity_factors":["Very short document (approximately 300 words)","Only 6 specific engine models in applicability section","Simple conditional logic: check list → if on list, do action; if not, stop","Only 2 external references (manufacturer service bulletins)","Clear, single compliance timeframe (200 hours/120 days)","No defined terms section — uses plain language and standard aviation acronyms (FCU, ASB, P&WC)","No nested exceptions or cross-references to other legislation"],"plain_english_summary":"This CASA safety order requires operators and maintainers of specific Pratt & Whitney Canada PT6A engines (PT6A‑64/65AG/65B/66A/67AG/67B) to check fuel control unit part and serial numbers against manufacturer bulletins (P&WC ASB A13341R1 or A14305R1). If a unit is listed, inspect and repair or replace it per the ASB; if not, no action. Do this within 200 flight hours or 120 days, and before next flight after the check. It prevents potential in‑flight engine shutdowns in single‑engine aircraft."},"flash_summary":{"complexity_score":2,"scope_assessment":{"changed":false,"description":"This AD is narrowly focused on a specific unsafe assembly condition affecting Woodward FCUs on certain PT6A engine models. It requires inspection and, where the manufacturer’s ASBs indicate, corrective action. The measure remains constrained to that original safety issue and does not expand the scope beyond inspecting and remediating the identified FCU assembly concern."},"complexity_factors":["Narrow applicability: six specific PT6A engine models listed in the Applicability section","Short, three-step requirement structure (inspect; if not listed — stop; if listed — follow ASB)","Cross-reference to two manufacturer Alert Service Bulletins (P&WC ASB A13341R1 and A14305R1) for detailed instructions","Dual compliance timing metric (200 flight hours OR 120 calendar days, whichever first)","Requirement that subsequent corrective action be completed prior to next flight (creates operational urgency)","Reference to an external foreign AD (Canadian AD CF-2002-04), which may require checking multiple regulatory sources"],"plain_english_summary":"**What this directive does (mechanics)\n\n- Applies to: all Pratt & Whitney Canada PT6A-64, -65AG, -65B, -66A, -67AG and -67B turbine engines (\"Applicability\").\n\n- Main requirement: Inspect the engine's Woodward Fuel Control Unit (FCU) to see whether its part number and serial number appear in the \"effectivity\" lists of either Pratt & Whitney Canada (P&WC) Alert Service Bulletin A13341R1 or A14305R1 (\"Requirement\" 1).\n\n  - If the FCU is NOT listed in the effectivity of those ASBs, no further action is required (\"Requirement\" 2).\n  - If the FCU IS listed, carry out the inspection and follow-up actions (repair, replacement or other disposition) set out in the applicable P&WC ASB (\"Requirement\" 3).\n\n- Timing: The initial check must be performed within 200 flight hours or 120 calendar days from the AD becoming effective, whichever happens first (\"Compliance\" 1). Any further work required because the FCU is listed must be completed before the next flight after the inspection (\"Compliance\" 2 and 3).\n\n- Purpose stated by the regulator: The AD responds to an investigation that found some Woodward FCUs may have been assembled incorrectly, creating a safety hazard—particularly for single-engine aircraft that use these engines (\"Background\").\n\nWhy it matters (practical effects)\n\n- Who this affects: aircraft owners/operators, maintenance organisations and mechanics who operate or maintain aircraft powered by the listed PT6A variants.\n\n- Who decides and who provides technical steps: Civil Aviation Safety Authority (CASA) issues the directive and enforces compliance; P&WC Alert Service Bulletins contain the detailed inspection and corrective-action instructions that owners/operators must follow.\n\n- What behaviour changes: operators must check each affected engine's FCU, match part and serial numbers against the ASB effectivity lists, and, where listed, perform the ASB-prescribed inspection/repairs before returning the aircraft to flight.\n\nCosts, incentives and trade-offs (practical considerations)\n\n- Direct costs and who pays: operators/owners bear the costs of inspecting each FCU (labour, record checks) and any subsequent repair or replacement required by the ASBs. If engines are grounded to await parts or maintenance, operators also incur downtime costs.\n\n- Concentrated benefits, diffuse costs: The safety benefit accrues to operators and passengers of affected aircraft (concentrated on those aircraft), while the compliance cost is spread across the fleet operators of the listed engine models.\n\n- Opportunity cost and operational disruption: Compliance within the short time window (200 flight hours / 120 days) may require scheduling maintenance earlier than planned, disrupting flight operations or requiring temporary removal from service.\n\n- Supply and implementation risk: If many FCUs require repair or replacement, parts or qualified maintenance slots could be scarce, increasing delays and costs.\n\n- Regulatory reliance and discretion: The AD delegates the specific technical actions to the manufacturer’s ASBs rather than prescribing precise technical steps in the AD; operators must follow the ASB content as authoritative.\n\n- Effects on competition and private choice: The AD requires adherence to manufacturer-issued service instructions for specific components; it does not restrict who may perform the work provided the organisation meets applicable maintenance qualifications, but it may favour maintenance providers with access to authorised parts or technical procedures.\n\nConcrete mechanics and compliance obligations (summary of legal steps)\n\n- Inspect (within 200 fh / 120 days) the FCU and check P/N and S/N against P&WC ASB A13341R1 and A14305R1 (Requirement 1; Compliance 1).\n- If not listed in those ASBs, no further action (Requirement 2).\n- If listed, carry out the inspection and disposition exactly as the relevant ASB requires, and complete that work before next flight (Requirement 3; Compliance 2 and 3).\n\nNotes and cross-references\n\n- The AD references the manufacturer’s ASBs for the detailed technical procedure and also notes a related Canadian AD (CF-2002-04). Operators will need to consult the ASBs to determine the exact corrective actions and spare-parts requirements.\n\n(Sections cited above are the AD's Applicability; Requirement paragraphs 1–3; Compliance paragraphs 1–3; and Background.)"}},"importantCases":[],"_links":{"self":"/api/acts/ad-pt6a-31-fuel-control-unit","history":"/api/acts/ad-pt6a-31-fuel-control-unit/history","analysis":"/api/acts/ad-pt6a-31-fuel-control-unit/analysis","conflicts":"/api/acts/ad-pt6a-31-fuel-control-unit/conflicts","importantCases":"/api/acts/ad-pt6a-31-fuel-control-unit/important-cases","documents":"/api/acts/ad-pt6a-31-fuel-control-unit/documents"}}