{"id":"F2006B09222","name":"AD/DHC-8/65 - Thunderstorm Lights","slug":"ad-dhc-8-65-thunderstorm-lights","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":53083,"registerId":"commonwealth-F2006B09222-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/DHC-8/65 - Thunderstorm Lights","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)  \nBombardier (Boeing Canada/De Havilland) DHC-8 Series Aeroplanes\n\nAD/DHC-8/65 Thunderstorm Lights 10/99\n\nApplicability: DHC-8 Series 100 aeroplanes Serial Numbers 003 through 020 inclusive without Modification 8/0198 incorporated.\n\nRequirement: Install Bombardier Modification 8/0198 (Electrical Power - Thunderstorm Lights - Change Power Supply from Left Secondary Bus to Left Essential Bus) in accordance with Bombardier Regional Aircraft Ltd Service Bulletin 8-24-69 dated 8 December 1998.\n\nNote: Transport Canada AD CF-99-21 refers.\n\nCompliance: Within six months from the effective date of this Directive.\n\nThis Airworthiness Directive becomes effective on 7 October 1999.\n\nBackground: In aeroplanes without Modification 8/0198, the thunderstorm lights are supplied with electrical power from the left secondary bus rather than the essential bus. Should an aeroplane without the modification lose all generated electrical power, compliance with the flight manual emergency procedures will result in cockpit lighting not being available.\n\nThis Directive ensures that this anomaly is corrected.","sortOrder":0}],"analysis":{"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":false,"description":"The directive is corrective and narrowly targeted: it obliges installation of a specified modification on identified aeroplanes without expanding regulatory scope beyond those aircraft or introducing new operational restrictions. It implements a wiring/power‑supply change to address a specific equipment availability risk (Requirement; Background; Applicability)."},"complexity_factors":["Narrow applicability to a small serial‑number range (Applicability) which reduces legal and operational breadth.","Mandatory technical installation of a specified manufacturer modification following a specific service bulletin (Requirement; Service Bulletin 8‑24‑69) — requires maintenance resources and technical compliance.","Firm compliance timeframe of six months (Compliance) — creates scheduling/operational impacts for affected operators.","Safety‑critical electrical re‑routing (Background) — the change affects emergency systems and thus has certification and testing implications.","Cross‑reference to foreign regulator action (Transport Canada AD CF‑99‑21) — may require coordination or recognition across authorities."],"plain_english_summary":"This Airworthiness Directive requires DHC‑8 Series 100 aeroplanes (serial numbers 003–020) that do not have Bombardier Modification 8/0198 to have that modification fitted. The change moves thunderstorm lights’ power from the left secondary bus to the left essential bus so cockpit thunderstorm lighting remains available if all generated electrical power is lost. Operators must install the modification per Bombardier Service Bulletin 8‑24‑69 within six months of the directive’s effective date."},"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This is a discrete, targeted safety directive addressing a specific electrical system anomaly in a limited fleet of aircraft. It has not expanded beyond its original purpose."},"complexity_factors":["Single, specific technical requirement with no conditional logic or exceptions","Only one defined applicability criterion (serial number range plus modification status)","No cross-references to other legislation or regulations beyond a single note about a Canadian equivalent","Straightforward compliance deadline with no phased or alternative compliance options","Background explanation provided in plain operational terms rather than dense technical cross-references"],"plain_english_summary":"This CASA Airworthiness Directive mandates a wiring change on certain Bombardier DHC-8 Series 100 (S/N 003–020) to feed cockpit thunderstorm lights from the left essential bus instead of the left secondary bus. It affects owners/operators without Modification 8/0198 and must be complied with within six months of 7 October 1999. The change ensures those lights remain powered during total electrical failure, preserving instrument visibility in storm/emergency conditions."}},"importantCases":[],"_links":{"self":"/api/acts/ad-dhc-8-65-thunderstorm-lights","history":"/api/acts/ad-dhc-8-65-thunderstorm-lights/history","analysis":"/api/acts/ad-dhc-8-65-thunderstorm-lights/analysis","conflicts":"/api/acts/ad-dhc-8-65-thunderstorm-lights/conflicts","importantCases":"/api/acts/ad-dhc-8-65-thunderstorm-lights/important-cases","documents":"/api/acts/ad-dhc-8-65-thunderstorm-lights/documents"}}