{"id":"F2006B09182","name":"AD/DHC-8/27 Amdt 1 - Passenger Service Units Printed Circuit Boards","slug":"ad-dhc-8-27-amdt-1-passenger-service-units-printed-circuit-boards","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":52951,"registerId":"commonwealth-F2006B09182-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/DHC-8/27 Amdt 1 - Passenger Service Units Printed Circuit Boards","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-8/27\n\nAmdt 1\n\n  \nPassenger Service Units Printed Circuit Boards 2/94\n\nApplicability: All DHC-8 aircraft serial number 3 to 369, which have accumulated more than 600 flight hours and which are fitted with Passenger Service Units (PSU) with the following part numbers:\n\n| 10-1418-1 | 10-1081-1 | 10-1081-4 | 10-1081-7 | 10-1418-2 |\n| --------- | --------- | --------- | --------- | --------- |\n| 10-1081-2 | 10-1081-5 | 10-1081-8 | 10-1081-3 | 10-1081-6 |\n\nRequirement: Action in accordance with Bombardier Regional Aircraft Division Alert Service Bulletin A8-33-30 Revision A dated 18 December 1992.\n\nNote: Transport Canada CF-93-01R1 dated 3 December 1993 refers.\n\nCompliance: The original compliance was prior to 1 May 1993, unless already accomplished in the 300 flight hours before 1 April 1993 and thereafter at intervals not to exceed 600 flight hours until Modification No 8/1950 is incorporated.\n\nThe compliance for this amendment is: unless previously accomplished in accordance with the previous issue of this Directive, then prior to 3 March 1994 and thereafter at intervals not to exceed 600 hours time in service, until Modification No 8/1950 is incorporated in accordance with Bombardier Regional Aircraft Division Service Bulletin 8-33-34 dated 10 August 1993.\n\nBackground: Signs of overheating of the PSU printed circuit boards (PCB) and power supply connectors have been reported by DHC-8 operators. An investigation has indicated that this overheat problem was caused by moisture ingress into the PSU connectors which led to corrosion of the PCB pins/connector interfaces. The corroded PCB and/or connectors, if not detected and corrected, may lead to an excessive overheat condition and a potential fire hazard.\n\nThis amendment clarifies the aircraft serial number range, increases the number of affected PSUs and advises the Service Bulletin Number which provides terminating action.","sortOrder":0}],"analysis":{"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":true,"description":"This amendment clarifies the affected aircraft serial number range, increases the number of PSUs identified as affected, and specifies the service bulletin that provides the terminating modification, thereby expanding and clarifying the population subject to recurring inspections until Modification No 8/1950 is incorporated (Background; Applicability; Requirement)."},"complexity_factors":["Technical specificity: precise aircraft serial number range and multiple PSU part numbers listed, requiring operators to match equipment identity (Applicability).","Recurring compliance schedule: inspections at intervals not to exceed 600 flight hours until a terminating modification is installed (Compliance).","Terminating action dependency: compliance ends only when Modification No 8/1950 is incorporated per a separate service bulletin, creating a two‑step remedy (Requirement; Compliance).","Cross‑jurisdictional reference: notes and references Transport Canada and specific Bombardier service bulletins, requiring operators to follow external documents (Note; Requirement).","Operational cost and logistics: repeated inspections, possible PCB/connector repairs or replacements, and final modification impose direct costs and downtime on operators (Compliance; Background).","Safety‑driven trigger: action is tied to a specific failure mode (moisture ingress → corrosion → overheating/fire), which focuses measures but requires technical inspection capability (Background)."],"plain_english_summary":"This directive requires DHC‑8 operators (aircraft s/n 3–369 with specified Passenger Service Units) to carry out recurring inspections of PSU printed circuit boards and to install a terminating modification per Bombardier service bulletins (Requirement; Compliance). It responds to moisture ingress and connector corrosion that can overheat PSUs and create a fire hazard (Background). Operators pay for inspections, repairs and the terminating mod; inspections recur every 600 flight hours until Modification No 8/1950 is incorporated (Compliance)."},"flash_summary_failed":{"failed":true,"reason":"A positive credit balance is required for all requests, including BYOK, so fallback providers remain available. Add credits at https://vercel.com/d?to=%2F%5Bteam%5D%2F%7E%2Fai%3Fmodal%3Dtop-up to continue.","source":"analysis-cron"},"kimi_summary":{"content_quality":"ok","complexity_score":3,"scope_assessment":{"changed":true,"description":"The amendment has expanded the scope from the original directive. It clarifies the aircraft serial number range (now explicitly 3 to 369), increases the number of affected PSU part numbers covered, and adds a terminating action (Modification No 8/1950) that provides a permanent fix rather than indefinite repeated inspections. The compliance deadline was also extended from the original 1 May 1993 to 3 March 1994 for those not already compliant."},"complexity_factors":["Multiple conditional compliance dates (original vs amendment deadlines)","Cross-reference to external technical documents (Bombardier Service Bulletin A8-33-30 Revision A, Service Bulletin 8-33-34, Transport Canada CF-93-01R1)","Specific part number identification requiring table lookup","Nested compliance logic: 'unless already accomplished... then prior to... and thereafter at intervals... until...'","Technical aviation terminology requiring domain knowledge (PSU, PCB, serial number ranges, flight hours accumulation)"],"plain_english_summary":"This Airworthiness Directive requires operators of Bombardier DHC‑8 (Dash 8) aircraft (serials 3–369) meeting certain hours and PSU fittings to inspect and remediate a moisture‑induced corrosion/overheating fire risk in overhead passenger service units, using Bombardier’s Alert Service Bulletin. Inspections repeat until a terminating modification is installed. Compliance is mandatory for continued legal operation in Australian airspace and prevents potential in‑flight fires."}},"importantCases":[],"_links":{"self":"/api/acts/ad-dhc-8-27-amdt-1-passenger-service-units-printed-circuit-boards","history":"/api/acts/ad-dhc-8-27-amdt-1-passenger-service-units-printed-circuit-boards/history","analysis":"/api/acts/ad-dhc-8-27-amdt-1-passenger-service-units-printed-circuit-boards/analysis","conflicts":"/api/acts/ad-dhc-8-27-amdt-1-passenger-service-units-printed-circuit-boards/conflicts","importantCases":"/api/acts/ad-dhc-8-27-amdt-1-passenger-service-units-printed-circuit-boards/important-cases","documents":"/api/acts/ad-dhc-8-27-amdt-1-passenger-service-units-printed-circuit-boards/documents"}}