{"id":"F2011L01072","name":"AD/DHC-1/21 Amdt 2 - Wing to Fuselage Attachment Links","slug":"ad-dhc-1-21-amdt-2-wing-to-fuselage-attachment-links","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":86874,"registerId":"commonwealth-F2011L01072-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-1/21 Amdt 2 | Wing to Fuselage Attachment Links | 13/2011 |\n| ------------------ | --------------------------------- | ------- |\n\n| Applicability: | English production (C1) all models and Portuguese (T Mk 20) production models.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                               |\n| -------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------ |\n| Requirement:   | Action in accordance with British Aerospace T.N.S. No. 161, Issue 3, dated 1 August 1985.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                    |\n| Compliance:    | Within 100 hours time in service after the effective date of this AD or at the next scheduled inspection for Maintenance Release issued after the effective date of this AD, whichever is the later, and at any time the wing attachment links are removed.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                  |\n|                | This Amendment becomes effective on 21 June 2011.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                            |\n| Background:    | Cases have been reported where the wing to fuselage attachment links have been fitted out of alignment resulting in chafing of the spar and/or tie bar, by the links.Amendment 1 of this AD revised the requirements to reflect Issue 3 of the Requirement Document which revised the shimming procedure.This amendment is issued to include the Portuguese manufactured Chipmunk (T Mk 20) in the applicability of the AD. A recent review indicates that TNS 161 may be applicable to T Mk 20 Chipmunks, depending on the wing attach fitting part number fitted to the aircraft. This part number will need to be determined by a physical inspection or aircraft records.There is no change to the requirements or compliance (except to require compliance after the effective date of this amendment). |\n\n![](image.001.png)  \nGlen Steemson  \nDelegate of the Civil Aviation Safety Authority\n\n16 June 2011","sortOrder":0},{"sectionNumber":"AD/DHC-1/21 Amdt 2","sectionType":"part","heading":"AD/DHC-1/21 Amdt 2","content":"## AD/DHC-1/21 Amdt 2","sortOrder":1},{"sectionNumber":"Wing to Fuselage Attachment Links","sectionType":"part","heading":"Wing to Fuselage Attachment Links","content":"## Wing to Fuselage Attachment Links","sortOrder":2},{"sectionNumber":"13/2011","sectionType":"part","heading":"13/2011","content":"## 13/2011","sortOrder":3}],"analysis":{"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"},"flash_summary":{"complexity_score":4,"scope_assessment":{"changed":true,"description":"Scope was expanded to include Portuguese‑manufactured Chipmunks (T Mk 20) where the wing attach fitting part number makes T.N.S. 161 applicable; the substantive requirement and compliance timeline remain unchanged except for the amended effective date (Applicability, Background, Requirement, Compliance)."},"complexity_factors":["Reference to an external technical document (British Aerospace T.N.S. No.161, Issue 3) which must be obtained and followed (Requirement).","Applicability depends on aircraft origin and on the specific wing‑attach fitting part number for Portuguese T Mk 20s, requiring physical inspection or records review to determine applicability (Applicability, Background).","Conditional compliance timing tied to 'within 100 hours TIS or at the next scheduled inspection for Maintenance Release, whichever is later', creating scheduling coordination issues (Compliance).","Requirement that corrective action also be taken whenever wing attachment links are removed imposes ongoing compliance whenever parts are disturbed (Compliance).","No change to substantive requirements from the prior amendment but expansion of affected fleet increases administrative scope (Background)."],"plain_english_summary":"_This Airworthiness Directive requires owners/operators of De Havilland DHC‑1 (Chipmunk) English (C1) and certain Portuguese (T Mk 20) production aircraft to carry out the checks and corrective work in British Aerospace T.N.S. No.161 Issue 3 to prevent misaligned wing‑to‑fuselage links that can chafe spars or tie bars._ Compliance must occur within 100 flying hours after the AD’s effective date (21 June 2011) or at the next scheduled maintenance release, and whenever the links are removed. Operators bear inspection and repair costs; applicability for T Mk 20 depends on the wing‑attach fitting part number (Applicability, Requirement, Compliance, Background)."},"kimi_summary":{"content_quality":"ok","complexity_score":3,"scope_assessment":{"changed":true,"description":"The original AD (prior to Amendment 2) applied only to English production C1 models. This amendment expands the scope to include Portuguese T Mk 20 production models, significantly broadening the aircraft population covered by the safety directive. The expansion required adding a conditional applicability test (checking part numbers via inspection or records) rather than a simple model-based applicability."},"complexity_factors":["Single technical requirement referencing an external document (British Aerospace T.N.S. No. 161, Issue 3) rather than spelling out the procedure","Conditional applicability requiring physical inspection or records review to determine if Portuguese T Mk 20 aircraft are affected","Dual compliance trigger (100 hours time in service OR next scheduled inspection, whichever is later) plus additional trigger (whenever links are removed)","Cross-reference to previous amendments (Amendment 1) and background context requiring understanding of prior versions","Limited defined terms but reliance on aviation-specific nomenclature (TNS, time in service, Maintenance Release)"],"plain_english_summary":"Owners/operators of De Havilland Chipmunk aircraft must inspect and correctly align the wing-to-fuselage attachment links per British Aerospace T.N.S. No.161 Issue 3 to stop chafing of the wing spar and tie bar that could weaken the structure and risk wing failure. The AD applies to English-built C1 models and, as amended, also Portuguese-built T Mk 20s; inspections are due within 100 flight hours after 21 June 2011 or at the next scheduled check."}},"importantCases":[],"_links":{"self":"/api/acts/ad-dhc-1-21-amdt-2-wing-to-fuselage-attachment-links","history":"/api/acts/ad-dhc-1-21-amdt-2-wing-to-fuselage-attachment-links/history","analysis":"/api/acts/ad-dhc-1-21-amdt-2-wing-to-fuselage-attachment-links/analysis","conflicts":"/api/acts/ad-dhc-1-21-amdt-2-wing-to-fuselage-attachment-links/conflicts","importantCases":"/api/acts/ad-dhc-1-21-amdt-2-wing-to-fuselage-attachment-links/important-cases","documents":"/api/acts/ad-dhc-1-21-amdt-2-wing-to-fuselage-attachment-links/documents"}}