{"id":"F2006L00441","name":"AD/DHC-8/109 - Fuel Access Panel Attachment Anchor Nut","slug":"ad-dhc-8-109-fuel-access-panel-attachment-anchor-nut","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":117127,"registerId":"commonwealth-F2006L00441-current","compilationNumber":null,"startDate":"2026-04-03","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"Bombardier (Boeing Canada/De Havilland) ","sectionType":"division","heading":"Bombardier (Boeing Canada/De Havilland) DHC-8 Series Aeroplanes","content":"### Bombardier (Boeing Canada/De Havilland) DHC-8 Series Aeroplanes\n\n| AD/DHC-8/109 | Fuel Access Panel Attachment Anchor Nut | 3/2006 |\n| ------------ | --------------------------------------- | ------ |\n\n| Applicability: | Model DHC-8-400, DHC-8-401, and DHC-8-402 aircraft, serial numbers 4001, and 4003 through 4115.                                                                                                                                                                                                                                                                                                                             |\n| -------------- | --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |\n| Requirement:   | Action in accordance with the requirements of Transport Canada AF CF-2005-08R1.Note: Bombardier Service Bulletins 84-57-10 Revision C, 84-57-11 Revision B, and 84-57-12 Revision B, or later Transport Canada approved revisions, refer.                                                                                                                                                                                   |\n| Compliance:    | As specified in the Requirement document, with a revised effective date of16 March 2006.                                                                                                                                                                                                                                                                                                                                    |\n|                | This Airworthiness Directive becomes effective on 16 March 2006.                                                                                                                                                                                                                                                                                                                                                            |\n| Background:    | There have been a number of reported cases of corrosion of dome anchor nuts at the centre wing upper surface fuel access panel attachment locations during “C” checks. In some cases, anchor nut domes were severely corroded and perforated. This condition, not corrected, could result in arcing and ignition of fuel vapour in the centre wing fuel tank during a lightning strike; and consequent fuel tank explosion. |\n\n![](image.001.png)  \nDavid Villiers  \nDelegate of the Civil Aviation Safety Authority\n\n3 February 2006","sortOrder":0},{"sectionNumber":"AD/DHC-8/109","sectionType":"part","heading":"AD/DHC-8/109","content":"## AD/DHC-8/109","sortOrder":1},{"sectionNumber":"Fuel Access Panel Attachment Anchor Nut","sectionType":"part","heading":"Fuel Access Panel Attachment Anchor Nut","content":"## Fuel Access Panel Attachment Anchor Nut","sortOrder":2},{"sectionNumber":"3/2006","sectionType":"part","heading":"3/2006","content":"## 3/2006","sortOrder":3}],"analysis":{"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":4,"scope_assessment":{"changed":false,"description":"The instrument applies only to specified DHC-8-400 series serial numbers and requires corrective action per Transport Canada AF CF-2005-08R1. The text does not identify any change to the substantive scope of affected aircraft or mandated work; it only sets/revises the effective date to 16 March 2006."},"complexity_factors":["Applicability limited to a defined subset of DHC-8-400 aircraft by model and serial numbers (Applicability).","Mandates actions 'in accordance with the requirements of Transport Canada AF CF-2005-08R1' and refers to Bombardier Service Bulletins 84-57-10 Rev C, 84-57-11 Rev B, 84-57-12 Rev B (Requirement) — creates dependency on external documents.","Revised effective date specified (Compliance: 'revised effective date of 16 March 2006'), which affects scheduling and legal compliance windows.","Safety-critical technical remedy (inspect/repair anchor nut domes) driven by reported corrosion and risk of arcing/ignition (Background) — implies potential for parts replacement and access during 'C' checks.","Cross-jurisdictional reliance on Transport Canada material requires operators/maintainers to obtain and apply foreign-issued procedures, increasing administrative steps.","Limited scope of affected fleet reduces breadth but concentrates compliance burden on those owners/operators, potentially requiring targeted maintenance planning."],"plain_english_summary":"Requires operators of specified Bombardier DHC-8-400 series aeroplanes (serial 4001, 4003–4115) to carry out work per Transport Canada Airworthiness Directive AF CF-2005-08R1 (and referenced Bombardier service bulletins) to inspect and repair fuel access panel anchor nuts. Effective 16 March 2006. The directive responds to corrosion of anchor nut domes that, if not corrected, could allow arcing and ignition of centre wing fuel vapour during a lightning strike, risking fuel tank explosion."},"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This is a standard, narrow Airworthiness Directive targeting a specific mechanical defect in specific aircraft. It has not expanded beyond its original safety purpose."},"complexity_factors":["Very short document (under 300 words)","Only 3 defined aircraft models and specific serial number ranges","Single requirement referencing external technical documents rather than spelling out detailed procedures","No nested exceptions or conditional logic","Clear, single compliance date","Straightforward cause-and-effect safety rationale"],"plain_english_summary":"This AD requires operators of certain Bombardier DHC-8-400 series aircraft (serials 4001, 4003–4115; models -400, -401, -402) to inspect and repair corroded anchor nuts on centre wing fuel tank access panels. Corrosion can cause sparks during lightning and ignite fuel vapour, so compliance with Transport Canada and Bombardier repair instructions by 16 March 2006 is mandatory. This is a legally binding safety requirement."}},"importantCases":[],"_links":{"self":"/api/acts/ad-dhc-8-109-fuel-access-panel-attachment-anchor-nut","history":"/api/acts/ad-dhc-8-109-fuel-access-panel-attachment-anchor-nut/history","analysis":"/api/acts/ad-dhc-8-109-fuel-access-panel-attachment-anchor-nut/analysis","conflicts":"/api/acts/ad-dhc-8-109-fuel-access-panel-attachment-anchor-nut/conflicts","importantCases":"/api/acts/ad-dhc-8-109-fuel-access-panel-attachment-anchor-nut/important-cases","documents":"/api/acts/ad-dhc-8-109-fuel-access-panel-attachment-anchor-nut/documents"}}