{"id":"F2011L01062","name":"AD/DHC-1/3 Amdt 1 - Fuel Line Cock to Filter - Replacement","slug":"ad-dhc-1-3-amdt-1-fuel-line-cock-to-filter-replacement","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":86868,"registerId":"commonwealth-F2011L01062-current","compilationNumber":null,"startDate":"2026-04-02","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-1/3 Amdt 1 | Fuel Line Cock to Filter - Replacement | 12/2011 |\n| ----------------- | -------------------------------------- | ------- |\n\n| Applicability: | English production (C1) all models and Portuguese (T Mk 20) production models.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                    |\n| -------------- | --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |\n| Requirement:   | Accomplish modification per De Havilland modification document H-188, latest revision.Note 1: De Havilland TNS No. 111 dated 3 August 1955 refers. As stated in this TNS, operators should check the aircraft modification records to determine if this modification has already been incorporated.Note 2: Advice should be sought from De Havilland support if there is any doubt as to this modifications applicability to their particular aircraft.                                                                                                                                                                                                                                                                                                                           |\n| Compliance:    | Unless previously accomplished, prior to further flight.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                          |\n|                | This Amendment becomes effective on 21 June 2011.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                 |\n| Background:    | This modification introduces a fuel feed pipe that is manufactured from tungum instead of aluminium between the fuel cock and fuel filter. This was due to the fracture of an aluminium fuel feed pipe part number C1-P-45.This modification was introduced in 1955, and up until now, Australia has had no Portuguese manufactured Chipmunks on the register, hence the CASA AD has only been effective for English production Chipmunks. This amendment is to include the Portuguese manufactured Chipmunk in the applicability for this AD, as a recent check of the De Havilland support modification listing, shows that this modification is also applicable to the Portuguese model (T Mk 20).There are no technical changes to the requirements or compliance of this AD. |\n\n|     | The original issue of this AD became effective in June 1955. |\n| --- | ------------------------------------------------------------ |\n\n![](image.001.png)\n\nGlen Steemson  \nDelegate of the Civil Aviation Safety Authority\n\n14 June 2011","sortOrder":0},{"sectionNumber":"AD/DHC-1/3 Amdt 1","sectionType":"part","heading":"AD/DHC-1/3 Amdt 1","content":"## AD/DHC-1/3 Amdt 1","sortOrder":1},{"sectionNumber":"Fuel Line Cock to Filter - Replacement","sectionType":"part","heading":"Fuel Line Cock to Filter - Replacement","content":"## Fuel Line Cock to Filter - Replacement","sortOrder":2},{"sectionNumber":"12/2011","sectionType":"part","heading":"12/2011","content":"## 12/2011","sortOrder":3}],"analysis":{"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This amendment does not expand the scope beyond the original safety purpose. The original 1955 directive addressed a fuel pipe fracture risk; this 2011 amendment simply extends the same requirement to an additional aircraft variant (Portuguese T Mk 20) that has now entered the Australian register. The technical requirements remain identical."},"complexity_factors":["Very short document (under 400 words)","Only 2 defined applicability categories (English C1 models, Portuguese T Mk 20)","Single straightforward requirement with one reference to external technical document (H-188)","No nested conditions or exceptions — compliance is absolute ('prior to further flight')","Minimal cross-referencing (only to 1955 technical note and modification document)","Clear effective date and simple amendment purpose (expanding applicability only)"],"plain_english_summary":"This mandatory AD requires owners of De Havilland DHC-1 Chipmunk aircraft to replace the aluminium fuel pipe between the fuel cock and filter with a tungum pipe due to cracking that can cause fuel leaks and engine failure. It applies to English-made C1 Chipmunks and now includes Portuguese T Mk 20s on Australia’s register. If the modification isn’t recorded, it must be completed before the next flight."},"flash_summary":{"complexity_score":2,"scope_assessment":{"changed":true,"description":"Scope expanded: the amendment adds Portuguese‑manufactured Chipmunks (T Mk 20) to the AD's applicability. The technical requirement and compliance timing remain unchanged (Background: 'include the Portuguese manufactured Chipmunk...'; 'There are no technical changes to the requirements or compliance of this AD.')."},"complexity_factors":["Narrow technical scope: single physical part replacement (Background).","Clear mandated action referencing an external modification document (H‑188) for implementation details (Requirement).","Immediate compliance timing: 'prior to further flight' creates operational urgency for affected aircraft (Compliance).","Applicability expansion requires operators to check historical records to determine if mod already applied (Applicability; Note 1).","Potential need to consult De Havilland support if applicability is unclear introduces limited administrative discretion (Requirement Note 2).","Possible logistical burden for parts sourcing and fitter availability, though the AD contains no new technical specifications beyond H‑188 (Background; Requirement)."],"plain_english_summary":"This airworthiness directive requires owners/operators of De Havilland DHC‑1 Chipmunk aeroplanes (English production C1 and Portuguese T Mk 20) to replace the aluminium fuel feed pipe between the fuel cock and fuel filter with a tungum pipe, by following De Havilland modification H‑188. The change must be done before the next flight if not already accomplished, to address fractures of the original aluminium part (Requirement; Compliance; Background)."},"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-1-3-amdt-1-fuel-line-cock-to-filter-replacement","history":"/api/acts/ad-dhc-1-3-amdt-1-fuel-line-cock-to-filter-replacement/history","analysis":"/api/acts/ad-dhc-1-3-amdt-1-fuel-line-cock-to-filter-replacement/analysis","conflicts":"/api/acts/ad-dhc-1-3-amdt-1-fuel-line-cock-to-filter-replacement/conflicts","importantCases":"/api/acts/ad-dhc-1-3-amdt-1-fuel-line-cock-to-filter-replacement/important-cases","documents":"/api/acts/ad-dhc-1-3-amdt-1-fuel-line-cock-to-filter-replacement/documents"}}