{"id":"F2011L01074","name":"AD/DHC-1/19 Amdt 2 - Flap Layshaft Operating Cam","slug":"ad-dhc-1-19-amdt-2-flap-layshaft-operating-cam","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":86875,"registerId":"commonwealth-F2011L01074-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-1/19 Amdt 2 | Flap Layshaft Operating Cam | 12/2011 |\n| ------------------ | --------------------------- | ------- |\n\n| Applicability: | English production (C1), all models, and Portuguese (T Mk 20) production models.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |\n| -------------- | ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |\n| Requirement:   | Inspect in accordance with British Aerospace Technical News Sheet (TNS) No.170 Issue 2, dated 1st December 1995.Note: TNS 170 superseded TNS 155.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                       |\n| Compliance:    | At the next Check 4 inspection after the effective date of this AD; and thereafter at each subsequent Check 4 inspection.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                               |\n|                | This Amendment becomes effective on 21 June 2011.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                       |\n| Background:    | Reports were received of cracking or fracture of the brazing joint of the arm and associated tube, which together form the flap operating rod. Cracking of the operating cam has also been reported.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 review indicates that this inspection is also applicable to the Portuguese model (T Mk 20).There is no change to the requirements or compliance.Amendment 1 was issued in August 1997 to include the current issue of the applicable Technical News Sheet.The original issue of this airworthiness directive became effective on 17 March 1969. |\n\n![](image.001.png)  \nGlen Steemson  \nDelegate of the Civil Aviation Safety Authority\n\n15 June 2011","sortOrder":0},{"sectionNumber":"AD/DHC-1/19 Amdt 2","sectionType":"part","heading":"AD/DHC-1/19 Amdt 2","content":"## AD/DHC-1/19 Amdt 2","sortOrder":1},{"sectionNumber":"Flap Layshaft Operating Cam","sectionType":"part","heading":"Flap Layshaft Operating Cam","content":"## Flap Layshaft Operating Cam","sortOrder":2},{"sectionNumber":"12/2011","sectionType":"part","heading":"12/2011","content":"## 12/2011","sortOrder":3}],"analysis":{"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":true,"description":"The 2011 amendment expanded the AD's applicability to include Portuguese-manufactured Chipmunks (T Mk 20) in addition to English production (C1). There was no change to the inspection requirements, compliance intervals, or procedures; only the covered aircraft types were broadened."},"complexity_factors":["Relies on an external technical document (British Aerospace TNS No.170 Issue 2) for inspection procedures rather than prescribing steps in the AD itself.","Compliance timing is tied to a maintenance milestone (‘Check 4’), requiring operators to map the AD to their maintenance schedules.","Applicability spans multiple production sources (English C1 and Portuguese T Mk 20), requiring verification of aircraft provenance.","Technical inspection targets include a brazed joint, arm/tube assembly and operating cam — locating and assessing these parts requires maintenance expertise.","Regulatory history with prior amendments (original AD 1969; Amendment 1 in 1997) requires practitioners to track superseded documents.","No alternative compliance methods or explicit corrective actions are set out in the AD itself, so operators must follow the referenced TNS or seek approval.","Enforcement rests with CASA (delegate), creating administrative oversight and potential follow-up on inspection records."],"plain_english_summary":"This Airworthiness Directive requires owners/operators of De Havilland DHC-1 (Chipmunk) aeroplanes — English production (C1) and Portuguese production (T Mk 20) — to inspect the flap layshaft operating cam and the brazed joint of the flap operating rod following British Aerospace Technical News Sheet No.170 Issue 2. Inspections are required at the next scheduled Check 4 after 21 June 2011 and at every subsequent Check 4.  \n\nThe measure responds to reported cracking and brazing-joint failures. Owners/operators pay inspection costs; the Civil Aviation Safety Authority (delegate) enforces compliance. The 2011 amendment only broadened which production sources are covered; the inspection procedure and intervals did not change."},"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"},"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 1969 directive addressed flap layshaft operating cam safety. This 2011 amendment simply adds Portuguese-manufactured aircraft to the existing applicability after determining they share the same design vulnerability. The substantive inspection requirements remain unchanged from previous amendments."},"complexity_factors":["Very short document (approximately 250 words of substantive content)","Only 1 defined term implicitly used ('Check 4' — a standard maintenance inspection interval, not defined in the document itself)","No cross-references to other legislation or regulations","Single, straightforward compliance requirement with clear timing","No conditional logic or exceptions — applies uniformly to all listed aircraft models","Simple amendment structure: expands applicability without changing substantive requirements"],"plain_english_summary":"This AD requires owners/operators of De Havilland DHC-1 Chipmunk aircraft — including English-built models and Portuguese T Mk 20s — to inspect the flap layshaft operating cam for cracking at the next and every subsequent \"Check 4\" maintenance, using the procedure in British Aerospace Technical News Sheet No. 170 Issue 2. It amends the original 1969 directive to add Portuguese-built aircraft after reports of cam cracking that could cause loss of flap control during landing."}},"importantCases":[],"_links":{"self":"/api/acts/ad-dhc-1-19-amdt-2-flap-layshaft-operating-cam","history":"/api/acts/ad-dhc-1-19-amdt-2-flap-layshaft-operating-cam/history","analysis":"/api/acts/ad-dhc-1-19-amdt-2-flap-layshaft-operating-cam/analysis","conflicts":"/api/acts/ad-dhc-1-19-amdt-2-flap-layshaft-operating-cam/conflicts","importantCases":"/api/acts/ad-dhc-1-19-amdt-2-flap-layshaft-operating-cam/important-cases","documents":"/api/acts/ad-dhc-1-19-amdt-2-flap-layshaft-operating-cam/documents"}}