{"id":"F2006B06146","name":"AD/PC-6/42 - Collector Tank Venting","slug":"ad-pc-6-42-collector-tank-venting","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":46941,"registerId":"commonwealth-F2006B06146-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/PC-6/42 - Collector Tank Venting","content":"---\nmeta-content-style-type: text/css\nmeta-content-type: application/xhtml+xml; charset=utf-8\nmeta-generator: Aspose.Words for .NET 22.10.0\n---\n\n?xml version=\"1.0\" encoding=\"utf-8\" standalone=\"no\"?>\n\nCOMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY\n\nSCHEDULE OF AIRWORTHINESS DIRECTIVES\n\n \n\n![](image.001.png)  Pilatus Porter PC-6 Series Aeroplanes\n\n \n\nAD/PC-6/42 Collector Tank Venting 2/96\n\nApplicability: All PC-6 aircraft up to and including aircraft S/N 915 fitted with a turboprop engine excepting aircraft S/N 902 which has previously been modified by Pilatus.\n\n \n\nRequirement: Unless previously carried out action in accordance with Pilatus Service Bulletin No\n\n171. Requirements of Pilatus SB 118, issued December 1972, must be incorporated prior to compliance with this Directive.\n\n \n\nCompliance: Prior to 30 April 1996.\n\n \n\nBackground:  The manufacturer has advised that due to the collector tank not completely refilling fuel starvation may occur when an aircraft is used for parachute dropping or sky- diving missions.\n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n","sortOrder":0}],"analysis":{"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This is a discrete, targeted safety directive addressing a specific mechanical defect in a specific aircraft model. It has not expanded beyond its original purpose of preventing fuel starvation in PC-6 aircraft during parachute operations."},"complexity_factors":["Very short document (under 200 words)","Only 4 operative provisions: applicability, requirement, compliance deadline, and background","Single cross-reference to manufacturer service bulletins (SB 171 and SB 118)","Simple conditional logic: one exception (S/N 902) and one sequencing requirement (SB 118 before SB 171)","No defined terms section — uses plain aviation terminology","No nested exceptions or recursive definitions"],"plain_english_summary":"**What this is:** This is an Airworthiness Directive (AD) — a mandatory safety order issued by Australia's Civil Aviation Safety Authority (CASA) for specific Pilatus Porter PC-6 aircraft.\n\n**Who it affects:** Owners and operators of PC-6 aircraft with serial numbers up to 915 that have turboprop engines, **except** for aircraft S/N 902 (which was already fixed by the manufacturer).\n\n**What it requires:** These aircraft must be modified according to **Pilatus Service Bulletin No. 171** — a technical instruction from the manufacturer. However, there's a catch: if the aircraft hasn't already been updated per an older bulletin (SB 118 from December 1972), that older update must be done **first** before complying with this Directive.\n\n**Why it matters:** The manufacturer discovered a dangerous flaw: the fuel \"collector tank\" (a reservoir that ensures steady fuel flow to the engine) doesn't always refill completely. During parachute dropping or skydiving operations, this can cause **fuel starvation** — meaning the engine could cut out mid-flight due to lack of fuel, even when there's fuel in the tanks. This creates a serious crash risk during these specific flight manoeuvres.\n\n**Deadline:** The modification had to be completed before 30 April 1996."},"flash_summary":{"complexity_score":4,"scope_assessment":{"changed":false,"description":"The instrument's scope is self-contained in the document: it applies to specified PC‑6 serial numbers (up to S/N 915, excluding S/N 902) and requires compliance with Pilatus service bulletin material (including SB 118) by the stated date. The text provides no indication that the scope has been broadened or narrowed from some earlier or different intent."},"complexity_factors":["Targeted applicability by serial number (Applicability) — narrows which aircraft are affected but requires operators to verify S/N status.","Sequencing requirement (Requirement) — SB 118 must be incorporated prior to compliance, creating a dependency that affects planning and cost.","Incomplete citation in the text (Requirement) — the Service Bulletin number is left blank, producing ambiguity about the exact modification reference.","Fixed compliance date (Compliance) — a definitive deadline imposes scheduling and potential operational disruption for operators.","Operational trigger explained (Background) — the safety issue arises specifically during parachute/sky‑diving missions, concentrating the operational impact on certain operators.","Regulatory enforcement format — an Airworthiness Directive imposes mandatory action rather than guidance, increasing legal/compliance consequences for owners/operators."],"plain_english_summary":"This Airworthiness Directive requires owners/operators of Pilatus PC-6 turboprop aircraft (all up to and including S/N 915, excluding S/N 902) to modify the collector tank venting to prevent possible fuel starvation during parachute or sky‑diving operations. It mandates compliance with Pilatus service bulletin instructions and incorporation of Pilatus SB 118 before carrying out the directive, with a stated compliance deadline of 30 April 1996. Operators bear the cost, downtime and maintenance action required."}},"importantCases":[],"_links":{"self":"/api/acts/ad-pc-6-42-collector-tank-venting","history":"/api/acts/ad-pc-6-42-collector-tank-venting/history","analysis":"/api/acts/ad-pc-6-42-collector-tank-venting/analysis","conflicts":"/api/acts/ad-pc-6-42-collector-tank-venting/conflicts","importantCases":"/api/acts/ad-pc-6-42-collector-tank-venting/important-cases","documents":"/api/acts/ad-pc-6-42-collector-tank-venting/documents"}}