{"id":"F2006B09253","name":"AD/DHC-8/93 - APU Fuel Line Chafing","slug":"ad-dhc-8-93-apu-fuel-line-chafing","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":53198,"registerId":"commonwealth-F2006B09253-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"AIRWORTHINESS DIRECTIVE","sectionType":"part","heading":"AIRWORTHINESS DIRECTIVE","content":"# AIRWORTHINESS DIRECTIVE\n\n![](image.001.png)  \n\nFor the reasons set out in the background section, the CASA delegate whose signature appears below issues the following Airworthiness Directive (AD) under subregulation 39.1 (1) of CASR 1998. The AD requires that the action set out in the requirement section (being action that the delegate considers necessary to correct the unsafe condition) be taken in relation to the aircraft or aeronautical product mentioned in the applicability section: (a) in the circumstances mentioned in the requirement section; and (b) in accordance with the instructions set out in the requirement section; and (c) at the time mentioned in the compliance section.\n\n![](image.001.png)  \n\nBombardier (Boeing Canada/De Havilland) DHC-8 Series Aeroplanes","sortOrder":0},{"sectionNumber":"AD/DHC-8/93 APU Fuel Line Chafing 11/200","sectionType":"part","heading":"AD/DHC-8/93 APU Fuel Line Chafing 11/2003","content":"# AD/DHC-8/93 APU Fuel Line Chafing 11/2003\n\nApplicability: DHC-8 Series 100, 200 and 300 aeroplanes, serial numbers 003 to 585 inclusive, with Auxiliary Power Unit (APU) installation per Standard Option Only (S.O.O.) 8155 or Change Request (CR) 849SO08155.\n\nRequirement: Carry out the inspection and rectification (if required) of the APU fuel tube assembly, Part Number (P/N) 82830105-139, in accordance with Bombardier Service Bulletin (SB) 8-49-19, dated 13 May 2003, or SB 8-49-19, Revision A, dated 7 July 2003.\n\nNote: Transport Canada AD CF-2003-22 refers.\n\nCompliance: With six months from the effective date of this Directive.\n\nThis Airworthiness Directive becomes effective on 30 October 2003.\n\nBackground: Investigation of a fuel leak incident revealed chafing of the APU fuel tube assembly on the bleed air duct shroud located in the centre wing area. The APU fuel tube assembly is attached to a fairlead by two clamps. In some instances, incorrect installation of the clamps on the fairleads may result in insufficient clearance, and cause contact between the fuel line and the bleed air duct, or gust lock cable, resulting in chafing of the APU fuel tube. The intent of this Directive is to provide inspection instructions and corrective actions to ensure the integrity of the APU fuel tube.\n\n![](image.002.png)  \n\nJim Coyne\n\nDelegate of the Civil Aviation Safety Authority 18 September 2003\n\n![](image.001.png)  \n\nThe above AD is notified in the Commonwealth of Australia Gazette on 8 October 2003.","sortOrder":1}],"analysis":{"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This Airworthiness Directive maintains its original narrow scope. It addresses a specific unsafe condition (APU fuel line chafing) on specific aircraft models through a targeted inspection requirement. There is no evidence of scope creep; the directive remains tightly focused on the original safety issue identified in the background."},"complexity_factors":["Single, specific technical requirement referencing external manufacturer documentation (Service Bulletin)","Narrow applicability limited to specific aircraft series, serial number range, and specific equipment configurations","Simple compliance deadline (single fixed period from effective date)","No nested exceptions, conditional logic, or alternative compliance paths","Minimal defined terms (only standard aviation abbreviations: APU, P/N, S.O.O., CR, SB)","No cross-references to other legislation beyond a single note about a Canadian equivalent directive"],"plain_english_summary":"This airworthiness directive requires owners/operators of Bombardier DHC-8 Series 100/200/300 (S/N 003–585) with the specified APU installation to inspect the APU fuel-tube assembly for chafing and incorrect clamp installation and to repair or replace damaged or misrouted tubing per Bombardier Service Bulletin 8-49-19.  \n\nAction is mandatory within six months of 30 October 2003 to prevent fuel leaks that could lead to fire."},"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"},"flash_summary":{"complexity_score":2,"scope_assessment":{"changed":false,"description":"Scope remains focused on inspecting and rectifying chafing of the APU fuel tube assembly on specified DHC-8 aeroplanes. The AD implements the corrective actions set out in Bombardier Service Bulletin 8-49-19 (or Revision A) and requires completion within six months; it does not expand applicability or introduce additional requirements beyond those inspection/rectification instructions."},"complexity_factors":["Narrow applicability: specific aircraft series and serial number range (003–585) and specific APU installation (S.O.O. 8155 or CR 849SO08155)","Single, identified part number (P/N 82830105-139) targeted for inspection and possible rectification","Mandatory compliance with an external technical document (Bombardier SB 8-49-19 or Revision A) rather than detailed procedural steps in the AD","Fixed compliance timeframe (six months) requiring operators to schedule maintenance within that period","Regulatory basis cited (CASR 1998 subregulation 39.1(1)) and cross-reference to Transport Canada AD CF-2003-22","Operational burden limited to inspection and corrective action, but potential variability in labour and parts costs depending on findings"],"plain_english_summary":"This Directive requires operators of Bombardier (DHC-8) Series 100/200/300 aeroplanes (serials 003–585) with a specified APU installation to inspect a particular APU fuel tube (P/N 82830105-139) and fix any chafing found, following Bombardier Service Bulletin 8-49-19 (or Revision A). The action must be completed within six months. It matters because chafing can cause a fuel leak; the operator bears the cost and must schedule maintenance to comply with the inspection and corrective instructions."}},"importantCases":[],"_links":{"self":"/api/acts/ad-dhc-8-93-apu-fuel-line-chafing","history":"/api/acts/ad-dhc-8-93-apu-fuel-line-chafing/history","analysis":"/api/acts/ad-dhc-8-93-apu-fuel-line-chafing/analysis","conflicts":"/api/acts/ad-dhc-8-93-apu-fuel-line-chafing/conflicts","importantCases":"/api/acts/ad-dhc-8-93-apu-fuel-line-chafing/important-cases","documents":"/api/acts/ad-dhc-8-93-apu-fuel-line-chafing/documents"}}