{"id":"F2007L01555","name":"AD/DHC-2/27 Amdt 3 - Horizontal Stabiliser Front Spar","slug":"ad-dhc-2-27-amdt-3-horizontal-stabiliser-front-spar","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":66046,"registerId":"commonwealth-F2007L01555-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"DHC-2 (Beaver) Series Aeroplanes","sectionType":"division","heading":"DHC-2 (Beaver) Series Aeroplanes","content":"### DHC-2 (Beaver) Series Aeroplanes\n\n| AD/DHC-2/27 Amdt 3 | Horizontal Stabiliser Front Spar | 7/2007 |\n| ------------------ | -------------------------------- | ------ |\n\n| Applicability: | All Viking Air Ltd. (formerly Bombardier Inc.) DHC-2 Mk. I, Mk. II and Mk. III aircraft. |\n| -------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------ |\n| Requirement: | 1. Perform the following, in accordance with Viking Air Service Bulletin (SB) 2/47 Revision E, dated 23 January 2007, or later Transport Canada approved revision:a. For all aircraft, remove the tailplane front spar pick-up brackets and carry out a fluorescent penetrant inspection of the tailplane front spar web for cracks in the area of the pick-up brackets in accordance with Appendix A of Viking Air SB 2/47 Revision E, or later Transport Canada approved revision.(i) If cracks are found on aircraft pre-mod 2/758 (aircraft having no gusset plate installed on the rear face of the tailplane front spar), replace the tailplane front spar before further flight.(ii) If cracks are found on the spar web of aircraft with Modification 2/758, replace the spar within 400 flight hours time in service after the crack finding.(iii) Replace previously repaired front spars with stop-drilled cracks as found during the above inspections within 12 months after the effective date of this Directive. Replace spars with cracks that have progressed beyond previously stop-drilled holes before next flight.b. In addition to the Requirement 1.a. fluorescent penetrant inspection, for aircraft without Modification 2/466, visually inspect the front spar web in the area of the lightening holes for cracks between the pick-up brackets. If cracks are found, replace the spar before next flight.2. Incorporate Modifications 2/436, 2/466 and 2/758, unless already accomplished.Report cracks detected during any Requirement 1.a. inspection to Viking Air Limited Technical Support, at technical.support@vikingair.com.Note: Transport Canada AD CF-1991-42R1 refers. |\n\n| Compliance: | 1. Within 200 hours time in service after 5 July 2007, if not previously accomplished in accordance with SB 2/47 Revision D.1.a. Repeat the inspection within 2 years of the last inspection, and thereafter at intervals not to exceed 2 years.2. Within 12 months after the effective date of this Directive. |\n| ----------- | ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |\n| | This Amendment becomes effective on 5 July 2007. |\n| Background: | Cracks have been discovered in the tailplane front centre spar web and gusset plate of an Australian aircraft.Amendment 1, effective 6 March 1992, corrected an oversight in the Compliance and introduced a reference to Transport Canada AD CF-91-42.Amendment 2 updated the revision status of the requirement document, with no change to the compliance.Amendment 3 is issued in response to a revision of the related Transport Canada AD, which was prompted by reports of cracks in the front spar centre web of the tailplane at the pick-up bracket and at lightening holes. The TC AD revision was issued to reflect the new requirements to inspect the tailplane front spar web behind the pick-up brackets using fluorescent penetrant inspection, instead of the visual inspection method used previously.The original issue of this AD became effective on 30 April 1992. |\n\n![](image.001.png) \nDavid Punshon \nDelegate of the Civil Aviation Safety Authority\n\n16 May 2007","sortOrder":0},{"sectionNumber":"AD/DHC-2/27 Amdt 3","sectionType":"part","heading":"AD/DHC-2/27 Amdt 3","content":"## AD/DHC-2/27 Amdt 3","sortOrder":1},{"sectionNumber":"Horizontal Stabiliser Front Spar","sectionType":"part","heading":"Horizontal Stabiliser Front Spar","content":"## Horizontal Stabiliser Front Spar","sortOrder":2},{"sectionNumber":"7/2007","sectionType":"part","heading":"7/2007","content":"## 7/2007","sortOrder":3}],"analysis":{"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"},"flash_summary":{"complexity_score":6,"scope_assessment":{"changed":true,"description":"Amendment 3 widens and tightens inspection requirements by replacing the prior visual inspection with fluorescent penetrant inspection behind the pick-up brackets and at lightening holes, adds mandatory incorporation of specific modifications, and sets distinct replacement timing for cracked or previously repaired spars (Requirement 1; Requirement 2; Compliance). This increases inspection scope and the compliance burden on owners/operators."},"complexity_factors":["Conditional actions based on modification status (different outcomes for aircraft with or without Mod 2/758) (Requirement 1.a.i–ii)","Multiple mandatory modifications to be incorporated (Mods 2/436, 2/466, 2/758) (Requirement 2)","Change of inspection technique from visual to fluorescent penetrant and removal of pick-up brackets (Requirement 1.a)","Different replacement deadlines depending on crack type and prior repairs (Requirement 1.a.i–iii and 1.b)","Periodic inspection scheduling with initial 200 flight‑hour deadline and 2‑year recurring interval (Compliance)","Reporting obligation to Viking Air Technical Support for detected cracks (Requirement note)","Cross-reference to external documents (Viking Air SB 2/47 Rev E and Transport Canada AD) creating dependency on later approved revisions"],"plain_english_summary":"Mandates inspections and, where necessary, replacement of the horizontal stabiliser (tailplane) front spar on all Viking Air DHC-2 Mk I/II/III aircraft, using fluorescent penetrant inspection per Viking Air SB 2/47 Revision E and requiring incorporation of Mods 2/436, 2/466 and 2/758 (Requirement 1).\n\nOwners/operators must remove pick-up brackets for inspection, report cracks to Viking Air, and replace spars immediately or within specified flight‑hour/time limits; initial inspection due within 200 flight hours after 5 July 2007 and recurring every two years (Compliance)."},"kimi_summary":{"content_quality":"ok","complexity_score":4,"scope_assessment":{"changed":true,"description":"This started as a 1992 directive requiring visual inspections. Amendment 3 (2007) significantly expanded the scope: it changed the inspection method from visual to fluorescent penetrant (more sensitive crack detection), added requirements for different aircraft configurations (pre-mod vs. post-mod), introduced mandatory installation of three separate modifications, added reporting requirements, and created a tiered response system based on crack severity and aircraft modification history. The directive evolved from a simple 'inspect and replace if cracked' order to a complex, multi-layered safety regime."},"complexity_factors":["Multiple conditional requirements based on aircraft modification status (pre-mod 2/758 vs. with Mod 2/758)","Different compliance timeframes for different scenarios (immediate, 400 flight hours, 12 months, 200 flight hours)","Cross-reference to external technical document (Viking Air Service Bulletin 2/47 Revision E) and Canadian aviation authority (Transport Canada AD CF-1991-42R1)","Technical aviation terminology requiring specialized knowledge (fluorescent penetrant inspection, stop-drilled cracks, lightening holes, pick-up brackets)","Nested exceptions and alternative compliance paths (unless already accomplished, or later approved revision)","Amendment structure with historical context (references to Amendments 1, 2, and original 1992 issue)"],"plain_english_summary":"This AD requires owners/operators of Viking Air DHC‑2 “Beaver” aircraft to inspect the horizontal stabiliser front spar for cracking and replace it if detected, and to fit specified reinforcing modifications if not already installed. Cracks have been found in Australia and Canada; spar failure could cause loss of control.\n\nInspections must begin promptly (initial and repeat schedules apply) and repairs/modifications within set timeframes; affected parties must also report any cracking to Viking Air."}},"importantCases":[],"_links":{"self":"/api/acts/ad-dhc-2-27-amdt-3-horizontal-stabiliser-front-spar","history":"/api/acts/ad-dhc-2-27-amdt-3-horizontal-stabiliser-front-spar/history","analysis":"/api/acts/ad-dhc-2-27-amdt-3-horizontal-stabiliser-front-spar/analysis","conflicts":"/api/acts/ad-dhc-2-27-amdt-3-horizontal-stabiliser-front-spar/conflicts","importantCases":"/api/acts/ad-dhc-2-27-amdt-3-horizontal-stabiliser-front-spar/important-cases","documents":"/api/acts/ad-dhc-2-27-amdt-3-horizontal-stabiliser-front-spar/documents"}}