{"id":"F2006B09183","name":"AD/DHC-8/28 Amdt 1 - Underwing Fairing Angles","slug":"ad-dhc-8-28-amdt-1-underwing-fairing-angles","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":52954,"registerId":"commonwealth-F2006B09183-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/DHC-8/28 Amdt 1 - Underwing Fairing Angles","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)  \nBombardier (Boeing Canada/De Havilland) DHC-8 Series Aeroplanes\n\nAD/DHC-8/28\n\nAmdt 1\n\n  \nUnderwing Fairing Angles 12/95\n\nApplicability: DHC-8 aircraft, Models 311 and 315, serial numbers 240 through 279.\n\nRequirement: Inspect the rear face of the left hand and right hand underwing fairing angles for cracks, in accordance with Part A of the Accomplishment Instructions in de Havilland Service Bulletin A8-53-46 Rev A.\n\nNote: Transport Canada AD CF-93-10R1 refers.\n\nCompliance: Inspect before 6930 flights or within 100 flights from 7 June 1993, which ever occurs later. Re-inspect at intervals not to exceed 6930 flights until replaced with new angles.\n\nThe Compliance of the initial issue of this Directive remains unchanged. This Amendment is effective from 9 November 1995.\n\nNote: If an angle is replaced, the inspection requirement for the new angle reverts to that specified for the standard aircraft, which has a threshold of 40000 flights and a repeat interval of 8194 flights (Maintenance Task 5310/15K refers).\n\nBackground: A number of titanium fairing angles made for the model 301 were reworked to fit model 311 aircraft during manufacture. The rework entailed weld-filling three fastener holes and re-drilling the holes to suit the model 311 aircraft. The welds were made of commercially pure titanium, with a hardness of one third that of the angle parent material, and there is evidence that in some cases the holes may not have been fully plugged. As a result the fatigue durability of the reworked components P/N 85350927-107SP and -108SP, is unknown and more frequent inspections are required.\n\nAs the affected aircraft can only be narrowed down to the block of serial numbers specified above, all aircraft within this block must be treated as if they were fitted with the suspect fairing angles.\n\nAmendment 1 is issued in response to a revision of the related Country of Origin AD which introduces the Model 315 to the Applicability.","sortOrder":0}],"analysis":{"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":true,"description":"Amendment 1 expands applicability to include Model 315 in the affected serial-number block (240–279). Initial compliance requirements remain unchanged; the amendment only broadens the set of aircraft to which the inspection regime applies."},"complexity_factors":["Narrow applicability defined by specific models and serial-number block (Models 311 & 315, S/N 240–279) — requires accurate aircraft tracking and record checks.","Flight-based compliance thresholds: an initial threshold (before 6930 flights or within 100 flights from 7 June 1993, whichever later) and repeat interval (not to exceed 6930 flights) — operational scheduling and logbook counting burden.","Change-in-condition rule for replaced parts: new angles revert to standard inspection thresholds (40,000 flights threshold; 8,194 flight repeat interval) — introduces conditional inspection regime and cross-referencing (Maintenance Task 5310/15K).","Technical root cause: reworked titanium welds and uncertain fatigue durability of P/N 85350927-107SP and -108SP — creates forensic inspection focus rather than a fixed life-limit replacement.","Dependence on external documents: inspections must follow de Havilland Service Bulletin A8-53-46 Rev A and related Transport Canada AD — requires access to and compliance with referenced materials."],"plain_english_summary":"Requires operators of Bombardier (De Havilland) DHC‑8 Models 311 and 315 (serial numbers 240–279) to inspect both underwing fairing angles for cracks using the manufacturer's service bulletin, initially within the stated flight threshold and then at regular flight‑interval rechecks until the angles are replaced. CASA issues and enforces the directive; operators and their maintenance organisations must arrange and pay for inspections and any replacements. The amendment adds Model 315 to the aircraft covered; replacement angles follow the standard, longer inspection schedule."},"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":true,"description":"The original directive (initial issue) only applied to Model 311 aircraft. Amendment 1 expands the scope to include Model 315 aircraft, effectively doubling the number of potentially affected aircraft types. This expansion was made to align with a revised Canadian airworthiness directive, indicating the safety issue was broader than initially identified."},"complexity_factors":["Single, specific technical requirement (visual inspection for cracks)","Limited applicability (only 2 aircraft models, specific serial number range)","Clear compliance timeline with simple arithmetic (flight counts)","Only 2 defined technical terms requiring explanation (fairing angles, P/N numbers)","No nested exceptions or conditional logic beyond the replacement clause","Short document (approximately 250 words)","Single cross-reference to a service bulletin and one maintenance task"],"plain_english_summary":"Airworthiness Directive requires repeated inspections of underwing fairing angle brackets on Bombardier DHC‑8 Models 311 and 315 (S/N 240–279) because modified welding introduced softer material that can develop fatigue cracks. All aircraft in that serial range are treated as affected and must be inspected until the parts are replaced with improved components. Amendment 1 adds Model 315 to the original Model 311 requirement to reduce the risk of wing‑fairing structural failure."},"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-8-28-amdt-1-underwing-fairing-angles","history":"/api/acts/ad-dhc-8-28-amdt-1-underwing-fairing-angles/history","analysis":"/api/acts/ad-dhc-8-28-amdt-1-underwing-fairing-angles/analysis","conflicts":"/api/acts/ad-dhc-8-28-amdt-1-underwing-fairing-angles/conflicts","importantCases":"/api/acts/ad-dhc-8-28-amdt-1-underwing-fairing-angles/important-cases","documents":"/api/acts/ad-dhc-8-28-amdt-1-underwing-fairing-angles/documents"}}