{"id":"F2009L02195","name":"AD/DHC-8/147 - Main Landing Gear Airworthiness Limitation Items","slug":"ad-dhc-8-147-main-landing-gear-airworthiness-limitation-items","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":140389,"registerId":"commonwealth-F2009L02195-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-8/147 | Main Landing GearAirworthiness Limitation Items | 7/2009 |\n| ------------ | ----------------------------------------------- | ------ |\n\n| Applicability: | DHC-8 Aircraft, Models 400, 401 and 402, serial numbers 4001, 4003, 4004, 4006 and 4008 through 4227.                                                                                                                                                                                                                                                                                                                                                                                                                 |\n| -------------- | --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |\n| Requirement:   | Action in accordance with the requirements of Transport Canada AD CF-2009-17.                                                                                                                                                                                                                                                                                                                                                                                                                                         |\n| Compliance:    | As specified in the Requirement document, with a revised effective date of2 July 2009.                                                                                                                                                                                                                                                                                                                                                                                                                                |\n|                | This Airworthiness Directive becomes effective on 2 July 2009.                                                                                                                                                                                                                                                                                                                                                                                                                                                        |\n| Background:    | Certain main landing gear components have prematurely failed during certification testing. The DHC-8-400 Maintenance Requirements Manual, Airworthiness Limitations Items, has been revised to incorporate the revised safe life limits for the main landing gear lock actuator assembly, retraction actuator assembly rod end and piston, and the upper bearing in the main landing gear shock strut assembly. Failure of these components could adversely affect the structural integrity of the main landing gear. |\n\n![](image.001.png)  \nDavid Villiers  \nDelegate of the Civil Aviation Safety Authority\n\n19 May 2009","sortOrder":0},{"sectionNumber":"AD/DHC-8/147","sectionType":"part","heading":"AD/DHC-8/147","content":"## AD/DHC-8/147","sortOrder":1},{"sectionNumber":"Main Landing GearAirworthiness Limitatio","sectionType":"part","heading":"Main Landing GearAirworthiness Limitation Items","content":"## Main Landing Gear  \nAirworthiness Limitation Items","sortOrder":2},{"sectionNumber":"7/2009","sectionType":"part","heading":"7/2009","content":"## 7/2009","sortOrder":3}],"analysis":{"flash_summary":{"complexity_score":4,"scope_assessment":{"changed":false,"description":"The instrument adopts Transport Canada AD CF-2009-17 for the listed DHC-8 400-series serial numbers and does not expand applicability or add new categories of requirement beyond the revised airworthiness limitation items. The only explicit domestic change noted is a revised effective date of 2 July 2009 (Requirement; Compliance)."},"complexity_factors":["Narrow, serial-numbered applicability reduces breadth but requires fleet-level tracking (Applicability).","Cross-reference to an external regulator's directive (Transport Canada AD CF-2009-17) creates a dependency on that document (Requirement).","Revised effective date and specified compliance timing require administrative changes to maintenance scheduling (Compliance).","Technical nature: changes modify safe-life limits for multiple landing-gear components (lock actuator assembly, retraction actuator rod end and piston, upper bearing) requiring engineering/maintenance actions (Background).","Direct operational costs: inspections, part replacements and manual revisions fall to operators (Background).","Enforcement and administrative discretion by CASA delegate for implementation and oversight (signature block: David Villiers, Delegate of the Civil Aviation Safety Authority)."],"plain_english_summary":"This Airworthiness Directive requires operators of Bombardier DHC-8 models 400, 401 and 402 (specified serial numbers) to adopt revised safe-life limits for certain main landing gear components, implementing Transport Canada AD CF-2009-17. It takes effect on 2 July 2009. Operators must update the Maintenance Requirements Manual and carry out the inspections or replacements set out in the revised airworthiness limitation items. Operators pay for the work; the Civil Aviation Safety Authority (via its delegate) enforces compliance."},"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This is a targeted safety directive addressing a specific mechanical failure mode in a defined aircraft population. The scope remains precisely limited to the landing gear components identified in the original Transport Canada directive."},"complexity_factors":["Very short document (under 300 words)","Only 3 specific components identified for action","Single cross-reference to external document (Transport Canada AD CF-2009-17)","No defined terms section","Simple conditional structure: applies to specific serial numbers, requires specific action by specific date","No nested exceptions or complex logical operators"],"plain_english_summary":"CASA has issued a mandatory Airworthiness Directive requiring owners/operators of specified Bombardier DHC‑8‑400 series aircraft (serials 4001, 4003, 4004, 4006, 4008–4227) to adopt Transport Canada maintenance measures that reduce safe‑life limits for three critical main landing gear components (lock actuator, retraction actuator rod end/piston, and upper shock‑strut bearing).\n\nPremature failures occurred during certification testing; if these parts fail in service the main gear could collapse during landing or taxi. Compliance is legally mandatory by 2 July 2009."},"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"}},"importantCases":[],"_links":{"self":"/api/acts/ad-dhc-8-147-main-landing-gear-airworthiness-limitation-items","history":"/api/acts/ad-dhc-8-147-main-landing-gear-airworthiness-limitation-items/history","analysis":"/api/acts/ad-dhc-8-147-main-landing-gear-airworthiness-limitation-items/analysis","conflicts":"/api/acts/ad-dhc-8-147-main-landing-gear-airworthiness-limitation-items/conflicts","importantCases":"/api/acts/ad-dhc-8-147-main-landing-gear-airworthiness-limitation-items/important-cases","documents":"/api/acts/ad-dhc-8-147-main-landing-gear-airworthiness-limitation-items/documents"}}