{"id":"F2006B08799","name":"AD/DC3/21 - Instrument Panel Junction Box - Inspection","slug":"ad-dc3-21-instrument-panel-junction-box-inspection","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":52158,"registerId":"commonwealth-F2006B08799-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/DC3/21 - Instrument Panel Junction Box - Inspection","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)  Douglas DC3 Series Aeroplanes\n\n \n\nAD/DC3/21 Instrument Panel Junction Box - Inspection NK\n\nApplicability: All models.\n\n \n\nRequirement: 1. Inspect the undercarriage warning light dimming resistors inside the instrument panel junction box for possible short circuiting to terminals of frame.\n\n \n\n2. Re-position resistors as necessary to preclude any possibility of short circuiting. OR ANOs Part 100 Appendix “A” Notice No. 7/31;\n\nOR ANO 105.1.16.1.6.8.\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":2,"scope_assessment":{"changed":false,"description":"The instrument itself does not indicate any departure from an original or broader scope; it explicitly states applicability to all models and prescribes inspection and repositioning of the specified resistors. No text in the instrument suggests a change in scope from an earlier intent."},"complexity_factors":["Narrow technical focus: single component (dimming resistors) and single location (instrument panel junction box).","Simple required actions: inspection and repositioning rather than complex modification or testing.","Applicability to all models increases the breadth of operators affected, though not the technical complexity.","Use of the discretionary phrase \"as necessary\" (Requirement 2) introduces judgement-based variability in compliance.","References to external ANO documents require cross-referencing other instruments for alternative compliance procedures."],"plain_english_summary":"This directive requires owners/operators of all Douglas DC‑3 series aircraft to have maintenance personnel inspect undercarriage-warning-light dimming resistors in the instrument-panel junction box for potential shorting to the airframe and to reposition them if needed (or comply with specified ANOs). It matters because it prevents possible electrical short circuits; costs are inspection time, labour and possible aircraft downtime, and the phrase “as necessary” leaves judgment to inspectors, creating some variability in implementation."},"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This is a discrete, targeted safety directive focused on a specific electrical component in a specific aircraft type. It has not expanded beyond its original purpose of preventing short circuits in DC-3 instrument panels. The inclusion of alternative compliance paths (British ANOs) is standard aviation regulatory practice and does not represent scope creep."},"complexity_factors":["Extremely short document — only 2 substantive requirements","No defined terms section","Minimal conditional logic (simple 'inspect and fix OR follow alternative')","Single applicability criterion ('All models')","No cross-references to other legislation beyond optional alternative compliance paths","Clear, imperative language ('Inspect', 'Re-position')","Technical but not legally complex — assumes aviation maintenance knowledge rather than legal expertise"],"plain_english_summary":"**What this is:** An Airworthiness Directive (AD) — essentially a mandatory safety notice issued by Australia's Civil Aviation Safety Authority (CASA) for aircraft.\n\n**What it does:** This directive requires owners and operators of Douglas DC-3 aircraft to inspect a specific electrical component — the **instrument panel junction box** — for a dangerous fault. Specifically, technicians must check whether the resistors (electrical components that control brightness) for the undercarriage warning lights are touching the metal frame, which could cause a **short circuit** (unwanted electrical connection that can cause fires or system failure).\n\n**Who must act:** Anyone operating or maintaining Douglas DC-3 series aircraft in Australia.\n\n**What must be done:**\n- **Inspect** the junction box to see if the resistors are touching the frame\n- **Fix it** by moving the resistors so they cannot touch the frame and short out\n\n**Alternative compliance:** Operators can instead follow two older British aviation notices (ANO Part 100 Appendix \"A\" Notice No. 7/31, or ANO 105.1.16.1.6.8) if they prefer — these contain equivalent safety instructions.\n\n**Why it matters:** A short circuit in the instrument panel could cause electrical failure, fire, or loss of critical warning systems — particularly the undercarriage warning, which alerts pilots if their landing gear isn't properly deployed. This is a straightforward safety fix to prevent potentially catastrophic electrical problems in a vintage aircraft type still flying in Australia."}},"importantCases":[],"_links":{"self":"/api/acts/ad-dc3-21-instrument-panel-junction-box-inspection","history":"/api/acts/ad-dc3-21-instrument-panel-junction-box-inspection/history","analysis":"/api/acts/ad-dc3-21-instrument-panel-junction-box-inspection/analysis","conflicts":"/api/acts/ad-dc3-21-instrument-panel-junction-box-inspection/conflicts","importantCases":"/api/acts/ad-dc3-21-instrument-panel-junction-box-inspection/important-cases","documents":"/api/acts/ad-dc3-21-instrument-panel-junction-box-inspection/documents"}}