{"id":"F2006B05391","name":"AD/PA-18/12 Amdt 1 - Fuel Primer and Hydraulic Lines - Re-Routing","slug":"ad-pa-18-12-amdt-1-fuel-primer-and-hydraulic-lines-re-routing","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":46008,"registerId":"commonwealth-F2006B05391-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/PA-18/12 Amdt 1 - Fuel Primer and Hydraulic Lines - Re-Routing","content":"COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 \\- 105 CIVIL AVIATION SAFETY AUTHORITY\n\nSCHEDULE OF AIRWORTHINESS DIRECTIVES\n\n![](image.001.png)  \nPiper PA-18 and 19 (Super Cub) Series Aeroplanes\n\nAD/PA-18/12\n\nAmdt 1\n\n  \nFuel Primer and Hydraulic Lines \\- Re-Routing 4/85 DM\n\nApplicability: All models.\n\nRequirement: 1. To prevent contact with the exhaust muffler, re-route fuel primer line, and wheel brake hydraulic line if necessary, to ensure that they do not pass behind the muffler.\n\n2. Using clamps, secure the lines to the firewall \\- refer to Piper SL No. 213 for fuel primer line clamping instructions.\n\nNote: FAA AD 53-24-4 refers.\n\nCompliance: Within 25 hours time in service after 31 March 1985.\n\nBackground: This Directive has been amended to combine the intent of Piper SL No. 213 and FAA AD 53-24-4 into a single requirement. Re-routing, as applicable, of the fuel primer line and wheel brake hydraulic line is necessary to preclude the possibility of an in- flight fire.","sortOrder":0}],"analysis":{"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This is an amendment (Amdt 1) that consolidates two existing safety requirements into a single directive. The scope remains focused on the original safety issue (fire prevention through proper line routing) and has not expanded beyond this specific technical fix."},"complexity_factors":["Single, specific aircraft type (Piper PA-18/19 series)","Two straightforward mechanical requirements (re-routing and clamping)","Single compliance deadline with clear metric (25 hours time in service)","Only one cross-reference (Piper SL No. 213) and one related FAA directive mentioned in note","No defined terms section","No conditional logic or nested exceptions","Background provides clear safety rationale","Document length: approximately 200 words"],"plain_english_summary":"This is a **safety directive for aircraft owners and operators** of Piper PA-18 and PA-19 (Super Cub) aeroplanes.\n\n**What it does:**\n- Requires owners to **re-route fuel and brake lines** so they don't pass behind the exhaust muffler\n- Mandates **securing these lines to the firewall** using clamps\n- Prevents these lines from touching the hot exhaust, which could cause **in-flight fires**\n\n**Who it affects:**\n- Owners and operators of all Piper PA-18 and PA-19 Super Cub aircraft models\n- Maintenance organisations servicing these aircraft\n\n**Why it matters:**\nFuel and hydraulic fluid are highly flammable. If these lines contact the hot exhaust muffler, they can rupture and ignite. This directive prevents potentially catastrophic in-flight fires by ensuring lines are routed safely away from heat sources and properly secured.\n\n**Key requirements:**\n- **Re-route lines** if they currently pass behind the muffler\n- **Install clamps** on the firewall (following Piper Service Letter No. 213)\n- **Complete within 25 flight hours** after 31 March 1985\n\nThis directive combines two previous safety notices into one clear requirement."},"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":true,"description":"The Directive was amended to combine the intent of Piper Service Letter No. 213 and FAA AD 53-24-4 into a single, mandatory airworthiness requirement (Background). Mechanically, the amendment consolidates previous separate guidance into this AD’s single set of actions (re-route lines and secure them to the firewall), while maintaining applicability to all PA-18 and PA-19 models (Applicability; Background)."},"complexity_factors":["Narrow technical scope limited to routing and clamping of two specific lines (fuel primer and wheel brake hydraulic) (Requirement 1–2).","Conditional element: wheel brake hydraulic line action applies only 'if necessary', requiring on‑aircraft inspection and judgment (Requirement 1).","External references required: Piper Service Letter No. 213 for clamping instructions and a referenced FAA AD (Requirement 2; Note), creating a dependency on other documents.","Short, fixed compliance window imposes scheduling urgency (25 hours TIS after 31 March 1985) (Compliance).","Applicability is broad across the model line ('All models'), so many individual aircraft/owners could be affected though the technical fix is simple (Applicability)."],"plain_english_summary":"All Piper PA-18 and PA-19 (Super Cub) aeroplanes must have the fuel primer line—and the wheel brake hydraulic line if it currently passes behind the exhaust—re-routed away from the muffler and clamped to the firewall per Piper Service Letter No. 213. \n\nOwners/operators and maintenance personnel must complete this work within 25 hours TIS after 31 March 1985 to prevent contact with the muffler and reduce the risk of an in‑flight fire."}},"importantCases":[],"_links":{"self":"/api/acts/ad-pa-18-12-amdt-1-fuel-primer-and-hydraulic-lines-re-routing","history":"/api/acts/ad-pa-18-12-amdt-1-fuel-primer-and-hydraulic-lines-re-routing/history","analysis":"/api/acts/ad-pa-18-12-amdt-1-fuel-primer-and-hydraulic-lines-re-routing/analysis","conflicts":"/api/acts/ad-pa-18-12-amdt-1-fuel-primer-and-hydraulic-lines-re-routing/conflicts","importantCases":"/api/acts/ad-pa-18-12-amdt-1-fuel-primer-and-hydraulic-lines-re-routing/important-cases","documents":"/api/acts/ad-pa-18-12-amdt-1-fuel-primer-and-hydraulic-lines-re-routing/documents"}}