{"id":"F2006L00439","name":"AD/DHC-8/111 - Fuselage Bottom Skin and VHF Antenna Support Structure","slug":"ad-dhc-8-111-fuselage-bottom-skin-and-vhf-antenna-support-structure","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":117123,"registerId":"commonwealth-F2006L00439-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-8/111 | Fuselage Bottom Skin and VHFAntenna Support Structure | 3/2006 |\n| ------------ | ----------------------------------------------------- | ------ |\n\n| Applicability: | Models DHC-8-401 and DHC-8-402 aircraft, serial numbers 4003 through 4076, and 4078 through 4081.                                                                                                                                                                                                                                                                                                                                                                       |\n| -------------- | ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |\n| Requirement:   | Action in accordance with Transport Canada AD CF-2003-28.                                                                                                                                                                                                                                                                                                                                                                                                               |\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:    | The manufacturer received a report of an aircraft with an 8-inch crack on the fuselage skin in the vicinity of the forward No. 2 VHF antenna. Investigation revealed that four of eight cleats, part number 85307891, attaching the internal antenna support plate, had cracked as well. Since the original report, other aircraft were found to have cracked cleats. If undetected, cracking in the fuselage skin could result in rapid decompression of the aircraft. |\n\n![](image.001.png)  \nDavid Villiers  \nDelegate of the Civil Aviation Safety Authority\n\n3 February 2006","sortOrder":0},{"sectionNumber":"AD/DHC-8/111","sectionType":"part","heading":"AD/DHC-8/111","content":"## AD/DHC-8/111","sortOrder":1},{"sectionNumber":"Fuselage Bottom Skin and VHF Antenna Sup","sectionType":"part","heading":"Fuselage Bottom Skin and VHF Antenna Support Structure","content":"## Fuselage Bottom Skin and VHF  \nAntenna Support Structure","sortOrder":2},{"sectionNumber":"3/2006","sectionType":"part","heading":"3/2006","content":"## 3/2006","sortOrder":3}],"analysis":{"flash_summary_failed":{"failed":true,"reason":"Unauthenticated. Configure AI_GATEWAY_API_KEY or use a provider module. Learn more: https://ai-sdk.dev/unauthenticated-ai-gateway","source":"analysis-cron"},"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This is a standard, narrow Airworthiness Directive addressing a specific structural defect in specific aircraft. It has not expanded beyond its original safety purpose."},"complexity_factors":["Very short document (under 300 words)","Only 1 substantive requirement: comply with an external Canadian directive","No defined terms section","No nested exceptions or conditional logic","Simple applicability table with specific serial number ranges","Single compliance date with straightforward extension"],"plain_english_summary":"This mandatory Airworthiness Directive orders Australian owners/operators of certain Bombardier DHC‑8‑400 (Q400) aeroplanes (S/N 4003–4076, 4078–4081) to follow Transport Canada AD CF‑2003‑28 — inspect and repair fuselage skin and antenna cleat cracking by 16 March 2006. It addresses cracks that could lead to rapid decompression, so compliance is legally required to ensure continued safe flight."},"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":false,"description":"This instrument adopts the requirements of Transport Canada AD CF-2003-28 for the listed DHC-8-401/-402 serial numbers and sets an Australian effective date of 16 March 2006. The text provided does not broaden or narrow the applicability or substantive requirements beyond the referenced Transport Canada AD."},"complexity_factors":["Relies on an external document (Transport Canada AD CF-2003-28) for detailed procedures — requires cross-referencing.","Narrow, serial-number-specific applicability (multiple serial ranges).","Involves safety-critical structural inspections and possible repairs (risk: rapid decompression).","References a specific part number (cleat 85307891) — potential parts-supply or maintenance-procedure implications.","Revised effective date requires operators to comply by 16 March 2006 (scheduling and operational downtime).","Enforcement by the Civil Aviation Safety Authority — compliance monitoring and record-keeping burden."],"plain_english_summary":"This Airworthiness Directive requires operators of specific Bombardier DHC-8-401 and DHC-8-402 aeroplanes (listed serial numbers) to carry out inspections and any corrective work set out in Transport Canada AD CF-2003-28; it takes effect 16 March 2006.\n\nThe AD responds to discovered cracks in the fuselage bottom skin and cracked VHF-antenna support cleats (part 85307891). Operators must inspect and repair per the referenced AD; the regulator enforces compliance and operators bear inspection, repair and downtime costs."}},"importantCases":[],"_links":{"self":"/api/acts/ad-dhc-8-111-fuselage-bottom-skin-and-vhf-antenna-support-structure","history":"/api/acts/ad-dhc-8-111-fuselage-bottom-skin-and-vhf-antenna-support-structure/history","analysis":"/api/acts/ad-dhc-8-111-fuselage-bottom-skin-and-vhf-antenna-support-structure/analysis","conflicts":"/api/acts/ad-dhc-8-111-fuselage-bottom-skin-and-vhf-antenna-support-structure/conflicts","importantCases":"/api/acts/ad-dhc-8-111-fuselage-bottom-skin-and-vhf-antenna-support-structure/important-cases","documents":"/api/acts/ad-dhc-8-111-fuselage-bottom-skin-and-vhf-antenna-support-structure/documents"}}