{"id":"F2011L01635","name":"AD/DHC-1/40 - Canopy Lock - Modification","slug":"ad-dhc-1-40-canopy-lock-modification","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":126016,"registerId":"commonwealth-F2011L01635-current","compilationNumber":null,"startDate":"2026-04-03","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"De Havilland DHC-1 (Chipmunk) Series Aer","sectionType":"division","heading":"De Havilland DHC-1 (Chipmunk) Series Aeroplanes","content":"### De Havilland DHC-1 (Chipmunk) Series Aeroplanes\n\n| AD/DHC-1/40 | Canopy Lock - Modification | 16/2011 |\n| ----------- | -------------------------- | ------- |\n\n| Applicability: | All Canadian DHC-1B-2 Chipmunk aircraft serial numbers 139 to 195.                                                                                                                                                       |\n| -------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------ |\n| Requirement:   | Modify the canopy lock mechanism in accordance with De Havilland Aircraft of Canada Limited Technical News Sheets C-38 and C-38 Amendment 2.Note: Transport Canada Airworthiness Directives CF-53-11 and CF-54-02 refer. |\n| Compliance:    | As stated in the requirement document unless previously incorporated.                                                                                                                                                    |\n|                | This Airworthiness Directive becomes effective on 12 August 2011.                                                                                                                                                        |\n| Background:    | Difficulties have been reported in releasing the canopy due to the failure of the cable in the lock assembly. DHC Canada then amended this modification using an improved lever assembly following reports of cracking.  |\n\n![](image.001.png)  \nCharles Lenarcic  \nDelegate of the Civil Aviation Safety Authority\n\n5 August 2011","sortOrder":0},{"sectionNumber":"AD/DHC-1/40","sectionType":"part","heading":"AD/DHC-1/40","content":"## AD/DHC-1/40","sortOrder":1},{"sectionNumber":"Canopy Lock - Modification","sectionType":"part","heading":"Canopy Lock - Modification","content":"## Canopy Lock \\- Modification","sortOrder":2},{"sectionNumber":"16/2011","sectionType":"part","heading":"16/2011","content":"## 16/2011","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"},"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":true,"description":"The AD incorporates an amended modification: it requires the canopy lock change per De Havilland Technical News Sheets C‑38 and C‑38 Amendment 2, reflecting DHC Canada's later revision (an improved lever assembly) after reports of cracking. In effect, the directive updates the original modification specification rather than merely repeating an earlier requirement, and also cross‑references related Transport Canada ADs."},"complexity_factors":["Narrow, aircraft-specific applicability (serial numbers 139–195) — low breadth but high specificity.","Mandates technical compliance via external documents (De Havilland Technical News Sheets C‑38 and C‑38 Amendment 2) rather than prescribing step‑by‑step actions in the AD.","Cross-reference to Transport Canada ADs (CF‑53‑11 and CF‑54‑02) requires checking multiple regulatory instruments.","Compliance timing is governed by the referenced requirement document rather than detailed in the AD, creating reliance on the technical sheets for deadlines.","Implementation requires specialised maintenance skills, parts and possible part redesign (improved lever assembly), creating modest logistical and cost burden on owners/operators."],"plain_english_summary":"This Airworthiness Directive requires owners/operators of Canadian De Havilland DHC-1B-2 Chipmunks (serial numbers 139–195) to modify the canopy lock mechanism in accordance with De Havilland Technical News Sheets C‑38 and C‑38 Amendment 2. The change responds to reported cable failures and subsequent lever cracking. Aircraft owners pay for and arrange the work; compliance must follow the referenced technical documents and the AD is effective 12 August 2011."},"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This is a standard Airworthiness Directive with a tightly scoped, single-purpose safety mandate. It has not expanded beyond its original intent of addressing a specific mechanical defect in a specific aircraft model."},"complexity_factors":["Single, specific technical requirement referencing external documents rather than spelling out modifications in full","Narrow applicability — only 57 specific aircraft serial numbers affected (139-195)","No defined terms section, no conditional logic, no nested exceptions","Straightforward compliance structure: do X by Y unless already done","Document is essentially a safety bulletin with legal force, not a legislative instrument with multiple parts or schedules"],"plain_english_summary":"This AD orders owners/operators of Canadian-built De Havilland DHC-1B-2 Chipmunk aircraft (s/n 139–195) in Australia to modify the canopy lock mechanism because original lock cables have been failing, risking inability to exit in an emergency.  \n\nThe mandated fix follows the manufacturer’s Technical News Sheets (C‑38 and Amendment 2); compliance by the stated deadlines is legally required."}},"importantCases":[],"_links":{"self":"/api/acts/ad-dhc-1-40-canopy-lock-modification","history":"/api/acts/ad-dhc-1-40-canopy-lock-modification/history","analysis":"/api/acts/ad-dhc-1-40-canopy-lock-modification/analysis","conflicts":"/api/acts/ad-dhc-1-40-canopy-lock-modification/conflicts","importantCases":"/api/acts/ad-dhc-1-40-canopy-lock-modification/important-cases","documents":"/api/acts/ad-dhc-1-40-canopy-lock-modification/documents"}}