{"id":"F2006B08547","name":"AD/CHA/20 - Alternator - Field Cable Protection","slug":"ad-cha-20-alternator-field-cable-protection","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":51337,"registerId":"commonwealth-F2006B08547-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/CHA/20 - Alternator - Field Cable Protection","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)  American Champion (Aeronca, Bellanca) Series Aeroplanes\n\n \n\nAD/CHA/20 Alternator - Field Cable Protection 6/78\n\nApplicability: All models fitted with an Alternator System.\n\n \n\nRequirement: Install a 5 AMP circuit protective device (i.e. in line fuse or circuit breaker) in the field cable as close as practical to the master switch.\n\n \n\nCompliance: Within 100 hours time in service after 30 June 1978.\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\n \n\n \n\n \n\n \n\n \n","sortOrder":0}],"analysis":{"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":false,"description":"The directive applies to all models fitted with an alternator system and requires installation of a 5 AMP protective device in the alternator field cable within a specified time-in-service window. The text contains no indication that the scope was broadened or narrowed from an earlier form; it sets a single, narrowly focused technical requirement (Applicability; Requirement; Compliance)."},"complexity_factors":["Technical installation: requires an electrical modification to the alternator field cable (Requirement: \"Install a 5 AMP circuit protective device ... in the field cable\").","Interpretive ambiguity: phrase \"as close as practical to the master switch\" leaves room for judgement about exact placement (Requirement).","Applicability determination: applies to \"All models fitted with an Alternator System,\" so operators must identify whether their aircraft are within scope (Applicability).","Compliance timing: a fixed window tied to aircraft time-in-service must be calculated and tracked (Compliance: \"Within 100 hours time in service after 30 June 1978\").","Specification simplicity: device rating is specified (5 AMP) but acceptable device types are broadly stated (\"in line fuse or circuit breaker\"), which may require technical choice by the installer (Requirement)."],"plain_english_summary":"# What this directive does\n\n- This airworthiness directive requires installation of a 5 ampere (5 AMP) circuit protective device — either an inline fuse or a circuit breaker — in the alternator field cable of affected aeroplanes. (Requirement: \"Install a 5 AMP circuit protective device (i.e. in line fuse or circuit breaker) in the field cable as close as practical to the master switch.\")\n\n- It applies to every model that has an alternator fitted. (Applicability: \"All models fitted with an Alternator System.\")\n\n- Aircraft owners/operators had to complete the installation within 100 hours time in service after 30 June 1978. (Compliance: \"Within 100 hours time in service after 30 June 1978.\")\n\n# Who pays and who decides\n\n- Owners/operators of the affected aircraft are the ones who must carry out and pay for the installation. The directive specifies the technical requirement and the deadline; it does not set out a subsidy, funding mechanism or who supplies the parts. (Applicability; Requirement; Compliance.)\n\n# How it works mechanically\n\n- The directive mandates adding a protective device rated at 5 AMP into the alternator field cable to provide overcurrent protection for that circuit. The device must be installed \"as close as practical to the master switch,\" which places the protection near the aircraft's primary electrical control point. (Requirement.)\n\n# Stated purpose and how that maps to trade-offs\n\n- The directive's title and requirement indicate its purpose is to protect the alternator field circuit by adding a circuit protective device. (AD title; Requirement.)\n\n- Costs and incentives: the immediate expense and time are incurred by aircraft owners/operators who must buy a 5 AMP fuse or circuit breaker and have it fitted. There is no text in the directive providing financial assistance or exemptions. (Requirement; Compliance.)\n\n- Compliance burden and implementation risk: the directive requires a physical electrical modification. That creates a burden in the form of parts procurement and installation labour and requires competent electrical installation. The phrase \"as close as practical to the master switch\" introduces an element of judgement about exact placement, which can create variability in how the requirement is implemented. (Requirement.)\n\n- Administrative discretion: the directive sets a single technical requirement and a fixed compliance window; it does not specify an approval or exemption process, nor does it set out how compliance is to be documented in this text. (Requirement; Compliance.)\n\n# Effects on private activity\n\n- The measure constrains owners/operators to make a particular hardware change to continue operating affected aircraft. It does not alter operational rules, ownership, market access, or broader regulatory conditions beyond the specified installation. (Applicability; Requirement; Compliance.)\n\n# Concentrated benefits and diffuse costs\n\n- Benefits of adding circuit protection (reduced risk of electrical faults on the alternator field circuit) accrue to the specific aircraft whose circuits are protected. Costs (purchase and fitting of a 5 AMP device) are concentrated on the owners/operators of affected aircraft. The directive text does not create any compensating benefit or financial offset. (Requirement; Applicability; Compliance.)\n\n# Implementation checklist for an owner/operator (mechanical steps implied by the directive)\n\n- Confirm the aircraft model is fitted with an alternator system. (Applicability.)\n- Obtain an appropriate 5 AMP inline fuse or circuit breaker. (Requirement: \"5 AMP circuit protective device (i.e. in line fuse or circuit breaker)\")\n- Install the device in the alternator field cable as close as practical to the master switch. (Requirement.)\n- Complete installation within the specified compliance window. (Compliance.)\n\n# Source citations\n\nAll statements above are drawn from the directive text: the AD title, the Applicability line, the Requirement line, and the Compliance line."},"kimi_summary":{"content_quality":"ok","complexity_score":1,"scope_assessment":{"changed":false,"description":"This is a discrete, single-issue safety directive from 1978. It has not expanded beyond its original narrow purpose of requiring a specific electrical safety modification on a defined aircraft type."},"complexity_factors":["Single, unambiguous requirement with no defined terms section","No cross-references to other legislation or regulations","No conditional logic, exceptions, or nested provisions","Extremely short — approximately 50 words of substantive content","Plain language directive with clear mechanical instruction"],"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 aircraft.\n\n**What it does:** It requires owners or operators of American Champion aeroplanes (including older models previously made by Aeronca and Bellanca) to install a **5 amp fuse or circuit breaker** on the alternator's \"field cable\" (the wire that controls the alternator's electrical output). This device must be placed as close as possible to the master switch.\n\n**Why it matters:** The field cable can overheat or short-circuit if something goes wrong with the alternator. Without protection, this could cause an electrical fire in the aircraft. The fuse or circuit breaker acts as a safety cut-off, stopping excessive current before it becomes dangerous.\n\n**Who must comply:** Anyone operating an American Champion, Aeronca, or Bellanca aircraft with an alternator system — not just the battery-powered models.\n\n**When it had to be done:** Within 100 hours of flying time after 30 June 1978. (This is an old directive, so compliant aircraft should have had this modification for decades.)"}},"importantCases":[],"_links":{"self":"/api/acts/ad-cha-20-alternator-field-cable-protection","history":"/api/acts/ad-cha-20-alternator-field-cable-protection/history","analysis":"/api/acts/ad-cha-20-alternator-field-cable-protection/analysis","conflicts":"/api/acts/ad-cha-20-alternator-field-cable-protection/conflicts","importantCases":"/api/acts/ad-cha-20-alternator-field-cable-protection/important-cases","documents":"/api/acts/ad-cha-20-alternator-field-cable-protection/documents"}}