{"id":"F2011L01638","name":"AD/DHC-1/42 - Tailplane to Fuselage Pickup Modification","slug":"ad-dhc-1-42-tailplane-to-fuselage-pickup-modification","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":126023,"registerId":"commonwealth-F2011L01638-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-1/42 | Tailplane to Fuselage Pickup Modification | 16/2011 |\n| ----------- | ----------------------------------------- | ------- |\n\n| Applicability: | All Canadian DHC-1 Chipmunk aircraft serial numbers 1 through 62 and 101 through 190.                                                                                           |\n| -------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |\n| Requirement:   | Modify the tailplane to fuselage pickups in accordance with De Havilland Aircraft of Canada Limited Technical News Sheet C-30.Note: Transport Canada Directive CF-52-04 refers. |\n| Compliance:    | Within 30 hours time in service after the effective date unless previously accomplished.                                                                                        |\n|                | This Airworthiness Directive becomes effective on 12 August 2011.                                                                                                               |\n| Background:    | Cases have been reported of the tailplane rib attachment angles showing signs of cracking. Modification schemes depend on the condition of the attachment angles.               |\n\n![](image.001.png)  \nCharles Lenarcic  \nDelegate of the Civil Aviation Safety Authority\n\n5 August 2011","sortOrder":0},{"sectionNumber":"AD/DHC-1/42","sectionType":"part","heading":"AD/DHC-1/42","content":"## AD/DHC-1/42","sortOrder":1},{"sectionNumber":"Tailplane to Fuselage Pickup Modificatio","sectionType":"part","heading":"Tailplane to Fuselage Pickup Modification","content":"## Tailplane to Fuselage Pickup Modification","sortOrder":2},{"sectionNumber":"16/2011","sectionType":"part","heading":"16/2011","content":"## 16/2011","sortOrder":3}],"analysis":{"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This is a standard Airworthiness Directive with narrow, specific scope targeting a known safety defect in particular aircraft. It has not expanded beyond its original purpose of mandating a specific airframe modification."},"complexity_factors":["Single, specific technical requirement with clear reference to external technical document","Narrow applicability limited to specific serial number ranges","Simple compliance condition (time-in-service deadline)","No defined terms section, no cross-referencing to other legislation","Straightforward background explanation without nested conditions"],"plain_english_summary":"Owners and operators of Canadian-built De Havilland DHC-1 Chipmunk aeroplanes (S/N 1–62 and 101–190) must modify the tailplane attachment per De Havilland Technical News Sheet C-30. This CASA Airworthiness Directive, effective 12 August 2011, requires compliance within 30 flight hours to address cracking in tailplane rib attachment angles that could cause structural failure."},"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":false,"description":"The directive as presented sets a clear applicability (specified serial numbers) and a single required action with a 30‑hour compliance window. The text contains no statement or indication that the scope has been altered from an earlier instrument or that the applicability has been expanded or narrowed."},"complexity_factors":["Technical specificity: requires physical modification to structural fittings and competent maintenance action (Requirement; Background).","External-document dependency: mandates procedures set out in De Havilland Technical News Sheet C-30 rather than detailing steps in the AD (Requirement).","Condition-based variability: modification scheme depends on the condition of attachment angles, requiring inspection judgements (Background).","Applicability scope: applies only to specific serial number ranges (1–62 and 101–190), which narrows but precisely targets affected aircraft (Applicability).","Short compliance window: 30 hours time in service creates operational time pressure to schedule work (Compliance).","Regulatory enforcement and timing: effective date and CASA delegate signature fix enforceability and start point for compliance obligations (Compliance; Effective date)."],"plain_english_summary":"This Airworthiness Directive requires owners/operators of Canadian De Havilland DHC‑1 Chipmunk aircraft (serials 1–62 and 101–190) to modify the tailplane‑to‑fuselage pickup fittings in accordance with De Havilland Technical News Sheet C‑30 because tailplane rib attachment angles have shown cracking.\n\nOperators must complete the work within 30 hours time in service of the 12 August 2011 effective date; operators bear inspection and modification costs, must follow the manufacturer procedure, and are subject to CASA enforcement."},"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"}},"importantCases":[],"_links":{"self":"/api/acts/ad-dhc-1-42-tailplane-to-fuselage-pickup-modification","history":"/api/acts/ad-dhc-1-42-tailplane-to-fuselage-pickup-modification/history","analysis":"/api/acts/ad-dhc-1-42-tailplane-to-fuselage-pickup-modification/analysis","conflicts":"/api/acts/ad-dhc-1-42-tailplane-to-fuselage-pickup-modification/conflicts","importantCases":"/api/acts/ad-dhc-1-42-tailplane-to-fuselage-pickup-modification/important-cases","documents":"/api/acts/ad-dhc-1-42-tailplane-to-fuselage-pickup-modification/documents"}}