{"id":"F2006B09123","name":"AD/DHC-6/35 Amdt 2 - Wing Rear Spar Attachment Fittings","slug":"ad-dhc-6-35-amdt-2-wing-rear-spar-attachment-fittings","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":115676,"registerId":"commonwealth-F2006B09123-current","compilationNumber":null,"startDate":"2026-04-03","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/DHC-6/35 Amdt 2 - Wing Rear Spar Attachment Fittings","content":"COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 \\- 105 CIVIL AVIATION SAFETY AUTHORITY\n\nSCHEDULE OF AIRWORTHINESS DIRECTIVES\n\n![](image.001.png)  \nDHC-6 (Twin Otter) Series Aeroplanes\n\nAD/DHC-6/35\n\nAmdt 2\n\n  \nWing Rear Spar Attachment Fittings 3/92\n\nApplicability: Model DHC-6, all series, with serial numbers 1 through 330 inclusive, not incorporating modification 6/1301 or 6/1630.\n\nRequirement: 1. Action in accordance with de Havilland Service Bulletin 6/295 Revision B; subject to the following changes:\n\n    (a) Inspection Method A.1 (Radiographic) is to have the exposure time of 60 seconds increased to 120 seconds for the inboard X-ray tube location; and\n\n    (b) The X-ray beam angle of approximately 10 degrees is to be changed to approximately 5 degrees for all of the X-ray locations.\n\n2. Incorporate de Havilland modification 6/1301.\n\nNote: Transport Canada AD CF-73-03 R1 refers.\n\nCompliance: 1. At intervals specified in the Requirement Document, until modified in accordance with Requirement 2.\n\n2. Prior to 30 September 1993.\n\nThe compliance with paragraphs of the previous issue of this Directive were:\n\nFor Paragraph 1 \\- Within 200 hours time in service after 20 October 1972 and thereafter at intervals not exceeding 200 hours time in service.\n\nFor Paragraph 2 to 6 \\- Within the time limits as detailed in the respective paragraphs. This Amendment is effective from 6 March 1992.\n\nBackground: Inter-rivet cracking of the top flange of the attachment cap member, part number C6WM1032-1 and \\-2 located at the inboard end of the wing rear spar, has been found on a number of aircraft in service. Reports have also been received that the radiographic inspection set out in the de Havilland Service Bulletin 6/295 is not locating all the cracks.\n\nAmendment 2 is issued to align this Directive with a revision of the related Country of Origin AD, which requires terminating action in lieu of ongoing inspections.","sortOrder":0}],"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":"Yes. The amendment adds a terminating action (incorporation of modification 6/1301) in place of continued periodic inspections and aligns the Directive with the Country of Origin AD. Previously the Directive required recurring inspections (noted as 200‑hour intervals in earlier issue); Amendment 2 requires the modification by a specified date to end the inspection cycle."},"complexity_factors":["Technical specificity of radiographic parameters (increase exposure time from 60s to 120s at the inboard X‑ray tube location; change beam angle from ~10° to ~5°) requiring equipment setup and operator competence.","Two-step compliance: follow de Havilland Service Bulletin 6/295 Revision B (with specified deviations) and thereafter incorporate de Havilland modification 6/1301 as terminating action.","Applicability limited to specific serial numbers (1–330) and excludes aircraft already modified (6/1301 or 6/1630), requiring fleet-status tracking.","Dependence on external documents and cross-references (de Havilland Service Bulletin 6/295 Rev B; Transport Canada AD CF-73-03 R1) for detailed procedures.","Dual timing obligations: recurring inspections at intervals in the Requirement Document until modification, plus a fixed calendar deadline (prior to 30 September 1993) to incorporate the modification."],"plain_english_summary":"Requires longer X‑ray exposure and a smaller beam angle when radiographically inspecting the wing rear spar attachment fittings, and mandates fitting de Havilland modification 6/1301 by 30 September 1993. Applies to DHC‑6 (Twin Otter) aircraft serial numbers 1–330 that have not already incorporated mods 6/1301 or 6/1630.\n\nThe change responds to inter‑rivet cracking in attachment cap parts C6WM1032‑1/‑2; it tightens inspection technique and converts an ongoing inspection regime into a terminating modification action."},"kimi_summary":{"content_quality":"ok","complexity_score":3,"scope_assessment":{"changed":true,"description":"Originally this directive required ongoing repetitive inspections every 200 hours of flight time. Amendment 2 significantly changed the scope by introducing a 'terminating action' — a one-time permanent modification that ends the inspection requirement. This shifted from a continuous airworthiness monitoring approach to a 'fix it once and done' solution, aligning with the Canadian authority's revised approach."},"complexity_factors":["Multiple cross-references to external documents (de Havilland Service Bulletin 6/295 Revision B, Transport Canada AD CF-73-03 R1, modifications 6/1301 and 6/1630)","Technical aviation terminology requiring specialized knowledge (radiographic inspection, X-ray beam angles, time in service, part numbers)","Amendment structure with references to previous compliance deadlines that are now superseded","Conditional applicability based on serial number ranges and modification status"],"plain_english_summary":"Owners/operators of older DHC‑6 Twin Otter aircraft (serials 1–330) without mods 6/1301 or 6/1630 must perform improved inspections of wing rear spar attachment fittings because cracks have been found. The directive tightens the X‑ray technique (longer exposure and altered angle) and requires installation of modification 6/1301 by Sept 30, 1993 to eliminate recurring inspections. This closes a safety gap that could lead to wing structural failure."}},"importantCases":[],"_links":{"self":"/api/acts/ad-dhc-6-35-amdt-2-wing-rear-spar-attachment-fittings","history":"/api/acts/ad-dhc-6-35-amdt-2-wing-rear-spar-attachment-fittings/history","analysis":"/api/acts/ad-dhc-6-35-amdt-2-wing-rear-spar-attachment-fittings/analysis","conflicts":"/api/acts/ad-dhc-6-35-amdt-2-wing-rear-spar-attachment-fittings/conflicts","importantCases":"/api/acts/ad-dhc-6-35-amdt-2-wing-rear-spar-attachment-fittings/important-cases","documents":"/api/acts/ad-dhc-6-35-amdt-2-wing-rear-spar-attachment-fittings/documents"}}