{"id":"F2006B09221","name":"AD/DHC-8/64 - Wing Fuel Tanks - Access Panel Sealing","slug":"ad-dhc-8-64-wing-fuel-tanks-access-panel-sealing","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":53080,"registerId":"commonwealth-F2006B09221-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/DHC-8/64 - Wing Fuel Tanks - Access Panel Sealing","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-8/64 Wing Fuel Tanks \\- Access Panel Sealing 10/99\n\nApplicability: All DHC-8 aircraft, all Models, serial numbers 3 through 543.\n\nRequirements: Change Wing Tank Access Panel Seals, using ModSum 8Q1000797, in accordance with the provisions of Bombardier Service Bulletin 8-57-41, dated 9 February 1999.\n\nNote: Transport Canada Airworthiness Directive CF-99-20 dated 20 July 1999 refers.\n\nCompliance: Prior to 9 February 2000 unless previously accomplished.\n\nThis Airworthiness Directive becomes effective on 7 October 1999.\n\nBackground: During routine maintenance a sealing problem has been discovered with the upper wing tank access panels. An O-ring larger than specified had been fitted to the access panel during production with the result that the access panel fit was incorrect. This poor fit could lead to eventual loss of lightning protection for the fuel tanks through fretting and corrosion of the wing ladder plate and displacement of the adjacent channel seal.","sortOrder":0}],"analysis":{"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This is a discrete, single-issue airworthiness directive addressing a specific manufacturing defect. It has not expanded beyond its original scope of ensuring proper sealing of wing fuel tank access panels."},"complexity_factors":["Single, specific technical requirement (replace seals per manufacturer bulletin)","Clear applicability (all DHC-8 models, specific serial number range)","Single compliance deadline with straightforward exception clause","No defined terms section, no cross-references to other legislation beyond one related Canadian directive","Background explanation provided in plain language","Total length: approximately 150 words"],"plain_english_summary":"This mandatory AD orders operators of Bombardier DHC‑8 (Dash 8) aircraft (S/N 3–543) to replace oversized O‑ring seals on wing fuel‑tank access panels per Bombardier Service Bulletin 8‑57‑41.  \n\nThe replacement prevents panel rubbing and corrosion that can degrade lightning protection of fuel tanks — a serious fire/explosion risk — and must be completed by 9 February 2000 unless already rectified."},"flash_summary":{"complexity_score":2,"scope_assessment":{"changed":false,"description":"Scope appears unchanged from the directive's purpose: a targeted mandatory maintenance action for the upper wing tank access panel seals on specified DHC‑8 serials to restore panel fit and lightning protection. It neither expands to other systems nor narrows eligibility beyond the stated serial number range."},"complexity_factors":["Single, well‑defined corrective action (seal change)","Narrow applicability: DHC‑8 serial numbers 3–543 only","Fixed compliance deadline (one‑off action) which simplifies scheduling","References manufacturer service bulletin and ModSum (requires following external technical instructions)","Possible parts sourcing and shop‑labour costs for operators","Operational downtime for aircraft while work is performed","Safety rationale tied to corrosion/fretting and lightning protection — limited technical ambiguity","Cross‑reference to foreign (Transport Canada) AD but no additional procedural layers"],"plain_english_summary":"This Airworthiness Directive requires operators of De Havilland DHC‑8 aeroplanes (serials 3–543) to change the upper wing fuel tank access panel seals using ModSum 8Q1000797 per Bombardier Service Bulletin 8‑57‑41 by 9 February 2000. The work restores correct panel fit and the lightning-protection path for the wing tanks. Operators pay for parts and labour and incur short aircraft downtime; the mandated maintenance substitutes a known, one‑off compliance cost for a reduced risk of corrosion, fretting and loss of lightning protection."}},"importantCases":[],"_links":{"self":"/api/acts/ad-dhc-8-64-wing-fuel-tanks-access-panel-sealing","history":"/api/acts/ad-dhc-8-64-wing-fuel-tanks-access-panel-sealing/history","analysis":"/api/acts/ad-dhc-8-64-wing-fuel-tanks-access-panel-sealing/analysis","conflicts":"/api/acts/ad-dhc-8-64-wing-fuel-tanks-access-panel-sealing/conflicts","importantCases":"/api/acts/ad-dhc-8-64-wing-fuel-tanks-access-panel-sealing/important-cases","documents":"/api/acts/ad-dhc-8-64-wing-fuel-tanks-access-panel-sealing/documents"}}